微咸水喷灌对作物影响的研究进展

Review of the effect of sprinkler-irrigation with brackish water on crops

微咸水喷灌条件下,作物同时受到土壤盐分和喷灌水盐分的双重影响。大部分作物通过叶片吸收盐分的速率与盐分浓度和喷水历时基本上呈线性函数关系;同时,喷灌过程中不仅要监测灌溉水的电导率,而且与其他水源混合时也要监测离子组成,尽量降低Mg2+、Cl-和Na+的含量。喷灌频率的增加比喷水历时的增加更能增加作物盐分的吸收,并加重对作物的损伤。微咸水喷灌后短时间的淡水冲洗可以减少作物叶片对盐分的吸收。微咸水喷灌显著降低成熟植被的生物量和作物累积耗水量,造成作物一定程度的减产,而且具有累积效应;但作物产量和叶片汁液离子浓度没有明显的相关关系。今后,应重点研究以下5个方面的问题:(1)微咸水喷灌下作物的耐盐性评价指标,建立相应的评价体系;(2)选育耐微咸水喷灌的品种,尤其是用于草场恢复重建、城市绿化、盐渍土改良等耐盐牧草、草坪草的选育;(3)制定与微咸水喷灌相适应的灌溉制度,研究微咸水喷灌条件下作物叶片上和土壤中盐分的淋洗对微咸水喷灌具有重要的作用;(4)微咸水喷灌对作物影响的区域性和时效性,应建立微咸水喷灌对作物产量影响的区域性评价和研究长期微咸水喷灌对作物的影响;(5)微咸水喷灌对土壤盐分积累及分布的影响。

A review of sprinkler-irrigation with brackish water effects on crops showed that both soil salt and sprinkler-irrigated brackish water salt affected crop growth and productivity. Salt absorption rate by plant leaf was linear functionally related with water salt concentration and irrigation duration. In order to reduce sprinkler-irrigated water contents of magnesium, chlorine and sodium, it was critical to monitor electrical conductivity and ion composition of source waters. Generally, increasing irrigation frequency led to a greater increase in salt absorption and plant damage than increasing irrigation duration. Sprinkler-irrigation with fresh water fol- lowing sprinkler-irrigation with brackish water reduced leaf salt uptake. Sprinkler-irrigated brackish water limited not only biomass and cumulative water consumption of mature plants, but also reduced crop yield. However, crop yield was not significantly related with leaf sap ion concentration. It was suggested that future studies focused on five main research tasks. The first was the study of salt tolerance of crops under sprinkler-irrigation of brackish waters with aim of establishing a standard evaluation system. The second was breeding salt-resistant crop varieties to sprinkler-irrigation with brackish waters which could be especially useful in breeding salt-tolerant grass, turf-grass restoration, urban greening and saline soil amendments. The next suggested focus was developing adaptable irrigation schedules for sprinkler-irrigation with brackish water. It was also important to study the leaching of salt from leaves and soils under sprinkler-irrigation with brackish water condition. The next point was analyzing, in time and space, long/short-term impacts of sprinkler-irrigation with brackish water on the crops. The last point was to study the effects of sprinkler-irrigation with brackish water on the accumulation and distribution of soil salts.