移栽叶龄对水稻氮素吸收利用及~(15)N-肥料去向影响

利用15N示踪技术研究了不同叶龄移栽对水稻产量、氮肥吸收利用及其氮素去向的差异。结果表明,随移栽叶龄推迟,水稻产量显著降低,籽粒与秸秆氮肥吸收量、肥料利用率及其残留量也降低,而氮素损失增加。水稻所吸收的氮素约2/3来源于土壤氮,1/3来源于当季肥料施的氮。肥料利用率为20.8%~25.7%,氮肥残留率为17.9%~32.2%,有42.1%~61.3%的肥料损失。无论哪种叶龄移栽条件下,肥料主要残留在0~20cm土层中。研究表明水稻早栽能增加产量、提高肥料利用率,减少肥料损失,降低氮素对环境的污染。

EFFECT OF DIFFERENT TRANSPLANTING LEAF AGE ON RICE YIELD, NITROGEN UTILIZATION EFFICIENCY AND FATE OF 15N-FERTILIZER

 Field experiments were conducted to study rice yield, N uptake and fate by using 15N-urea at transplanting leaf age of 2-, 4- and 6-leaf, respectively. The results showed that rice yield significantly decreased with delay of transplanting leaf age, and 15N-fertilizer uptake by grain and straw of rice, nitrogen utilization and residue also decreased, but loss 15N-fertilizer increased. Under different transplanting leaf age, N absorption by rice mainly came from the soil. Almost 1/3 of total N was supplied by fertilizer, and 2/3 came from soil. The efficiency of fertilizer was 20.8%~25.7%, 15N-fertilizer residue ratio was 17.9%~32.2%, and 15N-fertilizer loss was 42.1%~61.3%. 15N-fertilizer Residue mainly distributed in 0~20 cm top soil under different treatments. The results indicated that transplanting young leaf age could increase rice yield and nitrogen utilization efficiency, and decrease loss of nitrogen fertilizer and pollution level on environment.