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2015 Vol. 14 No. 8 Previous Issue    Next Issue

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Review
Special Focus: Systems Research Helping toMeet the Needs and Managing the Trade-offs of a Changing W
Plant Protection
Animal Science · Veterinary Science
Soil & Fertilization﹒Irrigation﹒Plant Nutrition﹒ Agro-Ecology & Environment




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Review

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Breaking wheat yield barriers requires integrated efforts in developing countries Saeed Rauf, Maria Zaharieva, Marilyn L Warburton, ZHANG Ping-zhi, Abdullah M AL-Sadi, Farghama Khalil, Marcin Kozak, Sultan A Tariq 2015, 14(8): 1447-1474.  DOI: 10.1016/S2095-3119(15)61035-8 Abstract ( )   PDF in ScienceDirect   Most yield progress obtained through the so called “Green Revolution”, particularly in the irrigated areas of Asia, has reached a limit, and major resistance genes are quickly overcome by the appearance of new strains of disease causing organisms. New plant stresses due to a changing environment are difficult to breed for as quickly as the changes occur. There is consequently a continual need for new research programs and breeding strategies aimed at improving yield potential, abiotic stress tolerance and resistance to new, major pests and diseases. Recent advances in plant breeding encompass novel methods of expanding genetic variability and selecting for recombinants, including the development of synthetic hexaploid, hybrid and transgenic wheats. In addition, the use of molecular approaches such as quantitative trait locus (QTL) and association mapping may increase the possibility of directly selecting positive chromosomal regions linked with natural variation for grain yield and stress resistance. The present article reviews the potential contribution of these new approaches and tools to the improvement of wheat yield in farmer’s fields, with a special emphasis on the Asian countries, which are major wheat producers, and contain the highest concentration of resource-poor wheat farmers.

Special Focus: Systems Research Helping toMeet the Needs and Managing the Trade-offs of a Changing W

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Systems research helping to meet the needs and managing the trade-offs of a changing world Peter Carberry, Shu Geng, LIANG Wei-li, LI Ling-ling 2015, 14(8): 1475-1477.  DOI: 10.1016/S2095-3119(15)61137-6 Abstract ( )   PDF in ScienceDirect

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Impact of systems modelling on agronomic research and adoption of new practices in smallholder agriculture D J Connor, H van Rees, P S Carberry 2015, 14(8): 1478-1489.  DOI: 10.1016/S2095-3119(15)61069-3 Abstract ( )   PDF in ScienceDirect   An analysis of the impact of simulation modelling in three diverse crop-livestock improvement projects in Agricultural Research for Development (AR4D) reveals benefits across a range of aspects including identification of objectives, design and implementation of experimental programs, effectiveness of participatory research with smallholder farmers, implementation of system change and scaling-out of results. In planning change, farmers must consider complex interactions within both biophysical and socioeconomic aspects of their crop and animal production activities. For this, whole-farm models that include household models of food, workload and financial requirements have the most utility and impact. The analysis also proposes improvements in design and implementation of AR4D projects to improve the utility of simulation modelling for securing positive agronomic and livestock outcomes and lasting legacies.

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Transitioning from paternalism to empowerment of farmers in lowincome countries: Farming components to systems David Norman 2015, 14(8): 1490-1499.  DOI: 10.1016/S2095-3119(15)61041-3 Abstract ( )   PDF in ScienceDirect   Reasons for the initiation of farming systems/participatory approaches in non-Green Revolution (i.e., in more heterogeneous and less favourable production environments) areas in low-income countries is followed by a discussion of their evolution. Four phases are described along, with a brief description of some of the significant methods in which farmer participation has been sought, accessed and evaluated. They enabled/facilitated the evolutionary process. Although, over the last 40 years there has been a progress in making small-scale farmers much more visible in driving the agricultural research/development agenda through using the four basic stages embodied in the farming systems approach (i.e., descriptive, diagnosis, testing/ evaluation and finally dissemination), much still needs to be done. This leads on to a discussion as to some of the barriers still inhibiting true farmer empowerment and why further, such empowerment is imperative, if the agricultural challenges of this century are to be addressed successfully, namely substantially increasing agricultural productivity in an ecologically sustainable manner. Given the heterogeneity of the production environments and that many identified improvements are likely to be incremental rather than revolutionary in nature, this will require farmers’ intimate involvement in their identification, evaluation and dissemination. Discussion in the paper recognizes that there is increasing globalization/commercialization of agriculture and is predicated on the need to consider the whole farmer-research-development continuum involving multiple stakeholders (i.e., farmers, scientists, extension workers, input/output service providers and policymakers). Such a continuum has been explicitly recognized in the operational plans for the recently reformed international agricultural research (i.e., CGIAR) system. The paper concludes with a short discussion on the potential role of formal modelling.

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Strategies for increasing the capture, storage, and utilization of precipitation in semiarid regions B A Stewart, LIANG Wei-li 2015, 14(8): 1500-1510.  DOI: 10.1016/S2095-3119(15)61096-6 Abstract ( )   PDF in ScienceDirect   Crop production in semiarid regions is always challenging because of the high variability of amount and distribution of precipitation. These regions become more important each year, however, because the rapidly increasing and more prosperous world population seeks greater consumption of animal products (meat, milk and eggs) that requires additional grain to that consumed directly. The dry areas of the developing world where approximately 40% of the world population lives comprise about 40% of the earth’s land area. Crop production, particularly cereal grains, must increase in these areas to meet these growing demands. Grain yield of cereal crops is a function of the amount of water used for evapotranspiration (ET), the portion of ET used for transpiration (T), the units of water as T to produce 1 unit of biomass, and the harvest index (HI). The most important factor is the amount of evapotranspiration not only because it is closely proportional to grain yield, but because it tends to also make the other factors more favorable. Therefore, even small increases in ET can be significant. Strategies for manipulating soil and plant conditions for increasing ET, and how additional ET affects the other factors, are discussed for water deficient areas. The use of crop residues as mulch is highly beneficial but often insufficient in dryland regions or is required for animal feed and fuel. Plastic mulch, mainly restricted to China, has significantly increased grain yields in dryland areas by decreasing evaporation from the soil surface.

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Characterizing historical (1992–2010) transitions between grassland and cropland in mainland France through mining land-cover survey data Ying Xiao, Catherine Mignolet, Jean-Fran?ois Mari, Marc Beno?t 2015, 14(8): 1511-1523.  DOI: 10.1016/S2095-3119(15)61103-0 Abstract ( )   PDF in ScienceDirect   Grassland, as one of the largest ecosystems on the earth, supports various goods and services to humanity. Historically, humans have increased agricultural output primarily by cropland expansion and agricultural intensification. The cropland area was primarily gained at the expense of grassland and forests. Apart from grassland conversion, increasing consumption of calorie- and meat-intensive diets drives the intensification of livestock systems, which is shifting steadily from grazing to feeding with crops. To cope with the environmental degradation due to agriculture, various forms of ‘green payment’ were implemented to promote the adoption of sustainable farming practices over the last two decades in the European Union. The aim of this study is to monitor the recent transitions (1992–2010) between grassland and cropland during two Common Agricultural Policy (CAP) reforms at the French mainland scale. We proposed an innovative approach to link grassland conversion to agricultural commodities and farming systems practices. We first assessed the grassland-to-cropland conversion and further investigated the crop sequence patterns that were observed to be dominant after the conversion through mining land-cover survey data Teruti and Teruti-Lucas. We found the trends of the transitions between grassland and cropland over the two time intervals: The loss of grassland (1992–2003) and restoration or re-expansion of grassland (2006–2010) in mainland France. Our finding on the crop sequence patterns after the grassland conversion reveals two notable evolutions of agricultural production systems. These evolutions were related to the increase in the proportion of cropland in the total agricultural land use. One evolution was most likely influenced by the demand for fodder: The conversion from grazing livestock to feeding livestock. Another evolution was the conversion from livestock production to field crop production. Our results indicate that the intensification of livestock farming systems continued over the last two decades in France. We conclude that, the approach developed in this study can be considered as a generic method for monitoring the transitions between grassland and cropland and further identifying the crop sequence patterns after the grassland conversion from time-series land cover data.

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Climate change adaptation, greenhouse gas mitigation and economic profitability of conservation agriculture: Some examples from cereal systems of Indo-Gangetic Plains Tek B Sapkota, M L Jat, Jeetendra P Aryal, R K Jat, Arun Khatri-Chhetri 2015, 14(8): 1524-1533.  DOI: 10.1016/S2095-3119(15)61093-0 Abstract ( )   PDF in ScienceDirect   Achieving sustainability of the cereal system in the Indo-Gangetic Plains (IGP) of India under progressive climate change and variability necessitates adoption of practices and technologies that increase food production, adaptation and mitigation in a sustainable way. This paper examines conservation agriculture (CA) from the perspective of: (i) increased yield and farm income, (ii) adaptation to heat and water stresses, and (iii) reduction in greenhouse gas (GHGs) emissions. The analyses and conclusions are based on the literature and evidences from a large number of on-station as well as farmers’ field trials on CA in the cereal systems of IGP. Our analyses show that CA-based system substantially reduces the production cost (up to 23%) but produces equal or even higher than conventional system; thereby increasing economic profitability of production system. CA-based production systems also moderated the effect of high temperature (reduced canopy temperature by 1–4°C) and increased irrigation water productivity by 66–100% compared to traditional production systems thus well adapting to water and heat stress situations of IGP. Our continuous monitoring of soil flux of CO2, N2O and CH4 revealed that CA-based rice-wheat systems emit 10–15% less GHGs than conventional systems. This is the first time that CA and its components are synthesized and analyzed from food security-climate change nexus. From this holistic analysis, we suggest that wide-scale promotion of suitable CA practices by integrating into national agriculture development strategy is a way forward to address food security, climate change adaptation and mitigation challenges faced by present agriculture.

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Net energy yield and carbon footprint of summer corn under different N fertilizer rates in the North China Plain WANG Zhan-biao, WEN Xin-ya, ZHANG Hai-lin, LU Xiao-hong, CHEN Fu 2015, 14(8): 1534-1541.  DOI: 10.1016/S2095-3119(15)61042-5 Abstract ( )   PDF in ScienceDirect   Excessive use of N fertilizer in intensive agriculture can increase crop yield and at the same time cause high carbon (C) emissions. This study was conducted to determine optimized N fertilizer application for high grain yield and lower C emissions in summer corn (Zea mays L.). A field experiment, including 0 (N0), 75 (N75), 150 (N150), 225 (N225), and 300 (N300) kg N ha–1 treatments, was carried out during 2010–2012 in the North China Plain (NCP). The results showed that grain yield, input energy, greenhouse gas (GHG) emissions, and carbon footprint (CF) were all increased with the increase of N rate, except net energy yield (NEY). The treatment of N225 had the highest grain yield (10 364.7 kg ha–1) and NEY (6.8%), but the CF (0.25) was lower than that of N300, which indicates that a rate of 225 kg N ha–1 can be optimal for summer corn in NCP. Comparing GHG emision compontents, N fertilizer (0–51.1%) was the highest and followed by electricity for irrigation (19.73–49.35%). We conclude that optimazing N fertilizer application rate and reducing electricity for irrigation are the two key measures to increase crop yield, improve energy efficiency and decrease GHG emissions in corn production.

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Resource use efficiency, ecological intensification and sustainability of intercropping systems MAO Li-li, ZHANG Li-zhen, ZHANG Si-ping, Jochem B Evers, Wopke van der Werf, WANG Jingjing, SUN Hong-quan, SU Zhi-cheng, Huub Spiertz 2015, 14(8): 1542-1550.  DOI: 10.1016/S2095-3119(15)61039-5 Abstract ( )   PDF in ScienceDirect   The rapidly growing demand for food, feed and fuel requires further improvements of land and water management, crop productivity and resource-use efficiencies. Combined field experimentation and crop growth modelling during the past five decades made a great leap forward in the understanding of factors that determine actual and potential yields of monocrops. The research field of production ecology developed concepts to integrate biological and biophysical processes with the aim to explore crop growth potential in contrasting environments. To understand the potential of more complex systems (multi-cropping and intercropping) we need an agro-ecosystem approach that integrates knowledge derived from various disciplines: agronomy, crop physiology, crop ecology, and environmental sciences (soil, water and climate). Adaptation of cropping systems to climate change and a better tolerance to biotic and abiotic stresses by genetic improvement and by managing diverse cropping systems in a sustainable way will be of key importance in food security. To accelerate sustainable intensification of agricultural production, it is required to develop intercropping systems that are highly productive and stable under conditions with abiotic constraints (water, nutrients and weather). Strategies to achieve sustainable intensification include developing tools to evaluate crop growth potential under more extreme climatic conditions and introducing new crops and cropping systems that are more productive and robust under conditions with abiotic stress. This paper presents some examples of sustainable intensification management of intercropping systems that proved to be tolerant to extreme climate conditions.

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Soil carbon storage and stratification under different tillage/ residue-management practices in double rice cropping system CHEN Zhong-du, ZHANG Hai-lin, S Batsile Dikgwatlhe, XUE Jian-fu, QIU Kang-cheng, TANG Hai-ming, CHEN fu 2015, 14(8): 1551-1560.  DOI: 10.1016/S2095-3119(15)61068-1 Abstract ( )   PDF in ScienceDirect   The importance of soil organic carbon (SOC) sequestration in agricultural soils as climate-change-mitigating strategy has become an area of focus by the scientific community in relation to soil management. This study was conducted to determine the temporal effect of different tillage systems and residue management on distribution, storage and stratification of SOC, and the yield of rice under double rice (Oryza sativa L.) cropping system in the southern China. A tillage experiment was conducted in the southern China during 2005–2011, including plow tillage with residue removed (PT0), plow tillage with residue retention (PT), rotary tillage with residue retention (RT), and no-till with residue retention on the surface (NT). The soil samples were obtained at the harvesting of late rice in October of 2005, 2007 and 2011. Multiple-year residue return application significantly increased rice yields for the two rice-cropping systems; yields of early and late rice were higher under RT than those under other tillage systems in both years in 2011. Compared with PT0, SOC stocks were increased in soil under NT at 0–5, 5–10, 10–20, and 20–30 cm depths by 33.8, 4.1, 6.6, and 53.3%, respectively, in 2011. SOC stocks under RT were higher than these under other tillage treatments at 0–30 cm depth. SOC stocks in soil under PT were higher than those under PT0 in the 0–5 and 20–30 cm soil layers. Therefore, crop residues played an important role in SOC management, and improvement of soil quality. In the 0–20 cm layer, the stratification ratio (SR) of SOC followed the order NT>RT>PT>PT0; when the 0–30 cm layer was considered, NT also had the highest SR of SOC, but the SR of SOC under PT was higher than that under RT with a multiple-year tillage practice. Therefore, the notion that conservation tillage lead to higher SOC stocks and soil quality than plowed systems requires cautious scrutiny. Nevertheless, some benefits associated with RT system present a greater potential for its adoption in view of the multiple-year environmental sustainability under double rice cropping system in the southern China.

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Comparison of energy consumption and economic performance of organic and conventional soybean production - A case study from Jilin Province, China ZHANG Li-wei, Til Feike, Jirko Holst, Christa Hoffmann, Reiner Doluschitz 2015, 14(8): 1561-1572.  DOI: 10.1016/S2095-3119(15)61131-5 Abstract ( )   PDF in ScienceDirect   Modern agriculture heavily depends on energy consumption, especially fossil energy, but intensive energy input increases the production cost for producers and results in environmental pollution. Organic agricultural production is considered a more sustainable system, but there is lack of scientific research on the energy consumption between organic and conventional systems in China. The analysis and comparison of energy use between the two systems would help decision-makers to establish economic, effective and efficient agricultural production. Thus, the objectives of the present study are to analyze energy inputs, outputs, energy efficiency, and economic benefits between organic and conventional soybean (Glycine max (L.) Merrill) production. A total of 24 organic farmers and 24 conventional farmers in Jilin Province, China, were chosen for investigation in 2010 production year. Total energy input was 71.55 GJ ha–1 and total energy output was 96.18 GJ ha–1 in the organic system, resulting in an energy efficiency (output/input) of 1.34. Total energy input was 9.37 GJ ha–1 and total energy output was 113.4 GJ ha–1 in the conventional system, resulting in the energy efficiency of 12.1. The huge discrepancy in energy inputs and respective efficiencies lies in the several times higher nutrient inputs in the organic compared to the conventional production system. Finally, the production costs ha–1 were 33% higher, and the net income ha–1 25% lower in the organic compared to the conventional soybean production system. It is recommended to improve fertilizer management in organic production to improve its energetic and economic performance.

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A comprehensive approach for assessing the economic contribution of forage and livestock improvement options to smallholder farming enterprises Neil MacLeod, Scott Waldron, WEN Shi-lin 2015, 14(8): 1573-1580.  DOI: 10.1016/S2095-3119(15)61091-7 Abstract ( )   PDF in ScienceDirect   The importance of livestock production activities to improving the livelihoods of smallholder farming households and the efficiency of their underlying farming systems is increasingly recognized. A rapid increase in livestock numbers, especially beef cattle, and special purpose forages is being promoted for smallholder farms which have traditionally undertaken subsistence cropping activities or simple livestock rearing activities using low quality feedstuffs. Because limited plantings of specialized forages combined with a poor knowledge of animal nutrition are a challenge to establishing sustainable livestock enterprises, much public policy and research is now being focused on the use of new forages and improved feeding practices. A number of economic studies have suggested that specialized forage growing and livestock feeding activities can make a positive contribution to smallholder welfare. The studies have typically compared the total level of farm or household income with and without livestock activities. Little attention is given to how much the new forage or livestock activities actually contribute to or draw resources from other farm activities to assess their real economic contribution to the enterprise, and the availability of simple tools to assist in making such assessments are limited. This paper describes a simple modelling approach that was developed for an Australian Centre for International Agricultural Research (ACIAR)-supported project to explore the real as opposed to apparent economic impact of integrating improved forages and livestock within smallholder farming systems in the Red Soils region of south-central China. Application of the model is demonstrated using a simple case study of a smallholder enterprise that plans to introduce a new beef cattle rearing activity to its existing farm activity mix. The case study highlights the importance of explicitly valuing transfers of resources between different farm activities to gauge the real contribution of those activities to economic returns.

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Yield and quality of maize stover: Variation among cultivars and effects of N fertilization LIANG Ming-yuan, WANG Gui-yan, LIANG Wei-li, SHI Peng-fei, DANG Jing, SUI Peng, HU Chun-sheng 2015, 14(8): 1581-1587.  DOI: 10.1016/S2095-3119(15)61077-2 Abstract ( )   PDF in ScienceDirect   Biomass yields and concentrations of crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude fiber (CF) were analyzed for five cultivars of summer-sown maize (Zea mays L.) stover grown in field trials at three rates of N fertilization, and sampled immediately after grain harvest. The results revealed differences in yields and concentrations of nutrients according to stalk height and hence harvest portion among the cultivars. N application greatly increased biomass yield and CP, especially in upper stalks and to a lesser extent, EE. Concentrations of NDF and ADF decreased as N rate increased. The results show that stovers from all local popular maize cultivars are suitable as animal fodder and that moderate N application improves feed quality of stover.

Plant Protection

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Effects of phosphate solubilization and phytohormone production of Trichoderma asperellum Q1 on promoting cucumber growth under salt stress ZHAO Lei, ZHANG Ya-qing 2015, 14(8): 1588-1597.  DOI: 10.1016/S2095-3119(14)60966-7 Abstract ( )   PDF in ScienceDirect   Salinity is one of the major abiotic stresses limiting crop growth and yield. This study investigated the underlying mechanisms of Trichoderma asperellum Q1 in promoting cucumber growth under salt stress, including the abilities of the strain to solubilize phosphate and to produce phytohormone. The results showed that T. asperellum Q1 could solubilize inorganic or organic phosphate and the activities of phosphatases and phytase could be detected in the culture supernatant. In hydroponic experiments, the growth of cucumber seedlings was increased in the hydroponic system treated by culture filtrate of strain Q1 with tricalcium phosphate or calcium phytate under salt stress. This strain also exhibited the ability to produce indole acetic acid (IAA), gibberellic acid (GA) and abscisic acid (ABA) in liquid medium without any inducers. The levels of those three phytohormones in cucumber seedling leaves also increased after inoculated with this strain, along with increased root growth and root activities of the plant. These results demonstrated the mechanisms of T. asperellum Q1 in alleviating the suppression effect of salt stress involving the change of phytohormone levels in cucumber plant and its ability of phosphate solubilization.

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Comparison and optimization of the method for Cry1Ac protoxin preparation in HD73 strain ZHOU Zi-shan, YANG Su-juan, SHU Chang-long, SONG Fu-ping, ZHOU Xue-ping, ZHANG Jie 2015, 14(8): 1598-1603.  DOI: 10.1016/S2095-3119(14)60950-3 Abstract ( )   PDF in ScienceDirect   Bacillus thuringiensis is one of the most widely used bioinsecticides, and cry gene is the major insecticidal gene. Because Cry1Ac protein shows strong toxicity against many lepidopteran species, it has been applied widely in spraying products and transgenic Bt-crops. The preparation of Cry protoxin is the first step in the very important processes of understanding the insecticidal mechanism, resistance screening, and biosafety assessments. The media for crystal production and the method for Cry protoxin preparation were varied, however, it was not clear which was better for preparing a larger amount of Cry protoxin. In this paper, three media for crystal production and the method for Cry1Ac protoxin preparation from HD73 strain were compared to find an efficacious way to prepare a large number of Cry1Ac protoxin. The results showed that the 1/2 LB (Luria-Bertani) medium was the ideal medium for crystal production, because the total yield of Cry1Ac protoxin in 300 mL 1/2 LB medium was (112.38±5.64) mg, the highest one among three media; the repeated crystal solubilization method was better for the preparation of the Cry protoxin comparing with the continuous crystal solubilization method. It will be a reference for other Cry protoxin preparation, especially for larger number.

Animal Science · Veterinary Science

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Identification of novel and differentially expressed microRNAs in ovine ovary and testis tissues using solexa sequencing and bioinformatics CHANG Wei-hua, ZHANG Yong, CHENG Zhang-rui, ZHAO Xing-xu, WANG Juan-hong, MA You-ji, HU Jun-jie, ZHANG Quan-wei 2015, 14(8): 1604-1616.  DOI: 10.1016/S2095-3119(14)60900-X Abstract ( )   PDF in ScienceDirect   MicroRNAs (miRNAs) are small, single stranded, non-coding RNA molecules, about 19–25 nucleotides in length, which regulate the development and functions of reproductive system of mammal. To discover novel miRNAs and identify the differential expression of them in ovine ovary and testis tissues, the study constructed two libraries by using next-generation sequencing technologies (Solexa high-throughput sequencing technique). As a result, 9 321 775 and 9 511 538 clean reads were obtained from the ovary and testis separately, which included 130 562 (90 genes of ovary) and 56 272 (85 genes of testis) of known miRNAs and 486 potential novel miRNAs reads. In this study, a total of 65 conserved miRNAs were significantly differentially expressed (P<0.01) between the two samples. Among them, 28 miRNAs were up-regulated and 3 miRNAs were down-regulated on ovary compared with testis. In addition, the known miRNAs with the highest expression level (5 miRNAs) and 30 novel miRNAs with the functions related to reproduction were validated using the real-time quantitative RT-PCR. Moreover, the gene ontology (GO) annotation and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis showed that differentially expressed miRNAs were involved in ovary and testis physiology, including signal transduction, gonad development, sex differentiation, gematogenesis, fertilization and embryo development. The results will be helpful to facilitate studies on the regulation of miRNAs during ruminant reproduction.

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Macromineral requirements of Dorper×thin-tailed Han crossbred female lambs JI Shou-kun, XU Gui-shan, DIao Qi-yu, DenG Kai-dong, JIanG Cheng-gang, TU Yan, ZHanG nai-feng 2015, 14(8): 1617-1626.  DOI: 10.1016/S2095-3119(14)60901-1 Abstract ( )   PDF in ScienceDirect   A comparative slaughter trial was conducted to determine the net mineral requirements for maintenance and growth of Dorper crossbred female lambs raised from 20 to 35 kg of body weight (BW). Thirty-five Dorper×thin-tailed Han crossbred female lambs of (20.3±1.14) kg BW were used: 7 lambs were randomly chosen and slaughtered at the beginning of the experiment as the baseline group for measuring the initial body composition; another 7 lambs were randomly chosen and offered a pelleted mixed diet ad libitum and slaughtered at (27.0±0.73) kg BW; the remaining 21 lambs were randomly divided into 3 groups of 7 animals each and subjected to the same diet either ad libitum or at 70 or 40% of ad libitum intake. The 21 lambs were fed in 7 slaughter groups, with each group consisting of one lamb from each treatment (ad libitum, 70 or 40% of ad libitum intake). The 3 groups were slaughtered when the sheep fed ad libitum attained (33.8±0.52) kg of BW. The body composition of five minerals (Ca, P, Na, K, and Mg) was determined. The net mineral requirements for maintenance were 35.01, 25.18, 9.30, 31.35, and 2.03 mg kg–1 empty BW (EBW) for Ca, P, Na, K, and Mg, respectively, and the net growth requirement per kg of EBW gain ranged from 9.73 to 8.87 g of Ca, 5.83 to 5.27 g of P, 1.73 to 1.63 g of Na, 3.73 to 4.08 g of K, and 0.26 to 0.25 g of Mg for Dorper crossbred lambs in China, respectively. The estimates of mineral requirements with Dorper crossbred lambs in the current study were not consistent with the recommendations from previous studies.

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Dormancy release and germination of Echinochloa crus-galli grains in relation to galactomannan-hydrolysing enzyme activity SONG Bing-yan, SHI Jin-xiao, SONG Song-quan 2015, 14(8): 1627-1636.  DOI: 10.1016/S2095-3119(14)60940-0 Abstract ( )   PDF in ScienceDirect   Echinochloa crus-galli, one of the world’s most serious weeds, influences seriously the yield and quality of cereal crop plant. It is well known that E. crus-galli grain is dormant, but its dormant type, as well as its dormancy release and germination in relation to galactomannan-hydrolysing enzyme activity were poorly understood. The cooperation of endo-β-mannanase (EC 3.2.1.78), β-mannosidase (EC 3.2.1.25) and α-galactosidase (EC 3.2.1.22) can hydrolyze the cell walls rich in mannan-based polymers. In the present paper, the mature grains are used as experimental materials, we investigated the water uptake of grains, the effect of removing partial endosperm, after-ripening, stratification and phytohormone on grain germination, and the change in endo-β-mannanase, β-mannosidase and α-galactosidase activities of grains during after-ripening and germination. The results showed that the freshly-collected grains were water-permeable and had only phase I and II of water uptake, while the grains after-ripened for 150 d had an obvious phase III of water uptake. In alternating photoperiod, the germination of grains freshly-collected was zero at 10–35°C, and that of half grains was 11% at 20°C only. The grain germination was notably promoted by after-ripening and stratification, but not by gibberellic acid and 6-benzyladenine at 0.0001–1 mmol L–1. β-Mannosidase activity increased during 0 to 300 d of after-ripening and then decreased. The activity of endo-β-mannanase and α-galactosidase of grains decreased with after-ripening. During grain germination, endo-β-mannanase and β-mannosidase activities obviously increased, while α-galactosidase activity decreased. Our data showed that E. crus-galli grain was a deep physiological dormant, the dormancy release by after-ripening was related to an increasing β-mannosidase activity, and its germination was closely associated with an increasing endo-β-mannanase and β-mannosidase activity; which have provided new knowledge to decrease the harm of E. crus-galli on production of cereal crop plant.

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A novel real-time RT-PCR with TaqMan-MGB probes and its application in detecting BVDV infections in dairy farms ZHANG Yong-qiang, LIU Hai-sheng, WU Xiao-dong, WANG Xiao-zhen, LI Jin-ming, ZHAO Yonggang, Lü Yan, REN Wei-jie, GE Sheng-qiang, WANG Zhi-liang 2015, 14(8): 1637-1643.  DOI: 10.1016/S2095-3119(15)61134-0 Abstract ( )   PDF in ScienceDirect   A real-time RT-PCR assay using TaqMan-MGB probes was developed to detect and type the bovine viral diarrhea virus (BVDV) in cattle. Universal primers and TaqMan-MGB probes were designed from the 5´-untranslated region of known pestiviral sequences. Prior to optimizing the assay, cRNAs were transcribed in vitro from the BVDV 1 and BVDV 2 RTPCR products to make standard curves. The detection limit of the assay was 1.72×102 copies for BVDV 1 and 2.14×102 copies for BVDV 2. The specificity of the assay evaluated on several BVDV strains including bovine herpesvirus 1 (BHV 1), foot and mouth disease virus (FMDV) and several classical swine fever virus (CSFV) strains showed specific detection of the positive virus over 40 cycles. The assay was highly reproducible with the coefficient of variance ranging from 1.04 to 1.33% for BVDV 1 and from 0.83 to 1.48% for BVDV 2, respectively. Using this method, we tested a total of 2 327 cattle from three dairy farms for the presence of BVDV persistently infected (PI) animals. In this assay, each RT-PCR template contained a mixture of ten samples from different animals. The occurrence rate of PI cattle in three farms ranging from 0.9 to 2.54% could represent partly the PI rates in cattle farm in China. In conclusion, using our real-time PCR assay, we could effectively detect and type BVDV and identify PI cattle in a rapid and cost-effective manner.

Soil & Fertilization﹒Irrigation﹒Plant Nutrition﹒ Agro-Ecology & Environment

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Modified fertilization management of summer maize (Zea mays L.) in northern China improves grain yield and efficiency of nitrogen use CHENG Yi, ZHAO Jie, LIU Zhen-xiang, HUO Zhi-jin, LIU Peng, DONG Shu-ti ng, ZHANG Ji-wang, ZHAO Bin 2015, 14(8): 1644-1657.  DOI: 10.1016/S2095-3119(14)60879-0 Abstract ( )   PDF in ScienceDirect   Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited. Modified fertilization management and planting density are efficient methods for increasing crop yield. Field experiments were designed to investigate the influence of modified fertilization management and planting density on grain yield and nitrogen use efficiency of the popular maize variety Zhengdan 958, in four treatments including local farmer’s practice (FP), high-yielding and high efficiency cultivation (HH), super high-yielding cultivation (SH), and the control (CK). Trials were conducted in three locations of the Huang-Huai-Hai Plain in northern China. Compared with FP, SH was clearly able to promote N absorption and dry matter accumulation in post-anthesis, and achieve high yield and N use efficiency by increasing planting density and postponing the supplementary application of fertilizers. However, with an increase in planting density, the demand of N increased along with grain yield. Due to the input of too much N fertilizer, the efficiency of N use in SH was low. Applying less total N, ameliorating cultivation and cropping management practices should be considered as priority strategies to augment production potential and finally achieve synchronization between high yield and high N efficiency in fertile soils. However, in situations where soil fertility is low, achieving high yield and high N use efficiency in maize will likely depend on increased planting density and appropriate application of supplementary fertilizers postpone to the grain-filling stage.

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Effects of different irrigation methods on micro-environments and root distribution in winter wheat fields Lü Guo-hua, SONG Ji-qing, BAI Wen-bo, WU Yong-feng, LIU Yuan, KANG Yao-hu 2015, 14(8): 1658-1672.  DOI: 10.1016/S2095-3119(14)60927-8 Abstract ( )   PDF in ScienceDirect   The irrigation method used in winter wheat fields affects micro-environment factors, such as relative humidity (RH) within canopy, soil temperature, topsoil bulk density, soil matric potential, and soil nutrients, and these changes may affect plant root growth. An experiment was carried out to explore the effects of irrigation method on micro-environments and root distribution in a winter wheat field in the 2007–2008 and 2008–2009 growing seasons. The results showed that border irrigation (BI), sprinkler irrigation (SI), and surface drip irrigation (SDI) had no significant effects on soil temperature. Topsoil bulk density, RH within the canopy, soil available N distribution, and soil matric potential were significantly affected by the three treatments. The change in soil matric potential was the key reason for the altered root profile distribution patterns. Additionally, more fine roots were produced in the BI treatment when soil water content was low and topsoil bulk density was high. Root growth was most stimulated in the top soil layers and inhibited in the deep layers in the SDI treatment, followed by SI and BI, which was due to the different water application frequencies. As a result, the root profile distribution differed, depending on the irrigation method used. The root distribution pattern changes could be described by the power level variation in the exponential function. A good knowledge of root distribution patterns is important when attempting to model water and nutrient movements and when studying soil-plant interactions.