日光温室不同水肥措施下水氮迁移特性

为探索宁夏日光温室中不合理灌溉对番茄水分利用、氮素迁移特性的影响,通过田间试验方法,在不同灌溉方式(T1漫灌4.50t·hm~(-2)、T2滴灌3.15t·hm~(-2))及氮肥用量(T1常规量800kg·hm~(-2)、T2推荐量600kg·hm~(-2))处理下测定了土壤水分分布、番茄水分利用率和土壤剖面氮素淋溶特征。结果表明,在番茄的不同生育期,0~80cm土层深度滴灌+推荐施肥土壤含水率大于漫灌+习惯施肥,而80~200cm土层结果与之相反,可见,滴灌后水分主要保蓄在80cm以上土层,而漫灌方式水分渗出耕层土壤的量更多。滴灌+推荐施肥处理瞬时叶片水分利用率、番茄水分利用效率明显高于漫灌+习惯施肥,但两处理产量差异不明显。在当季蔬菜生长期间,不同处理30~50cm土层的硝态氮质量分数均最高,随着灌溉次数的增多,硝态氮逐渐向下迁移,漫灌+习惯施肥在100~200cm土层硝酸盐质量分数高于滴灌+推荐施肥处理,此质量分数明显高于国内其他蔬菜栽培地区。水资源浪费与不合理水肥利用引起的地下水污染问题在宁夏日光温室蔬菜栽培中已相当突出,值得引起相关部门的重视。

Migration Characteristic of Water and Nitrogen by Different Water and Fertilizer in Sunlight Greenhouse

In order to explore the migration characteristic of water and nitrogen by unreasonable water and fertilizer in Ningxia sunlight greenhouse, a field experiment was conducted in Ningxia province to study how much N is lost from soil through NO^-₃-N leaching under different nitrogen fertilizer applications (800 and 600 kg·hm^-2) and irrigation methods (drip irrigation and flood irrigation). The results revealed that the water contents in 0-80 cm soil profile was more under drip irrigation as compared to flood irrigation while the response was opposite within 80-200 cm soil profile where flood irrigation was better in retaining the water contents. During the whole growth period, the contents of NO^-₃-N remained higher in 30-50 cm soil profile under both treatments. Continuous application of irrigation water accelerated NO^-₃-N leaching towards deep soil. The contents of NO^-₃-N were significantly higher under flood irrigation and conventional N fertilizer (800 kg·hm^-2) as compared to drip irrigation and recommended N fertilizer. The contents of NO^-₃-N lost through leaching is very high in this area. It is a serious wastage of precious water resource and fertilizer, and which may pollute the underground water in the province. These issues should be considered by the local government sectors.