陇东黄土旱塬作物组合系统农田耗水规律研究

本文根据１９８８－１９９１年陇东黄土旱塬作物组合模式（即作物轮作与复种模式）田间试验土壤水分测定资料，对作物组合系统中主要组分作物田间耗水量及其构成特征、变异规律及农田土壤水分的利用程度进行了研究，并探讨了不同作物组合系统的田间耗水量及其构成特征。结果表明，不同作物组合系统的田间耗水量及其构成特征存在明显差异；作物田间耗水量是一个动态变量，因作物种类、降水年型等不同而异，并与生育期有效降水量呈显著正相关；来自播前土壤有效储水的土壤供水量对秋播作物冬小麦和冬油菜生育期水分不足有重要补偿作用，是维持其较高的生产稳定性的关键原因；无论丰水年还是欠水年，冬小麦、玉米、谷子和马铃薯４种主要作物在农田水分利用程度上均存在一定差异。

STUDY ON THE WATER CONSUMPTION LAW OF COMPLEX CROP SYSTEMS IN THE TABLELANDS OF THE EASTERN GANSU LOESS PLATEAU

ield water consumption,constitution,variational law ,and utilization degree of availablesoil water for the main crop components in the complex crop systems were studied in this pa-per,and at the same time the field water consumption and its constitution for diffenent com-plex crop systems was also examined based on the soil water observations from the experi-ments of crop rotations with multiple cropping conducted on the tablelands of the EasternGansu Loess Plateau during 1988-1991. The results showed that:there were quite great dif-ferences in the field water consumption among the crops and the crop systems , crop waterconsumption was a dynamic variable that varied within the species and the year types of pre-cipitation,and effective precipitation with the phenological stages had a great impact on cropwater consumption,soil water supply from the pre-sowing available soil water played an im-portant role in compensation for precipitation shortages during the growing period of winterwheat and winter rape sown in autumn and was a key factor maintaining production stabilityof the above two crops, the four major crops of winter wheat, corn, miilet and potato dif-feread greatly in the utilization degree of available soil water either in a dry year or in a wetyear.