垄膜沟灌对旱区农田土壤盐分及硝态氮运移特征的影响

引黄水量的执行性削减加剧了河套灌区农业水资源的紧缺程度及土壤次生盐渍化问题。采取合理的节水灌溉模式对缓解河套灌区农业用水紧张、改良盐渍化土壤、营造适宜作物生长的土壤环境具有重要意义。为明晰垄膜沟灌对河套灌区土壤盐分及硝态氮运移特征的影响及调控效果,通过4次田间沟灌试验,对比研究了高水、中水、低水及高肥、低肥6个组合处理条件下土壤盐分以及土壤硝态氮的变化特征。结果表明:垄膜沟灌条件下灌水量对土壤全盐量的影响高于施肥量,中水处理土壤全盐量始终维持在一个适宜且稳定的水平。灌水量和施肥量对土壤硝态氮含量均有不同程度的影响,中、低水处理后期硝态氮的淋溶显著低于高水处理。垄膜沟灌种植模式下中水低肥处理增加了土壤水分的有效性,抑制了土壤反盐,减少了垄上硝态氮的淋溶,在节水节肥的基础上为作物的生长发育提供了一个适宜的土壤环境,利于生物量的累积及最终产量的形成,在一定程度上解决了河套灌区引黄灌溉配额减少与漫灌洗盐方式严重浪费水资源之间的矛盾,为当地垄膜沟灌技术的推广提供了一定的理论依据与技术支撑。

Effects of Ridge with Plastic Mulch-Furrow Irrigation on Soil Salt and Nitrate Nitrogen Transport Characteristics in Arid Areas

The reducing of yellow water quota and increasing of irrigation area aggravated the shortage of agriculture water resources and soil salinization in the Hetao Irrigation District. It is of great significance to alleviate the stress of agricultural water, improve saline soil by adopting reasonable irrigation methods, and establish a good soil environment which is suitable for crop growth in the irrigation district. In order to investigate the transport characteristics of soil salt and nitrate nitrogen under ridge with plastic mulch-furrow irrigation in the Hetao Irrigation District, four times field irrigation experiments were conducted to determine the effect of high water and high fertilizer (I1F1), high water and low fertilizer (I1F2), middle water and high fertilizer (I2F1), middle water and low fertilizer (I2F2), low water and high fertilizer (I3F1), low water and low fertilizer (I3F2) on soil salinity and soil nitrate nitrogen. The results showed that the irrigation amounts shows higher influence on soil salinity than fertilizer amounts under ridge with plastic mulch-furrow irrigation. The soil salt content of middle water treatment always maintained a suitable and stable level. The amount of irrigation and fertilizer had different effects on soil nitrate nitrogen content. The nitrate leaching in the later stage of middle and low water treatments was significantly lower than that of high water treatment. The treatment of middle water and low fertilizer under ridge with plastic mulch-furrow irrigation increased soil moisture availability, inhibited soil salinity, and reduced the leaching of nitrate nitrogen on the ridge, had a good desalination effect on the basis of saving water and fertilizer which provide a suitable soil environment for the growth and development of crops and conducive to the accumulation of biomass. In a certain extent, the contradiction between the reduction of yellow water quota and the severe waste of water resources in leaching salt throught flooding irrigation was solved. It provided theoretical basis and technical support for the promotion of ridge with plastic mulch-furrow irrigation technology in the Hetao Irrigation District.