杭嘉湖平原桑园生态系统的土壤结构状况及其与土壤肥力的关系

Studies on the Relationship between the Soil Structure Properties and Soil Fertility in Mulberry Garden Ecosystem of Hang-Jia-Hu Plain

研究了杭嘉湖平原桑园生态系统的土壤结构状况及其与土壤肥力的关系。结果表明高产桑园土壤>0.25mm的水稳性团聚体含量较高,团聚体组成以粒径1～0.25mm为主,且土壤养分贮量丰富,速效养分充足,三相比例协调,生物活动活跃。高肥土壤各级水稳性团聚体的有机碳含量比低肥土壤高,且以2～1、1～0.25mm粒级团聚体有机碳含量较高,统计分析结果表明粒径以2～1、1～0.25,>0.25mm团聚体含量与有机碳呈极显著相关。建立一个稳定合理的农业生态结构,增施有机肥料,合理耕作以及冬季塘泥培土和套种绿肥是恢复和改善桑园土壤结构状况的有效措施。在施用有机肥的同时养殖蚯蚓改善土壤结构效果显著;中耕可创造临时性0.25～3mm的土壤团聚体,降低>5mm的大团聚体。

This paper deals with the relationship between the soil structure and soil fertility in mulberry garden soil ecosystem of Hang-Jia-Hu plain area. Results showed that the content of -water-stable aggregate(>0.25mm in diameter),mean weight diameter of aggregates in high yield mulberry garden soil were more than that of low yield mulberry garden soil. The water-stable aggregates of 1-0.25mm in diameter are major component of the aggregates. The good structure in high yield mulberry garden soil may play an importent part in providing a better soil nutrient condition and soil aeration, stimulating the activity of earthworm in the soils. For the aggregates in diameter from 5 to 0.25mm, the content of total organic matter in high yield mulberry garden soil is higher than that in low yield mulberry garden soil. Regression analysis showed that the amount of aggregates belonged to 2-1, 1-0.25, < 0.25 in diameter was significantly positively correlated with the content of total organic matter. It is suggested that the improvement of agroecosystem structure, application of organic fertilizer, deep ploughing, plantation of green manure and the ultilization of pond sludge may induce the good structure properties of mulberry garden soils. Organic manure and earthworm not only increase the amount of water-stable aggregates, but also reduce the ratio of aggregate fracture. Deep ploughing also increases the temporary aggregate in diameter from 0.25 to 3 mm.