内蒙古旱作农区农业干旱灾害度初步研究   总被引：2，自引：0，他引：2  

甄江红 《干旱区资源与环境》1997,11(2):93-98

本文通过对旱作农区旱灾的孕实环境、旱灾特征及灾情分析，提出了一种综合评价旱灾对农业生产危害程度的定量化方法，并在此基础上对旱作农区各旗（县）进行灾情分区，从而为抗旱减灾提供理论依据。  相似文献   

Optimizing supplemental irrigation: Tradeoffs between profitability and sustainability     

Theib Oweis  Ahmed Hachum 《Agricultural Water Management》2009,96(3):511-516

Water production functions are used to model yield response to various levels of supplemental irrigation (SI), to assess water productivity coefficients, and to identify optimum irrigation under various input-output price scenarios. The SI production function is taken as the difference between the total water production function (irrigation + rain) and that of rainwater. Theoretical analysis of the unconstrained objective function shows that the seasonal depth of SI to maximize profit occurs when the marginal product of water equals the ratio of unit water cost to unit product sale price. Applying this analysis to wheat in northern Syria, the production functions of SI under different rainfall conditions are developed. Coupled with current and projected water costs and wheat sale prices, the functions are used to develop an easy-to-use chart for determining seasonal irrigation rates to maximize profit under a range of seasonal rainfall amounts.Results show that, for a given seasonal rainfall, there is a critical value for the ratio of irrigation cost to production price beyond which SI becomes less profitable than rainfed production. Higher product prices and lower irrigation costs encourage the use of more water. Policies supporting high wheat prices and low irrigation costs encourage maximizing yields but with low water productivity. The resulting farmer practice threatens the sustainability of water resources. Balancing profitability versus sustainability is a challenge for policy makers. Our analysis can help national and local water authorities and policy makers determine appropriate policies for water valuation and allocation; and assist extension services and farmers in planning irrigation infrastructure and farm water management.  相似文献   

两种供水条件下两穗型小麦品种籽粒淀粉积累及相关酶活性的变化特征   总被引：9，自引：0，他引：9  

戴忠民  王振林  高凤菊  李文阳  闫素辉  蔡瑞国  张敏  尹燕枰 《作物学报》2007,33(4):682-685

在灌溉和旱作2种栽培条件下,研究了大穗型（山农710331和潍麦8号）和多穗型（济南17和鲁麦21）小麦籽粒淀粉积累及相关酶活性的变化特征。结果表明,淀粉积累速率（SAR）和蔗糖合成酶（SS）、ADPG焦磷酸化酶（AGPase）、淀粉合成酶（SSS和GBSS）和淀粉分支酶（SBE）等活性均存在明显的基因型差异。灌溉条件下大穗型品种籽粒淀粉合成相关酶的活性显著高于多穗型品种,旱作栽培条件下两穗型品种间差异变小。旱作栽培宜于增加灌浆前、中期AGPase、SS和SBE的活性,尤其对多穗型品种。大穗型品种在灌浆中后期比多穗型品种具有更强的淀粉合成能力,但对水分较为敏感。用 Richards方程模拟籽粒淀粉积累过程表明,大穗型品种籽粒淀粉积累时间长、速率高,是其淀粉积累量高的原因。  相似文献   

施肥对雨养区马铃薯干物质累积及肥效的影响   总被引：1，自引：0，他引：1  

孟炀  何文寿  侯贤清  曹哲 《分子植物育种》2019,17(12):4144-4152

针对宁夏雨养农业区,选择具有代表性的海原县树台乡马铃薯种植基地,设置氮磷钾肥不同施肥处理,于2016~2017年开展了马铃薯田间试验,探讨雨养区施肥对马铃薯干物质累积及肥效的影响。试验结果表明,不同施肥处理对马铃薯干物质积累、产量及水肥利用效率影响不同,其中氮磷钾肥配施处理马铃薯干物质快速积累期增长速度最快,施用氮、磷、钾在淀粉积累期马铃薯块茎累积量分别提高了36.4%、40.5%、18.5%。两年期间,氮磷钾肥配施处理的水分利用效率最大,2016、2017年较无肥区分别增长35.3%、51.0%,平均增长43.2%。在氮磷钾配施条件下,氮、磷、钾肥增产量分别是5 496.6 kg/hm^2、4 739.4 kg/hm^2、3 044.1 kg/hm2,其增产率分别为31.1%、30.6%、17.1%。每千克N、P2O5、K2O分别增产马铃薯30.5 kg、52.7 kg、67.7 kg。氮、磷、钾肥利用率分别为38.3%、18.2%、53.9%,其中钾肥利用率较高。  相似文献   

屯留县旱农实验区农林牧优化结构研究     

李茂松  罗其友 《干旱区资源与环境》1992,6(3):57-66

调整农林牧结构是干旱、半干旱地区农业走出低谷、摆脱困境的战略措施。本文通过对实验区资源评价、农业生产的历史考察和现状辨识。明确了农业发展的优势和主要问题,运用线性规划模型确立了多目标兼顾的农林牧优化结构。  相似文献   

特旱年旱地玉米限额补灌水肥效应分析   总被引：1，自引：0，他引：1  

张定一  张虎 《山西农业科学》1998,26(4):40-43

采用田间试验方法研究了旱地玉米限额补灌的水肥效应。结果表明，玉米小喇叭口期灌水675mm／hm2，平均增产玉米2171.5kg／hm2，增产率89．27％，灌水生产效率为3.217kg／mm;3种肥料的增产效果为N＞M＞P。未灌水条件下，3种肥料的增产效果为M＞P＞N。配合施用的增产效果为NPM＞NP。  相似文献   

临丰116旱地覆膜栽培的抗旱增产原因分析     

乔蕊清  高银奎 《山西农业科学》1998,26(3):25-29

在旱地覆膜栽培条件下，临丰116具有良好的苗型结构和产量结构，抗旱节水优势强，叶片功能期长，耐高温，抗干热风，根穗比值大，抗倒伏，不早衰，穗大，粒重，产量高。该品种是旱地覆膜栽培较理想的配套品种。同时探讨了覆膜栽培配套品种的育种目标。  相似文献   

沟谷地玉米垄作覆膜效应研究   总被引：1，自引：0，他引：1  

张定一  王建军  张虎 《山西农业科学》2001,29(3):17-19

1996～ 1997年在山西省隰县的黄土高原沟谷地进行了旱地玉米 5种垄作覆膜方式的比较研究。结果表明 ,秋耕起垄地膜顶凌覆盖效果最明显 ,与秋耕地膜播时覆盖 (CK)相比 ,播前 0～2 0 0cm土体贮水量增加 56 .35mm ,玉米生育期集水率为 53.0 % ,土壤温度平稳适中 ,改善了土壤环境 ,促进了玉米生长发育 ,使玉米产量增加了 37.12 % ,水分利用率提高了 1.93kg/mm。  相似文献   

Water management options based on rainfall analysis for rainfed maize (Zea mays L.) production in Rushinga district, Zimbabwe     

I.W. Nyakudya  L. Stroosnijder 《Agricultural Water Management》2011,98(10):1649-1659

Maize (Zea mays L.), the dominant and staple food crop in Southern and Eastern Africa, is preferred to the drought-tolerant sorghum and pearl millet even in semi-arid areas. In semi-arid areas production of maize is constrained by droughts and poor rainfall distribution. The best way to grow crops in these areas is through irrigation, but limited areal extent, increasing water scarcity, and prohibitive development costs limit the feasibility of irrigation. Therefore, there is need for a policy shift towards other viable options. This paper presents daily rainfall analysis from Rushinga district, a semi-arid location in Northern Zimbabwe. The purpose of the rainfall analysis was to assess opportunities and limitations for rainfed maize production using 25 years of data. Data was analysed using a variety of statistical methods that include trend analysis, t-test for independent samples, rank-based frequency analysis, Spearman's correlation coefficient and Mann-Whitney's U test. The results showed no evidence of change in rainfall pattern. The mean seasonal rainfall was 631 mm with a standard deviation (SD) of 175 mm. December, January and February consistently remained the major rainfall months. The results depicted high inter-annual variability for both annual and seasonal rainfall totals, a high incidence of droughts ≥3 out of every 10 years and ≥1 wet year in 10 years. Using the planting criteria recommended in Zimbabwe, most of the plantings would occur from the third decade of November with the mode being the first decade of December. This predisposes the rainfall to high evaporation and runoff losses especially in December when the crop is still in its initial stage of growth. On average 5 to more than 20 days dry spells occupy 56% of the rainy season. Seasonal rainfall exhibited negative correlation (P < 0.001; R = −0.746) with cumulative dry spell length, and wet years were free from dry spells exceeding 20 days. The most common dry spells (6-10 days), are in the range in which irrigated crops survive on available soil water. Therefore, they can be mitigated by in situ rainwater harvesting (RWH) and water conservation. The potential evapotranspiration of a 140-day maize crop was estimated to be 540 mm. Consequently, short season maize cultivars that mature in less than 140 days could be grown successfully in this area in all but drought years. However, sustainable maize production can only be achieved with careful management of the soil as a medium for storing water, which is essential for buffering against dry spells. To this end soil restorative farming systems are recommended such as conservation farming, in situ RWH techniques for dry spell mitigation and a cropping system that includes drought-tolerant cereal crops as for example sorghum and pearl millet, and perennial carbohydrate sources as for example cassava to provide stable crop yields.  相似文献   

Effects of different management practices on the soil–water balance and crop yield for improved dryland farming in the Chinese Loess Plateau     

Ke Jin  Wim M. Cornelis  Wouter Schiettecatte  Junjie Lu  Yuqing Yao  Huijun Wu  Donald Gabriels  Stefaan De Neve  Dianxiong Cai  Jiyun Jin  Roger Hartmann 《Soil & Tillage Research》2007,96(1-2):131-144

Field experiments were carried out to study the effects of different soil management practices on the water balance, precipitation use efficiency (PUE), and crop yield (i.e. winter wheat and peanut) on a loess soil near Luoyang (east edge of the Chinese Loess Plateau, Henan Province, China). Field plots were set up in 1999 including following soil management practices: subsoiling with mulch (SS), no-till with mulch (NT), reduced tillage (RT), two crops per year (i.e. winter wheat and peanut, TC), and a conventional tillage control (CT). The field plots were equipped to monitor all components of the soil–water balance except evapotranspiration, which was computed by solving the water balance equation. The results showed that although soil management had smaller influence on the magnitude of the water balance components than did precipitation variations, small influences of the applied soil management practices on water conservation during the fallow period can greatly affect winter wheat yield. SS increased consistently precipitation storage efficiency (PSE) and PUE over the 5 years compared to CT except during the wettest year. NT also had a noticeable effect on postharvest water storage during the fallow period; however, the influence on yield of NT depended on the amount of precipitation. TC lowered the winter wheat yield mainly due to the unfavorable soil moisture conditions after growing peanut in summer; however, the harvested peanut gained an extra profit for the local farmer. No matter which kind of soil management practices was adapted, PSE never exceeded 41.6%, which was primarily attributed to high evapotranspiration. From data of five consecutive agricultural years between 2000 and 2005, it could be concluded that SS resulted in the highest PSE, PUE and crop yield. TC also showed promising results considering the economic value of the second crop. NT performed slightly less as SS. CT gave intermediate results, whereas RT was the worst alternative.  相似文献