【Objective】 The period from 1950s to 2007 was divided into two stages,i.e., 1950s-1980 and 1981-2007, then the geographical shift of northern limit for tropical crops and the possible risk of cold damage in the cold-sensitive areas after the shift were analyzed and compared. 【Method】 Using the standard of China farming system regional planning and some agro-meteorological indicators, the geographical shift of safe northern limit were compared and analyzed and the change map were draw by ArcGIS. Using the synthesized index of cold damage, the risks of cold damage in sensitive area of planting tropical crops were evaluated. 【Result】 Compared with the results during the period from 1950s to 1980, in the 80% climate guarantee rate, the safe northern limit moved northward by 0.86 latitude during the period from 1981 to 2007. Its interdecadal change was obvious, and the respective annual rating of moving northward was 0.03 and 0.06 latitude during the 1990s and the period 2000-2007. In the 80% climate guarantee rate, the risk of cold damage in sensitive area of planting tropical crops reached 3.0 times higher than the non-sensitive area, especially the risk caused by severe or very severe cold damage reached 3.5 times. 【Conclusion】 The safe Northern limit has shown an obvious northward moving under climate warming and the rate of northward moving shows an accelerated trend. The risk of cold damage is increased in the moving sensitive region of the safe northern limit.

With repeated and wide use of herbicides in agricultural systems, 324 herbicide resistant biotypes of 188 species (112 dicots and 76 monocots) have evolved worldwide. The development of herbicide resistance in weeds, rapid increase and widespread of herbicide resistant weeds have become an increasing threat to weed management and crop production in the world, the consequences leading to economic loss and food safety have become a global concern. In the last decades, a significant progress has been made in the areas of herbicide resistance, many of the findings have proven that at least three very different mechanisms endowed herbicide resistance, an altered target site, enhanced detoxification and sequestration in weeds，weeds can also evolve cross resistance and multiple resistance to herbicides with different modes of action. This review described the currant status of world wide herbicide resistant weeds, resistance mechanisms in 8 major herbicide classes, research methodologies to provide useful information and references for researches in herbicide resistance, and posed the lessons learnt from other countries, clarified and stated the future directions we should forward to.

Advances in study of mechanisms of foliar nutrition and foliar fertilizer application were reviewed. Plant leaves can absorb nutrients as roots do. There are two basic pathways for nutrients entering into the plant tissue: one is through the stomata and the other is via cuticle hydrophilic pores. Some plant leaves also can absorb nutrients actively through plasmodesmata. So the foliar uptake of nutrients depends upon plant types and the state of plants growth, composition of foliar fertilizer, characters of nutrients and environmental factors such as temperature, illumination and so on. Foliar application to dicotyledon is better than to monocotyledon because of different leaf types and structures of surface wax, and of different varietals plants of homogeneity. It is necessary to spray right fertilizers at right stage of plant growth. Some assistants, such as surfactants are required to enhance nutrients absorption in foliar fertilizers, however, most of the surfactants have a poor solubility among compositions of foliar fertilizers as they are pesticides surfactants. The development of foliar application was promoted by the research on mechanism of foliar nutrition, and now foliar application is becoming an important fertilization method. But soil application can not be replaced by foliar application of fertilizers. Foliar spray can be only as an efficiency assistant method to soil application because the quantity of nutrients supplied is limited. In recent years, foliar fertilizers developed promptly both in quantity and variety, but the quality is poor in China. So the techniques of foliar application need to be improved. Scientists should intensify their research on the mechanism of foliar nutrition and the utilization of assistants in foliar fertilizers. In future, it is necessary to enhance the quality of foliar fertilizers and foliar fertilization, study on optimization of specialized foliar fertilizers and the techniques of foliar application.

Abstract : Total crop residue in China is about 600 million tons every year. Crop residue incorporation has increased crop yield and soil quality. However, there are two main problems, one is residue is difficult to rot under field conditions, which effect next cultivation. The other is field capacity for residue is limit. Therefore, biomass charcoal can be a good choice. Biomass charcoal has a high surface area, high nutrient retention capacity and high water retention capacity due to its porous structure. Transformation of crop residue into stable C pools (black carbon) can reduce the release of the greenhouse gas CO2 into the atmosphere and can increase C sequestration in the soil. Black carbon is also a soil conditioner which increases the CEC, nutrient availability, decreases nutrient leaching and provides more space for microbe. Adding black carbon to soil can significantly increase seed germination, plant growth, and crop yields.

【Objective】 The effects of water stress on photosynthesis and associated physiological characters of capsicum were studied, the aims were to reveal the relationship between photosynthetic traits and drought tolerance of two cultivars. 【Method】 The experiment was conducted under two water levels: no stress (75%-80% of field capacity) and stress (30%-40% of field capacity). The responses of plants growth, physiological changes, photosynthetic parameters, chlorophyll fluorescence, stomatal characters, ultrastructure of chloroplast were investigated. 【Result】 The results showed that, under the water stress condition, the growth of the plants was inhibited, the total plant dry weight declined significantly, and root/ shoot increased. Leaf water potential, leaf relative water content and leaf pigment decreased, the contents of malondialdehyde, the proline as well as the activities of superoxide dismutase and peroxidase increased. The Pn, Gs, Tr, Ci, ΦPSII, ETR and qP decreased, but the NPQ and WUE increased. The stomata became smaller and the density decreased, and most of them closed. The chloroplasts became round in shape, the lamellae arranged disorderly and the number of starch grain decreased or disappeared. 【Conclusion】 The decrease of net photosynthetic rate was considered as a result of stomatal restriction. The changes of photosynthetic parameters, chlorophyll fluorescence, stomata characters and the ultrastructure of chloroplast correlated significantly to drought resistance.

Abstrac:【OBJECTIVE】It is one of the most widely area and damaging environmental problems about soil heavy metal pollution in current. So, it is wide spread concern, and received general attention. A number of assessment methods of heavy metal pollution in soil have proposed at home and abroad, and which had analyzed and made a conclusion by author. Which would lay a foundation for assessment of heavy metal pollution in soil.【METHOD】The single factor index, nemerow index method, comprehensive evaluation mode of geometric mean, pollution load index, index of geo-accumulation, the potential ecological risk index, sediment enrichment factor, potential ecological eisk index, fuzzy mathematical method, grey clustering method, geostatistics method on GIS, method for health risk assessment, method of environment risk index, and so on typical soil heavy metal pollution assessment methods and models in domestic and foreign were summarized. The advantages, disadvantage and application range of those methods were analyzed.【CONCLUSION】It is indicated by the comparison analysis that a variety of evaluation methods have certain limitations and inadequacies. It was necessary for select on better evaluation methods to carry out full analysis of the sample points, comparison of trial and error with the purpose of evaluation and focus on in pollution assessment of soil heavy metals. Finally, combining a variety of methods according to the actual situation were put forward. At the same time，it should start from the ecological effects of heavy metal pollution, development of biological evaluation method.

In order to boost the study and agricultural application of biochar in China, in the article, the research literatures and findings about biochar were retrospected and reviewed, and future research issues were suggested, the summaries were as follows: biochar was a solid byproduct derived from biomass pyrolysis in low or zero oxygen environment, highly organic carbon, porous, alkaline, highly capability of adsorption, multi-propose materials. Biochar was an excellent soil amendment which could increase soil organic carbon content, improve soil water-holding and nutrient-retention capacity, reduce nutrient losses from soils, and was beneficial to inhabit and activity of microbes in soils, especially for mycorrhizal fungi (MF). Biochar alone increased crop growth and yield in specific circumstances, but the effects of the co-application or combination of biochar with fertilizers on crop growth and yield showed positive in nearly all soils, which was attributed to reciprocal or synergistic effects of both fertilizer and biohcar because of fertilizer alleviating nutrient deficiency of biochar itself which endowed fertilizer with nutrient slow release characteristics. Biochar delayed nutrient release of fertilizer to soil, reduced nutrient losses from fertilizer and soil, increased nutrient utilizing efficiency, and was efficient-promoting carrier to fertilizer. Biochar was a carbon-sequestrating carrier which was extremely stable in soil, and could sequestrate carbon in soils for hundreds to thousand years. The multi-win technology was the thermal conversion of biomass wastes into biochar which was used to agriculture. However widely and deeply studies should be given to many issues about biochar. Thus, strong emphasis will given to basic and applied research on biochar in order to boost biochar production and agricultural use, finally agricultural ‘black revolution’ in 21st century.

【Objective】 The objective of the experiment is to study the effect of long-term cotton continuous cropping on soil physical-chemical and biological characters. 【Method】 Both cotton micro-experiment and conventional chemical methods were adopted to study the changes of soil physical-chemical properties and soil enzyme activities under long-term continuous cropping.【Result】 Results showed that compared with 1 year cropping, both soil organic matter content and soil salt content were increased by 10.56%, 18.09%, 37.34%, 55.64% and 122%, 132%, 124%, 146%, respectively, under 5-20 years continuous cropping, while soil bulk density began to decline. With the time of continuous cropping increasing, the soil alkali-hydrolyzable N content was remarkably raised, but the soil available K content was decreased by 60.4%, 35.9% and 39.8% under 5-20 years continuous cropping, the soil available P content was enhanced in 5-year continuous cropping and then stable in 10, 15 and 20 years continuous cropping. The activities of urase, catalase, protease, invertase and phosphatase decreased in 5-10 years continuous cropping, while those enzyme activities increased in 15-20 years, the soil peroxidase activity increased with the continuous cropping year increasing. 【Conclusion】 In the oasis area of Xinjiang, under long-term continuous cropping, stalk returning can ameliorate soil physical characters, increase soil salt content, but soil N, P, K proportion was imbalanced. The enzyme activity of soil decreased in a short period of time (from 1 to 10 years), the obstacles of continuous cropping were more obvious.

【Objective】 The objective of this study is to reveal the spatial-temporal change characteristics of grain production and arable land changes in China as well as the sensitivity of grain yield changes to arable land from 1990 to 2005. 【Method】 Contrastive analyzing the dynamic relationship of China's grain production and arable land changes by constructing models of gravity center fitting and sensitivity analyzing in this paper. 【Result】 The results of study show that the gravity center of China’s grain production and arable land distribution are both expressed as Move to northern and middle regions, which means both of them are almost the same in space. The center of arable land had been moved 17.3 km along the track of Northwest - Southwest - Northeast, and the center of grain production had been moved 223.3 km along the track of Northeast - Southwest - Northeast. The distance between the two centres of grain production and arable land was almost contrary to grain yield. When one center is close to the other, the grain yield reduced, otherwise grain yield increased.【Conclusion】 The increase of grain yield in China is affected by unit yield and planting areas, and the sensitivity of grain yield changes to arable land is enhanced. The diminishing returns of fertilizers and pesticides show that the dependence of grain production on arable land resources is increasing. It is very important to realize a mechanism and policy innovation for guarantee of national food security and arable land protection.

Plant polysaccharide involved in various physiological metabolism of the body, had broad phacology effect, such as regulation of immune, anti-tumor, resisting guard against a seni1ity, antivirus, hypoglycemic, antioxidation and so on. At present, the studies on increasing the production of polysaccharide and exploring the mechanism of its pharmaceutical activities were very popular. The article summarized the progress in structure, extraction method, pharmacological action, as well as in medicine, food, agricultural and other areas of application in the past years and provides reference for the utilization of plant polysaccharide.

To study the approaches for maize yield increase, this paper has analyzed the change and development of maize production techniques in the past 5 decades and more in China from the perspectives of main measures, technical characteristics and mechanisms for per unit area yield increase. The results showed that maize yield per unit area in China increased by 4 205.1 kg or 437.3% from 1949 to 2007, with annual growth rate of 85.84 kg?hm-2, and the total yield increased from 12.418 million tons to 152.30 million tons, an increase of 12.3 times, of which 68.4% was contributed by yield increase per unit area and 31.6% by planting area expansion. Total yield increase was mainly relied on yield increase per unit area. Maize production techniques have been developed in breeding and planting. Maize breeding and popularization experienced four stages: selection and popularization of open-pollinated varieties, intervarietal hybrid, double-cross hybrid and triple-cross hybrid, single-cross hybrid. After heterosis was extensively used, disease-resistant gene selection, plant type improvement, green-keeping and late-maturing have become main development trends of breeding techniques to increase maize yield potential. In future, the development trend of maize varieties is close planting, adversity resistance, high adaptability, high yield and adaptability for mechanized operation. Planting techniques has shifted from popularization of individual techniques and improvement of farmland conditions to technical integration and modeled cultivation. In future, varieties suitable for high-density and with high adversity resistance and simplified high-yield and high-effective planting techniques with mechanization as carrier will be the development trend. With constant increase of planting density, the mechanisms for maize yield increase have shifted from yield increase per plant to improvement of plant types, colony enlargement, green keeping, late maturing and increase of colony yield via extension of photosynthesis and filling time, improvement of colony uniformity, and high effective carbohydrate production and translocation after florescence. In addition, higher requirements have been set for lodging resistance, disease resistance and adaptability of colony. Based on the above analysis, it is proposed the main technical requirements and measures for maize yield increase in the near future in China.

【Objective】 The purpose of this study was to investigate the effects of wheat-residue application and nitrogen (N) management on grain yield and quality and nitrogen use efficiency in direct-seeding rice. 【Method】 A mid-season japonica rice cultivar of Yangjing 9538 was directly sown in the field. Three treatments of N-fertilizer application, farmers’ N-fertilizer practice (FFP), site-specific N management (SSNM) based on chlorophyll measurement (SPAD) readings, and no N application, and with or without wheat residue application were conducted. Grain yield and quality and N use efficiency were determined. 【Result】In comparison with the wheat-residue removal treatment, the wheat-residue application (the residue was incorporated into soil) treatment reduced panicles, but increased spikelets per panicle, filled-grain percentages and 1 000-grain weight, therefore increased grain yield. This treatment also improved rice appearance and cooking qualities, under either SSNM or FFP. In comparison with FFP, SSNM increased grain yield, reduced the grain protein content, and improved rice cooking quality. In comparison with the wheat-residue removal plus FFP treatments, the wheat-residue application plus SSNM treatments enhanced the maximum grain filling rate and mean grain filling rate and shortened the active grain filling period, leading to an increase in grain weight. Such treatments increased N harvest index, N recovery efficiency, N agronomic use efficiency, N physiological efficiency, and N partial factor productivity. 【Conclusion】 The results suggest that wheat-residue application combined with SSNM could not only increase grain yield and quality, but also improve N use efficiency in direct-seeding rice.

Rice is a staple grain crop in China and also the highest yielding one in grain crops. Using Chinese agricultural statistical data and the literature, this paper analyzed the successful experience of innovation and practice, problems and development trend in high-yield cultivation technology in rice, the characteristics of four periods of rice production in China, the contribution of supporting cultivation technology for variety to yield increase, and high-yield cultivation techniques developed in different periods. The characteristics of rice cultivation technology in world are briefly expounded. Supporting cultivation technology for dwarf varieties, hybrid rice, and super rice in the evolution of rice variety and rice industry development was reviewed. The current problems of high yielding cultivation of rice was analyzed. The development of high-yield rice cultivation technology was also discussed. Innovation of supporting cultivation technology based on the growth characteristics of new variety, rice cropping system, rice production models, and ecological environment exploits yield potential of variety and realizes the increase of yield and profit, promotes the development of the rice industry, and improves the environment and raises the efficiency of resource utilization.

本文分析了国、内外木薯产业的发展近况，包括木薯栽培品种、生产近况、贸易近况、产业研究进展。探讨了我国木薯产业面临的机遇与挑战，通过比对国外木薯产业的发展，得出其对我国木薯产业发展的启示，并提出促进我国木薯产业发展的政策建议。

Abstract：The paper has made detailed summarization of the nitrogen utilization of plants from the the following three parts: the effect of nitrogen on plants growth and development, the physiological and molecular mechanism of the nitrogen utilization in order to provide theotetic guidence for the crop nutritional breeding and improve its nitrogen utilization efficiency.

Salinity is one of the important environmental factors on plant growing. The paper summarized the research progress of the effects of salt stress on seed germination, growth and development and photosynthesis, and reviewed the adaptive mechanism of the plant to salinity, including the structure of plant, active oxygen scavenging , osmo-regulation matter, ionic homeostasis.

In order to study the sources, functions and affecting factors of soil enzymes, prospect the development of soil enzyme, soil enzyme research progresses at home and abroad were analyzed and summarized. Soil enzymes are mainly from soil microbial activity, soil plants and animals. Soil enzymes are metabolic power of soil organism, they play an important role in the material cycle and energy flows of the soil ecosystems. Soil enzymes are biological activity of soil quality and can evaluate soil fertility. Soil enzyme activities are significantly related to soil nutrients, soil animalcule, plants, fertilizer, farming and other agricultural management practices, pesticides and heavy metals pollutions can also affect soil enzyme.

Rice planting mechanization is a difficult point of the whole-course mechanized development in crop production in China. Based on the reviewing of development situation of rice planting mechanization in China, the high-yielding rules and cultivation techniques of three mechanized planting methods were highlighted and illustrated. (1) Growth characteristics and high-yielding rules of blanket-seedling mechanical transplanting rice grown in floppy disks were generalized systematically. Firstly, population photosynthesis and matter production at the middle and later period were improved by developing appropriate dynamics of stems and tillers and LAI. Secondly, it was the emphasis to increase the effective and efficient biomass accumulation in the middle period, and matter production after heading and the final biological yield. Thirdly, the sufficient population spikelets were composed of enough panicles and larger spike harmoniously, with normal seed-setting rate and 1000-grain weight at the same time. Moreover, the supporting cultivation techniques for high yield were as follows. ① Nursing standardized seedlings for providing biological basis of building starting point of high-yielding population. ② Precise mechanical planting was conducive to the formation of high-yielding population. ③ Promoting tillers growth earlier in the early period could make sure of suitable stems and tillers for high yield slightly before the critical leaf-age for productive tillers. ④ Field draining earlier and lighter, with an appropriate number of peak seedling (1.4-1.5 folds of expected panicle number), could create conditions for reapplying fertilizer of strong stalk and spikelet promotion as early as possible. ⑤ Committed to optimize the growth in the middle period and increase the effective and efficient biomass accumulation, a right amount of population stems and tillers with strong stalk and large panicle was beneficial to constitute a high-efficiency photosynthetic layer. ⑥ Strengthening material production and accumulation for increasing the enrichment of population sink. (2) Many advantages of the high-yielding cultivation of pot-seedling mechanical transplanting rice were also introduced systematically, such as nursing elder seedlings with soil bowl, almost no damage to machine-transplanting precisely, achieving designed basic seedling of high-yielding cultivation accurately, forming an appropriate number of population stems and tillers with strong stalk and large panicle, improving ventilation and light conditions of population, strengthening the resistance to lodging, coordinating source-sink, strengthening strong photosynthetic production in the middle and later periods, making full use of temperature and solar radiation, creating (super) high yield stably and annual yield in the multiple cropping rotation systems, etc. And the key agronomic techniques for high-yielding cultivation of pot-seedling mechanical transplanting rice were as below. ① Nursing age-lengthening seedlings precisely; ② Precise quantitative mechanical planting; ③ Reapplying tillering fertilizer and spikelet- promoting fertilizer appropriately. (3) Characteristics of growth and yield formation of mechanical drilling rice were reviewed, presented with its supporting techniques including determined planting areas reasonably, selecting large-panicle varieties with appropriate growth duration and strong lodging, mechanical sowing earlier and extremely, chemical weed control and fertilizer management. Simultaneously, the existed main problems in the process of rice planting mechanization in China were analyzed further. According to China’s national conditions, the cultivation model raising nurturing standardized seedlings professionally and mechanical transplanting precisely as well as stable high-yielding-high-efficiency agronomic techniques should be the basic direction of mechanized cultivation for the majority of the localities. And mechanical seeding could be applied in several areas with abundant heat of rice season. Then the corresponding research and development (R & D) focuses for mechanized planting of rice were referred. ① High-yielding cultivation of blanket-seedling mechanical transplanting rice should be classified as the main direction of mechanization in the major rice producing areas so as to R & D further. There were several focal points such as enhanced flexibility of blanket-seedling age and seedling quality, straw machine-returning and land preparation and seedling planting precisely, promoting earlier and stably in the field, cultivating a right amount of population stems and tillers with strong stalk and large panicle and increasing population sink. ② Reducing equipment costs, improving operating efficiency and building stable (super) high-yielding-high-efficiency agronomy techniques were the research priorities of pot-seedling mechanical transplanting rice. ③ However, for the mechanical drilling rice, attention should be focused on improving the quality of previous straw machine-returning and land preparation through efficient mechanical operations, and mechanical precise direct seeding and early germinating for achieving expected seedlings. Finally, the technology integration and demonstration of the whole-process mechanized models under the local main mechanized cultivation methods should be done well in accordance with their characteristics in each main region of rice.

【Objective】 Rice is one of the important food crops in China. The realization of its super-high-yielding has a great significance for food security of the country. This study investigated the rule of grain yield components from high-yield to super-high-yield and the characters of super-high-yielding Japonica super rice. 【Method】 The grain yield and its components and the population sink and its filling of grain yield of three types of populations (High Yield: 8 250-9 750 kg?hm-2; Higher Yield:9 750-11 250 kg?hm-2; Super High Yield:＞11 250 kg?hm-2) in four Japonica super rice (Wujing 15, Huaidao 9, Xudao 3 and Changyou 1) were analyzed. 【Result】 Super-high-yielding rice had more population spikelets than the high-yielding rice and higher-yielding rice (The difference among them was significant). There was no significant difference in filled-grain and 1000-grain- weight among the grain yield of three types of populations. The relationship between the population spikelets and grain yielding was significant at safe maturity. In order to enlarge the population spikelets, it almost depended on enriching panicles from high-yield to higher-yield, and increasing spikelets per panicles was the major factor from higher-yield to super-high-yield. There was no significant difference in filling rate of sink among the grain yield of three types of populations, but the amount of actual filling of sink in super-high-yielding rice was more than the high-yielding rice and higher-yielding rice at safe maturity. 【Conclusion】 The characters of super-high-yielding rice are enriching the amount of actual filling of sink through keep normal filling rate of sink, and thus forming a safe and large sink made up of enough big panicles.

【Objective】Huang-Huai-Hai area is one of the most important areas that produce food crops. Frequent drought and flood are the main limiting factors for crop production, and the soil compaction, low topsoil and low water holding capacity are also the main factors causing the low and unstable yields of winter wheat and summer maize. Tillage and straw returning are two effective ways to reduce soil compaction, enhance water holding capacity and water use efficiency. The objective of the experiment was to study the effects of tillage, straw returning and their interaction on water consumption characteristics and water use efficiency in the winter wheat and summer maize rotation system.【Method】The experiment was conducted by a combination of different tillage ways and straw managements. Soil water consumption amount, soil water reduction amount, soil evaporation, grain yield and water use efficiency were analyzed by using six treatments which were conventional tillage with all straw returning, conventional tillage with no straw returning, deep tillage with all straw returning, deep tillage with no straw returning, subsoil tillage with all straw returning, subsoil tillage with no straw returning in the winter wheat and summer maize rotation system. The effects of tillage, straw returning and their interaction on water consumption characteristics and water use efficiency were analyzed.【Result】The results showed that, there were significant effects of tillage and straw returning on soil bulk density, soil water consumption amount, soil water reduction amount, soil evaporation, grain yield and water use efficiency. Compared with conventional tillage, deep tillage and subsoil tillage mainly decreased soil bulk density at 20-40 cm soil depth, increased the water consumption and soil water reduction amount at 0-100 cm soil depth of winter wheat and summer maize, while decreased the water consumption during fallow periods. Moreover, deep tillage and subsoil tillage also decreased soil evaporation during the growth period of summer maize. Deep tillage increased, but subsoil tillage decreased the soil evaporation during the growth period of winter wheat. Straw returning also decreased the soil bulk density, increased soil water reduction amount, increased soil water consumption amount during the growth period of winter wheat, but decreased the soil water consumption amount during summer maize growth period and fallow period. Moreover, straw returning increased soil water consumption, increased soil evaporation during the growth period of winter wheat, but decreased soil evaporation during the growth period of summer maize. Compared with the conventional tillage, the total grain yield of deep tillage and subsoil tillage increased by 10.7% and 9.8%, the water use efficiency increased by 8.8% and 6.3%. The total grain yield and water use efficiency of straw returning were 6.3% and 7.6% higher than the no straw returning treatment, respectively. A significant interaction between tillage system and straw returning was observed in soil water cosumption characteres, grain yield and water use efficiency of winter wheat and summer maize. Compared with conventional tillage with no straw returning, the total soil water consumption amounts of deep tillage with straw returning and subsoil tillage with straw returning increased by 3.3% and 2.4%, the soil water consumption amounts during the growth period of winter wheat and summer maize increased by 4.2% and 3.3%, while the soil water consumption amounts during the fallow period decreased by 7.0% and 9.9%. Moreover, the grain yields of deep tillage with straw returning and subsoil tillage with straw returning increased by 18.0% and 19.3%, the water use efficiency increased by 15.9% and 15.1%. 【Conclusion】In the six treatments, deep tillage with straw returning and subsoil tillage with straw returning showed the highest total grain yield and water use efficiency, and there was no significant difference in grain yield and water use efficiency between deep tillage with straw returning and subsoil tillage with straw returning. Therefore, it was concluded that deep tillage or subsoil tillage with straw returning is the most appropriate tillage practice in Huang-Huai-Hai area.

As an efficient tool to measure the nuclear DNA content and ploidy level, flow cytometry has been playing very important role in many fields of botany research. Through plenty of flow cytometry experiments, a set of universal experimental procedure for detecting the nuclear DNA content and ploidy level was summarized in the laboratory of molecular ecology, Lanzhou University. At the same time, we had elaborated key points at every experimental stage and solutions to the problems caused by too much fragments which could result in the failure of an experiment, which might provide guidance for the future experiments, and promote applications of flow cytometry in plant research.

【Objective】The various effects of different straw biochar on nutrient content and microbial community structure were studied in order to provide information for soil amelioration and proper management of straw residue.【Method】Through a 135-day laboratory incubation experiment and used a red paddy soil that originated from the Quaternary, the influences of rice and corn straw biochar that pyrolyzed at 300℃, 400℃ and 500℃ on soil pH, organic carbon, nutrient content, microbial biomass carbon and profile of microbial PLFAs community structure were investigated. The experiment consisted of seven treatments: control soil (CK), soil amended with 300℃ (RB300), 400℃ (RB400) and 500℃ (RB500) rice straw biochar, soil incorporated with 300℃ (CB300), 400℃ (CB400) and 500℃ (CB500) corn straw biochar. 【Result】 Feedstock type and pyrolysis temperature had a significant influence on the nutrient contents and chemical properties of biochar products. Compared with control, the two straw biochar amendments increased pH value by 0.16 unit and enhanced the contents of soil organic carbon, available P and available K by 26.1%, 20.6% and 281.8%, respectively. Under the same pyrolysis temperature, the application of rice straw biochar mainly promoted the level of available K while corn straw biochar improved the content of available P. Application of 300℃ straw biochar had no significant effect on soil available and mineral N contents. Compared with the control, soils amended with RB500 and CB500 were, respectively, 10.4% and 8.1% less in available N, while significantly increased by 63.6% and 100.7% in NO₃^--N concentration. Although the concentrations of microbial biomass carbon and total phospholipid fatty acids for soils amended with straw biochar were 63.4% and 47.5% higher than control soil, there was no significant difference between the control soil and soils with 300℃ straw biochar. Both the two types of biochar enhanced the contents of G-, G+, fungi and actinobacteria and shown as 300℃＜400℃＜500℃. Results of PCA indicated that rice straw biochar amendment had more effect on the structure of soil microbial community than corn straw biochar. The microbial community compositions of three rice straw biochar were separated from each other while no distinctive recognized among the three corn biochar. Results of CCA suggested that straw biochars can affect the composition of microbial community through altering soil chemical and nutrient properties, as soil available P, soil organic carbon and available had significant correlation with the distribution of soil microbial community. 【Conclusion】 Both the two straw biochars could ameliorate the acidity and nutrient content of red paddy soil, and enhance the level of soil microbial biomass. Soil microbial community structure had been affected in the presence of straw biochars and rice straw biochar had more effective influence than corn straw biochars.

【Objective】The characteristics of yield formation and population dynamics and mechanisms of high-yielding formation were identified in pot seedling of mechanical transplanting japonica rice.【Method】Twenty-four japonica rice cultivars which have different weights of single panicle were grown by unified high-yielding cultivation in 2010, and were divided into three panicle types by clustering analysis with average single panicle in maturity. Three panicle types of japonica rice cultivars including large panicle type (LPT, Yongyou 2640 and Yongyou 8) and medium panicle type (MPT, Wuyunjing 24 and Ningjing 3) and small panicle type (SPT, Huaidao 5 and Huaidao 10) were field-grown from 2011 to 2012 in Diaoyu town, Xinghua county, Jiangsu province, China. By setting carpet seedling of mechanical transplanting rice (CS) as CK, the yield and yield formation, number of population stem and tiller, leaf area index (LAI) and dry matter accumulation of pot seedling of mechanical transplanting rice (PS) were investigated, and high-yielding formation mechanisms of PS were also explored in respect of seedling quality, matter accumulation after transplanting, plant type, staged photosynthetic matter production, photosynthetic potential (PP), crop growing rate (CGR) and net assimilation rate (NAR), matter transport in stem and sheath and root activity. 【Result】 Yield was significantly or very significantly higher in PS than CS. The range of increased yield was 8.71%-11.11% in large panicle-type variety, medium panicle-type variety was 6.85%-7.89%, and small panicle-type variety was 5.30%-6.34%. The increased yield was mainly attributed to higher total spikelets in PS, which owning to sufficient panicle and expanding spikelets per panicle. Compared with CS, PS had earlier tiller, suitable peak seedling tillers, slower reducing rate of tillers after jointing, enough effective panicles and higher ratio of productive tillers to total tillers at maturity. Leaf area index and dry matter accumulation in PS was significantly higher at the critical stage for effective tiller and very significantly greater at and after booting stage, and higher 5.17%-11.00% and 5.36%-9.20% at maturity than CS. The mechanisms of high-yielding formation in PS was that: After transplanting, there had strong seedling, better population started quality, earlier seedling establishment, faster tiller, more tillers of low position and greater dry matter weight of aboveground and root; They formed higher photosynthetic efficiency and quality population at heading, which had tighter plant type, better canopy, bigger leaf area, higher specific leaf weight, stronger stem and sheath, greater grain-leaf ratio; At the late growing stage, there had stronger root activity, slower decreasing rate of leaf area, higher photosynthetic potential and crop growing rate and net assimilation rate, greater dry matter accumulation, more coordinated matter export and translocation of stem and sheath.【Conclusion】With better population started quality and earlier tiller, pot seedling of mechanical transplanting rice had obvious advantages, especially, higher photosynthetic matter production and greater dry matter accumulation at the middle and late growing stages, which the yield formation characteristics were sufficient panicle, larger panicle type and more spikelets per panicle

The recent development and current status of research on the cotton weed in China were summarized, including the weed occurrence, distribution rule, population dynamics, weed damage and control techniques. Although the research on basic theory and chemical management technologies of cotton weed in China has got a faster development, problems of frequent herbicide injury, dominant weed population changes, lag in control techniques and deficiencies of transgenic resistant herbicide cotton still exit. Therefore, the study on basic theory should be strengthened. On the basis of chemical control, we should speed up the creation of novel chemical herbicide, strengthen the monitoring and management of herbicide resistant weeds, and carry out further research on biological weed control and herbicide resistant cotton.

【Objective】 As Longnan region of Gansu province is one of the largest and most important over-summering areas of Puccinia striiformis f. sp. tritici in China, the objective of this study is to determine the genetic structure of P. striiformis f. sp. tritici populations in this region. 【Method】 Population genetic diversity of the P. striiformis f.sp. tritici population containing 409 isolates collected from 8 different areas in Longnan, Gansu province was investigated with TP-M13-SSR technique. 【Result】 For the Longnan population, the average number of alleles (Na) per locus was 1.95, and the effective number of alleles (Ne) was 1.43. The Nei's gene diversity (H) and Shannon's information index (I) were 0.27 and 0.41, respectively. The genetic diversity of Wudu, Wenxian and Qingcheng populations was much higher than that of Huixian, Chengxian and Xihe populations. Analysis of AMOVA showed that there were about 12.5% of the total variations among the collections, 87.5% of the total variation presented within collections. Gen flow (Nm) was 1.83. 【Conclusion】 The important conclusion is that the populations of P. striifornis f. sp. tritici possessed relatively high levels of genetic diversity but a lower genetic differentiation in Longnan of Gansu. The main genetic variation presented within collections. There is an extensive gene flow and migration of pathogen among the regions in Longnan of Gansu.

Field experiment about cotton chemical and manual detopping was conducted in Akesu (41°17′N, 86°26′E), Xinjiang, with cultivar CCRI 49 as material, from 2008 to 2010. The chemical detopping agent contained slow-released mepiquat chloride and additives, and was applied at the same time as the manual detopping in cotton. The results indicated that the plants detopped by chemical agent were taller and narrower than those detopped by hands, which resulted in more light transmittance in middle and lower layer of cotton canopy. Additionally, chemical detopping did not alter the boll weight, but reduced the lint percent slightly. The boll number per plant and yield for chemical detopping were greater than those for manual detopping in 2010, but the same as the latter in 2009. There were no significant difference in comprehensive fiber quality between chemical detopping and manual detopping. It was concluded that the chemical detopping is a potential practice to replace the manual detopping in cotton in Xinjiang.

There are three phases of DNA fingerprint technology based on molecular marker：the first is RFLP based on Southern blot，the second are several markers based on PCR and the third is SNP（single nucleotide polymorphism）.Research and application of variety identification technology was discussed，four main molecular marker technologies applied in cotton variety identification were introduced in detail as follow:RFLP,RAPD,AFLP and SSR.Technology principle,research and application status,advantage and disadvantage about each molecular marker applied in cotton variety identification were expatiated.As compared，the viewpoint was put forward:SSR marker was the most appropriate molecular marker in cotton variety identification,and the necessity of construction of Chinese cotton DNA fingerprint database based on SSR marker technology was analyzed.

The dynamics of the activities of protective enzymes and MDA content in two kinds of genetically modified (GM) cotton varieties and their non-GM parents after being piercing-sucked by Lygus lucorum were studied. The results showed that: before and after the vaccination of Lygus lucorum, there were no significant difference on the activities of protective enzymes and MDA content between two kinds of GM cotton varieties and their non-GM parents, so it has no effect on physiological indices when exogenous genes were introduced into cotton. Throughout the period of Lygus lucorum's attacking, there was very significant difference in the activities of protective enzymes and MDA content to the same cotton variety; the three indicators, SOD, MDA and PAL activities or content, showed significant or very significant differences in the interaction effect between variety and bug accepting time, and the rest of the interaction was not significant.

Wheat grain natural transverse sections of 12 periods were observed and analyzed using scanning electron micrographs technology and Bio-Quant system IV image analyzer in order to detect the developing process of A- and B-type starch granules. In addition, the chemical composition and starch granule-bound proteins (SGPs) of A- and B-type starch granules were tested and analyzed. The results showed that A-type starch granules in wheat began from 3 d post anthesis (DPA) till grain maturing and B-type starch granules occured after 15 DPA till grain maturing. Approximately 98.5% of chemical compositions in both A- and B-type starch granules were amylose and amylopectin, and more than half of which were amylopectin. The amylopectin contents, average chain length, and chain length distribution (degree of polymerization> 40) of amylopectin in A-type starch granules were significant higher than that of B-type starch granules. SGP-145, SGP- 140, and SGP-26 kD were associated with A-type starch formation in wheat grain.

Chinese agriculture is facing increasing challenges: the constraints of resources and the environment is increasingly tightening, the price difference between domestic and international markets is enlarging, and the growth in agriculture output and farmers' income is becoming hard to achiere. So, Chinese agriculture has a urgent need of transformation and upgrading, optimizing the structure and improving the quality and efficiency. Big data, as a strategic resource such as material and energy, which plays an important role in the production factors coupling, collaboration, and other aspects of agricultural systems, is becoming an important driving power of agricultural modernization development. At present, big data technology has made progress in agricultural information acquisition, analysis, processing, services, and application in the precise production decision, food security, mining consumer’s demand, guide trade and market. Facing the difficulties of agriculture transformation and upgrading, both of technology innovation and organization innovation need to be formed. On the one hand, developing a data cross fusion, laying solid foundation of modern agricultural benchmark data, breaking an agricultural intelligent model analysis processing system and development and promoting the continuous innovation in data service; On the other hand, setting up data consciousness, strengthening legislation, and improving the governance structure on top of the data, in particular, to deal with data security and data sharing.

The role of plant endogenous hormones lies in regulating plant growth and development and improving crop yield and quality, and its accurate determination has important implications for the regulation of plant growth and development, the genetics and breeding of crop, the promotion of cultivation technology and the identification of hormone residues. This article will summarize three aspects of plant hormones: the physiological action, the molecular mechanisms, the regulation of production and quality and the determination method, in order to provide reference index for the study of plant hormones.

The purpose of this experiment was to identify the best cultivation method of maize and provide references for enhancing yield of maize cultivars. To study the effects of different tillage methods on soil physical properties and yield with different growing stages, a field experiment was conducted with randomized block design. The effects of different tillage methods on soil moisture content, bulk density, porosity in 0-45 cm soil depth varied with different growing stages. Among all the 6 tillage methods, the effect of 25-35 cm subsoiling depth on those physical properties mentioned above was the most obvious. In addition, after the subsoiling treatment, maize yield components, such as corn ear length, ear diameter, barren-tip length, number of rows per ear, kernels per row and 100-grain weight were improved at different degrees compared with CK. The maize yield with subsoiling treatment was 0.06%-3.13% higher than CK, but not significantly. Subsoiling could increase soil moisture, decrease soil bulk density, increase the porosity, function as water conservation and increase maize yield. Among them, the combination of 35 cm subsoiling depth and rotary tillage was the most optimal.

Effects of nitrogen application rates and mepiquat chloride （DPC） sparing doses on content of chlorophyll and SPAD value in leaf of earliermiddle spring cotton variety Yuza 35 and shortseason one Yinshan 1 were studied.The results showed that content of chlorophyll and SPAD value in leaf of two cotton varieties increased with enhancing nitrogen application rates or DPC sparing doses.There were significantly positive correlations between SPAD value and content of chlorophyll in leaf in most growth stages.But content of chlorophyll in leaf decreased more quickly than SPAD value in later growth stage,i.e.,the content of chlorophyll in leaf in boll opening stage decreased significantly than that in full bolling stage, and the SPAD value in boll opening stage decrease slightly than that in full bolling stage.Therefore,SPAD value is still efficient to conduct leaf color threshold when DPC is applied to cotton,but attention should be paid to the different tendency of content of chlorophyll and SPAD value in later growth stage of cotton.

Four strains of the Q biotype and one of the B biotype of the whitefly Bemisia tabaci collected from China were characterised for resistance to four neonicotinoid insecticides and pymetrozine. Q biotype strains showed moderate to strong resistance to imidacloprid, thiamethoxam and acetamiprid, but little or no cross-resistance to dinotefuron. Resistance to neonicotinoids was consistently associated with resistance to pymetrozine, despite the latter having a distinct (though unresolved) mode of action. The single B biotype strain proved largely susceptible to all the insecticides investigated. Resistance in the Q biotype strains was associated with over-expression of a cytochrome P450 monooxygenase gene, CYP6CM1, whose substrate specificity presumably accounts for the observed cross-resistance profiles.

North China is the most important food basket of China, where the majority of wheat and corn are produced. Most crops grown in North China are irrigated, thus water security is food security. Since the 1980s, drying has been frequently observed, as shown by a reduction in precipitation, cutoff in riverflow, and shrinkage of lakes. This increase in drying cannot be explained by climate change alone. We propose that intensive land-use in this area in recent decades has had a significant impact. The objectives of the study are to develop a quantitative model of the concurrent processes of climate change and land-use in North China, and to estimate the relative contributions of each on the observed drying. We integrated relevant socioeconomic data, land-use data, and climate data in the model, and carried out a detailed multitemporal (decade, year, day) analysis. Results showed that land-use has greatly changed since 1999. This change is mainly associated with an extremely important 1999 national policy of “returning farmland and grazing land to forest and grassland”. We found an interesting interaction between climate change and land use policy on riverflow, runoff, and evapotranspiration. During 1970s and 1980s, climate change explained more than 80%, while the land-use change explained only 10% of the riverflow change. The relative contributions were 45 and 45% in the 1980s-1990s and 35 and 55% in the 1990s-2000s respectively for climate change and land-use change. Since the 1990s land-use change has also contributed more to runoff change than climate change. The opposite trend was found for changes in evapotranspiration. Water availability for agriculture in northern China is simultaneously stressed by extensive changes in land-use and rapid climate change. Adaptation of ecological principles, such as the “returning farmland/grazing land to forest and grassland” policy, and other adjustments of economic developmental strategies can be effective tools to mitigate the water shortage problem in northern China and promote sustainable agricultural and food development.

Based on the cotton pot experiment involving four varieties (three were upland cotton and one was sea island cotton) and two N treatments and field experiment with different N treatments,the spatial differences of N and Chlorophyll contents (SPAD value) in the four upper fully expanded leaves and their relationships with whole leaf and plant N concentration were investigated. The results showed that leaf N contents and SPAD values at different leaf positions differed obviously,leaf N contents and SPAD values increased and differences among different position leaves decreased at high N rates. The sensitivity of the fourth leaf from the top to N was the highest,and next was that of the second leaf from the top was the lowest,while that of the first and the third leaves varied within the varieties. The SPAD value of the fourth leaf from the top was most correlated with whole leaf and plant N concentration among the top four leaves through the bud stage,initialflowering stage. The CV of SPAD value of the fourth leaf from the top was the smallest under optimal N level. It was suggested that the fourth leaf from the top was the most ideal indicator when using SPAD value or leaf color difference to diagnose N status in cotton.

The purpose of this paper is to document the likely impacts of climate change on China’s agriculture and the current adaptation efforts made by government and farmers. The review of literature shows that climate change will have a significant impact on agriculture, primarily through its effect on crop yields. The extent of predicted impacts highly depends on the crop, the CO2 fertilization effect assumption and adaptation abilities. Market response to the production shocks resulting from climate change will lessen the impacts on agricultural production predicted by natural scientists. On adaptation, the government’s major efforts have been in the developing new technologies, reforming extension system and enhancing institutional capacity. Farmers do adapt to climate change, but their adaptation measures cannot fully offset the negative impacts of climate change. The paper concludes and makes implications for future studies.

It is in general thought that nitrogen (N) fertilizer is overused in Chinese croplands and that the overuse has resulted in severe environmental problems. As the biggest reactive nitrogen producer and N fertilizer consumer in the world, China is facing a great challenge to reduce nitrogen consumption in agriculture. The objectives of this review are to examine the sources and fate of reactive nitrogen in agroecosystems, to find out why N fertilizer consumption reaches such a high level, and provide with suggestions for better N management practices. To understand the current agricultural use of reactive N in China, principles of biogeochemical N cycling are used to discuss N flows in the agroecosystems in the year 2010, with focus on N input/output and balances in crop-soil systems. At the national level, input of reactive N to croplands was excessive in 2010, and the surplus was approximately equal to the quantity of the reactive N recycled back to crop fields by atmospheric N deposition and irrigation with N-polluted water, about 5 Tg N. Generally speaking, the use of N fertilizer in cereal crops is not extraordinarily high since N fertilizer is also distributed for other uses: Forestation, feeding livestock and fishes, and application to the green fields in urban areas. It is common and significant that there are much higher N application rates to fruit tree plantations and vegetable production, especially to the greenhouse vegetable growing system, in comparison with that applied to cereal crops. With the facts of the limited arable lands, low recycling rates of organic wastes, and low input of biological fixed N, crop production has to depend heavily on the use of N fertilizer in China. There is a low acreage of arable land per capita, with 8% of global arable land feeding 20% of the world population. Recycled rate of nutrient N in the organic wastes are lower than 30% and input of biological N fixation to croplands is less than 15%. Therefore, to meet the demands of Chinese population for both food and improving diets under the condition of the predominance of the croplands with medium to low productivities, high N fertilizer input is understandable. However, N fertilizer consumption is much higher than the national average in some highly productive regions, including the Huang-Huai-Hai Plain, the Yangtze Basin, and Zhujiang Delta (Guangdong) regions, and is closely connected with higher crop yields/multiple cropping indices, and smaller proportion of legume crops to the total cropping area. It is clear that the N losses from food production-processing-consumption chain have resulted in resource wasting and environmental risks. On the other hand, part of the environment received reactive N from the losses of croplands and the other pollution sources, returns to the fields via atmospheric deposition and the irrigations with polluted waters, and becomes an important source of N input to croplands. Due to the complexity of N transformation in agroecosystems and biogeochemical N cycling, N losses are unavoidable. Therefore, the best management practices at various spatial levels should be taken as the options to reduce the fertilizer use in croplands to the minimum. Integrated measures, including multi-disciplinary researches and the cooperation of various social sectors, have been suggested to optimize N management practices at each spatial level, in order to reach the fundamental goals of maintaining/improving soil fertility, securing food, reducing nitrogen fertilizer use, and minimizing environmental risks.

Wheat grain natural transverse sections of 12 periods were observed and analyzed using scanning electron micrographs technology and Bio-Quant system IV image analyzer in order to detect the developing process of A- and B-type starch granules. In addition, the chemical composition and starch granule-bound proteins (SGPs) of A- and B-type starch granules were tested and analyzed. The results showed that A-type starch granules in wheat began from 3 d post anthesis (DPA) till grain maturing and B-type starch granules occured after 15 DPA till grain maturing. Approximately 98.5% of chemical compositions in both A- and B-type starch granules were amylose and amylopectin, and more than half of which were amylopectin. The amylopectin contents, average chain length, and chain length distribution (degree of polymerization> 40) of amylopectin in A-type starch granules were significant higher than that of B-type starch granules. SGP-145, SGP- 140, and SGP-26 kD were associated with A-type starch formation in wheat grain.

【Objective】The characteristics of yield formation and population dynamics and mechanisms of high-yielding formation were identified in pot seedling of mechanical transplanting japonica rice.【Method】Twenty-four japonica rice cultivars which have different weights of single panicle were grown by unified high-yielding cultivation in 2010, and were divided into three panicle types by clustering analysis with average single panicle in maturity. Three panicle types of japonica rice cultivars including large panicle type (LPT, Yongyou 2640 and Yongyou 8) and medium panicle type (MPT, Wuyunjing 24 and Ningjing 3) and small panicle type (SPT, Huaidao 5 and Huaidao 10) were field-grown from 2011 to 2012 in Diaoyu town, Xinghua county, Jiangsu province, China. By setting carpet seedling of mechanical transplanting rice (CS) as CK, the yield and yield formation, number of population stem and tiller, leaf area index (LAI) and dry matter accumulation of pot seedling of mechanical transplanting rice (PS) were investigated, and high-yielding formation mechanisms of PS were also explored in respect of seedling quality, matter accumulation after transplanting, plant type, staged photosynthetic matter production, photosynthetic potential (PP), crop growing rate (CGR) and net assimilation rate (NAR), matter transport in stem and sheath and root activity. 【Result】 Yield was significantly or very significantly higher in PS than CS. The range of increased yield was 8.71%-11.11% in large panicle-type variety, medium panicle-type variety was 6.85%-7.89%, and small panicle-type variety was 5.30%-6.34%. The increased yield was mainly attributed to higher total spikelets in PS, which owning to sufficient panicle and expanding spikelets per panicle. Compared with CS, PS had earlier tiller, suitable peak seedling tillers, slower reducing rate of tillers after jointing, enough effective panicles and higher ratio of productive tillers to total tillers at maturity. Leaf area index and dry matter accumulation in PS was significantly higher at the critical stage for effective tiller and very significantly greater at and after booting stage, and higher 5.17%-11.00% and 5.36%-9.20% at maturity than CS. The mechanisms of high-yielding formation in PS was that: After transplanting, there had strong seedling, better population started quality, earlier seedling establishment, faster tiller, more tillers of low position and greater dry matter weight of aboveground and root; They formed higher photosynthetic efficiency and quality population at heading, which had tighter plant type, better canopy, bigger leaf area, higher specific leaf weight, stronger stem and sheath, greater grain-leaf ratio; At the late growing stage, there had stronger root activity, slower decreasing rate of leaf area, higher photosynthetic potential and crop growing rate and net assimilation rate, greater dry matter accumulation, more coordinated matter export and translocation of stem and sheath.【Conclusion】With better population started quality and earlier tiller, pot seedling of mechanical transplanting rice had obvious advantages, especially, higher photosynthetic matter production and greater dry matter accumulation at the middle and late growing stages, which the yield formation characteristics were sufficient panicle, larger panicle type and more spikelets per panicle