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玉林冬季免耕马铃薯分期播种试验及优质高产气候分析 总被引：1，自引：0，他引：1
对玉林市主栽的马铃薯品种黑龙江K 3紫花,采用稻草免耕、地膜覆盖和常耕栽培三种栽培措施分五次播种进行试验,表明,稻草免耕技术不但对地面温度、土壤湿度有很好调节功能,而且与地膜覆盖和常耕栽培产量差异达极显著水平。以播期为11月30日的产量最高,播期为12月10日产量最低。 相似文献
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水稻的人工手栽已有2000年的历史，在水稻栽培发展史上起到了重要作用，但是传统的手工移栽作业费工费时，极为艰辛，且劳动生产率低下，影响着水稻生产的进一步发展。水稻抛秧栽培技术始于60年代日本，在我国经历了60～70年代的试验、探索阶段，80年代得到示范推广，是近年来开始应用并迅速发展起来的一项水稻轻型栽培技术，它改变了沿袭几千年的农民弯腰拔秧、插秧的传统水稻栽秧习惯。 相似文献
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水稻旱育抛秧高产特征及其机制的数值模拟研究 总被引：2，自引：0，他引：2
用１９９６、１９９７年的分期播种田间试验资料,建立进育抛秧发育期模型和产量构成因子模型,包括茎蘖动态模型、千粒重增长模型,每穗实粒数模型,分析高产特征及机制。结果指出,水稻抛秧移栽与手插移栽相比,移栽迟滞期短,群体茎蘖２数粳稻高１６％,汕稻高２３％;千粒重,粳稻低１％,灿稻高９％;每穗实数无区别;部产量,粳稻高１６％,灿稻高９％。抛栽秧苗随机均匀分布,入土深度较浅,从而营造了合理的群体结构提高了产 相似文献
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在日本东北地区南部太平洋沿岸地区(宫城县),水渍稻田传统的水稻移栽日期为五月十日左右。据认为,在此日期之前移栽,气温不够高,不足以支持水稻生长,因此是困难的,水稻甚至会受害。但该地区太阳辐射强度的峰值时期之一是春季。本文的工作目的在于:通过提早水稻移裁日期,充分利用该地区春季丰富的辐射能,来提高水 相似文献
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水稻抛秧栽培是近几年兴起的一种新的栽培方式，l992年于洪区试种2．7ha．后经示范推广，到1996年大面积种植7300ha，增产幅度为6．8％。几年种植实践表明，利用此新技术已收到省工、省力和增产节支的效果，为实现水稻生产的高产高效开辟了新途径。为探索水稻抛秧技术的科学依据，在几年种植经验基础上，我们于l995～1996年进行了抛秧田小气候、生育性状及产量效应关系的对比试验。 相似文献
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1前言水稻抛秧栽培是近几年兴起的一种新的栽培方式，1992年于洪区试种2．7ha，后经示范推广，到1996年大面积种植73O0ha，增产幅度为6．8％。几年种植实践表明，利用此新技术已收到省工、省力和增产节支的效果，为实现水稻生产的高产高效开辟了新途径。为探索水稻抛秧技术的科学依据，在几年种植经验基础上，我们于1995一1996年进行了抛秧田小气候、生育性状及产量效应关系的对比试验。2材料与方法两年的水稻抛秧田对比试验均在大兴乡东风村，1995年试验田O．53ha，对照田O．33ha，1996年试验田O．73ha，对照田O．92ha，供试品种为辽粳32… 相似文献
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结合试验资料,对旱育抛秧水稻进行了研究人为旱育抛秧水稻子物重增长和千粒重的增加均符合Logistic曲线;相对生长速率随生育期逐渐减小,且光、温对相对生长连串的作用是互补的;灌浆速度也受温、光的限制,水稻的发育速度通过温、光模式来反映快慢。为了实现抛栽高产的目的,必须掌握适宜的栽培秧龄、密度和基本苗数。 相似文献
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Summary Minimum tillage, no-tillage and mulching have been broadly used in modern Chinese agricultural production in the past 20 years. The application area has reached 12.34 million hectares, and a corn, soybean, rape, wheat, peanut and rice have been involved in these tillage systems. These techniques have provided obvious benefits of soil and water conservation on sloping farm-land in the hill regions; obtained remarkable effects of storing water and reducing drought in the dryland farming regions; and resulted in some success in the reclamation of saline soil. The common characteristics in different regions are building a good agri-ecological environment, improving soil physical properties, enhancing the capacity of storing water, regulating the activity of soil micro-organisms, improving the accumulation of soil organic matter and nutrients, fertilizing the land and increasing crop production. In comparison with the traditional tillage systems, crop production increased 10–20% and the benefit of soil and water conservation was 40–90%.With 2 Figures 相似文献
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The Denitrification-Decompostion (DNDC) model was used to estimate the impact of change in management practices on N2O emissions in seven major soil regions in Canada, for the period 1970 to 2029. Conversion of cultivated land to permanent grassland would result in the greatest reduction in N2O emissions, particularly in eastern Canada wherethe model estimated about 60% less N2O emissions for thisconversion. About 33% less N2O emissions were predicted for a changefrom conventional tillage to no-tillage in western Canada, however, a slight increase in N2O emissions was predicted for eastern Canada. GreaterN2O emissions in eastern Canada associated with the adoption of no-tillage were attributed to higher soil moisture causing denitrification, whereas the lower emissions in western Canada were attributed to less decomposition of soil organic matter in no-till versus conventional tilled soil. Elimination of summer fallow in a crop rotation resulted in a 9% decrease in N2O emissions, with substantial emissions occurringduring the wetter fallow years when N had accumulated. Increasing N-fertilizer application rates by 50% increased average emissions by 32%,while a 50% decrease of N-fertilizer application decreased emissions by16%. In general, a small increase in N2O emissions was predicted when N-fertilizer was applied in the fall rather than in the spring. Previous research on CO2 emissions with the CENTURY model (Smith et al.,2001) allowed the quantification of the combined change in N2O andCO2 emissions in CO2 equivalents for a wide range of managementpractices in the seven major soil regions in Canada. The management practices that have the greatest potential to reduce the combined N2O andCO2 emissions are conversion from conventional tillage to permanent grassland, reduced tillage, and reduction of summer fallow. The estimated net greenhouse gas (GHG) emission reduction when changing from cultivated land to permanent grassland ranged from 0.97 (Brown Chernozem) to 4.24 MgCO2 equiv. ha–1 y–1 (BlackChernozem) for the seven soil regions examined. When changing from conventional tillage to no-tillage the net GHG emission reduction ranged from 0.33 (Brown Chernozem) to 0.80 Mg CO2 equiv. ha–1 y–1 (Dark GrayLuvisol). Elimination of fallow in the crop rotation lead to an estimated net GHG emission reduction of 0.43 (Brown Chernozem) to 0.80 Mg CO2 equiv.ha–1 y–1 (Dark Brown Chernozem). The addition of 50% more or 50% less N-fertilizer both resulted in slight increases in combined CO2 and N2O emissions. There was a tradeoff in GHG flux with greaterN2O emissions and a comparable increase in carbon storage when 50% more N-fertilizer was added. The results from this work indicate that conversion of cultivated land to grassland, the conversion from conventional tillage to no-tillage, and the reduction of summerallow in crop rotations could substantially increase C sequestration and decrease net GHG emissions. Based on these results a simple scaling-up scenario to derive the possible impacts on Canada's Kyoto commitment has been calculated. 相似文献
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Previous research has demonstrated that soil carbon sequestration through adoption of conservation tillage can be economically profitable depending on the value of a carbon offset in a greenhouse gas (GHG) emissions market. However adoption of conservation tillage also influences two other potentially important factors, changes in soil N2O emissions and CO2 emissions attributed to changes in fuel use. In this article we evaluate the supply of GHG offsets associated with conservation tillage adoption for corn-soy-hay and wheat-pasture systems of the central United States, taking into account not only the amount of carbon sequestration but also the changes in soil N2O emission and CO2 emissions from fuel use in tillage operations. The changes in N2O emissions are derived from a meta-analysis of published studies, and changes in fuel use are based on USDA data. These are used to estimate changes in global warming potential (GWP) associated with adoption of no-till practices, and the changes in GWP are then used in an economic analysis of the potential supply of GHG offsets from the region. Simulation results demonstrate that taking N2O emissions into account could result in substantial underestimation of the potential for GHG mitigation in the central U.S. wheat pasture systems, and large over-estimation in the corn-soy-hay systems. Fuel use also has quantitatively important effects, although generally smaller than N2O. These findings suggest that it is important to incorporate these two effects in estimates of GHG offset potential from agricultural lands, as well as in the design of GHG offset contracts for more complete accounting of the effect that no-till adoption will have on greenhouse gas emissions. 相似文献
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采用土壤深松 45cm、30 cm处理打破犁底层 ,1 996～ 1 998年连续进行 2个年度的冬小麦保墒、增产效应田间试验 .试验结果表明 :土壤深松处理后可减少冬小麦全生育期 0～ 1 0 0 cm的作物耗水量 ,促进根系对 1 0 0～ 2 0 0 cm土层土壤水分的利用 ,提高冬小麦的产量耗水比 .土壤深松处理能明显增加 0～ 30 cm土层的土壤湿度和含水量 ,降低 0～ 50 cm土层的土壤容重 .有利于冬小麦根系、茎、叶的生长发育和总生物量的累积 .土壤深松 45cm处理 2年平均冬小麦增产 7.0 % ,土壤深松 30 cm处理第一年增产 7.7% .冬小麦土壤深松保墒增产效应的适宜深松深度为 30 cm. 相似文献
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Assessing the site-specific impacts of climate change on hydrology, soil erosion and crop yields in the Loess Plateau of China 总被引：1，自引：0，他引：1
Climate changes may have great impacts on the fragile agro-ecosystems of the Loess Plateau of China, which is one of the most severely eroded regions in the world. We assessed the site-specific impacts of climate change during 2010?C2039 on hydrology, soil loss and crop yields in Changwu tableland region in the Loess Plateau of China. Projections of four climate models (CCSR/NIES, CGCM2, CSIRO-Mk2 and HadCM3) under three emission scenarios (A2, B2 and GGa) were used. A simple spatiotemporal statistical method was used to downscale GCMs monthly grid outputs to station daily weather series. The WEPP (Water and Erosion Prediction Project) model was employed to simulate the responses of agro-ecosystems. Compared with the present climate, GCMs projected a ?2.6 to 17.4% change for precipitation, 0.6 to 2.6°C and 0.6 to 1.7°C rises for maximum and minimum temperature, respectively. Under conventional tillage, WEPP predicted a change of 10 to 130% for runoff, ?5 to 195% for soil loss, ?17 to 25% for wheat yield, ?2 to 39% for maize yield, ?14 to 18% for plant transpiration, ?8 to 13% for soil evaporation, and ?6 to 9% for soil water reserve at two slopes during 2010?C2039. However, compared with conventional tillage under the present climate, conservation tillage would change runoff by ?34 to 71%, and decrease soil loss by 26 to 77% during 2010?C2039, with other output variables being affected slightly. Overall, climate change would have significant impacts on agro-ecosystems, and adoption of conservation tillage has great potential to reduce the adverse effects of future climate changes on runoff and soil loss in this region. 相似文献
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The optimal choice of residue management, crop rotations, and cost of carbon sequestration: empirical results in the Midwest US 总被引：1，自引：0，他引：1
This study investigates the cost of soil carbon sequestration in the Midwest US. The model addresses several missing components in earlier analyses: the link between the residue level choice and carbon payments, crop rotations, carbon loss when shifting from conservation to conventional tillage and the spatial pattern of carbon sequestration across different soil types. The results suggest that for $100 per metric ton of carbon, 1.5 million metric tons of carbon could be sequestered per year on the 19.9 million hectares of cropland in the study region. These estimates suggest less carbon potential than existing studies because the opportunity costs associated with conservation tillage are fairly high. Annual carbon rental payments are found to be more efficient, as expected, but for smaller programs, per hectare rental payments are not substantially more costly. 相似文献
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Global agricultural development programs aim to support smallholder farmers and farming communities by strengthening sustainable and resilient food production systems – which can also promote climate change mitigation as a co-benefit by reducing the emissions and enhancing removals of greenhouse gases (GHG). This study presents estimated GHG emissions reductions of almost 100 agricultural development projects over 51 low- and middle-income countries supported by the International Fund for Agriculture Development (IFAD), USAID-Feed the Future (FTF) Initiative, and Foreign, Commonwealth and Development Office (FCDO, previously DfID). Together, these projects promoted a net GHG emissions reduction of 6.5 MtCO2e per year. The forest management and promotion of improved agroforestry systems in the project areas contributed the most to the total mitigation co-benefits of the investment portfolios (∼3.9 MtCO2e/y). Improved crop management with minimum tillage practices, residue incorporation, water management in paddy rice, and the use of organic fertilizers also made a large contribution to the GHG emissions reduction (∼1.5 MtCO2e/y). Grass and pasture land management across the selected projects account for a net emission reduction of 0.2 MtCO2e/y. The implementation of improved agricultural practices in combination proves more effective for improving productivity and generating mitigation co-benefits than used in isolation. However, the aggregate impacts of soil organic carbon (SOC) sequestration should be interpreted carefully, which quickly can be lost quick. The interventions promoted by the global agricultural development programs have shown immense potential in reducing net GHG emissions or emission intensity in agriculture and allied sectors. For moving forward to achieve the net-zero and 1.5 °C goals including food security, the global agriculture development programs need to prioritize working on agriculture policy development and implementation so that agriculture expansion does not continue to drive land-use change. This needs to move from the traditional agriculture development programs to transformational changes. 相似文献
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《Global Environmental Change》2000,10(3):197-209
The use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This, in turn, will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual, site-specific conservation practices on changes in soil organic carbon. There is a general absence, however, of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage, the Conservation Reserve Program, and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices, it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was about 12.2 million Mt. By 2008, there will be an increase of about 25%. Given that there is a significant potential for conservation practices to lead to an increase in carbon sequestration, there are a number of policy options that can be pursued. These include education and technical assistance, financial assistance, research and development, land retirement, and regulation and taxes. 相似文献
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DNDC, a rainfall-driven and process-oriented model of soil carbon and nitrogen biogeochemistry, is applied to simulate the nitrous oxide emissions from agricultural ecosystem in Southeast China. We simulated the soil N2O emission during a whole rice-wheat rotation cycle (from Nov. 1, 1996 to Oct. 31, 1997) under three different conditions, which are A) no fertilizer, B) both chemical fertilizer and manure and, C) chemical fertilizer only. The processes of N2O emission were discussed in detail by comparing the model outputs with the results from field measurement. The comparison shows that the model is good at simulating most of the N2O emission pulses and trends. Although the simulated N2O emission fluxes are generally less than the measured ones, the model outputs during the dryland period, especially during the wheat reviving and maturing stages in spring, are much better than those during the paddy field period. Some sensitive experiments were made by simulating the N2O emissions in spring, when there is a smallest gap between the simulated fluxes and the measured ones. Meanwhile, the effects of some important regulating factors, such as the rainfall, N deposition by rainfall, temperature, tillage, nitrogen fertilizer and manure application on N2O emission during this period were analyzed. From the analysis, we draw a conclusion that soil moisture and fertilization are the most important regulating factors while the N2O emission is sensitive to some other factors, such as temperature, manure, tillage and the wet deposition of atmospheric nitrate. 相似文献
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利用GVG线采样技术提取农作物种植面积及其精度分析 总被引：5，自引：0，他引：5
GVG(GIS&Video&GPS)线采样系统提出以线状样区代替以往成数抽样中的点样区与面积样区概念,通过统计线状样区内作物种植面积成数来反映区域总体农作物种植面积成数。通过 GVG实地采样,将其结果与解译遥感影像提取的作物种植面积成数结果进行了对比分析,结果显示采用GVG线采样方式精确度较高,其采样系统具有实用性和推广价值。 相似文献