不同氮钾配比对直播早稻氮素吸收与利用的影响

摘要

在3个施氮量分别配合3个施钾量的条件下，探讨了不同氮钾配比对直播早稻氮素代谢和吸收利用的影响。结果表明，以N2 K3处理氮素总积累量和利用率最高。同一施氮水平下增施钾肥提高氮积累量，处理间差异显著。相同施钾水平下，施氮165 kg/hm2和210 kg/hm2，氮积累量差异不显著。提高直播稻氮、钾施用水平，增加了穗分化期之前氮素积累比例。增施氮、钾用量更有利于提高营养器官氮量分配比例，稻穗氮素分配比例随着施钾量的提高下降。各器官的氮素转运率和对稻穗氮的贡献率随着氮用量的提高而增加；施氮165 kg/hm2和210 kg/hm2水平下增施钾肥，叶片和叶鞘氮转运率下降；施氮210 kg/hm2水平下，施钾量对氮素转运率的影响规律不明显。 NR、GOGAT、GS活性，抽穗前随着施氮量的增加而提高；抽穗后通常N2最高。NR、GOGAT、GS活性随着钾肥量增加而提高。3个施氮水平中N2氮肥农学利用率最高。同一施氮水平增加钾肥用量提高氮肥利用率，在中、低氮水平下效果显著。增施氮、钾肥，氮素收获指数下降。直播稻栽培施氮量为165 kg/hm2、施钾量为210 kgh/m 2为最佳配组。%Under the condition of different proportion of three nitrogen amounts with three potassium a -mounts ,the effects of different proportions of nitrogen and potassium amounts on the nitrogen absorption and u -tilization were discussed .The result indicated:the total accumulation and utilization of nitrogen were the highest in the N2 K3 treatment.At the same nitrogen level,the nitrogen accumulation increased with potassium fertiliz-er amount,there were significant differences among different treatments.The nitrogen accumulation showed no significant difference when the nitrogen amount was 165 kg/hm2 and 210 kg/hm2 at the same level of potassi-um fertilization.The increase of nitrogen and potassium amounts was conducive to raising nitrogen accumulation before the panicle differentiation stage of direct-seeded rice .The increase of nitrogen and potassium amounts was conducive to raising the nitrogen distribution proportions in vegetative organs ,and nitrogen distribution pro-portion in panicle decreased with increase of amount of potassium applied .The nitrogen translocation rate and contribution rate of each organ nitrogen to grain increased with the increase of nitrogen fertilizer amount .The ni-trogen transport rate of leaf and sheath declined with increased amount of potassium fertilizer at the level of ni -trogen fertilizer of 120 kg/hm2 and 165 kg/hm2 .Potassium fertilizer had obvious influence on the nitrogen translocation rate at the level of nitrogen amount of 210 kg/hm2.The activites of NR,GOGAT,GS increased with nitrogen fertilization before heading .The activity of nitrogen metabolism enzyme of N 2 treatment was the highest usually after heading .The activites of NR,GOGAT,GS increased with potassium fertilizer .The nitrogen agronomy utilization ratio of N 2 was the highest at three nitrogen fertilizer levels .Increase of potassium fertilizer amount improved the utilization rate of nitrogen with the same amount of nitrogen fertilization ,this effect was significant at low nitrogen levels .The increase of fertilization amount of nitrogen and potassium decreased the harvest index of nitrogen .165 kg/hm2 of nitrogen and 210 kg/hm2 of potassium made the best coordination group for cultivation of direct-seeded rice .