气候变化对灌区农业需水量的影响研究

气候变暖不仅影响水资源量及其时空分布的变化,而且也会使农作物蒸发蒸腾量增加,从而加剧农业水资源供需矛盾。因此,研究气候变化对农业需水量的影响对保障农业用水安全具有重要的意义。本文利用陕西省宝鸡峡灌区11个气象站28 a的气象资料,分析了灌区气候变化特征;计算了主要作物需水量和农田灌溉需水量;利用单因素敏感性分析法研究了气候变化对农业需水量的影响。研究结果表明:灌区年平均气温显著上升,降水量持续下降,蒸发量明显增大,大部分地区相对湿度和风速显著下降,而日照时数有所增加;冬小麦、玉米、棉花和油菜生育期需水量明显增加;各气候因素对农田灌溉需水量影响顺序为:降水量>相对湿度>最高气温>日照时数>平均气温>风速,气温的上升、相对湿度的下降、降水量的减少以及日照时数的增大使作物需水量明显增大,而灌溉面积减小使农业需水量有减少的趋势。

Impacts of climate change on agriculture water requirement in irrigation district

Climate change not only affects the changes of water resources and its spatial and temporal distribution,but also will increase the crop evapotranspiration and thereby increase the contradiction between supply and demand of agriculture water resources.Therefore,study on impacts of climate change on agriculture water requirement in irrigation destrict will have a great significance on the protection of agricultural water’s security.Using the weather data of 28 years from 11 weather stations in Baojixia irrigation district in Shaanxi Province,the article analyzed the characteristics of climate change in irrigation destrict,calculated the main crop water requirement and the farmland net irrigation water requirements and also used the sensitivity analysis to study the impacts of climate change on agriculture water requirement.The results show that there is significant increase on annual temperature,and sustained decrease on precipitation,and increase on evaporation.The relative humidity and wind speed in most regions is significant trend of decline,while sunshine duration is increasing trend.The water demand of wheat,corn,cotton and canola at growth stage show clear upward trend.The influence of weather factors on farmland net irrigation water requirement is as follow:precipitation>relative humidity>maximum temperature>sunlight hours>mean temperature>wind speed.Increase of temperature,dropping in relative humidity and precipitation,and increase in sunshine duration will result in obvious increase in main crop water requirements.As crop planting area decrease,agriculture water requirement has a trend of decrease.