长期施用有机肥措施下松嫩平原苏打盐碱土壤盐碱障碍消减的驱动机制研究

Soil salinization is a important problem of soil degradation all over the world, and result in great damage to agricultural production. Cattle manure application is effective measure for improvement in saline-alkaline soils. However, many studies on improvements in saline-alkaline soils with cattle manure application were performed in recent years, which focused on increase in crop yield, qualitative comments of soil physic-chemical properties as well as microorganism activities in the soils treated with cattle manure, and lacked in-depth study on mechanism of soil saline-alkaline obstacle abatement based on long-term cattle manure application. In view of main obstacle factor of serious soil salinization in the west Songnen plain, the study on mechanism of soil saline-alkaline obstacle abatement under long-term cattle manure application in solonetzic soils was carried out in songnen plain of China using plot experiment based on existing long-term location test of sodic saline-alkaline soil improvement by cattle manure application. We will carry out the researches: Characteristics of soil salinity barrier abatement; the main physical and chemical mechanisms of soil saline-alkaline obstacle abatement under long-term cattle manure application; formation of forecasting model of soil saline-alkaline obstacle abatement , which could ascertain the nature of improvement in sodic saline-alkaline soils with cattle manure application. The results from our study can provide the theory and technical supports for improvement in saline-alkaline soils and the further research of soil science in other areas, and resources, which has great realistic significance and strategic significance in China.

土壤盐碱化是世界性的土壤退化问题，给农业生产造成了极大的损失。施用有机肥是改良盐碱土的有效措施，已开展的各项研究工作多是停留在应用层面，或者对土壤理化性状及微生物活性等进行定性的评述，缺少以长期定位试验为基础的施用有机肥措施下盐碱土改良的深入研究。针对松嫩平原西部土壤盐渍化现象严重这一项关键的障碍因素，以松嫩平原典型苏打盐碱土已有的施用有机肥改良盐碱土的长期定位试验为平台，通过田间小区试验的方式，重点开展长期施用有机肥措施下苏打盐碱土壤盐碱障碍消减的驱动机制研究，重点研究：土壤盐碱障碍消减规律；土壤盐碱障碍消减的主要物理和化学驱动机制；构建盐碱障碍消减的预报模型。本项目研究成果对盐碱土的科学利用、苏打盐碱土区其他学科领域科研工作的深入开展具有重要的科学意义；同时，对耕地总量的动态平衡、粮食产量形成与国家可持续发展都具有重要的战略意。

土壤盐碱化是世界性的土壤退化问题，给农业生产造成了极大的损失。针对松嫩平原西部土壤盐渍化现象严重这一项关键的障碍因素，以松嫩平原典型苏打盐碱土已有的施用有机肥改良盐碱土的长期定位试验为平台，通过田间小区试验的方式，重点开展长期施用有机肥措施下苏打盐碱土壤盐碱障碍消减的驱动机制研究，重点研究：重点研究：土壤盐碱障碍消减规律；土壤盐碱障碍消减的主要物理和化学驱动机制；构建盐碱障碍消减的数学模型。通过3年的研究表明：施用有机肥各处理的土壤盐碱性质低于未施用有机肥的处理，并且随施用有机肥年限的增加呈现出递减的变化趋势（0-20cm土层对照处理的pH=10.25、EC=2.04 dS m-1、碱化度=55.24%；0-20cm土层施用有机肥处理的平均pH=8.59、EC=0.42 dS m-1、碱化度=13.35%），同时施用有机肥年限越多的盐碱土壤盐碱性质动态波动越平缓，表层土壤盐碱成分低于深层土壤（20-40cm土层对照处理的pH=10.66、EC=0.76 dS m-1、碱化度=65.13%；20-40cm土层施用有机肥处理的平均pH=9.01、EC=0.59 dS m-1、碱化度=24.10%）。可溶性盐分和交换性Na+降低是苏打盐碱土壤盐碱障碍消减的关键（EC与pH相关系数=0.81**；EC与碱化度相关系数=0.98**；pH与交换性Na+相关系数=0.98**；碱化度与交换性Na+相关系数=0.99**），苏打盐碱土壤改良前期，盐碱障碍消减以物理机制为主导，随改良年限的增加，盐碱障碍消减的化学机制才得以显现。盐碱障碍消减的物理机制伴随盐碱土壤改良整个过程，是主要驱动机制。剔除冗余因子，构建了数学模型，通过该数学模型揭示了苏打盐碱土壤通透性增加促进土壤盐分下行运动，是降低土壤盐分的关键（0-20cm土层对照处理的土壤饱和导水率Ks=0.031 cm h-1；0-20cm土层施用有机肥处理的平均土壤饱和导水率Ks=11.4 cm h-1）。结合本项目发表SCI论文2篇，EI论文1篇，中文核心期刊1篇，出版国家林业总局普通高等学校“十三五”规划教材1部，培养1名博士后出站，8名本科生顺利毕业。本研究成果对盐碱土的科学利用、苏打盐碱土区其他学科领域科研工作的深入开展具有重要的科学意义，对耕地总量的动态平衡、国家可持续发展都具有重要的战略意义。