Effect Of Application Stage Of Panicle Fertilizer On Yield Formation And The Absorptivity Of Nitrogen And The Quality Of Rice

The experiments were carried out with mid-season rice Japonica,cv.Guangling xiangjing and Indica,cv.Liangyou peijiu as material, in the experimental field of Crop Cultivation and Physiology Key Laboratory during 2001-2003. Under different nitrogen application, the effect of application stage of panicle fertilizer on yield formation and the absorptivity-and-transference of nitrogen after jointing stage and the quality of rice were studied systematically. The results showed as follows:1. Different cultivars varied under different application stage of panicle fertilizer of rice. In Liangyou peijiu as total suitable amount of nitrogen application (15kg/mu), the application of panicle fertilizer of twice on time of 3rd and 1st to flag-leaf enhanced suitable panicles colony, increased the number of spikelet per panicle, coordinated a relationship between panicle and seeds, got high yield. As total amount (10kg/mu) was less, on time of 4th and 2nd to flag-leaf increased panicles, and enhanced kilograin weight and seed setting percentage, got high yield. In Guangling xiangjing as suitable total amount, on time of 4th and 2nd to flag-leaf benefitted to coordinate a relationship between panicle, enhanced kilograin weight and seed setting percentage, and seeds enhanced yield. Educing from the experiments, on the bases of determining suitable total amount of nitrogen application and making the reasonable ratio of base-tiller fertilizer to panicle fertilizer, determining the optimal application stage of panicle fertilizer should optimize yield component, then got high yield.2. Under different application stage of panicle fertilizer, LAI of heading stage added the more along with reaching the earlier application stage of nitrogenous fertilizer. In Liangyou peijiu, total number of spikelet had the difference, total number of spikelet colony achieved the maximum and grain leaf ratio got the higher when panicle fertilizer was applied twice on time of 3rd and 1st to flag-leaf. In Guangling xiangjing on time of 4th and 2nd to flag-leaf, total number of spikelet colony reached the most, grain leaf ratio get suitably, the relation of source and warehouse was coordination, improved photosynthetic productivity, increased the yield.3. The results showed, along with reaching the earlier application stage of panicle fertilizer, the amount of N-absorption under the same application amount increasedfrom the jointing stage, the heading stage to the maturing stage. Under the different application amount, the amount of N-absorption under the high amount had the higher than the low amount. The amount of N-absorption from the jointing stage to the heading stage reached 45-50% of the total amount in the whole stages, and was the peak stage of the plant need. The amount of N-absorption of the jointing stage, the heading stage both correlated well distinctly with yield, but the amount of N-absorption of the maturing stage showed a parabolic curve relationship with yield.4. The results showed, the nitrogen requirement per 100kg grain increased with the additional application of nitrogenous fertilizer. Under the same application amount, the nitrogen requirement per 100kg grain of the earlier application was the higher than of the later application. In Liangyou peijiu under the same application amount, the nitrogen productivity of the earlier application was the higher than of the later application. On the contrary in Guangling xiangjing, the nitrogen productivity of the later application was the higher than of the earlier. N-availability ratio(NAR) in this season of Liangyou peijiu was the higher than of Guangling xiangjing, and that of the high amount had the higher than under the lower amount. In Liangyou peijiu under the high amount, NAR in this season reached the more when panicle fertilizer was applied twice on time of 4th and 2nd to flag-leaf, and under the lower amount, that reached the most on time of 3rd and 1st to flag-leaf. In Guangling xiangjing under the high amount, NAR in this season reached the highest on tim...