绿肥轮作对早稻生长动态及氮素吸收利用的影响

综合评价南方稻区不同冬季绿肥种植下水稻对氮素的吸收利用特性，为水稻高产栽培中氮肥的合理运筹和水稻氮素营养性状改良提供依据。比较不同冬季绿肥紫云英、油菜、黑麦草及混播绿肥对后作水稻产量、生长动态及氮素吸收利用的变化。结果表明：（1）处理紫云英—早稻—晚稻(MV-R-R)的早稻产量分别比黑麦草—早稻—晚稻(RG-R-R)、油菜—早稻—晚稻(RP-R-R)、混播绿肥—早稻—晚稻(MS-R-R)高6.61%、3.29%及0.78%。（2）在分蘖期、孕穗期、抽穗期和成熟期植株含氮率均是处理MV-RR达到最大，较其他处理平均分别高9.68%、19.72%、6.23%和8.66%。在分蘖期、孕穗期、抽穗期和成熟期植株吸氮量均是处理MV-R-R最高，处理RP-R-R最低。（3）处理MV-R-R在分蘖期至孕穗期、孕穗期至抽穗期及抽穗期至成熟期各处理的吸收量较其他处理平均分别高出21.81%、68.73%和286.5%，且绿肥轮作条件下水稻氮素阶段吸收量及其占总吸收量的比例均以抽穗至成熟期最小，最大值所处的生育阶段则是分蘖前。因此，MV-R-R处理具有较高的增产潜力，有利于提高氮肥利用效率，改善稻田氮素循环。

Effects of Green Manure Rotation on Rice Growth Dynamics and Nitrogen Uptake and Utilization

This study aimed to comprehensively evaluate different winter green manure on characteristics ofnitrogen uptake and utilization, to provide the basis for rational application of N fertilizer and improvement ofnitrogen nutrition in high-yield cultivation of rice. This experiment was set to compare milk vetch, rapeseed,ryegrass and mixed of green manure on rice yield, rice growth dynamics and nitrogen uptake and utilization inrice. The results showed that among the 4 different winter green manure, the early rice with treatment of MV-R-R（milk vetch- rice-rice） had the highest yield, compared with RG-R-R（ryegrass- rice- rice）, RP-R-R（rapeseed- rice- rice）, MS-R-R（mixed green manure- rice- rice）, treatment by MV-R-R increased riceyield by 6.61%, 3.29%, 0.78%, respectively. The treatment of MV-R-R in N content in plant of rice wasmaximized in the tillering, booting, heading and maturity periods, higher than the average of the othertreatments by 9.68%, 19.72%, 6.23% and 8.66%. At tillering, booting, heading and maturity, the treatment ofMV-R-Rwas the highest in N uptake, while RP-R-R was the lowest. The N periodic accumulation for MV-R-R were higher than the other treatments in the tillering to booting, booting to heading and heading to maturity periods, with the rate at 21.81%, 68.73% and 286.5% respectively. In addition, N periodic accumulation andits ratio to the total in the heading to maturity was the minimum, the maximum occurred before tillering undergreen manure rotation system. So the cropping system of milk vetch- rice- rice could increase nitrogen useefficiency andimprove Ncycling.