利用杂交中稻齐穗期剑叶叶绿素计读数（SPAD值）预测再生稻促芽肥高效施用量

 2005-2006年以杂交中稻组合Ⅱ优602、Ⅱ优7号、冈优725为材料，通过头季稻不同施氮量使施促芽肥时植株营养状况存在差异，在此基础上分别设促芽肥施用量处理，探究再生稻促芽肥高效施用量与头季稻齐穗期库源结构关系。头季稻基肥和分蘖肥施氮的农学利用率是促芽肥的1.31～3.35倍;头季稻齐穗期剑叶SPAD值与库源结构关系密切;头季稻齐穗期剑叶SPAD值、叶片含氮量和群体单位面积的总颖花量3个因子可以用来预测再生稻高产的促芽肥经济施用量。建立了根据头季稻齐穗期剑叶SPAD值（x）预测再生稻促芽肥的高效施氮量（y)的回归方程(y=-25.733x+1212.4，r=-0.9534*)。

Estimation of Efficient Rate of Nitrogen Application for Promoting Ratooning Bud Development Using Chlorophyll Meter Reading(SPAD Value) of Flag Leaf at the Full Heading Stage of Main Crop in Mid-Season Hybrid Rice

The relationship between the efficient rate of nitrogen applied at the full heading stage of main crop for promoting ratooning bud development(NABD) and the chlorophyll meter reading (SPAD value) of flag leaf at the full heading stage of main crop were studied using the hybrid rice combinations Ⅱ you 602,Ⅱ you 7 and Gangyou 725 as materials at different levels of basal fertilizer and fertilizer applied at the tillering stage of main crop and NABD in 2005 and 2006. The results indicated that nitrogen agronomic efficiency in main crop were increased by 31%-235% than that of NABD.There were highly significant correlations between SPAD values of flag leaf and the characteristics of source sink of main crop. The efficient amount of NABD were correlated with the SPAD values of flag leaf, leaf nitrogen content and total number of spikelets per m2 of main crop. There was a significant negative correlation between the efficient amount (y) of NABD and the SPAD values (x) of flag leaf of main crop (y=-25733x+1212.4，r=-0.9534*).