不同耕作方式下水分管理对水稻氮素吸收利用的影响?

2008年早季和晚季，以桂旱1号和金优253为试验材料,盆栽条件下利用15N示踪技术研究了湿润灌溉、交替灌溉、水层灌溉3种水分管理模式下和免耕、常耕2种土壤耕作方式下水稻氮素与吸收利用的差异。结果表明：（1）湿润灌溉栽培降低了2种耕作方式水稻的氮肥吸收量，其中对基肥和分蘖肥吸收量的降低达显著水平；（2）湿润灌溉栽培时施入稻田中的氮肥被当季水稻吸收利用的比率下降，在土壤中的残留比率增加；（3）常耕条件下，湿润灌溉水稻氮素吸收总量明显低于水层灌溉和交替灌溉水稻，但免耕条件下湿润灌溉对水稻氮素吸收总量的影响比较小；（4）湿润灌溉时水稻产量和氮素的生产效率下降。

Influence of Water Management and Tillage Patterns on Nitrogen Utilization of Rice

Taking the rice vatieties of Jinyou 253 and Guihan 1 as the material, pot experiments were conducted to evaluate the differences of nitrogen utilization by rice using 15N tracer techniques in the early and late seasons of 2008. Experiment was carried out under three water management modes (Wetting irrigation, alternation irrigation and water layer irrigation) and two soil tillages patterns (no tillage and conventional tillage). The results showed that: (1) Wetting irrigation reduced the nitrogen uptake from fertilizer by rice plants under both soil tillage patterns, and the differences were significant for the basal and tillering fertilization. (2) More nitrogen from fertilizer was absorbed by rice plants and less was reserved in soil under wetting irrigation condition. (3) Nitrogen uptake by rice plants under wetting irrigation condition was obvious lower than that of rice with alternation or water layer irrigation under the conventional tillage pattern, but the influence of wetting irrigation on nitrogen uptake was less under no tillage pattern. (4) Grain yield and nitrogen grain production efficiency were reduced under Wetting irrigation condition.