可降解地膜覆盖对土壤水分运移的影响规律研究

The water use in agriculture is accounts for more than 70% of the total water consumption in China. The water utilization rate of irrigation is only about 45%, to improve water use efficiency is an important way to save water. Degradable film mulching planting technology is one of the emerging research directions in the field of water saving of agriculture. While the basic research on the soil moisture migration characteristics of degradable film is less, which limited its water-saving potential into full play. This study used degradable film mulching in rice field and pot experiment, through the determination of parameters that evaporation, leakage of arable layer, and plant transpiration characteristic, et al. In order to clear the key environmental factors that affects the soil water infiltration and evaporation, to clarify the effect of degradable film mulching on paddy soil water consumption patterns; Through indoor experiment, soil water infiltration and evaporation process were simulated, observation of the dynamic soil moist body, distance of wetting front infiltration, the top layer leakage, surface evaporation, and other soil moisture indexes. To establish the models of relationship between time and moist peak, infiltration rate and infiltration distance, and establish the models of the relationship between evaporation, evaporation rate and topsoil seepage quantity, soil moisture, soil temperature, environment temperature and humidity factor. To analysis dynamic mechanism of the influence of soil moisture migration rule about degradable film mulching to soil water infiltration, evaporation, and the wet body. To reveal the influence of soil moisture migration rule. Researches results will provide the theoretical basis for biodegradable degradable film mulching crops planting technology parameters optimization and reasonable irrigation method is determined.

我国农业用水占总用水量的70%以上，灌溉水利用率仅为45%左右，提高水分利用率是节约水资源的重要途径。可降解地膜覆盖是实现农业节水的关键技术之一，而有关其土壤水分运移特性的基础研究较少，限制了节水潜力的充分发挥。本研究利用可降解地膜覆盖水稻田间和盆栽试验，通过测定棵间蒸发、耕层渗漏以及植株蒸腾特性参数等，明确影响土壤水分入渗和蒸发的关键环境因子，阐明地膜覆盖对稻田土壤水分消耗的影响规律；通过室内试验，模拟土壤水分入渗和蒸发过程，观测土壤湿润体动态、湿润锋入渗距离、土壤水分耕层渗漏和地表蒸发等指标，建立湿润峰入渗距离、入渗速率与时间的关系模型，建立蒸发量、蒸发速率及耕层渗漏量与土壤含水量、土壤温度、环境温度、湿度等因子间关系的数学模型；分析地膜覆盖对土壤水入渗、蒸发及湿润体动态的影响机制，揭示土壤水分运移规律。研究成果将为可降解地膜覆盖作物种植工艺参数优化、确定合理灌溉方法奠定理论基础。

通过不同厚度黑色可降解地膜、纸膜覆盖的水稻盆栽和田间试验，以不覆盖常规淹灌为对照，研究了地膜的降解特性和力学特性，以及地膜覆盖对稻田土壤水分含量、土壤温度、土壤水分耕层渗漏量和地表蒸散量（地表蒸发和植株蒸腾之和）的影响规律。地膜降解研究结果表明，随着黑色可降解地膜厚度的增加其降解速度减缓，但在本研究条件下黑色可降解地膜和纸膜都能够在覆膜90d内完全降解。分析地膜覆盖对土壤水分的影响结果表明，黑色可降解地膜和纸膜覆盖均具有显著提高稻田土壤温度、降低土壤水分耕层渗漏和地表蒸发的作用；在稻田有水层的情况下主要表现为抑制水分的耕层渗漏和地表蒸发，而在稻田无水层的情况下，与对照相比地膜减缓地表蒸发的作用达到了显著水平，对耕层渗漏的影响差异不显著；在地膜覆盖70d之后，随着地膜的降解，地膜对土壤水分消耗的抑制作用逐渐减弱。对比分析不同灌溉水分处理条件下地膜的节水效果表明，在K1水分处理条件下，地膜覆盖对稻田土壤水分、土壤温度和水稻产量的影响与对照处理差异不显著，而在K2和K3水分处理条件下，地膜覆盖具有明显地提升地温和降低水分消耗的作用，差异达到显著水平。综合分析地膜降解特性、地膜铺放机械化作业的可行性，以及经济效益和生态效益，本研究明确了应用厚度为0.01mm的可降解地膜，采用湿润灌溉方法，能充分发挥可降解地膜的节水潜力。项目利用厚度为0.01mm的黑色可降解地膜进行了室内土槽模拟试验，研究不同灌溉条件下的土壤水入渗和蒸发特性，得到了土壤水入渗相关的数学模型。.在本项目支持下，发表学术论文5篇，其中EI收录2篇；项目研究内容作为创新点之一获得了辽宁省科技进步二等奖；申报国家专利1项，培养硕士研究生1人；参加学术会议3次，其中做学术报告1次，会议论文参加成果展示1次。研究成果为可降解地膜覆盖种植技术的应用和机械化覆膜机具的设计奠定了前期基础。