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以长期定位施肥与小麦—玉米轮作田间试验为平台,研究了施肥对塿土土壤钾素的影响以及冬小麦生育期内土土壤速效钾、缓效钾及微生物量钾的变化。结果表明:氮磷肥不同施用量对土壤全钾基本没影响,而对速效钾、缓效钾及微生物量钾的影响较大。土壤速效钾和缓效钾均随施肥量的增加而减少,而微生物量钾随施肥量的增加而增加,且0—20cm土层土壤速效钾、缓效钾及微生物量钾含量均高于20—40cm土层。小麦生育期内,土壤速效钾和微生物量钾含量的变化一致,均是先上升再下降,再上升,又下降的变化。土壤中微生物量钾与有机碳、全氮均呈显著正相关关系,而与土壤速效钾和缓效钾无显著相关关系。氮磷肥在一定施用量范围内,促进了土壤无机态钾素的消耗,而提高了土壤微生物量钾的含量。土壤钾素的这种变化是作物吸收、施肥等因素共同作用的结果。
The effects of fertilization on soil potassium in soil and the changes of soil available potassium, slow-acting potassium and microbial biomass potassium during the growth period of winter wheat were studied by long-term localized fertilization and wheat-corn rotation field experiments. The results showed that different application rates of N and P fertilizer had no effect on total potassium in soil, but had significant effect on available potassium, slow-acting potassium and microbial biomass potassium. Both soil available potassium and slow-acting potassium decreased with the increase of fertilizer application, while microbial biomass potassium increased with the increase of fertilizer application. Soil available potassium, slow-acting potassium and microbial biomass potassium in 0-20cm soil layer were higher than 20- 40cm soil layer. Wheat growth period, soil available potassium and microbial biomass potassium content changes are the first rise and then decline, then rise and then decline in the change. Soil microbial biomass potassium and organic carbon, total nitrogen showed a significant positive correlation, but with soil available potassium and slow potassium had no significant correlation. In a certain range of application amount of nitrogen and phosphorus fertilizer, it promoted the consumption of soil inorganic K and increased the content of soil microbial biomass K. This change of soil potassium is the result of crop absorption, fertilization and other factors together.