氮肥运筹对水稻氮素吸收和稻田渗漏液氮素浓度影响

通过大田试验，设计3个不同氮肥水平（0、150、240kgN·hm^-2）和两种不同施肥比例（基肥：分蘖肥：穗粒肥：40％：30％：30％、基肥：分蘖肥：穗粒肥=30％：20％：50％），研究了氮肥运筹对水稻氮素吸收和稻田渗漏液氮素浓度的影响。结果表明，稻田渗漏液中NH4＋-N、NO3--N和总N浓度在施肥后第3d达到最大、随后降低，在施氮后的第7d，分别降为峰值的5．6％～16．9％、13．8％～22．5％、22．5％～34．5％。施氮水平处于0—240kgN·hm^-2时，水稻产量、氮素积累总量（totalNaccumulation，TNA）和稻田渗漏液Nm—N、N0i—N和总N浓度随着氮素水平的提高而显著增加；在较高氮肥水平（240kgN·hm^-2）下，与氮肥前移相比（基肥：分蘖HE：穗粒肥=40％：30％：30％），采用氮肥后移（基肥：分蘖肥：穗粒肥=30％：20％：50％）的施肥比例，水稻产量和成熟期TNA分别增加6．2％和16．4％，稻田渗漏液NO3--N及总N浓度分别降低8．9％和4．8％，而对NHZ—N浓度影响不显著，说明适宜的氮肥运筹可以增加水稻的产量和氮素吸收，减少氮素渗漏损失。

Effects of Nitrogen Management on Rice Nitrogen Uptake and Nitrogen Concentrations in the Leachate from Rice Field

Effects of nitrogen management on rice nitrogen uptake and nitrogen concentration in the leachate from rice field were examined by a field experiment. In this study, the nitrogen was applied in three splits as 40%basal, 30% at 10 days after transplanting （DAT）, 30% 36 DAT and 30% basal, 20% 10 DAT, 50% 36 DAT at three N rates as 0, 150, 240 kgN·hm^-2. The results showed that three N concentrations （NH4＋-N, NO3--N and total N ）in the leachate reached the highest on the third day after fertilizer application, and thereafter decreased. Three N concentrations at 7th day were separately in ranges of 5.6%~16.9%, 13.8%~22.5% ,22.5%~34.5% at the third day. Grain yield, nitrogen uptake and three N concentrations in the leachate were significantly increased as the N rates increased from 0 to 240 kgN·hm^-2. At the N rate of 240 kgN·hm^-2, grain yield and nitrogen uptake were 6.2% and 16.4% higher when the nitrogen was applied in three splits as 30% basal, 20% 10 DAT, 50% 36 DAT, compared with that of the N splits as 40%basal, 30% 10 DAT, 30% 36 DAT. However, the concentrations of NO3--N and total N in the leaehates were 8.9% and 4.8% lower in former splits than the latter splits, respectively. No obvious differences in the NH2-N concentration in the leaehates were observed among different N splits. The results revealed that appropriate fertilizer application in three splits as 30% basal, 20%10 DAT, 50% 36 DAT could increased grain yield, nitrogen uptake and decreased nitrogen leaching loss.