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1.
Conservation benefits of conservation tillage had been developed long before the production disadvantages were removed. Even though, in some cases, there are still production disadvantages and lower yields, compared to conventional tillage, conservation tillage is attractive to farmers primarily because of the potential for reduced production costs; conservation benefits are of secondary interest in most cases even though they accrue from the use of conservation tillage. This farmer interest in cost reduction will most certainly guide research inputs. Surveys of farmers have shown that more emphasis must be placed on all of the technology needed for a production system. In order to avoid financially-disastrous consequences, associated risk assessments are even required during the adoption period, i.e., the period when conservation tillage is replacing the conventional tillage.When a conservation-tillage-planting system is defined rigorously, based on the requirement that at least 30% of the surface should be covered with crop residue, the adoption averages about 25% of the cropland in the United States. Nine tillage management regions (TMR) in the United States were delineated based on climate, adapted crops and cropping systems. Adoption of conservation-tillage-planting systems ranged widely from 22 to 45% of the cropland in a TMR. Full-width systems such as mulch till, in which the whole field is tilled, were used much more than partial-width systems such as no-till, ridge till and strip till in which only strips are tilled. Adoption of these forms of conservation tillage are sensitive to the dominant-cropping systems in a TMR. Variations in adoption were often well related to the problems and benefits discussed by research on tillage-planting systems in the TMR.  相似文献   

2.
与传统耕作相比 ,管理措施中的保持耕作措施能减少农药随径流流失的量和增加淋溶量。本文分析了影响农药环境行为的机理 :提高土壤中有机质和水分含量可影响农药吸附性 ;提高入渗能力会增加农药淋溶量 ;增加蓄水保土效益可减少地表径流及农药流失  相似文献   

3.
陈素平  张乐勤 《水土保持通报》2017,37(3):167-173,187
[目的]探索安徽省粮食安全与耕地压力动态变化及驱动因素,为管理层制定粮食安全政策提供决策参考.[方法]运用耕地压力指数模型、C-D生产模型,采用偏最小二乘回归方法,对安徽省1995-2013年粮食生产与耕地压力的动态特征及驱动因素进行综合分析.[结果](1)人口增长与耕地面积减少的矛盾突出.人口由1995年6 000万,增至2013年6 929万,呈线性增长态势,而耕地面积则由1995年4.29×106 hm2减少至2013年4.19×106 hm2,呈下降态势;(2)研究时序内,耕地压力指数均值为0.345,承载力指数均值为0.747,耕地资源禀赋尚处盈余状态,为全国商品粮盈余地区,平均盈余率达25.32％;(3)粮食作物播种面积、农业固定资产投资对粮食生产具有正向影响,边际弹性系数分别为0.001 458,0.116 508,有效灌溉面积、劳动力、农机总动力、化肥、农膜、农药、农村用电量对粮食生产具有弱负向影响.[结论]加大财政支持力度,加快推进农业现代化进程,增强科技对粮食生产的贡献率,是保障安徽省粮食生产可持续发展的重要途径.  相似文献   

4.
Agriculture can be intensified and food production increased in the tropics through conservation-effective tillage, with other benefits being soil and water conservation, energy saving and improved timeliness of planting.

The agronomic and economic performance of conservation-effective tillage is extremely location-specific. Problems important in semi-arid regions may not be significant in humid tropical areas. This paper attempts to avoid broad generalizations and to indicate ways of developing the best combination of practices for each local situation. The widespread use of on-farm research and demonstration plots to obtain site-specific information would aid the rapid adaptation and adoption of conservation farming practices in developing countries within different regions. Acceptance of conservation tillage by small farmers in developing countries would be an evolutionary process, and their adoption of improved simple farm equipment and appropriate practices to control weeds should be intesively promoted.

A concerted effort to understand and respond to the needs of farmers, crops and soils will be essential in achieving the goal of increasing agricultural productivity while maintaining oil through conservation-effective tillage in the tropics.  相似文献   


5.
Abstract. The effects of nitrogen fertilizer and tillage systems on soil organic carbon (SOC) storage have been tested in many field experiments worldwide. The published results of this research are here compiled for evaluation of the impact of management practices on carbon sequestration. Paired data from 137 sites with varying nitrogen rates and 161 sites with contrasting tillage systems were included. Nitrogen fertilizer increased SOC but only when crop residues were returned to the soil; a multiple regression model accounted for just over half the variance (R2=0.56, P=0.001). The model included as independent variables: cumulative nitrogen fertilizer rate; rainfall; temperature; soil texture; and a cropping intensity index, calculated as a combination of the number of crops per year and percentage of corn in the rotation. Carbon sequestration increased as more nitrogen was applied to the system, and as rainfall or cropping intensity increased. At sites with higher mean temperatures and also in fine textured soils, carbon sequestration decreased. When the carbon costs of production, transportation and application of fertilizer are subtracted from the carbon sequestration predicted by the model, it appears that nitrogen fertilizer‐use in tropical regions results in no additional carbon sequestration, whereas in temperate climates, it appears to promote net carbon sequestration. No differences in SOC were found between reduced till (chisel, disc, and sweep till) and no‐till, whereas conventional tillage (mouldboard plough, disc plough) was associated with less SOC. The accumulation of SOC under conservation tillage (reduced and no till) was an S ‐shape time dependent process, which reached a steady state after 25–30 years, but this relationship only accounted for 26% of the variance. Averaging out SOC differences in all the experiments under conservation tillage, there was an increase of 2.1 t C ha?1 over ploughing. However, when only those cases that had apparently reached equilibrium were included (all no till vs. conventional tillage comparisons from temperate regions), mean SOC increased by approximately 12 t C ha?1. This estimate is larger than others previously reported. Carbon sequestration under conservation tillage was not significantly related to climate, soil texture or rotation.  相似文献   

6.
中国北方一年两作区保护性耕作技术研究   总被引：3，自引：0，他引：3  
该文主要研究适于中国北方半湿润偏旱区一年两作保护性耕作的技术模式。介绍了在“杨凌农业机械化保护性耕作新技术新机具试验示范园地"建立的小麦玉米一年两作区10种不同机械化保护性耕作的模式、试验方案以及自主研制开发的配套机具的性能;将不同模式与传统犁耕作业模式进行了对比试验与分析研究。结果表明：小麦生长全程秸秆粉碎还田、麦收后玉米免耕播种作业模式与传统犁耕无秸秆覆盖相比,小麦增产53%,玉米增产25％,土壤蓄水量增加1%～1.2%,各类保护性耕作模式土壤有机质平均增加1.03 g/kg 。另外,深松作业增产节水效果优于深耕作业;前茬小麦高留茬玉米免耕播种效果优于低留茬的玉米免耕播种。经济分析还表明,由于作物增产并降低了机械作业成本,保护性耕作技术模式的经济效益明显优于传统犁耕作业。  相似文献   

7.
Abstract

Long‐term effects of alternate tillage systems on soil‐test values for Coastal Plain soils were unknown. Therefore, soil pH, organic carbon, and Mehlich I extractable P, K, Ca, and Mg concentrations measured during an eight‐year tillage study on Norfolk loamy sand (fine‐loamy, silicious, thermic, Typic Paleudults) have been summarized. Yields for corn (Zea mays L.), wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.] are also summarized to provide an indication of nutrient removal by the crops. Soil‐test measurements after six years showed no significant differences in Mehlich I extractable nutrient concentrations for the 0‐ to 20‐cm depth between disked (conventional) and nondlsked (conservation) tillage treatments, but for pH, P, Ca, and Mg, the tillage by depth of sampling interaction was significant at P‐0.05. Stratification did not appear to affect crop yield. Soil organic matter concentration in the Ap horizon nearly doubled after eight years of research at this site. This change occurred within both tillage treatments, apparently because high levels of management produced good crop yields, residues were not removed, and even for the disked treatment, surface tillage was not excessive. These results show that long‐term average yields for corn and soybean on Norfolk soil will not be reduced by adopting reduced or conservation tillage practices. They also show that nutrient levels can be maintained at adequate levels for crop production on Coastal Plain soils by using current soil‐test procedures and recommendations for lime and fertilizer application.  相似文献   

8.
Soil organic matter is strongly related to soil type, landscape morphology, and soil and crop management practices. Therefore, long-term (15–36-years) effects of six cropland management systems on soil organic carbon (SOC) pool in 0–30 cm depth were studied for the period of 1939–1999 at the North Appalachian Experimental Watersheds (<3 ha, Dystric Cambisol, Haplic Luvisol, and Haplic Alisol) near Coshocton, OH, USA. Six management treatments were: (1) no tillage continuous corn with NPK (NC); (2) no tillage continuous corn with NPK and manure (NTC-M); (3) no tillage corn–soybean rotation (NTR); (4) chisel tillage corn–soybean rotation (CTR); (5) moldboard tillage with corn–wheat–meadow–meadow rotation with improved practices (MTR-I); (6) moldboard tillage with corn–wheat–meadow–meadow rotation with prevalent practices (MTR-P). The SOC pool ranged from 24.5 Mg ha−1 in the 32-years moldboard tillage corn (Zea mays L.)–wheat (Triticum aestivum L.)–meadow–meadow rotation with straight row farming and annual application of fertilizer (N:P:K=5:9:17) of 56–112 kg ha−1 and cattle (Bos taurus) manure of 9 Mg ha−1 as the prevalent system (MTR-P) to 65.5 Mg ha−1 in the 36-years no tillage continuous corn with contour row farming and annual application of 170–225 kg N ha−1 and appropriate amounts of P and K, and 6–11 Mg ha−1 of cattle manure as the improved system (NTC-M). The difference in SOC pool among management systems ranged from 2.4 to 41 Mg ha−1 and was greater than 25 Mg ha−1 between NTC-M and the other five management systems. The difference in the SOC pool of NTC-M and that of no tillage continuous corn (NTC) were 16–21 Mg ha−1 higher at the lower slope position than at the middle and upper slope positions. The effect of slope positions on SOC pools of the other management systems was significantly less (<5 Mg ha−1). The effects of manure application, tillage, crop rotation, fertilizer rate, and soil and water conservation farming on SOC pool were accumulative. The NTC-M treatment with application of NPK fertilizer, lime, and cattle manure is an effective cropland management system for SOC sequestration.  相似文献   

9.
To assess the topsoil carbon sequestration potential (CSP) of China's cropland, two different estimates were made: (i) a biophysical potential (BP) using a saturation limit approach based on soil organic carbon (SOC) accumulation dynamics and a storage restoration approach from the cultivation‐induced SOC loss, and (ii) a technically attainable potential (TAP) with a scenario estimation approach using SOC increases under best management practices (BMPs) in agriculture. Thus, the BP is projected to be the gap in recent SOC storage to either the saturation capacity or to the SOC storage of uncultivated soil, while the TAP is the overall increase over the current SOC storage that could be achieved with the extension of BMPs. The recent mean SOC density of China's cropland was estimated to be 36.44 t/ha, with a BP estimate of 2.21 Pg C by a saturation approach and 2.95 Pg C by the storage restoration method. An overall TAP of 0.62 Pg C and 0.98 Pg C was predicted for conservation tillage plus straw return and recommended fertilizer applications, respectively. This TAP is comparable to 40–60% of total CO2 emissions from Chinese energy production in 2007. Therefore, carbon sequestration in China's cropland is recommended for enhancing China's mitigation capacity for climate change. However, priority should be given to the vast dry cropland areas of China, as the CSP of China is based predominantly on the dry cropland.  相似文献   

10.
Abstract

Fertilizer placement for corn (Zea mays L.) has been a major concern for no‐tillage production systems. This 3‐yr study (1994 to 1996) evaluated fertilizer phosphorus (P) or potassium (K) rates and placement for no‐tillage corn on farmers’ fields. There were two sites for each experiment involving fertilizer P or K. Treatments consisted ofthe following fertilizer rates: 0,19,and 39 kg P ha‐1 or 0, 51, and 102 kg K ha‐I. The fertilizer was broadcast or added as a subsurface band 5 cm beside and 5 cm below the seed at planting. Early plant growth, nutrient concentrations, and grain yields were measured. At the initiation of the study, soil test levels for P and K at the 0–1 5 cm depths ranged from optimum (medium) to very high across sites. Effects of added fertilizer and placement on early plant growth and nutrient concentrations were inconsistent. Added fertilizer had a significant effect on grain yields in two of twelve site‐years. Therefore, on no‐tillage soils with high fertility, nutrient addition, and placement affected early plant growth and nutrient utilization, but had limited effect on grain yield. Consequently, crop responses to the additions of single element P or K fertilizers under no‐tillage practices and high testing soils may not result in grain yield advantages for corn producers in the Northern cornbelt regardless of placement method.  相似文献   

11.
本文收集整理1979--2008年有关中国保护性耕作的长期试验文献,整合分析了长期保护性耕作下中国农田表土有机碳的变化特征。采用的48篇有效文献涉及18个省（区、市）的59个长期试验点,涵盖12种土类。总样本88个（其中早地51个,水田37个）。结果表明,保护性耕作处理下旱地和水田表土有机碳年变化分别介于一0．30～0．75g·kg^-1·a^-1和-0．20～2．71g·kg^-1·a^-1,平均增幅分别达0．21g·kg^-1·a^-1和0．51g·kg^-1·a^-1。可见长期保护性耕作下,农田表土有机碳含量总体呈上升趋势,水田下增长高于旱地。和少免耕相比,秸秆还田更有利于促进表土有机碳的积累。统计分析还表明,结合秸秆还田的综合保护性耕作措施可以使水田和早地的有效固碳期限分别持续27a和23a,水田在保持较高固碳速率的同时,延长了有效固碳年限。耕地表土有机碳含量在保护性耕作下特别是秸秆还田可以较大幅度地提高,实行保护性耕作可以具有农业稳产与土壤固碳的双重意义。  相似文献   

12.
Soil compaction has been recognized as a problem limiting crop production, especially in the Southern Coastal Plain of the USA. Development of tillage and residue management systems is needed to alleviate soil compaction problems in these soils. Fertilizer nitrogen (N) management is also an important factor in these management systems. In 1988, a study was initiated with a wide-frame (6.3 m) vehicle to determine the interactive effects of traffic, deep tillage, and surface residue management on the fate of fertilizer N applied to corn (Zea mays L.) grown on a Norfork loamy sand (fine-loamy, siliceous, Thermic, Typic Kandiudults). Corn was planted into a winter cover crop of ‘Tibbee’ crimson clover (Trifolium incarnatum L.). Treatments included: traffic (conventional equipment or no traffic); deep tillage (no deep tillage, annual in-row subsoiling, or one-time only complete disruption); residue management (no surface tillage or disk and field cultivation). The one-time only complete disruption was accomplished by subsoiling at a depth of 43 cm on 25 cm centers in spring 1988. In 1990–1991, fertilizer applications were made as 15N-depleted NH4NO3 to microplots inside each treatment plot. The 1990 and 1991 data are reported here. In 1990 an extreme drought resulted in an average grain yield of 1.8 Mg grain ha−1, whereas abundant rainfall in 1991 resulted in 9.4 Mg grain ha−1. Deep tillage increased corn dry matter production in both years. In 1991, grain yields indicated that corn was susceptible to recompaction of soil owing to traffic when residues were incorporated with surface tillage. In the dry year, plant N uptake was increased 27% with deep tillage and decreased 10% with traffic. In the wet year, a surface tillage × deep tillage × traffic interaction was observed for total N uptake, fertilizer N uptake, and total fertilizer N recovery in the plant-soil system. When combined with traffic, plant N uptake was reduced with the highest intensity tillage treatment (135 kg N ha−1) because of rootrestricting soil compaction, and with the lowest intensity tillage treatment (129 kg N ha−1) because of increased N losses. In these soils, leaving residues on the soil surface can reduce the detrimental effect of traffic on corn production, but if no surface tillage is performed, deep tillage is needed.  相似文献   

13.
About 80% of Ethiopia's population is involved in rain‐fed agriculture. Moisture stress coupled with traditional tillage with breaking ard plough, locally known as ‘Maresha ’ are the major limiting factors for agricultural production. Soil erosion, low infiltration and decline agricultural productivity because of conventional tillage implement have been frequently reported. In order to curve this situation and meet the huge food demand of the growing population, different conservation tillage systems have been implemented. However, there is limited information about the impacts of the practices. This review paper therefore aimed at providing adequate information concerning the impacts of the practices on water balance and crop yield. Systematic, best evidence and narrative review techniques were used. Results revealed that the application of conservation tillage had brought significant improvement on water balance and agricultural production. Researchers found over 50% decreased in surface runoff, 9 to 40% improvement in water productivity and good crop transpiration (T = 53 mm season−1), compared to conventional tillage T = 49 mm‐season−1 because of conservation tillage implement. Moreover, doubled grain yield was obtained from ridging, subsoiling and wing plough (1076, 1044 and 1040 kg ha−1, respectively) compared to traditional tillage which resulted in 540 kg ha−1. Improving water balance and agricultural production in rain‐fed agriculture need to reduce evaporation and surface runoff through improving moisture retention and transpiration. This could be achieved by the adoption of conservation tillage which can improve on‐farm water balance, yields and water productivity among smallholder farmers in Ethiopia. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

14.
The effects of selected tillage and rotation systems on soil organic carbon and its fractions were studied on Chernozemic soils in south‐western and east‐central Saskatchewan. After practicing a no‐till fallow unfertilized‐wheat rotation for 7 years on an Orthic Brown Chernozem in south‐western Saskatchewan, total soil organic carbon (TOC) in the 0 – 5 cm and 5 – 10 cm layers was slightly lower than the tillage fallow‐unfertilized wheat comparable treatment. However, light fraction of organic carbon (LFOC) was similar in the two treatments. Comparison of the tillage fallow‐unfertilized wheat to a treatment involving conversion to a fertilized continuous cropping system for 10 years showed TOC increased slightly in the two depths and LFOC increased by 24 % and 29 % in the 0 – 5 cm and 5 – 10 cm layer, respectively, of the continuous cropping treatment. Microbial biomass carbon (MB‐C) was increased significantly at the 5 – 10 cm depth. After conversion of fallow‐wheat to alfalfa as perennial forage for 10 years, TOC increased by 80 % and 27 %, LFOC by 245 % and 286 %, and HFOC by 63 % and 20 % at 0 – 5 cm and 5 – 10 cm depths, respectively, compared to the tilled cereal‐fallow system. Meanwhile, water soluble organic carbon (WSOC) was not affected but MB‐C increased significantly. In an Orthic Black Chernozem in east‐central Saskatchewan, the depletion and restoration of organic carbon was observed when native sod was changed into cropland and then back to grassland. For example, the TOC of cropland under cereal‐fallow rotation for 62 years decreased by 42 % and 33 % at 0 – 5 cm and 5 – 10 cm depths, respectively, compared to native sod. The LFOC decreased by 79 % and 74 % in the layers, and reductions in WSOC and MB‐C were even greater. After cropland was re‐seeded to grassland for 12 years, the concentration of total organic carbon was increased by 16 % and 22 % while the mass of organic carbon was the same as the cropland in the two layers. The LFOC and MB‐C amounts in the grass seed‐down were double that of the cropped land, but the amounts of TOC, LFOC, and MB‐C in grass seed‐down were still significantly lower than the native sod.  相似文献   

15.
Soil compaction caused by random traffic or repetitive tillage has been shown to reduce water use efficiency, and thus crop yield due to reduced porosity, decreased water infiltration and availability of nutrients. Conservation tillage coupled with subsoiling in northern China is widely believed to reduce soil compaction, which was created after many years of no-till. However, limited research has been conducted on the most effective time interval for subsoiling, under conservation tillage. Data from conservation tillage demonstration sites operating for 10 years in northern China were used to conduct a comparative study of subsoiling interval under conservation tillage. Three modes of traditional tillage, subsoiling with soil cover and no-till with soil cover were compared using 10 years of soil bulk density, water content, yield and water use efficiency data. Cost benefit analysis was conducted on subsoiling time interval under conservation tillage. Yield and power consumption were assessed by based on the use of a single pass combine subsoiler and planter. Annual subsoiling was effective in reducing bulk density by only 4.9% compared with no-till treatments on the silty loam soils of the Loess plateau, but provided no extra benefit in terms of soil water loss, yield increase or water utilization. With the exception of bulk density, no-till and subsoiling with cover were vastly superior in increasing water use (+10.5%) efficiency and yield (+12.9%) compared to traditional tillage methods. Four years of no-till followed by one subsoiling reduced mechanical inputs by 62%, providing an economic benefit of 49% for maize and 209% for wheat production compared to traditional tillage. Annual subsoiling reduced inputs by 25% with an increased economic benefit of 23% for maize and 135% for wheat production. Yield and power consumption was improved by 5% and 20%, respectively, by combining subsoiling with the planting operation in one pass compared with multipass operations of subsoiling and planting. A key conclusion from this is that annual subsoiling in dryland areas of northern China is uneconomical and unwarranted. Four years of no-till operations followed by 1 year subsoiling provided some relief from accumulated soil compaction. However, minimum soil disturbance and maximum soil cover are key elements of no-till for saving water and improving yields. Improved yields and reduced farm power consumption could provide a significant base on which to promote combined planter and subsoiling operations throughout northern China. Further research is required to develop a better understanding of the linkages between conservation tillage, soil quality and yield, aimed at designing most appropriate conservation tillage schemes.  相似文献   

16.
为了探索旱地农业连作春玉米田不同保护性耕作措施下土壤蓄水保墒效果与不同施肥处理组合下春玉米的增产增收效应,在2014—2016年通过大田试验,研究了旱地农田冬闲期免耕、深松和翻耕3种耕作方式对玉米田冬闲期蓄水保墒效果及玉米生育期3种耕作处理与高、中、低有机肥3种施肥处理组合对春玉米生育期土壤水分动态、产量和经济效益的影响。结果表明,免耕和深松与翻耕相比,蓄水效果较好;2个试验年度冬闲期,免耕和深松较翻耕分别高1.3,0.9个百分点。免耕、深松较翻耕处理0—200 cm土层2年土壤平均贮水量分别增加20.8,22.1 mm;玉米生长生育期在高有机肥条件下,免耕、深松较翻耕处理0—200 cm土层土壤平均贮水量分别高44.2,34.6 mm;以高有机肥深松处理产量、WUE和纯收益最高。2年平均产量、WUE和纯收益分别为9 332.40 kg/hm^2,22.01 kg/(hm^2·mm)和5 104.1元/hm^2,高有机肥免耕处理次之,较高有机肥免耕处理增产和增收分别为7.4%和3.9%。综合考虑各处理土壤蓄水保墒效果和玉米增产增收效应,高有机肥深松是旱区连作玉米田最优的耕作和施肥处理组合。  相似文献   

17.
陇中黄土高原不同耕作措施下土壤磷动态研究   总被引：3，自引：0，他引：3  
许艳  张仁陟 《土壤学报》2017,54(3):669-680
依托陇中黄土高原旱作农田已实施13 a的保护性耕作试验,研究传统耕作、免耕、传统耕作秸秆还田、免耕秸秆覆盖、传统耕作地膜覆盖和免耕地膜覆盖6种耕作措施下土壤全磷及磷组分动态变化特征。结果表明:试验期各处理土壤全磷和总无机磷均逐年增长;两个秸秆还田处理总有机磷逐年增长,免耕地膜覆盖和免耕处理总体增长,传统耕作和传统耕作地膜覆盖处理相对稳定;各无机磷组分均总体增长,其中氢氧化钠提取态无机磷、水溶态无机磷和碳酸氢钠提取态无机磷涨幅较大,平均涨幅分别为253.6%、128.6%和66.9%;保护性耕作可不同程度地提高水溶态无机磷、碳酸氢钠提取态无机磷和氢氧化钠提取态无机磷含量,相同覆盖条件下免耕较传统耕作效果明显,尤其免耕秸秆覆盖处理最明显;耕作方式对浓盐酸提取态无机磷和残留磷的影响不明显;保护性耕作可提高碳酸氢钠提取态有机磷和氢氧化钠提取态有机磷含量,两个秸秆还田处理最明显,两处理也可提高浓盐酸提取态有机磷含量,但免耕、传统耕作地膜覆盖和免耕地膜覆盖处理下该组分含量降低。综上,采取保护性耕作可适当减少磷肥用量,保护性耕作尤其是免耕秸秆覆盖方式值得在该区推广。  相似文献   

18.
The purpose of this paper is to show how information from diagnostic research on small farmer decision-making about land preparation and tillage pratices may be integrated into experimental research on the design and evaluation of fertilizer technology. Analysis of different land preparation and tillage practices used by farmers in cassava production in Cauca department, Colombia is utilized to develop a model of farmers' decision-making in the choice of tillage techniques.

The decision model indicates that manual tillage practices which involve only partial field tillage are a response to relatively fixed constraints, which imply that it may be difficult for farmers facing these constraints to adopt fertilizer technology which requires full field tillage. Variables associated with choice of tillage method are identified and related to implications for experimental evaluation of fertilizer technology and the distribution of benefits from this research. The findings illustrate that diagnostic research on the agro-socioeconomic constraints faced by small farmers can alert researchers to limiting factors which require recognition in the design and testing of agricultural technology, in order to facilitate rapid and effective adoption by a majority of small farmers.  相似文献   


19.
以小浪底水库库区6种主要坡地景观类型(免耕农田、传统耕作农田、撂荒地、果园、林地、间作地)为例,研究了坡地不同景观配置对土壤水分时空分布及其产流产沙的影响。研究结果表明,雨季末期农田景观配置(免耕、传统耕作)土壤含水量的增量是撂荒地、果园、林地、间作地景观的1.51、2.32、5.63、2.66倍,蓄水效率比撂荒地、果园、林地、间作地分别高7.06%、11.92%、17.23%、13.07%。土壤水分的垂直梯度变化可归纳为增长型、降低型和波动型和增长降低4种类型;径流和泥沙总量林地最少,农田传统耕作最多,其径流量是林地的13.9倍。  相似文献   

20.
国外农田风蚀发生机理与防治技术的研究   总被引：16，自引：1，他引：16  
土壤风蚀是全球性土地退化的主要原因之一，也是世界上许多国家和地区的主要环境问题之一。该文简要回顾了国外对土壤风蚀发生机理、防治理念和技术的研究，提出林业上植树造林，牧业上防止草原退化，农业上实行保护性耕作是人类可以用来治理和控制土壤风蚀的3个重要原则。我国土壤风蚀和土地退化问题日趋严重，应在全国进行大力宣传，转变土壤风蚀治理的观念，使人们从思想上认识风蚀防治要从植树、种草、农田保护3个方面综合进行。同时，国家要从政策上、资金上为农田保护性耕作的大规模实施提供保证，促进保护性耕作在全国范围内的推广应用。  相似文献   

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