陆地棉是世界上最重要的纤维作物。株高作为植物株型的重要组成部分，影响着作物的种植模式、产量和经济系数。前期研究中，我们分离并鉴定了一个棉花HD-ZIP基因（GhHB12），该基因调控棉花的非生物和生物胁迫应答反应和生长发育过程。在本研究中，我们证明GhHB12基因受生长素诱导表达，过表达GhHB12基因能激活HY5、ATH1和HAT4基因的表达，抑制生长素的时空分布、极性运输和信号传导，并改变细胞壁扩张相关基因的表达，最终抑制棉花株高。这些结果表明，GhHB12可以通过影响生长素的信号传导和细胞壁的扩展来调节棉花株高。

本研究以东北农业大学鸡F₂资源群体（NEAURP）为材料，利用 Illumina HiSeq PE150平台进行全基因组测序（26个F₀个体进行10×重测序，519个F₂个体进行3×重测序）。使用SAMtools进行SNP calling，BEAGLE 4.0在默认参数设置下进行基因型填充。经过质量控制和基因型填充后，共有7,890,258个SNPs用于分析。根据GRCg6a参考基因组，使用ANNOVAR软件进行SNP注释。基于混合线性模型（MLM），使用GEMMA软件进行全基因组关联分析。使用F_ST和π两种选择信号方法评估F₂群体的遗传分化和遗传多样性。 GWAS与选择信号的整合分析表明，控制鸡骨骼肌产肉性状的遗传因子主要位于第1染色体（168.95Mb-172.43Mb）和第4染色体（74.37Mb-75.23Mb）上，共鉴定出17个可能影响目标性状的位置候选基因（ LRCH1、CDADC1、CAB39L、LOC112531568、LOC112531569、FAM124A、FOXO1、NBEA、GPALPP1、RUBCNL、ARL11、KPNA3、LHFP、GBA3、LOC112532426、KCNIP4、SLIT2），其中KPNA3和FOXO1是与鸡产肉性状相关的强烈候选基因。本研究的主要创新点是结合GWAS和选择信号分析方法解析鸡骨骼肌产肉性状的遗传结构，发现了一些新的影响鸡产肉性状的基因组区域和候选基因。

本研究通过两年大田试验，以两个高产超级稻品种为试验材料，设置了不施用氮肥、高氮肥投入的当地农民习惯栽培方式、优化氮肥管理措施1和优化氮肥管理措施2共计四种氮肥管理方式。试验结果表明通过控制氮肥投入总量、增加种植密度和优化氮肥追施比例等措施，实现高产优质和氮肥利用率的提高。与当地农民习惯相比，优化氮肥管理分别提高了产量和氮肥偏生产力1.70%和13.06%，提高了籽粒淀粉和直链淀粉含量，显著降低了蛋白质含量。在优化氮肥管理下，支链淀粉短支链A链(DP6-12)和B1链(DP13-25)含量显著增加，淀粉结晶度显著下降，同时淀粉的粘度值增加，淀粉的热力学特性变优，从而提高了稻米的蒸煮与食味品质。以上研究结果表明优化氮肥管理可以缓解高产水平条件下因大量氮肥投入而引起的稻米品质变劣，实现高产优质和氮肥利用率的协同提高的目标，对水稻的高产优质生产具有实践和指导意义。

探索如何提升居民的主观福利是当前学术研究的重要议题之一。本文采用2010年中国家庭追踪调查数据库探究宗族文化对农村老年人精神健康的影响。本文的研究结果发现，宗族文化能够显著地降低农村老年人口的抑郁得分。同时，研究结论也表明，宗族文化对老年人抑郁得分的影响并不存在显著的差异。本研究进一步发现宗族文化对农村老年人抑郁状况的改善作用在经济欠发达的农村地区更为明显。进一步探究宗族文化影响农村老年人抑郁得分的机制发现，宗族文化通过影响老年人的社会支持，进一步起到改善其抑郁状况的作用。本研究有助于丰富非正式制度对农村居民福利的影响的研究。同时，也能够为下一阶段政府制定相对贫困的纾解策略提供一定的决策参考。

瘦素受体（LEPR）是瘦素的高亲和力受体，在人类和动物肥胖中起着至关重要的作用。本研究的目的是以东北农业大学肉鸡双向选择品系（NEAUHLF）为研究材料，通过关联分析和电子计算分析相结合的方法，研究LEPR外显子功能变异对鸡脂肪沉积的影响。使用5种在线生物信息学工具预测编码区单核苷酸多态性（SNPs）的功能。进一步，通过基于氨基酸残基的保守性和稳定性分析、蛋白质配体结合位点的预测、蛋白质二级结构分析、蛋白质三级结构的建模等生物信息学分析，确定了高置信度SNPs的可能结构与功能。同时，对鸡LEPR基因外显子20个非同义单核苷酸多态性（nsSNPs）与腹脂性状进行了关联分析。5种在线生物信息学工具显示，rs731962924(N867I)和rs13684622（C1002R）是最可能影响鸡腹部脂肪性状的功能性nsSNPs。氨基酸残基稳定性和保守型分析显示，大部分nsSNPs可引起蛋白质稳定性下降，rs731962924（N867I）和rs13684622（C1002R）在进化过程中相对保守。蛋白质结构分析显示rs731962924（N867I）和rs13684622（C1002R）均在可引起LEPR蛋白质结构和功能的显著变化。关联分析显示rs13684622（C1002R）与鸡腹脂重和腹脂率显著相关（P=0.0413，P=0.0260）。因此，我们认为rs13684622（C1002R）可能是一个影响鸡腹脂沉积的重要功能性SNP，有望应用于分子标记辅助选择（MAS）中培育低脂肉鸡品系。本研究的主要创新点是结合了多种生物信息学方法和nsSNPs与腹脂性状之间的关联分析进行LEPR基因功能性SNPs的筛选，为后续进行深入的功能分析提供优先研究SNP（priorization SNP）。此外，本研究用到的关联分析与计算机电子计算分析相结合的方法为鉴定农业动物重要经济性状的功能性分子标记提供了一条新的途径。

Anthropogenic activities profoundly influence carbon sequestration in the Eurasian Steppe.  In particular, grazing has been identified as having a major effect on carbon sequestration.  However, the extent to which grazing affects regional patterns or carbon sequestration is unknown.  In this study, we evaluated the impact of regional grazing on grassland carbon sequestration using the Boreal Ecosystem Productivity Simulator (BEPS) and the Shiyomi grazing model.  Model performances were validated against the results from field measurements and eddy covariance (EC) sites.  Model outputs showed that in 2008, the regional net primary productivity (NPP) was 79.5 g C m^–2, and the net ecosystem productivity (NEP) was –6.5 g C m^–2, characterizing the region as a weak carbon source.  The Mongol Steppe (MS) was identified as a carbon sink, whereas the Kazakh Steppe (KS) was either carbon neutral or a weak carbon source.  The spatial patterns of grazing density are divergent between the MS and the KS.  In the MS, livestock was mainly distributed in China with relatively good management, while in the KS livestock was mainly concentrated in the southern countries (especially Uzbekistan and Turkmenistan) with harsh environments and poor management.  The consumption percentages of NPP in Turkmenistan, Tajikistan and Uzbekistan were 5.3, 3.3 and 1.2%, respectively, whereas the percentages in other countries were lower than 1%.  Correspondingly, grazing consumption contributed to the carbon sources of Turkmenistan, Tajikistan and Uzbekistan by 11.6, 6.3 and 4.3%, respectively, while it weakened the carbon sink in Inner Mongolia, China and Mongolia by 1.6 and 0.5%.  This regional pattern should be affected by different sub-regional characteristics, e.g., the continuous degradation of grassland in the southern part of the KS and the restoration of grassland in Inner Mongolia, China.

   This study was conducted to investigate the effects of dietary energy and protein dilution from age 8 to 14 d on growth performance, clinical blood parameters, carcass yield, and tibia parameters of broilers. Treatments were assigned in a completely randomized manner with factorial arrangement (4×4) including 4 levels of energy dilution and 4 levels of protein dilution. All birds were fed the same diet during the remaining period of time. The feeds were weighed every week, and the birds were weighed at 7, 14, and 42 d. At 14 d, blood samples were taken for clinical chemistry measurements, and 4 birds from each replicate were sacrificed to measure carcass yield and tibia parameters at 42 d. From 8 to 14 d, average daily feed intake (ADFI) of the 20% protein dilution group increased significantly compared with that of the 10% protein dilution group (P<0.05). The feed conversion ratio (FCR) of the group with 30% protein dilution and 15% energy dilution creased the most among all treatment groups. From 15 to 42 d, the ADFI and FCR of the 20% protein dilution group were greater than those of the 0 and 10% protein dilution groups (P<0.05), and the FCR of the 15% energy dilution group increased significantly (P<0.05). At 42 d, body weight (BW) of the 15% energy dilution group was less than that of the other groups (P<0.05). Significant interactions were observed in ADFI, FCR, and BW at 42 d of age between energy dilution and protein dilution (P<0.05). At 14 d, serum total protein levels of birds in the 20 and 30% protein dilution groups decreased significantly compared to that of the 10% protein dilution group (P<0.05). Blood urea nitrogen concentration of birds in the 20 and 30% protein dilution groups decreased significantly compared with those in 0 and 10% protein dilution groups (P<0.05). Triacylglycerol concentration of birds in the 20% protein and 10% energy dilution groups decreased significantly compared with that of the 0 dilution group (P<0.05). The carcass yields were unaffected by dilution of energy and protein (P>0.05). The bone breaking strength of the 15% energy dilution group decreased significantly compared with that of the 5% energy dilution group (P<0.05). This study suggested that dietary protein and energy reduced 10% from 8 to 14 d of age can not affect the growth performance and other indexes in broilers.

Plants maintain water balance by varying hydraulic properties, and plasma membrane intrinsic proteins (PIPs) may be involved in this process.  Leaf xylem and root hydraulic conductivity and the mRNA contents of four highly expressed ZmPIP genes (ZmPIP1;1, ZmPIP1;2, ZmPIP2;2, and ZmPIP2;5) in maize (Zea mays) seedlings were investigated.  Under well-watered conditions, leaf hydraulic conductivity (K_leaf) varied diurnally and was correlated with whole-plant hydraulic conductivity.  Similar diurnal rhythms of leaf transpiration rate (E), K_leaf and root hydraulic conductivity (K_root) in well-watered plants are important for maintaining whole-plant water balance.  After 2 h of osmotic stress treatment induced by 10% polyethylene glycol 6000, the K_root of stressed plants decreased but K_leaf increased, compared with well-watered plants.  The mRNA contents of four ZmPIPs were significantly up-regulated in the leaves of stressed plants, especially for ZmPIP1;2.  Meanwhile, ZmPIP2;5 was significantly down-regulated in the roots of stressed plants.  After 4 h of osmotic stress treatment, the E and leaf xylem water potentials of stressed plants unexpectedly increased.  The increase in K_leaf and a partial recovery of K_root may have contributed to this process.  The mRNA content of ZmPIP1;2 but not of the other three genes was up-regulated in roots at this time.  In summary, the mRNA contents of these four ZmPIPs associated with K_leaf and K_root change in maize seedlings during short-term osmotic stress, especially for ZmPIP1;2 and ZmPIP2;5, which may help to further reveal the hydraulic resistance adjustment role of ZmPIPs.  

    Grain traits are major constraints in rice production, which are key factors in determining grain yield and market values. This study used two recombinant inbred line (RIL) populations, RIL-JJ (japonica/japonica) and RIL-IJ (indica/japonica) derived from the two crosses Shennong 265/Lijiangxintuanheigu (SN265/LTH) and Shennong 265/Luhui 99 (SN265/LH99). Sixty-eight quantitative trait loci (QTLs) associated with 10 grain traits were consistently detected on the 12 chromosomes across different populations and two environments. Although 61.75% of the QTLs clustered together across two populations, only 16.17% could be detected across two populations. Eight major QTLs were detected on the 9, 10 and 12 chromosomes in RIL-JJ under two environments, a novel QTL clustered on the 10 chromosome, qGT10, qBT10 and qTGW10, have a higher percentage of explained phenotypic variation (PVE) and additive effect; 15 major QTLs were detected on the 5, 8, 9, and 11 chromosomes in RIL-IJ under two environments, a novel clustered QTL, qGT8 and qTGW8, on the 8 chromosome have a higher additive effect. Finally, the analysis of major QTL-BSA mapping narrowed the qTGW10 to a 1.47-Mb region flanked by simple sequence repeat markers RM467 and RM6368 on chromosome 10. A comparison of QTLs for grain traits in two different genetic backgrounds recombinant inbred line populations confirmed that genetic background had a significant impact on grain traits. The identified QTLs were stable across different populations and various environments, and 29.42% of QTLs controlling grain traits were reliably detected in different environments. Fewer QTLs were detected for brown rice traits than for paddy rice traits, 7 and 17 QTLs brown rice out of 25 and 43 QTLs under RIL-JJ and RIL-IJ populations, respectively. The identification of genes constituting the QTLs will help to further our understanding of the molecular mechanisms underlying grain shape.

A total of 479 bacterial strains were isolated from brine (Bohai, Qinhuangdao City, Hebei Province, China). Bioassay results indicated that 4 strains named Ha1, Ha17, Ha38, and Ha384 had herbicidal activity. And strain Ha1 had the highest effective herbicidal activity. As a result, this study aims to identify strain Ha1, characterize its physiological and biological activities, evaluate the herbicidal activity of its metabolites, and develop a ‘pesta’ formulation and assess its effectiveness on Digitaria sanguinalis. Ha1 was identified as Serratia marcescens based on 16S rDNA sequencing. This strain has a flagellum, a diameter of 0.5 to 0.8 μm, and a length of 0.9 to 2.0 μm. The indole test shows positive results, and the catalase enzyme exhibits strong positive reactions. Results further showed that the inhibitory concentration (IC50) of the crude extracts to D. sanguinalis radicula and coleoptile were 3.332 and 2.828 mg mL–1, respectively. Both the suppression of D. sanguinalis and the cell viability of the Ha1 formulation in ‘pesta’ were higher when stored at 4°C than at (25±2)°C. These results indicated that S. marcescens Ha1 can potentially be used as a biocontrol agent against D. sanguinalis.

Overestimation of nitrogen (N) uptake requirement is one of the driving forces of the overuse of N fertilization and the low efficiency of N use in China. In this study, we collected data from 1 844 site-years of rice (Oryza sativa L.) under various rotation cropping systems across the Yangtze River Valley. Selected treatments included without (N0 treatment) and with N application (N treatment) which were recommended by local technicians, with a wide grain range of 1.5–11.9 t ha–1. Across the 1 844 site-years, over 96% of the sites showed yield increase (relative yield>105%) with N fertilization, and the increase rates decreased from 78.9 to 16.2% within the lowest range <4.0 to the highest >6.5 t ha–1. To produce one ton of grain, the rice absorbed approximately 17.8 kg N in the N0 treatment and 20.4 kg N in the N treatment. The value of partial factor productivity by N (PFPN) reached a range of 35.2–51.4 kg grain kg–1 with N application under the current recommended N rate. Averaged recovery rate of N (REN) was above 36.0% in yields below 6.0 t ha–1 and lower than 31.7% in those above 6.0 t ha–1. Soil properties only affected yield increments within low rice yield levels (<5.5 t ha–1). There is a poor relationship between N application rates and indigenous nitrogen supply (INS). From these observations and considering the local INS, we concluded there was a great potential for improvement in regional grain yield and N efficiency.

CB-4, a bacterial strain with highly effective herbicidal activity, was isolated from infected corn leaves. Through morphology, physiological and biochemical tests, and 16S ribosomal DNA gene sequencing methods, CB-4 was identified as Pseudomonas aeruginosa. We conducted activity-evaluation experiments in the laboratory to assess the herbicidal potential of metabolites produced by strain CB-4. Crude extracts of strain CB-4 have high inhibition activity on Digitaria sanguinalis. In general, the root and shoot growth parameters of D. sanguinalis were significantly reduced by metabolites of strain CB-4. The IC50 of the culture filtrate extracts for the radicula and coleoptile of D. sanguinalis were 0.299 and 0.210 mg mL-1, respectively. Component 2 of the herbicidal activity of the crude toxin from strain CB-4 was successfully purified for the first time by using high-speed counter current chromatography with a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water (4:5:4:5, v/v) and high-performance liquid chromatography. We concluded that the metabolites of strain CB-4 have the potential to be developed as a microbe-based herbicide.

Carbon and nitrogen are the most important elements in the terrestrial ecosystem. Studying carbon and nitrogen distributions in plant and soil is important for our understanding of the ecosystem dynamics and carbon cycle on arid lands. A study was conducted in a typical arid area, the Yanqi Basin, Northwest China. Carbon and nitrogen distributions in plant tissues and soil profiles were determined at 21 sites with typical native plants and crops. Our results indicated that carbon content was similar between crops and native plants, and the average carbon contents in aboveground (42.4%) and belowground (42.8%) tissues were almost the same. Average nitrogen contents in crops were nearly the same (~0.7%) in aboveground and belowground tissues whereas mean nitrogen content was approximately 100% higher in aboveground (2.2%) than in belowground (1.2%) tissues for native species. Soil organic carbon (SOC) and total nitrogen (TN) in cropland (9.4 and 0.9 g kg-1) were significantly higher than those in native land (6.2 and 0.7 g kg-1). Multiple regression analyses indicated that carbon content in belowground tissue and nitrogen content in aboveground tissue were key factors connecting plant and soil in native land. However, there was no significant relationship for carbon or nitrogen between soil and crop, which might reflect human disturbance, such as plowing and applications of various organic materials.

Coexisting natural enemies that share a common host resource in the same guild usually exhibit variation in their life history traits, due to their need to share a similar ecological niche. In this study, we compared the immature development times and adult life history traits of two coexisting, host-feeding parasitoids, Diglyphus isaea Walker and Neochrysocharis formosa Westwood (Hymenoptera: Eulophidae), of which both attack larvae of the same agromyzid leafminers. These two species are both synovigenic, idiobiont parasitoids, whose adults consume host fluids (“host feeding”) and lay anhydropic eggs. Of the two, D. isaea has a larger body but little or no initial egg load, and engages in similar lifetime host-feeding events. However, it achieves higher fecundity, longer adult longevity, and higher host suppression ability than N. formosa, which has a smaller body and higher initial egg load. Although D. isaea engages in similar lifetime host-feeding events with N. formosa, all of its gains in life history traits per host-feeding event of D. isaea were larger than those of N. formosa. The age-specific fecundity and host mortality curves of N. formosa were more skewed in early life than those of D. isaea. In addition, the ovigeny index of N. formosa was negatively correlated to body size. Our results confirmed that two coexisting parasitoids, which share the same host resource, show different immature development patterns and life history traits, suggesting that different resource allocation mode could be a general rule of coexisting species sharing the same habitat or host.

A chemosensory protein named HarmCSP5 in cotton bollworm Helicoverpa armigera (Hübner) was obtained from antennal cDNA libraries and expressed in Escherichia coli. The real time quantitative PCR (RT-qPCR) results indicated that HarmCSP5 gene was mainly expressed in male and female antennae but also expressed in female legs and wings. Competitive binding assays were performed to test the binding affinity of recombinant HarmCSP5 to 60 odor molecules including some cotton volatiles. The resules showed that HarmCSP5 showed strong binding abilities to 4-ehtylbenzaldehyde and 3,4-dimethlbenz aldehyde, whereas methyl phenylacetate, 2-decanone, 1-pentanol, carvenol, isoborneol, nerolidol, 2- nonanone and ethyl heptanoate have relatively weak binding affinity. Moreover, the predicted 3D model of HarmCSP5 consists of six α-helices located among residues 33-38 (α1), 40-48 (α2), 62-72 (α3), 80-96 (α4), 98-108 (α5), and 116-119 (α6), two pairs of disulfide bridges Cys49-Cys55, Cys75-Cys78. The two amino acid residues, Ile94 and Trp101, may play crucial roles in HarmCSP5 binding with ligands and need further study for confirmation.

Soybean is planted worldwide and its productivity is significantly hampered by salinity. Development of salt tolerant cultivars is necessary for promoting soybean production. Despite wealth of information generated on salt tolerance mechanism, its basics still remain elusive. A continued effort is needed to understand the salt tolerance mechanism in soybean using suitable molecular tools. To better understand the molecular basis of the responses of soybean to salt stress and to get an enrichment of critical salt stress responsive genes in soybean, suppression subtractive hybridization libraries (SSH) are constructed for the root tissue of two cultivated soybean genotypes, one was tolerant and the other was sensitive to salt stress. To compare the responses of plants in salt treatment and non-treatment, SSH1 was constructed for the salt-tolerant cultivar Wenfeng 7 and SSH2 was constructed for the salt-sensitive cultivar Union. From the two SSH cDNA libraries, a total of 379 high quality ESTs were obtained. These ESTs were then annotated by performing sequence similarity searches against the NCBI nr (National Center for Biotechnology Information protein non-redundant) database using the BLASTX program. Sixty-three genes from SSH1 and 49 genes from SSH2 could be assigned putative function. On the other hand, 25 ESTs of SSH1 which may be not the salt tolerance-related genes were removed by comparing and analyzing the ESTs from the two SSH libraries, which increased the proportion of the genes related to salt tolerance in SSH1. These results suggested that the novel way could realize low background of SSH and high level enrichment of target cDNAs to some extent.

The full-length sequence of the odorant binding protein 5 gene, HarmOBP5, was obtained from an antennae cDNA library of cotton bollworm, Helicoverpa armigera (Hübner). The cDNA contains a 444 bp open reading frame, encoding a protein with 147 amino acids, namely HarmOBP5. HarmOBP5 was expressed in Escherichia coli and the recombinant protein was purified by affinity chromatography. SDS-PAGE and Western blot analysis demonstrated that the purified protein can be used for further investigation of its binding characteristics. Competitive binding assays with 113 odorant chemicals indicated that HarmOBP5 has strong affinity to some special plant volatiles, including (E)-β-farnesene, ethyl butyrate, ethyl heptanoate, and acetic acid 2-methylbutyl ester. Based on three-dimensional (3D) model of AaegOBP1 from Aedes aegypti, a 3D model of HarmOBP5 was predicted. The model revealed that some key binding residues in HarmOBP5 may play important roles in odorant perception of H. armigera. This study provides clues for better understanding physiological functions of OBPs in H. armigera and other insects.

Agricultural production plays an important role in affecting atmospheric nitrous oxide (N2O) concentrations. Field measurements were conducted in Dalian City, Liaoning Province in Northeast China from two consecutive years (2009 and 2010) to estimate N2O emissions from a spring maize field, a main cropping system across the Chinese agricultural regions. The observed flux data in conjunction with the local climate, soil and management information were utilized to test a process-based model, DeNitrification-DeComposition (DNDC), for its applicability for the cropping system. The validated DNDC was then used for exploring strategies to reduce N2O emissions from the target field. The results showed that the major N2O pulse emissions occurred with duration of about 3-5 d after fertilizer application in both years 2009 and 2010, which on average accounted for about 60% of the total N2O emissions each year. Rainfall and fertilizer application were the major factors influencing the N2O emissions from spring maize field. The average N2O fluxes from the CK (control plot, without fertilization) and FP (traditional chemical N fertilizer) treatments were 23.1 and 60.6 μg m-2 h-1 in 2009, respectively, and 21.5 and 64.3 μg m-2 h-1 in 2010, respectively. The emission factors (EFs) of the applied N fertilizer (270 kg N ha-1) as N2ON were 0.62% in 2009 and 0.77% in 2010, respectively. The comparison of modeled daily N2O emission fluxes against observations indicated that the DNDC model had a good performance even if without adjusting the internal parameters. The modeled results showed that management practices such as no-till, changing timing or rate of fertilizer application, increasing residue incorporation, and other technically applicable measures could effectively reduce N2O emissions from the tested fields. Our study indicated that avoiding application of N fertilizers at heavy rainfall events or splitting the fertilizer into more applications would be the most feasible approaches to reduce N2O emissions from spring maize production in Northeast China.

Real-time monitoring of nitrogen status in rice and wheat plant is of significant importance for nitrogen diagnosis, fertilization recommendation, and productivity prediction. With 11 field experiments involving different cultivars, nitrogen rates, and water regimes, time-course measurements were taken of canopy hyperspectral reflectance between 350-2 500 nm and leaf nitrogen accumulation (LNA) in rice and wheat. A new spectral analysis method through the consideration of characteristics of canopy components and plant growth status varied with phenological growth stages was designed to explore the common central bands in rice and wheat. Comprehensive analyses were made on the quantitative relationships of LNA to soil adjusted vegetation index (SAVI) and ratio vegetation index (RVI) composed of any two bands between 350-2 500 nm in rice and wheat. The results showed that the ranges of indicative spectral reflectance were largely located in 770-913 and 729-742 nm in both rice and wheat. The optimum spectral vegetation index for estimating LNA was SAVI (R822,R738) during the early-mid period (from jointing to booting), and it was RVI (R822,R738) during the mid-late period (from heading to filling) with the common central bands of 822 and 738 nm in rice and wheat. Comparison of the present spectral vegetation indices with previously reported vegetation indices gave a satisfactory performance in estimating LNA. It is concluded that the spectral bands of 822 and 738 nm can be used as common reflectance indicators for monitoring leaf nitrogen accumulation in rice and wheat.

We investigated the size distribution of water-stable aggregates and the soil carbon, nitrogen and phosphorus concentration
over aggregate size fractions based on a long-term (1990-2006) fertilization experiment in a reddish paddy soil. The results
showed that the largest water-stable aggregate (WSA) (>5 mm) and the smallest WSA (<0.25 mm) took up the first largest
proportion (38.3%) and the second largest proportion (23.3%), respectively. Application of organic materials increased
the proportion of the large WSA (>2 mm) and decreased the proportion of the small WSA (<1 mm), resulting in an increase
in the mean weight diameter of WSA, whereas application of chemical fertilizer had little effect. Application of organic
materials, especially combined with chemical fertilizers, increased total carbon, nitrogen and phosphorus concentrations
in all sizes of WSA, and total carbon, nitrogen and phosphorus were prone to concentrate in the large WSA. Further more,
application of organic materials improved the supply effectiveness of available phosphorus, whereas had little influence
on the labile carbon in WSA. Application of chemical fertilizers improved concentrations of total and available phosphorus
in all sizes of WSA, whereas had little influence on total carbon and nitrogen contents. Economical fertilization model
maintained the soil fertility when compared with full dose of chemical fertilizers, indicating that using organic materials
could reduce chemical fertilizers by about one third.We investigated the size distribution of water-stable aggregates and the soil carbon, nitrogen and phosphorus concentration over aggregate size fractions based on a long-term (1990-2006) fertilization experiment in a reddish paddy soil. The results showed that the largest water-stable aggregate (WSA) (>5 mm) and the smallest WSA (<0.25 mm) took up the first largest proportion (38.3%) and the second largest proportion (23.3%), respectively. Application of organic materials increased the proportion of the large WSA (>2 mm) and decreased the proportion of the small WSA (<1 mm), resulting in an increase in the mean weight diameter of WSA, whereas application of chemical fertilizer had little effect. Application of organic materials, especially combined with chemical fertilizers, increased total carbon, nitrogen and phosphorus concentrations in all sizes of WSA, and total carbon, nitrogen and phosphorus were prone to concentrate in the large WSA. Further more, application of organic materials improved the supply effectiveness of available phosphorus, whereas had little influence on the labile carbon in WSA. Application of chemical fertilizers improved concentrations of total and available phosphorus in all sizes of WSA, whereas had little influence on total carbon and nitrogen contents. Economical fertilization model maintained the soil fertility when compared with full dose of chemical fertilizers, indicating that using organic materials could reduce chemical fertilizers by about one third.