干旱区大田膜下滴灌土壤盐分运移与调控

膜下滴灌节水技术在新疆已推广应用了160多万hm2且面积仍在持续增加.为研究干旱区大田膜下滴灌土壤盐分运移特征,该文通过在新疆巴州灌溉试验站进行的膜下滴灌试验,结果表明,在单次滴灌后,剖面土壤内的盐分产生了定向重分布,形成脱盐区、稳定区与积盐区,具有调控田间尺度土壤盐分的作用.脱盐区的面积要大于积盐区.在0～40 cm的深度内,双管对表层盐分重分布的作用大于单管；在0～80 cm深度,双管对剖面盐分重分布的作用弱于单管.在棉田的整个生育期内,剖面土壤的盐分则受灌水周期的影响,呈上下振荡、振幅缩小且总体脱盐的变化趋势,形成了一种对作物生长有利的局部环境.膜下滴灌不仅是一种滴灌和覆膜相结合的节水技术,而且通过对其控制性精准灌溉的灵活应用,可达到生育期控盐与非生育期排盐的结合,从而为在干旱区实现节水控盐的目标提供技术保障.

Soil salt movement and regulation of drip irrigation under plastic film in arid area

Drip irrigation under plastic film had applied for more than 1.6×106 hm2 in Xinjiang, and the area was still increasing. In order to research soil salt movement of drip irrigation under plastic film in arid area, a series of tests had been carried out on mulched drip irrigation in Korla prefecture, located in the south of Xinjiang. According to the experimentations, some characteristics of drip irrigation under plastic film were discovered. After one times drip irrigation, the salt content of soil profile redistributed again and desalted zone, salt immovability zone and salt accumulation zone were formed. The results of calculation showed that the area of desalted zone were bigger than that of salt accumulation zone. Salt mainly accumulated under 40 cm layer or open filed area. Between depths of 0-40 cm, the effects of salt distribution by using double drip pipe were bigger than by using single drip pipe. Between depths of 0-80 cm, the effects of salt distribution by using single pipe were bigger than by using single double pipe. In the period of cottons growth, the profile salt content showed the trends of decrease under the action of periodic drip irrigation. And, a helpful micro-environment to cottons was formed. Thus, the drip irrigation under plastic film was not only a kind of accurate irrigation, but also could regulate soil salt on shallow profile under the field scale in crop growth and development period. This new approach could provide technical support for saving water and decreasing salt in arid area.