不同时期氮钾配施对杂交籼稻F优498产量形成的影响

摘要

The effects of combined application of nitrogen (N) and potassium (K) at different growth stage on yield formation were investigated with hybrid rice F you 498 as material. For N fertilizer treatments, the ratio of basal, tillering, spikelet-promoting and spikelet-preserving N were 5∶3∶1∶1(N1), 3∶3∶2∶2(N2), 3∶1∶3∶3(N3) and N0(no N fertilizer applied);For K fertilizer treatments, the ratio of basal, tillering, spikelet-promoting and spikelet-preserving N were 10∶0∶0∶0(K1), 7:0:3:0(K2), 3∶0∶7∶0(K3) and K0(no K fertilizer applied). The results showed that N1K1, N2K3 and N3K2 obtained the highest yield respectively with their corresponding N treatments, among which, N3K2 produced the maximum grains. For all N treatments, a larger proportion of K at later growth stage boosted the rate of productive tillers and effective panicle number, and for N2 and N3 treatments, total spikelets were also enhanced with more K applied later. A moderate reduction of K proportion at earlier stage was beneficial for dry matter accumulation at elonga-tion stage. For post-anthesis dry matter accumulation and its ratio, K1 at N1 and N2, and K3 at N3 were the optimal respectively. Compared with K2 and K3, K1 got the most advantageous Pn value of flag leaf after anthesis at N1, though its leaf area index (LAI) of top three leaves and SPAD value were relatively poor at and after anthesis. For N2 and N3, K1 could slow down the reduction of SPAD and Pn value, but K2 and K3 possessed more advantageous LAI of top three leaves, and obtained higher yield ultimately.%以杂交籼稻F优498为材料，设氮、钾不同施用时期配比处理，其中氮素处理基、蘖、促花、保花肥比例分别为：5：3：1：1（N1）、3：3：2：2（N2）、3：1：3：3（N3）、N0（不施氮）4个处理；钾素基、蘖、促花、保花肥比例10：0：0：0（K1）、7：0：3：0（K2）、3：0：7：0（K3）、K0（不施钾）4个处理，研究不同时期氮钾配施方式对水稻产量形成的影响。结果表明，不同的氮肥运筹条件下对应产量最高分别是N1K1、N2K3和N3K2处理，其中以N3K2处理产量最高，各氮肥运筹中提高后期施钾比例均能够提高水稻的成穗率和有效穗数，在N2、N3条件下提高后期钾肥施用比例能够提高总颖花量；适当减少前期施钾比例有利于拔节期干物质的积累，N1、N2条件下K1处理和N3条件下K3处理能够提高齐穗后干物质积累量和比例；N1条件下，与K2、K3处理相比，K1虽然齐穗期上3叶的LAI和齐穗后剑叶SPAD值较低，但其齐穗后剑叶的Pn值优势显著，产量更高；N2、N3条件下，K1虽然延缓齐穗后剑叶SPAD和Pn值的下降速度，但由于齐穗期上3叶的LAI较小，导致其产量低于K2、K3处理。