稻田年内水旱轮作的后效应研究

Residual Effects of the Paddy-Upland Yearly Rotation

在麦-稻-稻和麦-玉米-稻两种种植方式６年定位试验的基础上，对稻田年内水旱轮作的后效应进行了研究。结果表明：年内水旱轮作能显著地提高后作晚稻和大麦产量，但后效持续时间不长，到第三季后作物早稻增产已不明显。生产上两种种植方式以隔年轮换为好。增产的主要原因是年内水旱轮作改善土壤通透性，能增加土壤有效氮、磷、钾含量和提高根系活力，促进了作物生长和养分吸收，从而增加晚稻有效穗、结实率和实粒数，增加大麦有效穗和千粒重。试验也表明，增施肥料会降低轮作效果。

After a 6-year (1987-1993 ) long-term experiment with barley-rice-rice (BRR, CK ) and barley-corn-rice(BCR) cropping system, the effect of different cropping system on the yield and growth of the succeeding crops and its mechanism were studied in 1993-1994 in Zhejiang Province. The results showed that the yields of the succeeding crops late-rice andbarley after barley-corn-rice cropping system were significantly higher than that after barley-rice-rice cropping system. Therewas no significant difference in the yield of the 3rd succeeding crop early rice between two cropping system. It was more beneficial to the increasing of the crop yield and the improving of the soil fertility that two cropping system was rotated each otherevery year in production. The reason for those were mainly that the soil physical and chemical characteristics were more im. proved under BCR than under BRR, so that the hydrolytic N, available P, and available K content of paddy soil under BCRwere higher than those under BRR, the root oxidative power of the succeeding crop late rice was increased under BCR. All ofthose accelerate the growth of the succeeding crops and the absorption of nutrients. Then the effective panicle number, seedsetting rate and filled grain number of the succeeding crop late rice were increased and the effective panicle number and 1000grain weight of the succeeding crop barley were increased. The result also showed that the fertilizer application could reducethe residual effect of the paddy-upland yearly rotation.