作　　者： ; ; ; ; ; ;

机构地区： 中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室

出　　处： 《土壤通报》 2013年第4期925-930,共6页

摘　　要： 基于长期定位实验,分析了开垦初期石灰土土壤养分的变化特点及其对耕作管理方式的响应,结果发现:开垦初期,喀斯特坡地石灰土有机质(SOM)表现出急剧丢失的特征,在开垦后的第二年和第四年坡地玉米地SOM的损失率分别达42%和40%,坡地牧草地SOM的损失率分别达19%和35%;玉米地SOM的丢失量和丢失比例明显大于牧草地,说明牧草地的免耕种植和较大的根系生物量在一定程度上有利于遏制石灰土SOM的快速丢失;不同养分对开垦和施肥管理的响应不同,SOM和碱解氮(AN)对开垦响应最为强烈,均在开垦后降低或显著降低。磷(P)和钾(K)则对施肥管理的响应更为明显,在有施肥投入情况下,土壤P、K逐年升高;施用有机肥(农家肥和秸秆)有利于石灰土SOM和相关养分含量的提高,是一种更加环境友好的农田生态系统管理方式。相对于使用秸秆的处理,施用农家肥更有利于石灰土SOM和K的积累。 Soil nutrients loss induced by cultivation practices is one of the important processes that result in the occurrence of soil degradation and karst rock desertification in southwestern China, but we still know little about the response mechanisms of this soil process. Based on a four-year field reclamation trial, this study identified the characters of soil nutrients loss process and its response to tillage management practice. Results showed that soil organic matter （SOM） decreased rapidly with cultivation in the initial period, SOM loss ratio reached 42% and 40% respectively at the second and fourth years of cultivation in the maize planting slope land. But SOM loss ratio was 19% and 35% respectively at the second and fourth years of cultivation in the forage grass planting slope land. SOM loss quantity and loss ratio were higher in the slope farmland planting with maize compared with the forage grass, which indicated that no-tillage management and large root biomass of the forage grass planting system were beneficial for the conservation of SOM loss. Different soil nutrients responded differently to reclamation and fertilization. SOM and available nitrogen （AN） decreased significantly after reclamation. But reclamation had no significant effect on phosphorus （P） and potassium （K）, while P and K increased significantly in the fertilization treatments. The input of compost fertilization as either manures or straws had a benefit on the increase of SOM and soil nutrients content, suggesting that organic farming was more environmentally benign relative to chemical fertilization practice. The use of manures, relative to straws, enhanced more accumulation of SOM and K in the calcareous soil.

关 键 词： 喀斯特峰丛洼地 土壤退化 土壤肥力 石灰土 土壤有机质

领　　域： [农业科学] [农业科学]