土壤有机质对宁夏农业综合开发活动的响应

Response of soil organic matter to comprehensive agricultural development in Ningxia province

为深入分析宁夏农业综合开发活动对土壤有机质的影响,认识其对气候变化的适应意义,分别于北部平原灌区、中部干旱带和南部黄土丘陵区的3个农发项目典型示范点,选取典型用地、玉米地、未利用地3种土地利用类型,分析表层10～20 cm土壤有机质的变化规律。研究发现,生态区和土地利用类型是影响土壤有机质的重要因素,并存在极显著的交互作用。研究区土壤有机质在4.53～14.70 g·kg-1范围内变化,典型用地有显著改善,平均质量分数达10.40 g·kg-1。限定生态区条件下,北部平原灌区无论水稻还是玉米利用方式下,土壤有机质含量相对未利用地都出现显著提升,但是南部黄土丘陵区3种土地利用类型间并无显著差异,中部干旱带只有甘草地土壤有机质含量显著提升,幅度高达145%。限定土地利用类型条件下,3个生态区间典型用地土壤有机质出现显著差异,但是北部平原灌区和南部黄土丘陵区间未利用地以及玉米地表层土壤有机质差异并不显著。研究区农业综合开发活动对土壤有机质储存的作用以正效应为主,但是不同农业土地利用类型在不同生态区对土壤有机质的作用不尽相同。宁夏农业综合开发活动需要综合考虑生态区水土资源特征,选取适宜的农业土地利用类型,有效提升土壤有机质含量,积极应对气候变化。

In order to probe into the effects of comprehensive agricultural development on soil organic matter with its adaptation to climate change,the soil organic matter in the surface layer（10-20 cm） was investigated in three land use types（typically utilized land,cornland,and unused land）,respectively at three ecological regions such as irrigated areas in the north,arid areas in the middle and loess hilly areas in the south in Ningxia province.Both ecological regions and land use types,together with their interactions,were the main affecting factors on soil organic matter.The content of soil organic matter in the study regions changed from 4.53 g.kg-1 to 14.70 g.kg-1,while there was significantly higher content of soil organic matter in typically utilized land with the value of 10.40 g.kg-1.Under the condition of ecological regions,the content of soil organic matter was significantly higher in cornland or rice land than in unused ones in irrigated areas in the north;but there was no significant difference amonst the three land use types in loess hilly areas in the south;while the significantly higher content of soil organic matter was found only in GLycyrrhiza uralensis Fisch land in the arid areas in the middle part,with the value of 145%.Under the condition of land use types,significant differences in content of soil organic matter in typically utilized land were observed amonst the three ecological regions,but there were no significant differences in content of soil organic matter in cornland or unused land between irrigated land in the north and in loess hilly areas.In conclusion,there was a positive effect on the stock of soil organic matter through comprehensive agricultural development,but there were different effects on the content of soil organic matter in different ecolocial areas amongst different land use types.The soil and water properties should be considered integratively and the suitable land use types should be selected during the comprehensive agricultural development,thus beneficial to increase the content of soil organic matter and for the adaptation to climate change actively.