层次递进判别法对耕地利用方式与土壤原生动物群落关系的综合分析

Comprehensive analysis of the relationship between farmland use type and soil protozoan community by layer progressive discriminant

探讨了耕地利用方式对土壤理化性状和土壤原生动物群落生长状况的影响,以及土壤理化性状和土壤原生动物群落间的变化关系.设置了4a露天菜地、1a温室大棚、4a温室大棚和常规农田4种耕地利用方式,在5月份和10月份测定了土壤有机质、碱解氮、有效磷、速效钾、pH值、土壤含水量和土壤容重7个理化指标,分析了原生动物的种类、丰度和多样性指数,依据土壤原生动物指标的性质采用层次递进判别分析法和综合相关分析法进行了3个层次分析.结果表明,5月份和10月份的结果基本相同;耕地方式对有机质、碱解氮、pH值、土壤含水量有显著影响;对纤毛虫丰度有显著影响,对其他类群丰度和多样指数无显著影响.原生动物群落综合指标正确区别4种耕地方式的有效率达91.7%;土壤7个理化指标与原生动物7个指标两两之间基本不存在显著的直接相关性,但两指标群之间存在极显著的正相关系数.由此得出结论:耕地利用方式已造成土壤理化性状和原生动物群落总体上的差异性;土壤理化性状与土壤原生动物群落间存在极其显著的正相关关系.综合分析能够克服单一指标逐一分析的不足,更能全面、客观地反映4种耕地利用方式对土壤理化性状、土壤原生动物群落生长分布的影响以及土壤理化性状和土壤原生动物群落间的总体关系.

To explore the effects of farmland use types on soil physico-chemical properties and soil protozoan communities, as well as the relationship between them, four farmland use types were set up, including 4a open vegetable field, 4a greenhouse, 1a greenhouse, and conventional field. In May and October, the contents of soil organic matter, hydrolyzable nitrogen, available phosphorus, available potassium, pH value, soil moisture and bulk density were measured. On the base of protozoan community abundance, Shannon weaver index, evenness index and Simpson’s dominance index were calculated. These indices were analyzed in three levels by layer progressive discriminant and comprehensive correlation methods. Similar results were achieved in May and October. Four farmland use treatments had significant influences on the contents of the organic matter, hydrolyzable nitrogen, pH value and soil moisture and ciliate abundances. No significant differences existed during other indices.The efficiency of distinguishing four farmland types reached 91.7% by seven protozoan community indices. Significant direct correlation was merely found between 7 physical-chemical indices and protozoa community indices, but there were extremely significant positive correlation coefficients between the two index groups. Therefore, it concluded that four farmland use types had caused the differences of soil physical-chemical characters and protozoan community as a whole. There was an extremely significant positive correlation between the whole soil physical-chemical properties and the whole protozoan community. Comprehensive analysis can overcome the lack of single index, reflect the effect of four farmland use types on soil physical-chemical properties and protozoan community distribution more entirely and objectively, and explain the overall relationship between them.