干旱地区灌溉农田化肥施用现状与环境影响分析

The Agricultual Fertilization and its Impact on the Environment In the Arid Area

河西三地区氮、磷肥利用率较低 ,在整个作物生长期间 ,有 60～ 80 %的氮肥未被当季作物吸收利用而通过水、气进入环境。目前河西本地区仍有 97%的农田沿用大水漫灌方式进行灌溉 ,在春季灌水后和初冬灌冬水时 ,硝态氮大量随田间渗漏水排出 ,排出的氮、磷量占施肥量的 3 3 %和 58%以上。由此计算 ,通过农田排水和下渗损失的氮约 460 7.7t,磷约 4581 .7t,既污染了环境又加大了农业成本。所以加大有机肥施用量、发展绿色产品和采用节水灌溉、取缔大水漫灌方式是降低农业成本保护环境的有效途径。

The utilization of N-fertilizer and P-fertilizer is inefficient in the Hexi region.During the crop growing period,the 60-80% of the nitrogenous fertilizer cannot be absorbed,but enter the environment.The 97% of farmland is flooding irrigated.In spring and winter irrigating period,the NO_3-N is discharged with water leakage,which accounts for 33% of N and 58% of P out of the total fertilization.It is calculated that the total lost N and P through leakage and discharge from irrigation area amounts to 4.607×10 6kg and 4.582×10 6kg respectively.The lost fertilizer does not only pollute the environment but also increase agriculture cost.Therefore it is the effective way of lowing agriculture cost and protecting environment to increase the quantity of organic fertilization,develop green products,irrigate in economize water and forbid flooding.