1960—2015年呼伦贝尔草原气温和降水格局变化特征

［目的］利用1960—2015年呼伦贝尔草原区逐日气象数据，分析了该地区这56年来气温和降水的分布与变化规律。［方法］文章采用Mann Kendall非参数趋势检验和Sen′s斜率估计分析了温度、降水变化的趋势和变化速度。［结果］(1）呼伦贝尔草原区过去56年中气温呈现出极显著波动增加的趋势，其中第二季度增温的趋势最明显，年均温增加中值005℃。海拉尔区增温速度为草原区最快，年增加中值004℃。(2）呼伦贝尔草原区这56年中降水呈现出不显著的波动下降趋势，年降水减少中值041mm。其中第三季度降水量显著减少，年降水减少中值092mm，第一、四季度降水量显著增加，年降水增加中值007～023mm。第二季度变化较小。满洲里市降水量极显著下降，下降速度为草原区最高，年降水减少中值125mm。(3）1～5mm降水次数和总降水贡献呈显著增加趋势，年增加中值0102%， 5～30mm降水次数和降水贡献呈现减少趋势，单次降水30mm以上频率很低。(4）历时1～2d的降水是研究区最主要的连续降水类型，独立单日降水呈现不显著增加趋势， 2～3d连续降水呈现不显著减少趋势，连续4d和4d以上降水事件较为罕见。［结论］呼伦贝尔草原区过去56年整体看呈现出暖干化的趋势，年内尺度看降水呈现均匀化趋势，第三季度减少，第一、四季度增加。降水格局表现为分散化趋势，极端降水事件减少，小雨增加； 连续降水减少，单日独立降水增加。     

1961—2020年长湖流域极端降水事件变化特征及其与温度的关系

目的 长湖流域是调控长江中游地区生态平衡的重要湿地生态系统，其降水变化对区域水资源可持续利用和防灾减灾具有重要意义。方法 文章基于1961—2020年长湖流域逐日气象数据，选取9个极端降水指数，运用线性回归分析、相关分析和重标极差分析（rescaled range analysis，R/S）探讨了长湖流域极端降水事件的变化特征及其对气温变化的响应，并预测该区域极端降水事件未来演变趋势。结果 （1）1961—2020年长湖流域年降水量整体呈上升趋势，上升速率为5.4 mm/10年，多年平均降水量为1 151.9 mm；年内降水呈单峰模式，6月的降水量最高，占比为14.99%，12月最低，占比为2.37%。（2）长湖流域极端降水指数均呈上升趋势，除持续湿润日数（CWD）和持续干旱日数（CDD）增加趋势不明显外，其他指数上升趋势显著。（3）CWD和CDD与其他指数的相关性较低，除1日最大降水量（RX1day）与极端降水日数（R95d）相关性不显著以外，其他极端降水指数之间均呈显著相关关系。（4）R/S分析结果表明，未来长湖流域极端降水事件将持续前期的变化趋势。结论 长湖流域极端降水事件总体呈增加趋势，温度上升会对极端降水强度起促进作用。     

早籼稻谷就仓降水生产性试验报告

针对目前高水分粮或部分高水分粮混仓存放的现状，通过大功率风机实施快速均温、均水通风后，再采用小功率粮面排风扇进行负压降水、降温通风，达到降水目的，确保储粮安全。     

玉米的降水处理

玉米具有水分含量高、成熟度不一致、呼吸旺盛、易发热、霉变等特点，尤其是玉米种子，比其它谷类作物较难贮藏。因此，玉米在贮藏前必须要做好降水处理。降水处理的主要方法有以下几种：     

高水分玉米机械通风降水储存试验

胶东地区受地理条件的限制，玉米在10月份收获后，由于气温较低、降水困难，水分一般都在16％左右，而玉米的轮换通常在同期进行，为保证玉米的安全储存，烟台市粮油储备库采取机械通风降水和化学储藏相结合的方法，使库存的玉米安全度夏。     

高水分油菜籽机械通风降水试验

油菜籽1959吨，水分在14-30％，通过机械通风降水，水分降至9．8-14.5％，实现了安全贮存和保持了出油率。平均电耗为0．9-1．9度／降水1％·吨，费用较低，有效地解决了油菜籽收购、贮存难的问题。     

浅谈湖南稻谷降水清杂设备的需求及应用

近几年调查数据显示，稻谷收购质量呈逐年下降趋势，特别是水分和杂质等主要质量指标超标现象严重，如不进行有效遏制将威胁储粮安全。当市场管理缺位，收储企业迫切需要有效的清杂、降水设施，但目前有效清理设备供给现状不尽人意，开发适应大批量稻谷降水清杂设备，提高设备处理能力是值得深入研究的重要课题。     

旱作农业“土壤水库”的建设

内蒙古自治区有近７０％旱地，因降水有限，严重制约了旱地农业生产的发展。旱地由于单产较低，存在着巨大的增产潜力，只要提高科技水平，增加物质投入，蓄天上水，保土中水，在抗旱、节水、蓄水、保水上作文章，用宝贵的有限降水可挖掘出更大的增产潜力，因而，发展旱地...     

安徽万众一心战旱魔

自去年10月下旬以来，安徽省合肥以北大部分地区出现严重的旱冻灾害，特别是淮北小麦主产区29个县（市、区）已连续100多天没有有效降水，降水之少为历史罕见。截至2月7日，安徽小麦受旱面积达2830万亩，其中严重干旱1229万亩，点片死苗超过百万亩，灾区数干万干部农民心急如焚。     

玉米种子越夏贮藏

1．晾晒、降水。越夏玉米种子晾晒最佳时间为3月初至4月底。若种子库存量过大，可根据气候温度适当提前晾晒。晾晒时期水分没有达到入库标准可每天翻3～4次，气温较高的天气多翻几次可加快降水入库。入库种子温度不得超过10℃，以保证种子安全过夏。     

自然降雨与旱地谷子单产水平关系研究——以武安市为例

谷子抗旱性强,水分利用效率高,是我国北方干旱半干旱雨养旱作区的主要杂粮作物。文章主要研究干旱雨养旱作区降雨量对谷子单产的变化规律,从而为提高谷子降水利用效率以及实际生产提供理论依据。基于武安市1983~2012年期间30年的降雨数据和谷子单产数据,研究自然降雨与谷子单产水平关系。采用散点图、建立线性方程、线性回归显著性分析等研究方法,通过统计、对比描述等方式进行分析。结果显示:武安近30年的自然降雨量与谷子的单产之间具有正相关关系,且谷子7、8月份降雨量对其单产具有显著性影响。主要结论:谷子的单产随着降雨量的增加而增加,但不是无限增加,而是有一个最佳降雨临界点490mm;当降雨量在490mm以内变化时,谷子单产随着降雨量的增加呈现增长的趋势;当降雨量超过490mm时,谷子的单产与降雨量负相关;谷子的单产受7月和8月的降雨量影响显著,且2个月降雨量之和占全生育期的63.1%时,谷子的单产较高。     

Does fertilizer use respond to rainfall variability? Panel data evidence from Ethiopia

In this article, we use farmers' actual experiences with changes in rainfall levels and their responses to these changes to assess whether patterns of fertilizer use are responsive to changes in rainfall patterns. Using panel data from the Central Highlands of Ethiopia matched with corresponding village‐level rainfall data, the results show that the intensity of current year's fertilizer use is positively associated with higher rainfall levels experienced in the previous year. Rainfall variability, on the other hand, impacts fertilizer use decisions negatively, implying that variability raises the risks and uncertainty associated with fertilizer use. Abundant rainfall in the previous year could depict relaxed liquidity constraints and increased affordability of fertilizer, which makes rainfall availability critical in severely credit‐constrained environments. In light of similar existing literature, the major contribution of the study is that it uses panel data to explicitly examine farmers' responses to actual weather changes and variability.     

Smallholder farms’ adaptation to the impacts of climate change: Evidence from China’s Loess Plateau

The impacts of climate change on agriculture in developing countries will depend on the extent to which agricultural production in those regions adapts to climate change’s influences. This study uses a whole-farm land use optimisation approach to explore climate change impacts, when including adaptation, on farm profitability, production and associated greenhouse gas (GHG) emissions in the Loess Plateau of northern China. The results show that with adaptation activities, the losses in smallholder farm profitability caused by the climate change could be moderate. Declining rainfall results in land use changes that generate higher on-farm GHG emissions with the most economically beneficial adaptations. With 5 % or 10 % decline in annual rainfall, the introduction of agricultural carbon tax would generate substantial reduction in on-farm GHG emissions. With 30 % rainfall reduction, agricultural carbon tax is not likely to bring about considerable emission reduction. The economically optimised land uses are generally sensitive to potential changes. When rainfall reductions appear, there is a clear trend toward reducing cropping area and transiting to pasture. With 5–10% rainfall reductions, increasing agricultural carbon tax with same rainfall reduction leads to the expansion in cropping enterprises. However, with 30 % rainfall reduction, land allocations are not sensitive to agricultural carbon tax. When with declining annual rainfall, in the optimal enterprises more oats-pasture rotations are employed to reduce wheat dominated rotations. Besides land use patterns, adaptations through altering farm management practices are also necessary. The economically optimised sheep flock would be increased considerably with declining rainfall. Overall, policymakers are suggested to initial more educational schemes to tell smallholder farmers how to make the best use of available adaptation strategies and consider changes in climate when design and implement agricultural policy.     

西辽河平原区地下水水位动态与水资源可持续发展

根据西辽河平原区地下水位动态及气象、水文等资料,分析了地下水水位动态,确定了该区的地下水位动态类型:人工开采型,降水入渗开采型,降水入渗型,降水入渗蒸发型,径流型,降水入渗径流型。结果表明,西辽河平原区地下水动态主要影响因素为气象因素及人为因素,地下水的大量开采对该区水资源可持续利用产生了极大的影响。     

Do rainfall conditions push or pull rural migrants: evidence from Malawi

This article uses nationally representative data from Malawi's 2004/05 Integrated Household Survey (IHS2) to examine whether rainfall conditions influence a rural worker's decision to make a long‐term move to an urban or another rural area. Results of a Full Information Maximum Likelihood regression model reveal that (1) rainfall shocks have a negative association with rural out‐migration, (2) migrants choose to move to communities where rainfall variability and drought probability are lower, and (3) rainfall shocks have larger negative effects on the consumption of recent migrants than on the consumption of long‐time residents.     

Occupational diversification as an adaptation to rainfall variability in rural India

Occupational diversification among household members in rural India is investigated as an adaptation strategy against the risks arising from the variability of local rainfall. Nationally representative household‐level survey data are combined with the coefficient of variation of rainfall constructed based on historical rainfall data at the district level. The analysis finds that high rainfall variability has significant negative effects on the agricultural specialization of within‐household occupational choices. This result is reinforced by the finding that improved access to irrigation, education, credit, roads, and postal services, is associated with a lower occupational diversification within families and a greater specialization of household members in agricultural‐related employment.     

Peasant farmer behavior and cereal technologies: Stochastic programming analysis in Niger

Peasant farmers in Sahelian West Africa adjust to rainfall uncertainties in the agricultural season by making decisions sequentially as a function of the evolving rainfall patterns. Understanding such flexibilities in farmer decision-making is central to technology introduction. This paper determines how sequential decision-making under weather uncertainty affects the adoption and farm-level effects of cereal technologies in Niger. The study also draws policy implications for a price floor to arrest the substantial fall in cereal prices in good rainfall years when farmers have more grains to sell. The methodology used is Discrete Stochastic Programming. This paper shows that the ability of peasant farmers to adapt cropping and resource-management strategies to the rainfall patterns is the basis for their survival in this high-risk environment. Model results show that by (a) carrying a portfolio mix of varieties of varying maturities, and (b) making sequential decisions based upon rainfall expectations, farmers can adapt to the production uncertainties. Breeding programs should therefore be diversified to develop not only early-maturing cultivars, but also improved intermediate and long-season varieties.     

Demand for temperature and rainfall index insurance in India

Weather index insurance has been attracting considerable attention from academics and policymakers. This study investigates the demand for two types of index insurance sold in India: temperature index insurance for dry season and rainfall index insurance for subsequent monsoon season. Using data from randomized subsidy experiments, we separate purchase and quantity decisions and investigate how demand for rainfall insurance is correlated with demand for temperature insurance sold in the previous season. We find that the price (premium) does not influence purchase decisions per se but does significantly influence quantity decisions. The quantity demanded is less price‐sensitive for subsequent rainfall insurance than it is for temperature insurance. We also find that purchasers of temperature insurance tend to buy rainfall insurance more often than nonpurchasers do. However, a one‐time subsidy does not influence on subsequent demand, suggesting no price‐anchoring effect.     

Incorporating risk in the economic analysis of agronomic trials: fertilizer use on barley in Syria

In the drier areas of Syria yields of barley, the principal crop, are low. Due to the variability in rainfall, fertilizer use is perceived as risky. Barley-fertilizer trials have been conducted on farmer's fields over a period of four years to investigate whether the large yield response to fertilizer observed on research sites could be achieved under farmers' conditions. Data were pooled across years and sites and response functions estimated. Simple optimization analysis shows that economic optimum fertilizer rates vary considerably with rainfall and relative prices. Historical rainfall data are combined with the estimated response functions, and stochastic dominance analysis is used to compare the riskiness of fertilizer treatments in terms of net benefits and benefit-cost ratios. Results show that, given the estimated expected rainfall in barley producing areas, fertilizer use, especially at low levels, may not be as risky as has been believed. Extensions of the methodology to include other environmental variables, or to target recommendations, are discussed.     

德州市降水及旱涝灾害变化趋势分析

该文基于德州11县市1957～2009年降水量及全市范围内的所有旱涝灾害资料,分析了年降水量及旱涝灾害变化趋势,年平均降水量555.1mm,年降水量呈减少趋势,结果表明,平均每10年减少18.3mm。年平均旱灾2.5次,旱灾呈增加趋势,平均每10年增加0.235次,53年降水量与干旱次数的相关系数为-0.39,呈负相关。年平均涝灾2.5次,涝灾呈缓慢增加趋势,平均每10年增加0.05次,主要是由于特大暴雨等极端灾害性天气气候事件增加造成的,53年降水量与涝灾次数的相关系数为0.67,呈正相关。