曝气滴灌调控土壤通气性的机制与效应研究

In aeration drip irrigation, the soil is irrigated with a uniform mixture of water and micro air bubbles through a subsurface drip irrigation System. This novel technique is of great application prospect for its capability in increasing crop production and water use efficiency. In agriculture, the remediation of soil aeration is the basis of crop production increase and of higher water use efficiency for aeration drip irrigation. The status of micro air bubbles in soil and its effects on the soil air-filled pores morphology, oxygen diffusion process and root water uptake are the key issues in the aeration drip irrigation soil aeration remediation. In this study, the combined theoretical analysis, experimental observation and model simulation will be employed. Concretely, the distribution difference of oxygen diffusion rate (ODR) and the reduction function of Feddes of macro root water uptake mode between aeration drip irrigation and subsurface drip irrigation will be investigated; the remediation effect of aeration drip irrigation on root water uptake and soil aeration will be quantified to yield a method for estimating the embedded status of the micro air bubbles induced with aeration drip irrigation in soil; the ratio and the composition and proportion of both the connected and blocked air-filled pores in the soil after aeration drip irrigation will be analyzed; the model of soil pores status, water film thickness and oxygen transmission in the soil after aeration drip irrigation will be modified; the effects of aeration drip irrigation on the characteristic parameters of air pores, such as the tortuosity of air-filled pores in soil, equivalent soil air-filled pole radius, the number of air-filled pores in a soil transect and soil air-filled pore continuity index an oxygen diffusion coefficient, water film thickness outside roots, wi11 be simulated and evaluated. In general, these studies are aimed at prodding a theoretical instruction for a highly effective regulation of soil aeration in the oxygenated soil and the effectiveness evaluation of aeration drip irrigation.

曝气滴灌将水与微气泡均匀混合后浸润土壤，能有效提高作物产量和水分利用效率，是一种节水高效的新型灌溉技术。土壤通气性的改善是曝气滴灌增产增效的基础，微气泡在土壤内的赋存状况及其对土壤含气孔隙形态、氧扩散过程和根系吸水的影响是其调控土壤通气性的关键。本研究拟通过理论分析、试验观测与模型模拟相结合，以普通滴灌为对照，探讨滴灌湿润区内氧扩散率与根系吸水修正函数的分异特征，定量评价曝气滴灌对土壤通气性和根系吸水的修复效应，提出估算曝气滴灌微气泡在湿润区闭蓄程度的方法；诊断曝气滴灌条件下土壤含气孔隙中连通及堵塞组分的构成与比例，修正土壤孔隙形态、水膜厚度及氧传输模型，模拟并评价曝气滴灌对含气孔隙特征参数、土壤氧扩散系数以及根外水膜厚度的影响，揭示其改善土壤通气性的孔隙特征和氧扩散响应机制，为曝气滴灌土壤通气性的高效调控及其效应评价提供理论指导。

土壤通气性的改善是曝气滴灌增产增效的基础，本研究针对曝气滴灌调控土壤通气性的关键过程及参数，对比分析了曝气滴灌和普通滴灌对3种不同质地、3种不同容重土壤的湿润体特征值和通气性指标的影响，研究了不同灌水定额、灌溉水溶解氧浓度组合的曝气滴灌对土壤剖面的充气孔隙度、溶解氧浓度、氧气扩散速率等通气性指标时空动态的影响，明确了曝气滴灌改善土壤通气性的效应及主要参数，阐明了曝气滴灌提升土壤通气性的部分机制，为评价曝气滴灌调控土壤通气性的效应提供了理论依据。研究了曝气滴灌对涝渍番茄生长发育及产量和品质的影响，验证了曝气滴灌可以缓解淹水对番茄的缺氧胁迫，为补充曝气滴灌在多水系统中的增产提质效应提供了素材和理论依据。结果显示，与普通滴灌相比，曝气滴灌各处理条件下的土壤溶解氧浓度、氧气扩散速率、氧化还原电位和土壤呼吸速率均有显著增强，特别是容重较大、黏度较大的土壤及高灌水量下的加氧处理效果更好；曝气滴灌提高了淹水番茄的光合、产量和品质，一定程度上减弱了淹水胁迫对番茄生长发育的抑制作用。.本项目研究成果在《Land Degradation & Development》、《Journal of Soils and Sediments》、《核农学报》、《灌溉排水学报》等国内外期刊发表论文19篇，获得国家发明专利2件，2019年首位获得山东省科技进步二等奖、2020年第二位获得河南省技术发明二等奖2项，培养研究生4名。