石膏改良盐碱土研究进展

盐碱土因其瘦、板、生、冷、咸等作物生长障碍性特征而不宜耕种,但“端牢中国饭碗”的国家粮食安全战略则要求必须加大力度“向盐碱地要粮”。实践证明,施用天然或工业副产品石膏可有效改善盐碱土性状,从而提高盐碱地生产力。本研究梳理100多年来国内外相关研究进展,总结了现有石膏改良盐碱土的研究成果,拟为石膏改良盐碱土技术体系的完善和全面推广提供理论依据。分析认为,1895年以来开展的大量研究揭示了石膏改良盐碱土以交换过程和固持过程为主的作用机理;建立了多类石膏改良盐碱土适宜施用量计算公式,表明土壤容重、改土层厚度、土壤碱化度和土壤阳离子交换量等是影响石膏适宜施用量的代表性因素;制定了基于土壤盐碱化程度的石膏施用方法,明确了石膏施用对土壤理化生等方面的有益效果。目前,施用石膏改良盐碱土需配套灌溉措施,定额一般为每666.67 m²施用150～200 m³水,最适方式为喷灌或滴灌等持续性灌溉,不同盐碱度土壤及作物特性需要不同的施用量和施用方法及配套灌溉方法。现有的研究和实践成果为盐碱地高效利用提供了有力支撑,但仍需进一步融合统一适宜施用量计算公式,建立跨区域...

Progresses of gypsums for the improvement of saline-alkaline soil

Saline-alkaline soil is not suitable for farming because of its low fertility, consolidation, poor biological activity, low temperature, high salt content and other obstacles. However, the national food security strategy of “Secure the rice bowl in China” requires more efforts to “ask for grains from saline-alkaline land”. Practical experiences have proved that the application of natural or industrial by-product gypsum can effectively improve the properties of saline-alkaline soil, thus increasing the productivity of saline-alkaline land.This study compares the progress of related research at home and abroad for more than 100 years, reviews and summarizes the existing research results of gypsum improvement of saline-alkaline soil, and intends to providea theoretical basis for the improvement and comprehensive promotion of the gypsum improvement technology system. It is intended to provide a theoretical basis for the improvement and comprehensive promotion of the gypsum technology system for improving saline-alkaline soil.The analysis suggests that numerous studies conducted since 1895 have revealed the mechanisms based on the cation exchange process and immobilization process, established several formulas for calculating the suitable application amount, shown that soil bulk density, thickness of soil modification layer, exchangeable sodium percentage and soil cation exchange capacity are representative factors influencing the appropriate amount of gypsum application, and the method of gypsum application based on the degree of saline-alkaline soil was developed. The beneficial effects of gypsum application on soil physical and chemical biology were clarified. At present, the application of gypsum to improve saline-alkaline soil needs to be accompanied by irrigation measures, and the quota is generally 150-200 m³ of gypsum per 666.67 m². The best method is the continuous irrigation such as sprinkler irrigation or drip irrigation, and different saline-alkaline soil and crop characteristics require different application amounts and irrigation methods. The existing research and practical results provide strong support for the efficient use of saline-alkaline soil. However, there is still a need to further integrate and unify the appropriate application formula. The calculation formula of suitable application amounts should be further integrated and unified, and the calculation method should be established across regions and applicable to various scenarios. The biogeochemical processes of passively introduced elements should be studied in depth, and the response mechanism of soil ecosystem should be revealed; the monitoring level of ecological and environmental risks brought by gypsum application should be improved, and the long-term dynamic quantitative assessment should be carried out.