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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。
Based on the long-term experiment, the characteristics of limestone soil nutrient change and its response to tillage management were analyzed. The results showed that the limestone soil organic matter (SOM) in the karst slope showed a sharp loss characteristic. After the reclamation In the second year and the fourth year, the loss rates of SOM on slopeland maize fields reached 42% and 40% respectively, while the loss rates of SOMs on slopeland pastures reached 19% and 35% respectively. The loss and loss proportion of SOMs in maize fields were significantly larger than that of forage grasslands , Which indicated that no-tillage planting and larger root biomass in pasture land were conducive to curbing the rapid loss of SOM in lime soil. The response of different nutrients to reclamation and fertilization management was different. SOM and alkali hydrolysis of nitrogen (AN) The response was the strongest and both decreased or significantly decreased after reclamation. Phosphorus (P) and potassium (K) showed more obvious response to fertilization management. Soil P and K increased year by year with fertilization, and organic fertilizer (manure and straw) The increase of nutrient content is a more environmentally friendly management of agro-ecosystem. Compared with the use of straw treatment, the application of manure is more conducive to lime soil SOM and K accumulation.