轮耕对土壤物理性状及水稻产量影响的初步研究

针对南方稻田连续免耕存在的主要问题，进行了土壤轮耕效应的初步研究。试验选择双季稻区连续7年免耕稻田，设置免耕、旋耕和翻耕3种耕作处理（即免耕-免耕，免耕-旋耕和免耕-翻耕），早稻和晚稻采取同-耕作措施。研究结果表明：连续免耕后进行土壤耕作（翻耕、旋耕）可以降低耕作层土壤容重，增加土壤水贮量，尤为翻耕显著，早、晚稻均表现为这-趋势；晚稻收获时，表层0～5cm的毛管孔隙度表现为免耕-翻耕、免耕-旋耕在5％水平上显著高于免耕-免耕，而下层差异不显著；早、晚稻晒田时，表层0～5cm原状土饱和导水率均表现为免耕～翻耕在5％水平上显著高于免耕-免耕和免耕-旋耕，而5～10cm无显著性差异；早、晚稻的实际产量均表现为免耕-旋耕〉免耕-翻耕〉免耕-免耕，起主要作用的构成因素是有效穗数。

Preliminary study on effects of rotational tillage on soil physical properties and rice yield

Conservation tillage for paddy is very common in Southern China.However,problems such as bulk density and compaction increasing occurred for paddy fields with long-term conservation tillage,which was not favorable for paddy rice growth.In order to solve those problems,rotational tillage was introduced in this study.No-tillage(NT),rotary tillage(RT),and conventional tillage(CT) were conducted in the paddy field with seven years notillage in double rice cropping region,Hunan Province.And treatments were NTNT,NT-RT and NT-CT,respectively.The tillage methods were the same of early rice and late rice.Results showed as follows: NT-RT and NT-CT treatments showed lower soil bulk density and higher water storage than NT-NT during the rice-growing stage.The soil saturated mass water content and bulk density showed inverse proportion under tillage treatments.The capillary porosity at 0~5 cm soil layer was significantly higher for NT-RT and NT-CT than that for NT-NT at the 5% level,but it was not significant in deeper soil during late rice harvest.The situ soil saturated hydraulic conductivity at 0~5 cm soil layer was significantly higher under NT-CT than those under NT-NT and NT-RT at the 5% level,but the difference was not significant at 5~10 cm soil layer during drying field periods for both early rice and late rice.Yields from the highest to the lowest were NT-RT,NT-CT,NT-NT in order for both early rice and late rice,and the key of yield components was effective panicles of rice.