新疆盐碱地膜下滴灌棉田可持续利用系统分析

为新疆盐碱滴灌棉田实现"节水、压盐、稳产、增产"的目标,利用新疆玛纳斯县田间试验、农户土地利用调研和文献等数据,采用系统分析的方法,从自然、生态环境和社会经济等方面探究盐碱地膜下滴灌棉田可持续利用的可行方案。研究结果:1)短期膜下滴灌条件下,微咸水和淡水都使土壤根系层(0~30cm)处于脱盐状态,保证棉花生长的环境;且4个处理压盐效果从大到小依次为大水量淡水(N5000)、小水量淡水(N4500)、大水量微咸水(X5000)、小水量微咸水(X4500)。2)淡水处理在棉花絮期的株高、干物质总重和叶片数均高于微咸水处理;但是测定的棉花产量从高到低依次为N5000、X5000、N4500、X4500,因此,虽然微咸水一定程度上影响棉花的生长(株高、干物质总重和叶片数),但是大水量微咸水(X5000)灌溉对棉花产量影响不明显,仅比大水量淡水灌溉(N5000)减产92kg/hm2,减少1.45%。3)新疆膜下滴灌棉田地膜残留带来的生态环境问题主要包括影响土壤水分渗透、土壤含水量、孔隙度和容重等理化性质,抑制棉花生长发育和降低产量等;解决措施主要包括加强残膜回收机研发与应用、提高地膜厚度和质量、提前揭膜等改进农艺技术、秸秆还田及开发可降解膜等新技术。4)社会经济可持续性包括:构建长期稳定的土地流转机制;创新农户、农场经营管理方式;开展群众自主式土地整治,促进耕地集中连片,扩大农户土地经营规模;积极发展农村金融等小额贷款,确保土地投入;推广"一膜三带六行"种植模式(2.05m宽的地膜)和"矮、密、早"栽培技术;推广秸秆还田、秋早犁春早耙播耕作技术;完善劳务市场、培育新型职业农民。

Systematic analysis on saline-alkali land sustainable utilization of drip-irrigated cotton field under mulch in Xinjiang

From aspects of nature,ecological environment and social economy and in order to explore saline-alkali land sustainable utilization for saving water,decreasing soil salinity and improving cotton field production,datasets including field experiments in Manas County of Xinjiang,farmers'' land use investigation data and literature review were systemically analyzed in this study.The results showed that:1) For short term condition of drip irrigation under mulch,brackish water and fresh water had similar effects that make soil root layer (0-30 cm) in desalination status,which ensured the environment for cotton''s growth;and The order of four treatments by their effects to decrease soli salinity salt down in descending was as:large amount of fresh water (N5000),small amount of fresh water (N4500),large amount of brackish water (X5000),and small amount of brackish water (X4500).2) The effects of fresh water treatment was higher than that of brackish water treatment on the plant height,dry matter weight and leaf number of cotton in the flocculent period;The cotton production from high to low was N5000,X5000,N4500,X4500;Therefore,although brackish water affected the growth of cotton (plant height,dry matter weight and leaf number),the effect of large amount of brackish irrigation water on cotton yield was not obvious whose production was just 92 kg/hm² lower than that of large amount of fresh water treatment,which decreased by 1.45%.3) Ecological and environmental problems caused by drip-irrigated cotton field under mulch in Xinjiang mainly included affecting the residual soil moisture permeability,soil water content,soil porosity and physical and chemical properties (i.e.bulk density), resulting in the inhibition of cotton growth and decrease in yield.Solutions to solve the problems included strengthening the research and application of recycling machine of residual plastic film,improving the quality and thickness of plastic film,uncovering mulch in time,straw returning and developing biodegradable film.4) Social and economic sustainability included:building long-term and stable land circulation mechanism,promoting innovation of farmers'' and farms'' management approach;carrying out autonomous land consolidation to make arable land concentrated,expanding the farm size;actively promoting the development of the rural financial microfinance and ensuring land investment.To promote planting model of "one film three belts six lines" planting patterns (2.05 m mulch) and "short,dense,early" cultivation techniques;promoting straw returning,plow early in autumn sowing early in spring farming technology;and improving the labor market and cultivating new type of professional farmers.