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Advances and Prospects of Maize Cultivation in China     LI ShaoKun, ZHAO JiuRan, DONG ShuTing, ZHAO Ming, LI ChaoHai, CUI YanHong, LIU YongHong, GAO JuLin, XUE JiQuan, WANG LiChun, WANG Pu, LU WeiPing, WANG JunHe, YANG QiFeng, WANG ZiMing Scientia Agricultura Sinica   2017,50(11 ):1941 -1959. DOI:10.3864/j.issn.0578-1752.2017.11.001 Abstract  （1012） HTML （55） PDF（pc） （1167KB）（1949） Save Maize is the first major crop in China and in the world, it plays an important role in ensuring China’s food security. At present, in the face of the rapid development of economic society and a series of problems such as population growth and land reduction, resources shortage and ecological environment deterioration, maize cultivation science is facing new historic opportunities and challenges. In this crucial historical juncture, it is of great significance to review the scientific research and technical progress of maize cultivation in China and to explore the future development direction. Analysis shows that, the aim of maize cultivation research has been transformed from yield production to collaborative development of high yield, high quality, high efficiency, eco-friendly, security and other goals after 60 years of efforts. The research contents were gradually widened and further deepened with remarkable Chinese characteristics. Since entering into the 21th century, the research of maize cultivation has entered a golden development stage. In this stage, a series of breakthroughs in maize cultivation theory, key technology innovation and application have been achieved, which have taken a positive role in ensuring China’s food security. According to the demand of maize production for science and technology in the future and the development trend of modern science and technology, this article indicated that, in the future, high quality, high efficiency, eco-friendly, security will still be the main objectives of maize cultivation. In this article, the key directions and tasks of maize cultivation research in the next 20 years were put forward: (1) Continue to explore the potential of maize yield in different ecological areas and technologies that can realize these potentials, and make every effort to raise the level of yield per unit; (2) Transform the mode of production and take the improving efficiency of resource utilization and labor productivity as goals, reduce the production costs, improve product quality and the market competitiveness of maize; to develop silage and fresh maize so as to promote the diversified development of maize production; (3) In order to respond to the global climate change, carry out the theoretical and technological researches on yield stability and anti-disaster to realize the sustainable production of maize; (4) Based on modern information technology to carry out the researches of intelligent cultivation technology to achieve maize precise production and management; (5) Strengthen the basic researches of maize cultivation and tamp the researches on maize science and technology and the basement of maize production. Reference丨 Related Articles丨 Metrics

Analysis of Influencing Factors on Kernel Dry-Down-Rate of Maize Hybrids     WANG KeRu, LI ShaoKun Scientia Agricultura Sinica   2017,50(11 ):2027 -2035. DOI:10.3864/j.issn.0578-1752.2017.11.008 Abstract  （538） HTML （10） PDF（pc） （407KB）（1426） Save Grain moisture content of maize is the key factor that affects the quality of mechanical harvesting, safe storable level, and economic benefits. It has become an important technical and economic problem. At present, the high moisture content of grain in the corn harvest period not only restricts the popularization of corn combine harvesting technology, but also affects the change of maize harvest and production mode, and seriously affects the grain quality of maize. A review of relevant literature both at home and abroad shows that the moisture content of grain in harvesting period is controlled mainly by the dry-down rate of grain before and after physiological maturity, and this trait is heritable, and it has a significant difference among maize hybrids. The difference of grain drying rate is closely correlated with many agronomic traits of maize, such as length and thickness of bract, thickness of cob, shape of kernel, and size of ear. The ecological factors such as air humidity (saturation degree of environmental water deficit), temperature, solar radiation, wind speed, rainfall and so on, have important influences on grain drying rate at the late growth stage of maize. Agronomic measurements such as planting density, row spacing, irrigation and fertilization, also have some influence on drying rate of grain. The optimum period of harvesting grain with combine machine can be predicted by the grain moisture content and the drying rate of grain after physiological maturity. In this paper, it is suggested that, at present, the selection of maize hybrids having characteristics of suitable early maturity, and rapid drying rate of ear at grain filling stage and low moisture content of grain at physiological maturity is the key measure to realize grain mechanical harvest in maize production areas in China. At the same time, due to the combined effects on drying rate of grain by genotype, ecological and meteorological factors and cultivation measures, meanwhile, the corn planting regions are wide, the planting patters are diverse, and the maize variety types used are various in China, further studies on the physiological mechanism of kernel dry-down are needed, and systematic observation characteristics of drying rate of grain should be carried out, that will provide a theoretical basis and technical supports for promotion of grain machinery harvesting technology and improvement of maize grain quality. Reference丨 Related Articles丨 Metrics

Changes of Maize Planting Density in China     MING Bo, XIE RuiZhi, HOU Peng, LI LuLu, WANG KeRu, LI ShaoKun Scientia Agricultura Sinica   2017,50(11 ):1960 -1972. DOI:10.3864/j.issn.0578-1752.2017.11.002 Abstract  （486） HTML （33） PDF（pc） （494KB）（929） Save 【Objective】Enhancing the maize plant population has undergone a constant evolution over the years, with the purpose of increasing the crop yield. However, the rational density range was determined by environmental condition, varieties and management. The objective of this work was to reveal the approach of enhancing maize yield in the future by analyzing the change trend of planting density and its influencing factors in major producing regions. 【Method】 The research data have been obtained over the Project of Sending Agricultural Technology into Farmers’ Homes and National Maize Industrial Technology System from 2005 to 2016, including 23 provinces, more than 267 counties. From this investigation, 117 960 farmer production investigation data samples were obtained from the Northern China spring maize planting region (NM), the Northwest China maize planting region (NWM), the Huang-Huai-Hai Plain summer maize planting region (HPM), the Southwest China maize planting region(SM) and the Southern China sweet-waxy maize planting region (SWM). The number of harvested plants surveyed in nationwide investigation was used to analyze the planting density of maize main producing region and different ecological regions. The sample data were verified and complemented by averaging the values of 5 neighboring points. According to the regional environmental condition and planting patterns, the main maize producing regions have divided into 25 typical ecological regions. Boxplot analysis and Tukey’s honestly significant difference (HSD) test method were used to compare the planting density difference and its significance in different regions. Evolutionary trends of county-scale planting density in different ecological regions were subjected to the fitting linear model to analyze inter-annual trend of planting density and its significance.【Result】The results showed that there were significant differences of planting densities in different regions. At present (2014-2016), the planting density of the main producing region respectively were 6.77×104, 6.19×104, 5.91×104, 5.13×104 and 4.80×104 plants/hm2 in NWM, HPM, NM, SWM and SM. The planting density in NWM was significantly higher (P＜0.01) than other regions. Furthermore, planting density in SWM and SM was significantly lower (P＜0.01) than that in NWM, HPM and NM. From 2005 to 2016, the inter-annual variability of planting density showed a significant increase in NM. In NWM and SM, the planting density kept it steady between 2009 and 2016. The planting density in HPM increased obviously from 2005 to 2009 and remained stable after 2009. Planting density in SWM showed a significant decreasing trend.【Conclusion】Dense planting cultivation is commonly acknowledged by both the government and the academic researchers. However, the planting density evolution in the main production regions and different ecological regions is not uniform. Regional environmental condition is the key factor for determining the planting density, and reasonable cultivation techniques and appropriate density-resistant varieties are effective approaches to overcome environmental constraints and increase planting density. Consequently, further analysis of the promotion and restriction increase planting density factors, including environmental condition, varieties and management, will provide a theoretical foundation for establishing regional dense planting management mode. Reference丨 Related Articles丨 Metrics

Current Status of Maize Mechanical Grain Harvesting and Its Relationship with Grain Moisture Content     CHAI ZongWen, WANG KeRu, GUO YinQiao, XIE RuiZhi, LI LuLu, MING Bo, HOU Peng, LIU ChaoWei, CHU ZhenDong, ZHANG WanXu, ZHANG GuoQiang, LIU GuangZhou, LI ShaoKun Scientia Agricultura Sinica   2017,50(11 ):2036 -2043. DOI:10.3864/j.issn.0578-1752.2017.11.009 Abstract  （464） HTML （22） PDF（pc） （537KB）（647） Save 【Objective】Grain mechanical harvesting is the key technology of modern production of maize, and a developing direction of maize harvesting technology at home and abroad. Making clear the current problems of maize mechanical harvesting technology, and studying the main factors that affect the quality of combine harvest maize are important to promote the development of maize grain harvesting technology in China. 【Method】Since 2011, a number of experiments and demonstration of maize grain harvesting have been carried out in maize production regions, including the northwest, Northeast and North, and huang-huai-hai maize production regions. By the year of 2015, a total of 1 698 sets of sample data of grain harvesting quality were obtained from 168 plots of maize field in 15 provinces. 【Result】The results showed that, (1) the average grain breakage rate was 8.63%, the impurity rate was 1.27%, total grain yield loss of ear and kernel was 24.71 g·m-2, equivalent to the loss grain yield of 16.5 kg/667m2, the average total grain loss rate was 4.12%. The high grain breakage rate was the main quality problem for maize grain harvesting in China. The relationship between grain moisture content and broken rate can be fitted by the equation of quadratic polynomial, which is y=0.0372x2-1.483x+20.422(R2=0.452**, n=1698). In a certain range of kernel moisture content (＞19.9%), grain breakage rate increased with the increase of grain moisture content. 【Conclusion】At present, grain breakage rate for maize grain mechanical harvesting in China is high, and the high moisture content of kernel is the main controlling factor. It is recommended to select maize hybrids which have the characteristics such as appropriate early maturing, low moisture content of grain and rapid dry-down at mature period, and to harvest at right moment, and to match grain drying and storage facilities, are the key measurements to achieve grain mechanical harvesting in maize production areas in China. Reference丨 Related Articles丨 Metrics

Progresses in Research on Grain Broken Rate by Combine Harvesting Maize     WANG KeRu, LI ShaoKun Scientia Agricultura Sinica   2017,50(11 ):2018 -2026. DOI:10.3864/j.issn.0578-1752.2017.11.007 Abstract  （394） HTML （7） PDF（pc） （371KB）（949） Save Grain mechanical harvest is the developing direction of maize harvesting technology. It is the key technology to realize entire mechanization of maize production and change the mode of production. At present, the high kernel broken rate of maize harvesting not only lowers the grade of corn but also reduce corn sales price. Moreover, it leads to the decline of maize yield and increases the cost of grain artificial drying, and increases the difficulty of safe storage of maize. Therefore, high broken rate is the major problem that we are facing to popularize grain mechanical harvesting techniques. Kernel broken rates of different genotypes of maize differ significantly. As the resistance to kernel broken is a heritable trait, the anti-breaking maize varieties can be bred. Because of the significant influence that harvest machines and operational parameters have on kernel broken rates, it is also an effective measure to ensure low broken rate by choosing rotary (axial-flow) combines and adjusting its parameters according to the plants growth condition, maturity and moisture content of maize kernel. In addition, ecological environment also has significant influences on broken rates of grain. The factors of sunshine times, atmospheric temperature, relative humidity, and so on in the process of grain filling, natural drying, and harvesting period will affect the characters associated with grain broken such as grain hardness, test weight and kernel moisture content. Hence, according to ecological conditions in different regions, it is necessary to choose maize varieties which can match the local light and temperature conditions in the suitable growth period of maize, and to determine the suitable planting area for those maize varieties. Cultivation managing measures such as planting density, management of irrigation and fertilizers, harvesting time have obvious influences on kernel broken rates. Reasonable planting density, optimized nitrogen fertilizers management and moderate irrigation make for the reduction of broken kernels, and the most effective measure to reduce the kernel broken rate is harvesting at optimum harvest period. Reference丨 Related Articles丨 Metrics

Corn Kernel Weight and Moisture Content After Physiological Maturity in Field     LI LuLu, WANG KeRu, XIE RuiZhi, MING Bo, ZHAO Lei, LI ShanShan, HOU Peng, LI ShaoKun Scientia Agricultura Sinica   2017,50(11 ):2052 -2060. DOI:10.3864/j.issn.0578-1752.2017.11.011 Abstract  （368） HTML （7） PDF（pc） （1355KB）（934） Save 【Objective】 In Huang-huai-hai Plain, the earlier harvesting date and the higher grain moisture content of summer maize reduces the harvest quality of mechanical grain harvest technology. The delayed harvest can reduce the grain moisture content. It remains unknown whether the grain weight and the yield will decrease or not during the field drying process. Clearing the changes of maize grain moisture and grain weight after physiological maturity is of benefit to promoting the application of grain mechanical harvesting technology. 【Method】 In 2015 and 2016, twenty two mainly planted cultivars were investigated in Comprehensive Experiment Stations of Chinese Academy of Agricultural Sciences located in Xinxiang, Henan. Controlled pollination was applied in every cultivar. In 2015, from the 26th day after pollination to the 26th - 52th day after physiological maturity, the grain weight and grain moisture were measured to analyze their changes. In 2016, the same traits were measured from the 11th day after pollination to the 16th - 35th day after physiological maturity.【Result】 Results showed that the average 100-kernel dry weight was 30.8 g at physiological maturity ranging from 23.3 g to 37.4 g. The average kernel moisture content was 27.5% at physiological maturity ranging from 21.5% to 33.1%. When all cultivars were finally tested after the long drying-down in field, the average 100-kernel dry weight was 32.0 g ranging from 22.9 g to 38.4g and the average kernel moisture content was 17.3% ranged from 12.9% to 24.4%. Before physiological maturity, the kernel weight increased significantly with the days after pollination. After physiological maturity, the kernel moisture content reduced significantly while the kernel weight kept stable. There was no statistically significant correlation between the kernel moisture content and the kernel weight after physiological maturity.【Conclusion】In Huang-huai-hai Plain, during the drying-down in field, corn kernel moisture content reduced significantly after physiological maturity while kernel dry weight was stable. The delayed harvest is of help for lower kernel moisture content and can’t decrease the yield due to the loss of kernel weight. Reference丨 Related Articles丨 Metrics

Effect of Different Light Intensities on Root Characteristics and Grain Yield of Summer Maize (Zea Mays L.)     GAO Jia, SHI JianGuo, DONG ShuTing, LIU Peng, ZHAO Bin, ZHANG JiWang Scientia Agricultura Sinica   2017,50(11 ):2104 -2113. DOI:10.3864/j.issn.0578-1752.2017.11.016 Abstract  （338） HTML （4） PDF（pc） （448KB）（781） Save 【Objective】In recent years, the declining trend of global solar radiation has become a limiting factor in crop production, low light is one of the most important stresses to maize growth and yield formation. This study was conducted to investigate the effects of different light intensities on the root growth and yield of summer maize under field conditions. 【Method】In 2012-2014, Denghai 605 (DH605) was used as experimental material. Two treatments of both shading (S) and increasing light (L) from flowering to maturity stage during maize growth period were designed. The field experiment was conducted to explore the effects of different light on dry matter accumulation, root structure characteristics and yields of summer maize. The shading degree was 60% and the illumination intensity of the increasing light on cloudy day could reach 80 000-10 0000 lx. One non-shading and non-increasing light treatment was used as control. 【Result】 Compared to CK, root characteristics and grain yield under shading decreased, while those of L increased. Results showed that grain yields in S treatment were reduced by 79%, 61% and 60% from 2012 to 2014, compared to CK, while the yields in L treatment were increased by 13%, 7% and 15%. Yield, root/shoot ratio, root diameter, root length density, root absorption area and root active absorption area decreased, respectively, after shading from flowering to maturity stage; however, the yield, root/shoot ratio, root diameter, root length density, root absorption area and root active absorption area increased after increasing light from flowering to maturity stage. Shading had a strong impact on the development of roots in the upper soil layer, while roots in lower soil layers were less affected. Shading from flowering to maturity stage clearly decreased the photosynthetic rate, leaf pigments content, dry matter accumulation, root/shoot ratio, root length density, root absorption area and active absorption area. Overall, shading from flowering to maturity stage decreased the root morphologic and activity indices. Increasing light was beneficial to the improvement of the root of the robust growth and root activity. The root absorption areas in the 0-30 cm and 30-60 cm soil layers in L increased by 17%, 18%, 17% and 21%, 27%, 27% at VT+20, VT+40, and R6, respectively, compared to the control. The root active absorption areas increased by 11%, 18%, 17% and 27%, 33%, 28% at VT+20, VT+40, and R6, respectively, compared to the control. Increasing light made the plants could get more water and nutrients from the soil for the growth of the aerial part, increasing grain filling rate and grain yield. 【Conclusion】 In latter growing period, root characteristics and grain yield decreased under shading, while those of L increased. In order to fit rainy weather in latter period, the study suggest that adjusting plant date and optimizing management should be done to mitigate shading in this region. Reference丨 Related Articles丨 Metrics

Effects of Planting Density on Root Characteristics and Nitrogen Uptake in Summer Maize     SHI DeYang, LI YanHong, XIA DeJun, ZHANG JiWang, LIU Peng, ZHAO Bin, DONG ShuTing Scientia Agricultura Sinica   2017,50(11 ):2006 -2017. DOI:10.3864/j.issn.0578-1752.2017.11.006 Abstract  （330） HTML （9） PDF（pc） （502KB）（644） Save 【Objective】Maize is the first food crop in China, which plays an important role in national food security. Using density-tolerance hybrids and increasing plant density is one of the primary measures to achieve high yields of maize in modern times. However, the high planting density increased the pressure of maize growth space, resulting in the growth of single plant inhibited and the yield per plant decreased, at the same time, as the major organ to absorb moisture and nutrients from soil, the roots' growth can be inhibited by high plant density. To ascertain the relationship between the root characteristics of density-tolerance hybrids and grain yield, and nitrogen utilization under high plant density is the base of studying the genotype differences of root characteristics of different summer maize hybrids to plant density, and which is significant for root improvement of density-intolerance hybrids and management of nutrients and moisture under high planting density.【Method】This experiment was conducted during 2014-2015 at the Huanghuaihai Regional Corn Research Center of Shandong Agricultural University. With Zhengdan 958 (ZD958, density-tolerance hybrid) and Ludan 981 (LD981, density-intolerance hybrid) as the experimental materials, using the soil column culture in combination with the 15N-labeling technique, the responses of root characteristics, as well as nitrogen uptake and utilization, of different density-tolerance varieties to increased density were investigated at two planting densities (D1,  52 500 plants/hm2 and D2, 82 500 plants/hm2). 【Result】Grain yield of maize significantly increased with the increase of plant density, while the grain yield per plant of both hybrids significantly reduced. Over the growing process of both hybrids, the root biomass, length, surface area and active absorbing area of both hybrids were decreased with the increase of plant density. In D1 treatment, all root indicators of LD981 were higher than those of ZD958 at early growth stage but then turned to be lower or significantly lower than ZD958 after milk stage. In D2 treatment, no significant differences in various root indicators were observed between the two hybrids at early growth stage; however, the root indicators of LD981 were significantly lower than those of ZD958 at late growth stage. The leaf area per plant and net photosynthetic rate of ear leaf changed in a trend consistent with that of roots. The difference in root-shoot ratio in biomass under the impact of density increase was not significant between the two hybrids; but their root-shoot ratio in active area was significantly reduced. The N accumulation amount (NAA) per plant and N use efficiency (NUE) of both hybrids were significantly reduced, but the N fertilizer recovery rate (NRR) and the nitrogen partial factor productivity (NPFP) significantly improved with plant density increased. In addition, the proportion of N from fertilizer in NAA was not affected by the changes of density. In D2 treatment, the N content per plant, ratio of fertilizer N, NRR and NPFP of ZD958 were significantly higher than LD981. 【Conclusion】The roots of ZD958 proved to be less affected by plant density. At high density, it could maintain relatively high root weight, length, absorbing area and activity, and longer high value duration, which were beneficial to N uptake, the photosynthetic production and obtaining higher grain yield. This suggests that the well-developed roots can guarantee the plant nitrogen uptake at high density, contributing to the photosynthetic production of the aboveground part and thus achieving higher grain yield. The bigger seed set and stronger seed set adjustment ability of ZD958 promoting nitrogen were the primary reason of its higher NUE and NPFP than LD981 at high plant density. Reference丨 Related Articles丨 Metrics

Effects of High Temperature During Grain Filling Period on Superior and Inferior Kernels’ Development of Different Heat Sensitive Maize Varieties     ZHANG Ping, CHEN GuanYing, GENG Peng, GAO Ya, ZHENG Lei, ZHANG ShaSha, WANG Pu Scientia Agricultura Sinica   2017,50(11 ):2061 -2070. DOI:10.3864/j.issn.0578-1752.2017.11.012 Abstract  （302） HTML （2） PDF（pc） （421KB）（728） Save :【Objective】High temperature during grain filling period is likely to cause large negative impacts on maize kernel growth and development, which is one of the important factors affecting high and stable yield of maize. To avoid and relieve the damage of high temperature and to find out the effective methods, this study compared the effects of high temperature during grain filling period on kernel formation and development of maize varieties with contrasting heat sensitivities.【Method】The temperature non-sensitive variety (Zhengdan958) and temperature sensitive variety (Demeiya1) were used in vitro culture system to investigate the influence of high temperature on maize kernel development during grain filling period (17-28 days after pollination, DAP).【Result】High temperature accelerated grain filling rate at early stage for both varieties, but decelerated grain filling rate at late stage for both varieties. As a result, the duration was shortened for grain filling and thousand kernel weight was decreased. At 40 DAP, the dry weight of Zhengdan 958 superior and inferior kernels were reduced by 10.50% and 18.95%, the dry weight of Demaya 1 superior and inferior kernels were respectively reduced by 24.78% and 28.08%. Moreover, starch synthesis was influenced by reducing the activity starch synthase under high temperature. The degree of the reduction of Demaya 1 superior and inferior kernels is significantly higher than Zhengdan 958. At 40 DAP, the starch content of Zhengdan 958 superior and inferior kernels were respectively lower 5.20% and 6.46% than the controls, the starch content of Demeiya 1 superior and inferior kernels were lower 13.68% and 16.39% than the controls. The starch synthase activities of superior and inferior kernels of Demaya 1 were reduced by 19.67% and 30.03%, respectively. The starch synthase activity of Zhengdan 958 of superior and inferior kernels was reduced by 13.70% and 11.26%, respectively. The ABA and IAA content in maize kernels of both varieties with high temperature treatment increased significantly while the ZR content decreased, and the GA3 content in superior kernels of both varieties increased while the GA3 content in inferior kernels of both varieties didn’t change significantly.【Conclusion】It was found that the effects of high temperature during grain filling period were more serious on grain development of Demaya 1 than Zhengdan 958, and had more effects on the inferior kernels than superior kernels of both varieties. Reference丨 Related Articles丨 Metrics

Diurnal Variation and Directivity of Photosynthetic Carbon Metabolism in Maize Hybrids Under Gradient Drought Stress     LIU YunPeng, LIANG XiaoGui, SHEN Si, ZHOU LiLi, GAO Zhen, ZHOU ShunLi Scientia Agricultura Sinica   2017,50(11 ):2083 -2092. DOI:10.3864/j.issn.0578-1752.2017.11.014 Abstract  （302） HTML （5） PDF（pc） （714KB）（785） Save 【Objective】The daily cycle is a basic metabolic unit in maize growth period. Photosynthesis is one of the most sensitive physiological processes on the environmental change, and the photosynthetic carbon metabolism is the fundamental way for dry matter accumulation, the fixation and distribution of photosynthetic carbon under an environment with regular light and temperature changes determine the metabolic characteristics and environmental adaptability for a maize variety. In maize production, the environmental adaptability is different among varieties, and most of varieties have their appropriate regions for high-yielding and stable production. The aim of the experiment is to clarify the diurnal variation of photosynthetic rate, initial photosynthate concentration, and their responses under gradient soil drought stress for different maize hybrids, and give a reference for exploiting a new index in hybrid evaluation. 【Method】 The experiment was conducted with five maize hybrids (Zhengdan 958, Xianyu 335, Xundan 20, Nongda 108 and ND66) and four soil water regimes by setting the relative soil water content at 85% (adequate water supply control), 65%-70% (mild drought stress), 55%-60% (moderate drought stress) and 45%-50% (severe drought stress). Photosynthetic rate of ear leaf from 6:00 to 18:00 at 3 h intervals was determined, and sucrose concentration and starch concentration of ear leaf through day and night at 5 time points (0:00, 4:00, 10:00, 15:00 and 20:00) were synchronously determined at maize silking stage, and the contribution of unit photosynthetic rate to the increment of sucrose concentration (CISuC), contribution of unit photosynthetic rate to the increment of starch concentration (CIStC), and contribution to the ratio of sucrose increment/starch increment (CRSu/St) also were calculated.【Result】The maize photosynthesis presented a unimodal trend without “noon break” phenomenon in daytime, the rate peaked around noon under adequate water supply, but the peak decreased and appeared in advance as a result of drought stress, and it was consistent in different hybrids. The variation of sucrose, starch concentration in ear leaves presented a unimodal curve in the daily cycle, leaf sucrose concentration peak appeared earlier than that of starch but peak value was lower. The starch concentration decreased with stress aggravated, but the sucrose concentration was stable compared to that of starch. The increments of sucrose and starch concentration, and the ratio between them during the early period of photosynthesis in daytime were built relationships with photosynthetic accumulation during this period, respectively, and the CISuC, CIStC and CRSu/St of different maize hybrids under different water treatments were gotten. The CIStC of hybrid Nongda 108 was the highest and stable, and its CRSu/St was steadily lower than the other hybrids, so the hybrid belongs to the type of starch accumulation; the CRSu/St of hybrid Xianyu 335 was at the highest level, so Xianyu 335 benefits sucrose accumulation. 【Conclusion】 Under the conditions of this experiment, the contribution of unit photosynthetic rate to the ratio of sucrose increment/starch increment could be an index used for maize hybrid classification of photosynthetic carbon metabolism. Reference丨 Related Articles丨 Metrics

Dynamic Simulation of Relationship Between Light Interception and Growth of Maize Population and Its Application     CAO YiBing, HUANG ShouBing, WANG YuanYuan, XIA YuQing, MENG QingFeng, TAO HongBin, WANG Pu Scientia Agricultura Sinica   2017,50(11 ):1973 -1981. DOI:10.3864/j.issn.0578-1752.2017.11.003 Abstract  （297） HTML （5） PDF（pc） （468KB）（597） Save 【Objective】 The population light interception (PLI) has a great impact on growth, development, and grain production of maize (Zea mays L.) in interaction with canopy structure of maize population. It costs amounts of time and labor to measure the morphology index in the evaluation of maize canopy structure. And it is impossible to integrate solar radiation into the evaluation of canopy structure. Therefore, it is quite necessary to develop a simple but feasible model that combine canopy structure and solar radiation to improve the evaluation of maize canopy structure, and thus to guide farmers in crop management.【Method】Based on the canopy structure model and light distribution model, a simple and reliable light interception model of maize canopy was developed. In order to evaluate the prediction accuracy of this model, two field trials were conducted at Wuqiao Experimental Station of China Agricultural University in 2009-2011. Trial 1 was set up as a split-plot design with varieties (ZD 958 and DY 405) and plant densities (45 000, 60 000, and 75 000 plant/hm2) as main factors, and nitrogen management (No nitrogen; 180 kg·hm-2 N applied at sowing﹕13-leaf stage﹕silking stage=1﹕4﹕1; 270 kg·hm-2 N applied at sowing﹕13-leaf stage﹕silking stage =4﹕4﹕1) as second factor. Trial 2 was in a randomized complete block design, including one variety (ZD 958), one plant density (82 000 plant/hm2), and six sowing dates (April 20, May 5 and 20, June 4 and 18, and July 3, 2009). 【Result】The simulated PLI rates were significantly correlated with measured PLI rates at silking stage and mid kernel-filling stage, with r values of 0.91 and 0.85, respectively. During the entire kernel-filling stage, the PLI values first increased and then decreased, and the reduction became more obvious on 50 days after silking. Moreover, the PLI values remained at the highest level when plant density was greater than 60 000 plant/hm2. Additionally, population structure under sowing date of June 4 achieved the highest PLI, demonstrating its great potential of structure-function for the yield improvement. PLI and yield were positively correlated, while their correlation coefficient declined over time during grain-filling period, indicating that the dry matter allocation might play more important roles on yield during the late grain-filling period. The decline of correlation coefficient also depended on variety; variety with erecter leaves could remain a higher coefficient value over time. 【Conclusion】The potential to further improve maize yield through increasing plant density  (＞75 000 plant/hm2) is limited at experimental site. Some strategies should be concerned, such as (1) applying varieties with erect leaves and long-lasting canopy structure persistence during late grain-filling period, and (2) adjusting sowing date according to climate situation to increase population photosynthesis at early grain-filling period. Reference丨 Related Articles丨 Metrics

Effects of Application of Humic Acid on Yield, Nitrogen Use Efficiency of Summer Maize     PEI RuiJie, YUAN TianYou, WANG JunZhong, HU Na, LI YaNan Scientia Agricultura Sinica   2017,50(11 ):2189 -2198. DOI:10.3864/j.issn.0578-1752.2017.11.023 Abstract  （296） HTML （7） PDF（pc） （371KB）（387） Save 【Objective】The effect of humic acid on yield, nitrogen fertilizer utilization and economic benefit of summer maize was studied in order to provide a theoretical basis for increasing in yield of maize benefited from nitrogen fertilizer and reducing nitrogen fertilizer pollution to the ecological environment.【Method】A field experiment was started in 2014 in Boai county, Henan province where the cropping system was winter wheat and summer maize rotation and the soil was Fluvo-aquic soil. The experiment included 5 treatments: No N fertilizer (single PK fertilizer), conventional fertilization, conventional fertilization+humic acid, conventional fertilization and nitrogen reduction 15%+humic acid, conventional fertilization and nitrogen reduction 30%+humic acid, and the effects of different nitrogen application on the growth, yield and yield components of summer maize were studied. The effects of different parts of plants on nitrogen uptake, accumulation and distribution, nitrogen use efficiency and economic benefit of summer maize under different fertilization levels were analyzed.【Result】Compared with the conventional fertilization treatment, application of P, K fertilizers decreased the stem diameter, ear length, ear diameter, and leaf area index by 4.61%, 8.55%, 6.20%, 26.91%, bald length increased by 21.60%. Compared with single application of P, K fertilizer, conventional fertilizer treatment increased the single grain number per ear, 100-grain weight and yield by 8.01%, 10.85%, and 44.45%, respectively. The nitrogen content and nitrogen accumulation in grain were decreased by 6.67% and 54.07%, in addition, the conventional fertilization treatment increased the production value, net income and input-output ratio by 44.45% and 59.80%, and 43.84%, respectively, showing that nitrogen fertilizer can promote maize plant growth, improve each index of biological characteristics, greatly improve the summer maize, increase the concentration and accumulation of each part of maize plant, and further to improve the maize output value, net income and input-output ratio. Compared with the conventional fertilization treatment, the combination of humic acid and fertilizer could effectively improve the agronomic traits of summer maize, improve the yield of summer maize, promote the accumulation of nitrogen in plant and improve the utilization rate of nitrogen fertilizer. The effect of conventional fertilization with reduced nitrogen by 15% plus humic acid treatment was the best compared with the conventional fertilization, and the plant height, stem diameter, ear length were increased by 3.73%, 2.30%, and 0.12%, the length of bald decreased by 22.45%, the yield increased by 12.88%, grain nitrogen content, the accumulated amount of grain nitrogen, the total accumulated nitrogen amount of aerial part, and the harvest index were increased by 2.68%, 25.98%, 10.70%, and 13.79%, respectively. Nitrogen agronomic efficiency, nitrogen partial productivity, nitrogen contribution rate, and nitrogen utilization rate increased by 57.46%, 28.84%, 22.23%, and 59.86%, respectively. Net income increased by 8.66%. In the conventional fertilization with reduced nitrogen fertilizer by 15% and plus    3 000 kg·hm-2 of humic acid could effectively increase the yield of summer maize, improve nitrogen use efficiency; but 30% reduction in nitrogen led the output and income of summer maize decreased.【Conclusion】Nitrogen fertilizer has positive effects on maize growth and development, not only can promote the growth of summer maize, but also can increase the yield, improve the nitrogen content in different parts of plant, promote the absorption and distribution of nitrogen, improve the utilization rate of nitrogen fertilizer. However, excessive or small amount of nitrogen fertilizer can reduce economic benefits and ecological environment benefit. On the basis of the application of humic acid, the appropriate amount of nitrogen fertilizer could get higher production value and income. The conventional fertilization with nitrogen reduced by 15% plus 3 000 kg·hm-2 humic acid is the best fertilization mode in the study area. At the same time, while this fertilizer application method not only can promote the growth and development of summer maize, but also can improve the yield and composition of summer maize, promote nitrogen absorption and utilization of plants, improve the utilization of nitrogen fertilizer, increase the output value of summer maize and net income. It is of great significance to realize the high yield and high efficiency, resource conservation and ecological environment protection of modern agricultural production. Reference丨 Related Articles丨 Metrics

Analysis of Influential Factors on Mechanical Grain Harvest Quality of Summer Maize     LI LuLu, LEI XiaoPeng, XIE RuiZhi, WANG KeRu, HOU Peng, ZHANG FengLu, LI ShaoKun Scientia Agricultura Sinica   2017,50(11 ):2044 -2051. DOI:10.3864/j.issn.0578-1752.2017.11.010 Abstract  （288） HTML （9） PDF（pc） （472KB）（823） Save 【Objective】Mechanical grain harvest is the developing direction of maize production, and harvest quality is the main factor affecting its popularization and application. This harvest way in China is still in the preliminary stage. The application areas are larger in the Northwest and Northeast China while experimental demonstration is just actively carried out in Huang- Huai-Hai summer corn area. In this study, the influence factors on harvesting quality of mechanical grain harvest in summer maize were analyzed to provide supports for popularization and application of the technology. 【Method】From 2013 to 2015, twenty three different maize cultivars were planted in Xinxiang, Henan. Twice harvests were conducted in 2013 and 2015 and once in 2014. The moisture content and yield were measured before harvest. When mechanical harvest was finished, kernel samples were taken out from the harvester to investigate the moisture content immediately. Then, the grain broken rate and the impurity rate were measured in laboratory by hand-picked method. The ear and kernel loss rates were investigated in the field sample areas after harvest. 【Result】From 2013 to 2015, the results from 131 samples showed that corn kernel moisture content ranged from 20.80% to 41.08% and grain broken rate was between 4.98% and 41.36%. Grain broken rate increased with the rising grain moisture content. There were 38 samples that broken rate was below 8%, accounting for 29.01%. When kernel moisture content was under 26.92%, the broken rate could confirm to the standard of 8%. The results from 134 samples showed that the impurity rate was between 0.37% and 5.28%. There were 107 samples with impurity rate below 3% which accounted for 79.85%. The impurity rate also increased with the rising grain moisture content. From 2013 to 2014, the impurity rate did not meet the standard of 3% until grain moisture content was below 28.27% while the impurity rate was all below 3% with grain high moisture content in 2015. The loss rate from 108 samples ranged from 0.18% to 2.85% all of which confirmed to the national standard. Therefore, the loss rate didn’t limit the mechanical harvest quality. In this experiment, when kernel moisture content was lower than 26.92%, the broken rate and the impurity rate were below 8% and 3%, respectively, and the loss rate met the national standard simultaneously, which could ensure the quality of mechanical grain harvest. The study also found that there were significant differences in the broken rate and the impurity rate among different cultivars, representing the importance of proper cultivar. 【Conclusion】 Corn moisture content is the key factor for the quality of the grain mechanical harvest. Significant differences existed in harvest quality among cultivars when grain moisture contents were similar. Because of different growing conditions such as temperature between years, the grain moisture contents at harvest were different, but it is feasible for Huang-Huai-Hai summer maize region represented by Xinxiang, Henan to ensure the quality of grain mechanical harvest by choosing the adapted cultivars and adopting appropriate sowing and harvesting time. Reference丨 Related Articles丨 Metrics

Effect of Cultivation Measures and Their Interactions on Grain Yield and Density Resistance of Spring Maize     PIAO Lin, REN Hong, ZHAN Ming, CAO CouGui, QI Hua, ZHAO Ming, LI CongFeng Scientia Agricultura Sinica   2017,50(11 ):1982 -1994. DOI:10.3864/j.issn.0578-1752.2017.11.004 Abstract  （275） HTML （4） PDF（pc） （540KB）（506） Save 【Objective】The purpose of this study was to investigate the regulating effect of cultivation measures and their interactions on grain yield and density resistance of spring maize hybrids, and its contribution to increase of grain yield.【Method】Maize cultivar “Zhongdan 909” was used as experimental materials in 2013 and 2014, which exhibited high yield in the high plant population. From 45 000 plants/hm2 to 10 5000 plants/hm2, five plant population treatments were designed. Subsoiling (S), wide-narrow planting (W) and chemical regulator (C) as cultivation measures, and composed different cultivation modes by split-split-plot design. Path analysis, factor regression and ANOVA analysis of different cultivation modes based on the yield, and using stepwise regression to analyze the efficiency of resource utilization factors under different cultivation modes, combined with the meteorological data. 【Result】The chemical regulator (C) had a significantly positive effect on yield in the integrated measures mode (contribution rate, 27%-41%), which the effect rests with the plant density increasing by 11 700 plants/hm2 under only chemical regulator treatment; wide-narrow planting (W) showed obvious different effects among the treatments. However, the effect of subsoiling (S) on yield displayed priority to indirect effect (contribution rate, 24%-37%), nevertheless, subsoiling plus wide-narrow planting compared with tradition mode (RU) could increase yield by 11.28%. The yield improvement of multiple measures interaction was much higher than those of double measures interaction and a single measure. Compared with traditional mode, multiple measures, double measures and a single measure increased yield by 31.27%, 15.57% and 7.96%, respectively, in a normal year (2013); and increase yield by 15.02%, 11.32% and 5.65%, respectively, in a drought year (2014). The yield increasing was mainly due to the increased population density, and coordinated regulation among radiation use efficiency (RUE), growth degree days use efficiency (GUE) and nitrogen partial factor productivity, then achieved the high yield and high efficiency under integrated measures. 【Conclusion】The yield improvement of multiple measure interaction mode (SWC) was the highest, compared to the traditional mode, the multiple measures could increase plant density by 62 700 plants/hm2 and obtain yield improvement by 11.91%, which the improvement was mainly attributed to the optimized population density under multiple measures interaction and regulating effect from integrated measures on resources utilization efficiency of intensive spring maize. Reference丨 Related Articles丨 Metrics

Effects of Heat Stress Durations at Grain Formation Stage on Grain Yield and Starch Quality of Waxy Maize     YANG Huan, SHEN Xin, LU DaLei, LU WeiPing Scientia Agricultura Sinica   2017,50(11 ):2071 -2082. DOI:10.3864/j.issn.0578-1752.2017.11.013 Abstract  （274） HTML （9） PDF（pc） （609KB）（812） Save 【Objective】Clarifying the influence of heat stress durations at grain formation stage on grain yield and starch quality of waxy maize, which could afford a theoretical basis for waxy maize starch quality improvement.【Method】The pot trials were conducted at Yangzhou University in 2014 and 2015. After artificial pollination, heat stress treatments (35℃) were introduced by intelligent greenhouse and the heat stress durations were 1-5 d, 1-10 d, and 1-15 d after pollinations (DAP), respectively. The grain yield, grain protein and starch content, starch physicochemical parameters (starch granule size and distribution, chain-length distribution, crystallinity, pasting and thermal properties) were analyzed using Suyunuo 5 and Yunuo 7 as materials.【Result】Heat stress at grain formation stage reduced grain number and weight, which induced yield loss and the loss at 1-5, 1-10 and 1-15 DAP was 39.3%, 47.4%, 50.9%, respectively. Heat stress increased protein content and decreased starch content in grains, respectively. High temperature increased the starch average granule size and the granule size gradually decreased with the prolongation of heat stress durations. The starch maximum absorption wavelength, crystalline structure and setback viscosity present typical waxy character. Heat stress at grain formation stage increased the proportion of long-chains in amylopectin, and the values were the highest and the lowest at 1-10 DAP heat stress conditions for Suyunuo 5 and Yunuo 7, respectively, among different treatments. Relative crystallinity in response to heat stress durations was different between two varieties and two planting years. Generally, 10 d heat stress did not affect the pasting characteristics, while the peak, trough, breakdown, and final viscosities and pasting temperature were increased by 1-5 and 1-15 DAP heat stress and the increase of peak, trough and breakdown viscosities were the highest in 1-15 DAP heat stress. Compared with control, heat stress decreased gelatinization enthalpy and increased the other thermal characteristics. The gelatinization enthalpy was the lowest in 1-15 DAP heat stress, gelatinization temperatures were the highest in 1-5 DAP heat stress, and retrogradation percentage were similar among different heat stress durations.【Conclusion】Heat stress at grain formation reduced the grain yield and the reduction was gradually severe with the prolongation of heat stress durations. High temperature suppressed grain starch accumulation and increased the protein content. Starch pasting and thermal properties were changed as the starch granule size enlarged and proportion of long-chains in amylopectin increased. Among different heat stress durations, the peak and breakdown viscosities were the highest and setback viscosity was the lowest when high temperature was introduced at 1-15 DAP. The gelatinization temperatures were the highest under 1-5 DAP heat stress conditions and no difference was observed for retrogradation percentage among three heat stress treatments. Reference丨 Related Articles丨 Metrics

Optimal Nitrogen Application Rate and Nitrogen Requirement Characteristics in Spring Maize Under High Planting Density Condition     CAI HongGuang, YUAN JingChao, LIU JianZhao, YAN XiaoGong, ZHANG HongXi, LIANG Yao, REN Jun Scientia Agricultura Sinica   2017,50(11 ):1995 -2005. DOI:10.3864/j.issn.0578-1752.2017.11.005 Abstract  （258） HTML （4） PDF（pc） （447KB）（823） Save 【Objective】This research aims to evaluate requirement characteristics of spring maize and the response to nitrogen application rate at the middle region of Northeast, so as to make reasonable nitrogen management of spring maize with high planting density (75 000 plant/hm2). 【Method】The field experiment was conducted in 2011-2012 at the station of Institute of Crop Science, Chinese Academy of Agricultural Sciences in Gongzhuling of Jilin province. The hybrid “Xianyu335” was used as research materials. Five nitrogen application rates (No nitrogen N1, 70% optimized nitrogen N2, optimized nitrogen N3, 130% optimized nitrogen N4, high nitrogen N5) were set under the field conditions with the high grain yield management. The characteristics of accumulation and distribution of biomass and nitrogen in different organs of plants were monitored during the growth period. And the influence of grain yield and nitrogen translocation efficiency was studied in different nitrogen application rates. 【Result】There was a significant difference in grain yield, biomass, and nitrogen accumulation among the nitrogen application rates. The interaction between nitrogen application rates and years was also significant. The grain yield showed an odd peak curve with the nitrogen application rates and the highest grain yield was obtained in N3 treatment. The kernel numbers and 1000-kernel weight were the main contribution. The nitrogen accumulation in grain and nitrogen translocation efficiency were improved under reasonable nitrogen application condition, which was the important basis for the high grain yield. The percentage of grain within biomass was the highest in N3 treatment, and the percentage of nitrogen accumulation after silking stage was higher than that of other treatments. These results indicated that reasonable nitrogen management probably helped to the nitrogen uptake after silking stage. The quadratic equation between grain yield and nitrogen application rate was developed on the basis of two years field experiments, and the equation is y=-0.1715x2+ 79.73x+3940.1, R2=0.963. The optimum economy fertilizing quantity was 225.1 kg·hm-2. 【Conclusion】The translocation of biomass to grain was improved under reasonable nitrogen application condition, which also help to improve nitrogen uptake and translocation efficiency. Based on the moderate fertility black soil and the 75 000 plant/hm2 planting density for spring maize in the middle region of Northeast, the nitrogen application rate can be adjusted to around 225 kg·hm-2 according to the soil fertility and hybrids. Reference丨 Related Articles丨 Metrics

Improvement Effects of Rotational Tillage Patterns on Soil in the Winter Wheat-Summer Maize Double Cropping Area of Huang-Huai-Hai Region     YU ShuTing, ZHAO YaLi, WANG YuHong, LIU WeiLing, MENG ZhanYing, MU XinYuan, CHENG SiXian, LI ChaoHai Scientia Agricultura Sinica   2017,50(11 ):2150 -2165. DOI:10.3864/j.issn.0578-1752.2017.11.020 Abstract  （252） HTML （5） PDF（pc） （503KB）（577） Save 【Objective】A long-term practice of applying single soil rotary tillage pattern in this area has caused soil compaction, poor ability in retaining rainwater and providing nutrients. Effects of different rotational tillage patterns, which were pairwise combined with subsoiling (ST), rotary tillage (RT) and deep tillage (DT) with straw mulching, on soil long-term improvement effects were studied in the winter wheat-summer maize double cropping area of Huang-Huai-Hai region.【Method】The experiments of CRT (continuous rotary tillage), CST (continuous subsoiling), CDT (continuous deep tillage), DT/RT (rotary tillage in first year, deep tillage in second year, again deep tillage followed by alternating the next year) and DT/RT/RT (deep tillage in first year, rotary tillage in second year, rotary tillage in third year, again deep tillage followed by alternating the next year) were conducted before sowing winter wheat, and different rotational tillage patterns on the ratios of soil solid-liquid-gaseous, soil organic carbon storage, soil total nitrogen storage, soil enzyme activities, soil respiration, and crop economic benefits were analyzed. 【Result】The results showed that, there were significant effects of rotational tillage, soil depth and tillage year on the ratios of soil solid-liquid-gaseous, soil carbon organic storage, soil total nitrogen storage and soil enzyme activities. Compared with CRT, the CST patterns increased soil organic carbon sequestration, soil total nitrogen storage, soil urease and invetase activities of surface soil, and CDT, DT/RT, DT/RT/RT increased soil organic carbon sequestration, soil total nitrogen storage, soil urease and invetase activities at 10-40 cm soil layer of winter wheat and summer maize. With the increasing cultivation, the R value at 0-40 cm soil layer under the five rotational tillage patterns showed a trend of overall decrease, and the soil organic carbon storage and soil total nitrogen storage showed a trend of overall increase. The effect of DT/RT, DT/RT/RT was more significantly. Compared to pretreatment, the R values under CRT, CST, CDT, DT/RT, DT/RT/RT were significantly decreased by 20.8%, 33.1%, 29.5%, 29.7%, 30.7%, while the soil organic carbon storage significantly increased by 6.4%, 14.5%, 16.0%, 20.6%, 23.8% and the soil total nitrogen storage increased by 3.1%, 11.1%, 11.6%, 13.3%, 15.7%, respectively. There were significant effects of rotational tillage on the soil respiration rate. Compared with CRT, CST, CDT, DT/RT, and DT/RT/RT increased soil respiration rate by 20.7%, 19.3%, 13.7%, and 9.2% during winter wheat season, and increased by 19.1%, 18.1%, 15.2%, and 10.4% during summer maize season, respectively. However, DT/RT, DT/RT/RT declined soil respiration rate by 5.9%, 9.6% during winter wheat season, and declined by 3.3%, 7.3% during summer maize season, respectively, relative to CDT. Compared with DT/RT, the soil respiration rate of DT/RT/RT was declined by 4.1% during winter wheat season and declined by 4.3% during summer maize season. Rotational tillage, tillage year and tillage×year had significant effects on crop yield and economic benefits. Through comprehensive evaluation and analysis of the winter wheat and summer maize annual grain yield and economic benefits of five rotational tillage patterns in six years, DT/RT was the best, but DT/RT/RT had no significant difference relative to DT/RT. Compared with CRT, the average annual yields of 6 years under DT/RT/RT, DT/RT, CDT, CST were increased by 18.9%, 21.4%, 12.9%, 15.7%, and the average economic benefits were increased by 31.9%, 36.2%, 20.3%, 25.4%, respectively.【Conclusion】DT/RT/RT improved good tilth soil structure, increased the distribution of soil organic carbon characteristics, total nitrogen storage and enzyme activities of root zone in the top soil layer, declined farmland carbon emission, improved significantly crop yields and economic benefits. Therefore, DT/RT/RT can be selected as an suitable tillage practice for double-crop system of winter wheat-summer maize in Huang-huai-hai area, followed by DT/RT rotation tillage. Reference丨 Related Articles丨 Metrics

Effect of Coated-Urea Application Times on Yield and Nitrogen Use Efficiency of Summer Maize     SUN XuDong, SUN Hu, DONG ShuTing, ZHAO Bin, LIU Peng, ZHANG JiWang Scientia Agricultura Sinica   2017,50(11 ):2179 -2188. DOI:10.3864/j.issn.0578-1752.2017.11.022 Abstract  （252） HTML （1） PDF（pc） （386KB）（416） Save 【Objective】The measures of agricultural production will be simplified which is a trend in the future because of agricultural labor is decreasing. Huang-Huai-Hai Region is high temperature and rainy in summer corn season. Single basal fertilization is easy to release so fast that corn can’t have enough N at late growth stage which can’t meet the demand of maize growth. By studying different fertilizer application times, the optimum summer corn fertilization methods were explored for the simplification of production measures while guaranteeing the yield and improving the utilization efficiency of fertilizer. 【Method】 Denghai605 (DH605) and Zhengdan958 (ZD958) were used as test varieties. Five experimental treatments were designed including no nitrogen fertilization (CK), one-dose nitrogen application (JN), split nitrogen topdressing (SN), coated-urea as base fertilizer (BR), coated-urea application time at jointing stage (JR). The effect of fertilizer application time on accumulation of dry matter accumulation, nitrogen transport characteristics and yield by field experiment.【Result】Nitrogen fertilizer significantly improved maize yield. Compared with CK treatment of ZD958 and DH605, the yield of nitrogen treatments were increased by 18.9%-24.7% and 19.4%-28.9%. Compared with the JN treatment of ZD958 and DH605, the yield of SN were increased by 4.15% and 5.80%, and the grain number of ZD958 was significantly increased. Compared with BR treatment of ZD958 and DH605, the yield of SN was increased by 1.44% and 7.80%, and that of JR was increased by 2.10% and 10.13%, respectively. The grain number of ZD958 and 1000- grain weight of DH605 was increased significantly. The yield of JR was the highest in two years, but there was no significant difference between JR and SN. Compared with BR of ZD958 and DH605, the total nitrogen accumulation of JR were increased by 10.99% and 6.78%, the amounts of accumulated nitrogen after flowering were increased by 45.99% and 43.87%, nitrogen absorption rate after flowering were increased by 46.1% and 43.5%. Compared with SN treatment of ZD958 and DH605, the total nitrogen accumulation of JR were increased by 5.15% and 7.67%, and the post-anthesis nitrogen accumulation were increased by 18.78% and 30.49%, and the rate of nitrogen absorption after anthesis were increased by 18.39% and 30.51%. Compared with BR of ZD958 and DH605, the active N accumulation period (ANAP) of JR were increased by 13.74 days and 25.87 days, respectively, and the nitrogen content (NAAG) was increased by 12.78% and 10.49%, and the assimilating amount of nitrogen after anthesis (AANAA) was increased by 50.87% and 42.57%, and nitrogen translocation amount (NTA) was decreased by 24.82% and 25.38%, the nitrogen transport efficiency (NTE) was decreased by 19.16% and 12.04%, the partial factor productivity from applied N (PFPN) was increased by 2.07% and 10.19%, and the agronomic efficiency of applied nitrogen (AEN) was increased by 11.47% and 69.72%. The recovery efficiency of applied nitrogen (REN) was increased by 60.89% and 25.91%, and soil nitrogen dependence rate (SNDR) decreased by 9.90% and 6.36%, respectively. Compared with SN of ZD958, the ANAP of JR was increased by 12.77 d, NAAG and AANAA were increased by 3.44% and 20.17%, NTA and NTE were decreased by 18.93% and 15.76%, PFPN, AEN and REN were increased by 0.63%, 3.29% and 23.07%, while SNDR was decreased by 4.89% respectively. Compared with SN of DH605, the ANAP was increased by 22.76 d, NAAG and AANAA were increased by 10.26% and 28.67%, NTA and NTE were decreased by 15.56% and 7.80%, PFPN, AEN and REN were increased by 2.15%, 10.31% and 29.96%, while SNDR was decreased by 7.12%, respectively.【Conclusion】The coated urea applied at jointing stage instead of basal could increase corn grain nitrogen content, extended the active time of plant nitrogen accumulation. PFPN, AEN, REN were increased significantly, SNDR was reduced, more nitrogen directly affected grain growth, the amount of yield was equal to SN. JR is more convenient to meet maize’s demand of nutrients on the basis of one-dose nitrogen application, which help streamline production of summer maize. Reference丨 Related Articles丨 Metrics

Effect of Tillage Practice and Fertilization on Dry Matter Accumulation and Grain Yield of Summer Maize (Zea Mays L.)     ZHOU BaoYuan, SUN XueFang, DING ZaiSong, MA Wei, ZHAO Ming Scientia Agricultura Sinica   2017,50(11 ):2129 -2140. DOI:10.3864/j.issn.0578-1752.2017.11.018 Abstract  （250） HTML （7） PDF（pc） （486KB）（982） Save 【Objective】 Soil tillage practice and fertilization have remarkable influence on crop yield and nitrogen use efficiency. The objective of this study was to clarify physiological reason for differences of maize yield and nitrogen efficiency by exploring the effects of the slow release fertilizer on dry matter accumulation and transportation, and characteristics of photosynthesis of summer maize under different soil tillages.【Method】A field experiment was conducted at Xinxiang, Henan province from 2013 to 2014. The experimental design was a split plot. The main plot was three soil tillage management, rototilling (R), no-tillage (N) and sub-soiling (S), and the subplot was nitrogen application, N 270 kg·hm-2 slow release fertilizer treatment (SRF), and N 270 kg·hm-2 conventional compound fertilizer with two applications (CCF) (40% as basal application and 60% at the beginning of male tetrad stage). 【Result】Compared with conventional fertilization and soil tillage practices, the application of slow release fertilizer and the sub-soiling tillage significantly increased post-silking leaf area (LAI) and photosynthetic rate (Pn) of maize. At maturity, the decrease in LAI for SRF was 7.5% (N), 9.7% (R), and 11.8% (S) lower than those for CCF; the decrease in Pn for SRF was 7.3% (N), 11.5% (R), and 16.8% (S) lower than those for CCF averaged the two years. The LAI of the slow release fertilizer under the sub-soiling tillage (S-SRF) increased by 16.0%-47.9%, and the Pn increased by 14.5%-52.3% than that of other treatments. Higher post-silking LAI and Pn promoted the post-silking dry matter accumulation rate and duration increased, eventually increased post-silking dry matter accumulation and its transportation to grain. The averaged dry matter assimilation post-silking of applying the slow release fertilizer across two years were 1.5%, 21.4% and 24.4% higher, and the averaged dry matter accumulation post-silking of applying the slow release fertilizer across two years were 11%, 12.2% and 17% higher, respectively, compared to those in the conventional fertilizer treatment under rototilling, no-tillage, and sub-soiling. The post-silking dry matter accumulation and assimilation of S-SRF were significantly higher than that in other treatments, increased by 13.4%-28.9% and 17.4%-39.6%, respectively. The post-silking dry matter accumulation and assimilation were the main reason for yield increase. As a result, the application of slow release fertilizer and the sub-soiling tillage significantly improved the grain yield of summer maize by increasing 1000-kernel weight and harvest ear numbers, respectively. Among the treatments, the yield of the slow release fertilizer under the sub-soiling tillage (S-SRF) was 9.2%-23.2% higher than that in other treatments.【Conclusion】The sub-soiling tillage improved the spatial distribution of soil nitrogen, and the slow release fertilizer improved the temporal distribution of soil nitrogen. The integrated sub-soiling and slow release fertilizer improved N supply corresponded to maize critical growth stages and matched N uptake, which provided an approach for enhancing the nitrogen fertilizer use efficiency and grain yield in Huang-Huai-Hai plain. Reference丨 Related Articles丨 Metrics

Root Characteristics and Grain Yield of Summer Maize Under Different Winter Wheat-Summer Maize Tillage Systems     GAO Fei, LI Xia, REN BaiZhao, DONG ShuTing, LIU Peng, ZHAO Bin, ZHANG JiWang Scientia Agricultura Sinica   2017,50(11 ):2141 -2149. DOI:10.3864/j.issn.0578-1752.2017.11.019 Abstract  （239） HTML （2） PDF（pc） （416KB）（674） Save 【Objective】The cultivation pattern in the Huang-Huai-Hai Plain is double cropping system of winter wheat-summer maize. The key reason for the influence on root development and yield is the decrease of nutrient content and the tillage layer is becoming shallow which are caused by long-term no-tillage or rotary tillage is practiced in growing winter wheat and no-tillage is practiced in growing maize. It has a significant impact on root development and yield of crops. This study is to investigate the effects of different tillages on root characteristics and grain yield of summer maize in double cropping system in Huang-Huai-Hai Plain. 【Method】 Zhengdan958 (ZD958) was used as experimental materials. The field study consisted of tillage treatments before sowing winter wheat and summer maize: rotary tillage before winter wheat sowing and no-tillage before maize sowing (RN), tillage before wheat sowing and no-tillage before maize sowing (MN), and tillage before wheat sowing and rotary tillage before maize sowing (MR) were performed to explore the effects of tillage before winter wheat on root dry matter and root/shoot, root length and area, brace root quality, quantity of bleeding sap in stalk and grain yield. 【Result】The root dry weight, root/shoot ratio, root length, root surface area, root volume, brace root layer number, brace root article number and the brace root dry weight in 0-30 cm of MR and MN increased by 59.1%, 37.5%, 22.8%, 41.1%, 59.2%, 5.9%, 21.0%, 50.8%, and 68.5%, 50.0%, 16.7%, 33.7%, 44.0%, 3.9%, 20.1%, 57.6%, respectively. root TTC reducing capacity, TTC reducing quantity, root actively absorbing area, total root absorbing area and quantity of bleeding sap in 0-30 cm of MR and MN increased by 82.6%, 91.9%, 33.9%, 34.5%, 24.0%, and 109.9%, 108.5%, 83.8%, 65.1%, 14.7%, respectively. Compared to RN, actual ears, the spike grain number, 1000-kernel weight in MR and MN treatments were increased by 8.5%, 11.7%, 4.9% and 3.9%, 8.5%, 4.2%, respectively, and MR and MN treatments, respectively, increased yield by 29.5% and 23.7%. Ploughing before wheat seeding significantly improved the summer maize root quantity and quality characteristics, thus improved yield. Compared with MR, MN treatment significantly increased the total absorption area and active absorption area of the roots which increased by 22.8% and 37.21%, respectively. However, the root length, root surface area, root volume, root number, reductive amount and reductive intensity of TTC by root were not significantly different from those of MR. Compared with MN, the effective panicle number of MR increased by 4.7% but the spike grain number and 1000-kernel weight of two treatments showed no different, yield did not reach significant difference levels.【Conclusion】Compared to RN, MN and MR could significantly improve root properties and yield. The root characteristics and yield of MN and MR did not show significant difference, which indicated that the early wheat sowing was the main effect of winter wheat sowing on summer maize yield and root characteristics. In comprehensive comparison of three different farming methods, it was concluded that MN is the most suitable summer maize production farming method in Huang-Huai-Hai Plain. Reference丨 Related Articles丨 Metrics

Effect of Waterlogging at Early Period on Canopy Structure and Photosynthetic Characteristics of Summer Maize     REN BaiZhao, ZHANG JiWang, DONG ShuTing, ZHAO Bin, LIU Peng Scientia Agricultura Sinica   2017,50(11 ):2093 -2103. DOI:10.3864/j.issn.0578-1752.2017.11.015 Abstract  （236） HTML （6） PDF（pc） （1344KB）（457） Save 【Objective】 The objective of this study is to investigate the effects of waterlogging on canopy structure and photosynthetic characteristics of summer maize under field conditions. 【Method】 Two summer maize cultivars Denghai605 (DH605) and Zhengdan958 (ZD958) were used as experimental materials. Experimental treatments consisted of waterlogging at the third leaf stage for 3 d (V3-3) and for 6 d (V3-6), waterlogging at the sixth leaf stage for 3 d (V6-3) and for 6 d (V6-6), and no waterlogging (CK). The field experiment was performed to explore the effects of waterlogging for different durations (3 and 6 days) on photosynthetic intensity, net photosynthetic rate, canopy light transmittance and its hemispheric gray images, and grain yield of summer maize at the third leaf stage (V3) and sixth leaf stage (V6). 【Result】 Results showed that leaf area index was significantly reduced after waterlogging. Waterlogging significantly increased group light transmittance, and led to a remarkable reduction of light interception rate. Group light transmittance of summer maize was more susceptible to waterlogging damage at V3, followed by V6, and damage was increased with the increasing waterlogging duration. The light transmittances of ear layer were increased by 96.0% and 70.2% for V3-6 in DH605 and ZD958, respectively, compared to CK. That ground floor increased by 68.9% and 71.9% for V3-6 in DH605 and ZD958, respectively, compared to CK. Waterlogging significantly decreased group photosynthetic potential (LAD) and net photosynthetic rate (Pn)；The most decrease of Pn of two hybrids was found at V3-6, with 23.5% and 20.3% in DH605 and ZD958, respectively. LAD of V3-6 for DH605 was decreased by 68.5%, 45.0%, 31.6%, 25.0%, and 37.5% at seedling-V6, V6-the twelfth leaf stage (V12), V12-the flowering stage (VT), VT-the milking stage (R3), and R3-the physiological maturity stage (R6), respectively. ZD958 decreased by 62.4%, 37.1%, 25.8%, 21.7%, and 38.5%, respectively. The reduction of LAD and Pn led to the decrease of photoassimilates. Dry matter weight of V3-3, V3-6, V6-3, and V6-6 for DH605 was decreased by 12.4%, 24.8%, 9.3%, and 21.1%, ZD958 decreased by 17.3%, 26.7%, 12.5%, and 23.9%, respectively. In addition, waterlogging decreased harvest index, with the most significant reduction in V3-6 with a decrease of 13.3% and 13.8% for DH605 and ZD958. The degradation of canopy structure and photosynthetic characteristics resulted in a significant reduction of maize yield after waterlogging. Grain yield of V3-3, V3-6, V6-3, and V6-6 for DH605 was decreased by 23.2%, 35.9%, 17.0%, and 22.7%, ZD958 decreased by 20.0%, 35.7%, 15.0%, and 27.1%, respectively. 【Conclusion】 Waterlogging significantly decreased leaf area index and ground photosynthetic potential, led to the reduction of light interception rate and photosynthetic performance, decreasing net photosynthetic rate, eventually resulted in a remarkable reduction of summer maize yield. Canopy structure and photosynthetic characteristics of summer maize was more susceptible to waterlogging damage at V3, followed by V6, damage was increased with the increasing waterlogging duration. Reference丨 Related Articles丨 Metrics

Proteomic Analysis of Maize Reveals Expression Characteristics of Stress-Related Proteins During Grain Development     YU Tao, LI Geng, LIU Peng, DONG ShuTing, ZHANG JiWang, ZHAO Bin Scientia Agricultura Sinica   2017,50(11 ):2114 -2128. DOI:10.3864/j.issn.0578-1752.2017.11.017 Abstract  （220） HTML （7） PDF（pc） （1130KB）（531） Save 【Objective】In order to understand the molecular regulation mechanism of defense system in maize grain, the expression characteristics of stress-related proteins during grain development were studied by using approach of plant proteomics.【Method】Denghai 661 (DH661) was used as experimental material and planted at 67 500 plants/hm2 in field. The middle grains were harvested after flowering artificial saturation pollination at 3, 5, 10, 15, 20, 30, 40, 50 d, respectively. The total proteins were extracted by the TCA-acetone precipitation method and then were analyzed by isobaric tags for relative and absolute quantitation (iTRAQ) proteomics. The proteins in maize grain were identified by searching the Uniprot maize protein database and gene ontology (GO) annotation was used to classify the functions of these proteins according to the biological process, molecular function and cellular component. Quantitative analysis was applied to identify stress-related proteins that were significantly differentially expressed during grain development. Hierarchical cluster analysis was used to show the expression patterns of these stress-related proteins during grain development.【Result】A total of 4 751 proteins were identified in maize grain by matching the maize protein database, and these proteins were involved in diverse biological processes and molecular functions, of which the metabolic process and molecular processes were the main biological processes, and the catalytic activity and binding function were the main molecular categories, showing that these biological processes and molecular functions played important roles in maize grain development. Quantitative analysis detected 123 stress-related proteins were significantly differentially expressed during grain development, and these proteins were mainly involved in grain protein modification (33), reactive oxygen species (ROS) homeostasis (31), storage material protection (17), disease response (8) and other stress response process (34). The proteins related to protein modification mainly included a series of heat shock protein, peptidyl-prolyl cis-trans isomerase and protein disulfide isomerase, and these proteins significantly accumulated at different development stages, which played important roles in stability of protein structure. ROS related proteins contained a variety of antioxidants, and mainly significantly accumulated at both early and late development stages, which maintained the homeostasis of ROS. Storage material protection related proteins mainly contained a variety of protease inhibitors, oleosin and steroleosin, and the expression of these proteins were constantly raised with the grain development, which protected the synthesis and accumulation of storage material. The proteins involved in disease response also significantly accumulated at late development stage, which enhanced the grain resistance to biological stresses. Proteins involved in other stress response mainly included a series of late embryogenesis abundant protein (LEA), annexin, lipid transfer protein, nonspecific lipid transfer protein and lipoxygenase, of which all of the LEA significantly accumulated at late development stage, annexin and lipoxygenase significantly accumulated at early development stage, while lipid transfer protein and nonspecific lipid transfer proteins were accumulated at different development stages, showing that these proteins played important roles in different grain development stages.【Conclusion】Stress-related proteins were accumulated during maize grain different development stages, which constructed a harmonious, diverse and stable defense regulatory mechanism, and thus maintained the normal development of maize grain. Reference丨 Related Articles丨 Metrics

Response of Spatial Concordance Index Between Maize Root and Soil Nitrate Distribution to Water and Nitrogen Treatments     YIN Fei, WANG JunZhong, SUN XiaoMei, LI HongQi, FU GuoZhan, PEI RuiJie, JIAO NianYuan Scientia Agricultura Sinica   2017,50(11 ):2166 -2178. DOI:10.3864/j.issn.0578-1752.2017.11.021 Abstract  （213） HTML （3） PDF（pc） （470KB）（498） Save 【Objective】Root is a major organ of maize for the absorption of soil nitrogen nutrition. The spatial concordance index between maize root and soil nitrogen distribution might have an influence on nitrogen uptake and utilization of maize. The purposes of this study were: (1) to analyze the effects of water and nitrogen treatments on maize root distribution and the spatial concordance index between maize root and soil nitrate content; (2) to determine the effectiveness of spatial concordance index between maize root and soil nitrate content. 【Method】 From 2011 to 2015, the experiment was set in six treatments, including W0N0 (0), W0N1 (0+300 kg N·hm-2), W0N2 (0+360 kg N·hm-2), W1N0 (750 m3·hm-2 +0), W1N1 (750 m3·hm-2+ 300 kg N·hm-2), and W1N2 (750 m3·hm-2+ 360 kg N·hm-2), in which irrigation occurred at spike formation stage, and nitrogen applied at jointing stage (30%N) and spike formation stage (70%N). In maize growing season of 2015, soil samples were collected in and between maize planting lines at jointing, spike formation, silking, 20 days after silking, and mature stage. Root length density (RLD) and root dry weight density (RWD), soil nitrate content, spatial concordance index between root and soil nitrate content, and nitrogen absorption were analyzed. 【Result】 With the development of maize growth process, both in and between the lines of maize, RLD, RWD, and soil nitrate content increased first and then decreased. The maximum values of RLD and RWD occurred in 20 days after silking, and the maximum value of soil nitrate content occurred at spike formation stage. In the range of 0-360 kg·hm-2, with the increasing of nitrogen application rate, maize RLD and soil nitrate content before silking stage kept increasing. However, maize RWD and soil nitrate content after silking stage increased first and then decreased, and the maximum value occurred in 300 kg·hm-2 nitrogen application treatment. At the late stage of maize growth, irrigation increased RLD and RWD, but decreased soil nitrate content. With the increasing of soil layer depth, RLD1-N (the spatial concordance index between RLD and soil nitrate content at the maize planting line) and RWD1-N (the spatial concordance index between RWD and soil nitrate content at the maize planting line) showed a decreasing trend, RLD2-N and RWD2-N showed a trend of increasing first and then decreasing, the maximum value occurred in 10-30 cm soil layer. With the development of maize growth process, RLD1-N, RWD1-N, and RWD2-N , and RLD2-N in 0-40 cm soil layer showed a trend of increasing first and then decreasing. Compared with no nitrogen treatment, nitrogen applications significantly increased RLD1-N, RLD2-N, RWD1-N and RWD2-N. When increasing nitrogen from 300 kg·hm-2 to 360 kg·hm-2, the RLD2-N of 0-30 cm soil layer, the RWD1-N of 0-20 cm soil layer, the RLD1-N from jointing to silking stage, and the RWD2-N of 0-20 cm soil layer were decreased; and the RLD2-N of 40-50 cm soil layer, the RWD1-N of 20-50 cm soil layer, the RLD1-N and RWD2-N after silking stage were increased. RLD1-N, RLD2-N, RWD1-N, RWD2-N had a remarkable correlation with maize yield and nitrogen use efficiency, which the correlation coefficient was higher than between root length density, root weight density and maize yield, nitrogen use efficiency. 【Conclusion】Under field conditions, nitrogen fertilizer application increased RLD, RWD, RLD1-N, RLD2-N, RWD1-N and RWD2-N, but decreased RWD, RLD1-N before silking, RWD2-N, RLD2-N and RWD1-N when nitrogen fertilizer application exceeded 300 kg·hm-2. The spatial concordance index between root and soil nitrate can be a effective index to assess nitrogen use efficiency of maize. Reference丨 Related Articles丨 Metrics