太湖地区稻田保护性耕作条件下水稻生育期土壤肥力的变化

Effects of Protective Tillage of Paddy Fields on Soil Fertility under Different Rice Growing Stage in Taihu Region

在小麦—水稻、黑麦草—水稻和油菜—水稻3种种植模式下,研究土壤保护性耕作对太湖地区稻田水稻生育期土壤主要养分的变化及产量的影响。结果表明:3种种植模式下水稻成熟期土壤平均有机质、全氮、速效氮及速效磷含量均比移栽期有不同程度的提高,而速效钾含量则呈下降趋势;水稻产量以油菜—水稻种植模式为最高,其次为小麦—水稻和黑麦草—水稻种植模式。保护性耕作(秸秆全量还田、小麦或油菜免耕、水稻2次旋耕)和常规耕作Ⅱ(秸秆全量还田、小麦或油菜旋耕、水稻耕翻加旋耕)处理较少耕秸秆不还田、小麦或油菜免耕、水稻2次旋耕和常规耕作Ⅰ(秸秆不还田、小麦或油菜旋耕、水稻耕翻加旋耕)处理更有利于提高小麦—水稻和油菜—水稻种植模式的土壤有机质、全氮、速效氮、速效磷及速效钾含量,也有利于提高黑麦草—稻种植模式下的全氮、速效氮及速效钾含量。保护性耕作对麦—稻和黑麦草—稻种植模式的增产作用明显。

The experiment was carried out since 2004 at the Institute of Agricultural Sciences of Taihu Lake District, Jiangsu,with three cropping patterns （wheat--rice, ryegrass--rice, rape--rice） , two modes of tillage and two modes of crop straw returning to field, hence forming 12 experimental treatments. The soil organic matter（SOM） content, total nitrogen content（ TN）, available N（AN） content and available P （AP） content tested at maturity were increased compared to those in transplanting stage, while the soil available K （AK） content declined. Grain yield was rape--rice cropping pattern 〉 wheat--rice cropping pattern 〉 ryegrass--rice cropping pattern. Protective tillage and traditional tillage Ⅱ could obviously enhance SOM content, TN content, AN content, AP content and AK content under wheat--rice and rape--rice cropping pattern, and also could significantly increase TN content, AN content and AK content under ryegrass--rice pattern. Higher grain yield was obtained with protective tillage under wheat--rice and ryegrass--rice cropping pattern.