保水剂对风沙土保水特性的影响

Influences of super absorbent polymers on the water retention characteristics of aeolian sandy soil

在东北西部农业种植区,生长季干旱少雨极大制约作物的水肥利用效率,对我国粮食安全和水土资源利用的可持续性造成重大威胁。除工程措施外,合理的农用保水剂(SAP)施用是改善低产农田持水性能的必然途径。针对吉林省西部典型风沙土开展室内模拟试验,通过3因素多水平的正交试验设计,探究土壤田间持水量、凋萎系数和有效水含量等水土保持特性对保水剂的类型(地津Dijin、安信Anxin、沃特Wote和旱宝贝Hanbaobei)、粒径(大粒径和小粒径)及用量(0、0.2%、0.5%、1.0%、2.0%、4.0%和6.0%)的响应。结果表明:1)SAP的持水量受其类型、粒径、施用量及其相互作用的影响显著,而施用量是影响持水量的关键因素;2)土壤水分状况与SAP类型密切相关,土壤持水量Dijin>Anxin>Wote>Hanbaobei,SAP中K^(+)和Na^(+)的含量可能是影响保水性的主要因素,而非Ca^(2+)和Mg^(2+);3)随着SAP施用量的增加,土壤田间持水量、凋萎系数和有效水容量显著增加,与对照相比,最大增量分别为15.53、1.95和17.75倍,可有效增强严重干旱土壤中植物与SAP之间的竞争;4)与大粒径相比,小粒径SAP能显著提高土壤的田间持水量(1.21倍)和可用水量(1.23倍),而对凋萎系数则产生负面影响。综上,保水剂的合理选择与应用,对旱区水土资源持续性具有积极的推动作用,可以改善干旱土壤环境水分状况,实现低产农田“增粮”。

[Background]In the agricultural planting system in western areas of Northeast China,the drought during the growing season greatly restricts the water and fertilizer use efficiency of crops,threatens food security and the sustainability of water and land resources in China.The rational application of super absorbent polymers(SAP)has great potential to improve the soil available water-holding capacity of low yield farmland in addition to engineering measures.[Methods]Pot experiments were conducted on a typical aeolian sandy soil in the western part of Jilin province,to explore the responses of soil and water conservation characteristics such as field water-holding capacity,wilting coefficient,and soil water capacity to SAP types(Dijin,Anxin,Wote and Hanbaobei),particle size(big and small)and the application dosage(0,0.2%,0.5%,1.0%,2.0%,4.0%and 6.0%)of SAP.[Results]1)The water-holding capacity of SAP was significantly affected by its type,particle size,application dosages,and their interactions,among them,application dose was the key factor on water retention.2)The soil water status was closely related to the type of SAP,e.g.,soil water-holding capacity(Dijin>Anxin>Wote>Hanbaobei).The content of potassium and sodium ions in SAP may be the main factors affecting water retention,rather than calcium and magnesium ions.3)The field water-holding capacity,wilting coefficient,and available soil water capacity significantly increased with increasing of SAP application,the increment was up to 15.53,1.95,and 17.75 times more than control,respectively,which enhanced the competition between plant and SAP in severe dry soil.4)SAP with small particles significantly enhanced available soil field capacity(1.21 times)and water-holding capacity(1.23 times)compared with the large ones,whereas it showed negative effect on the wilting coefficient.[Conclusions]The reasonable application of SAP has a positive effect on promoting the sustainability of soil and water resources in arid areas,improving the water status,and achieving the goal of“yield improvement”in low production planting system.