黄土高原主要农作物水分盈亏与雨养农业问题

SURPLUS AND DEFICIENCY OF WATER FOR MAIN CROPS AND THE RAINFED FARMING IN THE LOESS PLATEAU

黄土高原在气候上属亚湿润向半干旱的过渡地区。水分缺乏是农业生产的重要限制因素。本文围绕降水和蒸发,主要作物的需水和降水间的相互关系,农田干湿状况和水分盈亏额进行了分析讨论。认为,发展雨养农业应该是黄土高原农业生产的一条基本方针;在雨养农业作物的选择上,除谷子可以在全区种植外,其他作物受地区局限性很大;发挥雨养农业生产潜力的基本途径应该是增加土壤水分含量和提高土壤有效水分的利用系数,为达到这一目的宜采用平整土地、增施肥料等一系列农业措施。

Climatically, the Loess Plateau is located in a transitional zone between the subhumid and semiarid regions. Water shortage for crops is the key limiting factor in agricultural production. The precipitation and evaporation, the relation between the water demand of main crops and precipitation, and the moisture situation in farmland and the surplus and deficiency of water are discussed in this paper. Based on these, the conclusions are: (1) developing rain-fed farming should be a fundamental policy in agricultural production in the Loess Plateau; (2) apart from millet, other crops are greatly limited by local conditions; (3) the basic way for increasing the production of crops should be to raise the moisture content of the soil and to increase the utilization coefficient of available moisture. So, levelling land, increasing the application of fertilizers and so on should be adopted in order to realize the above purposes.