长期定位施肥对湖南水稻土有效态微量养分的影响

Effect of long-term fertilization on levels of nutrition of available trace elements in paddy soils in Hunan province

为探明合理施肥和土壤培肥的理论依据,研究了长期定位施肥(长期不施肥、单施化肥、施30%有机肥、施60%有机肥共4个处理)对湖南主要水稻土微量养分(有效硼、有效铁、有效锰、有效铜、有效锌)含量的影响.结果表明,长期定位施肥处理影响不同水稻土的微量养分含量,其含量变动趋势及机理因不同土壤而异.相对于长期不施肥处理,各施肥处理土壤有效硼、有效铜、有效锌含量的增加是因施肥增加的土壤有机物料使土壤固定态硼、铜、锌活化所致,也因为施肥将硼、铜、锌带入了土壤;有效硼、有效铜、有效锌含量的减少是因在单施化肥处理下作物生物量的增加加强了对它们的吸收.有效铁、有效锰含量的增加主要是因施用有机肥降低了土壤Eh,也因施用有机肥将铁、锰带入了土壤;有效铁、有效锰含量的减少主要是因土壤pH上升及有机质固定所致.

The variation of trace elements caused by different fertilization in paddy soils in Hunan province were studied for the first time. Trace elements were measured based on long-term sited fertilization experiments with four treatments including CK, NPK, OM30, and OM60, which have been conducted for twenty years on purple tidal clayey earth, reddish yellow clayey earth, blue gray clayey earth, alluvial sandy earth, yellow clayey earth, and whitish clayey earth. The result shows： long-term sited fertilization altered the contents of trace elements nutrition in different paddy soils; the change trends and mechanisms for trace elements differ from various paddy soils and fertilizations. Compared with CK, the contents of available B, available Cu, and available Zn in the paddy soils under fertilization treatments are either increased either through freeing the trace elements fixed in soil by increasing organic matter or inputting B, Cu, and Zn with long term fertilization, or decreased because of the plants with larger biomass taking in more available B, Cu, and Zn under NPK treatment for long term~ the contents of available Fe and Mn went up due to the declining of Eh and pH in paddy soils and the inputting of Fe and Mn from organic manure fertilization, while it declined due to the rising ofpH and the intensifying of organic matter＇s adsorption.