EFFECT OF LATE-SEASON N-FERTILIZATION ON PHOTOSYNTHESIS AND YIELD OF TRANSPLANTED AND DIRECT-SEEDED TROPICAL FLOODED RICE .1. GROWTH DYNAMICS
EFFECT OF LATE-SEASON N-FERTILIZATION ON PHOTOSYNTHESIS AND YIELD OF TRANSPLANTED AND DIRECT-SEEDED TROPICAL FLOODED RICE .1. GROWTH DYNAMICS
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DOI：
10.1016/0378-4290(92)90042-8
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发表时间：
1992-01-01
影响因子：
5.8
通讯作者：
SCHNIER, HF
中科院分区：
文献类型：
--
作者：
DINGKUHN, M;DEDATTA, SK;SCHNIER, HF
湿法直播正在成为亚洲水稻（Oryza sativa L.）移植的越来越受欢迎的替代方案文化现代热带水稻品种，直播时，由于营养过度生长和叶片氮稀释生殖生长，往往低于其生物产量潜力。在1989年菲律宾干旱季节，采用“IR72”水稻进行田间研究，评价了晚季追施氮肥对冠层CO2交换率（P（n））、移植（TP）、穴播（DS）和撒播（BS）作物生长和产量的影响。在BS中，较高的播种量和没有移栽休克导致较高的分蘖数和叶面积指数（L）比TP。叶片氮浓度下降更快，因为BS更快速的增长。晚季追氮、撒施或叶面喷施均能提高叶片氮素浓度和磷素含量，增加小穗数，提高籽粒产量。小穗数的增加主要是由于追肥后小穗退化减少所致。不施氮肥时，粒重限制了籽粒产量，而施氮处理间粒重限制作用相当。穗数限制TP的产量，而每穗粒数更限制BS和DS。生殖生长各阶段的P（n）与籽粒产量相关，而成熟期的干物质则更多地取决于L。收获指数（HI）与叶片氮浓度的相关性最好。P（n）取决于L和叶面N浓度，但后者成为更多的限制植物发育先进。结果表明，晚季叶面施氮通过在限制期增加叶片氮素浓度，增加同化源，减少小穗退化，增加库，从而提高籽粒产量。考虑到叶片氮浓度和结实小穗数通常是BS产量的限制因素，晚季叶面追肥可能是一种专门改善BS栽培的手段。
Wet direct-seeding is becoming an increasingly popular alternative to transplanting in Asian rice (Oryza sativa L.) culture. Modern tropical rice cultivars, when direct-seeded, because of vegetative overgrowth and foliar N dilution during reproductive growth, often fall short of their biological yield potential. A field study using 'IR72' rice during the 1989 dry season in the Philippines evaluated the effect of late-season N top-dressing on canopy CO2 exchange rate (P(n)), growth and yield of a transplanted (TP), hillwise dibbled (DS) and broadcast seeded (BS) crop. In BS, the higher seeding rate and absence of transplant shock led to a higher tiller number and leaf area index (L) than in TP. Foliar N concentration decreased faster in BS because of more rapid growth. Late-season N top-dressing, broadcast or applied as foliar spray, increased foliar N concentration and P(n), and led to greater spikelet number and grain-yield. Higher spikelet number was explained by reduced spikelet degeneration after top-dressing. Grain weight limited grain-yield when no N was applied, but was equal among N-fertilized treatments. Panicle number limited yield for TP, whereas grain number per panicle was more limiting for BS and DS. The P(n) during various reproductive growth stages was correlated with grain-yield, whereas dry-matter at maturity depended more on L. Harvest index (HI) gave best correlations with foliar N concentration. The P(n) depended on both L and foliar N concentration, but the latter became more limiting as plant development advanced. It is concluded that late-season foliar N application raised grain-yield by enhancing the assimilate source through increasing foliar N concentration at a stage when it was limiting, and by enhancing the sink through the reduction of spikelet degeneration. Considering that both foliar N concentration and filled spikelet number are commonly limiting factors for BS yields, late-season foliar top-dressing may be a means to specifically improve BS rice culture.