Studies On Nitrogen Release And Use Efficiency Of Special Controlled Release Fertilizer For Maize

Studies were carried out on the nitrogen dynamic release and the fertilizer effects on summer maize of the special blended controlled release fertilizer for summer maize. The main results were as follows:1. The nitrogen fertilizer releasing period of the special blended controlled release fertilizer (BCRF) was between that of the none coated compound fertilizer (NCCF) and the whole coated compound fertilizer (WCCF). It matched the nitrogen release with the summer maize demand best. While, the nitrogen release of NCCF was relatively quick, but that of WCCF was relatively slow for maize absorption.2. BCRF could significantly improve the maize yield and its component facts both in the barrel trial and in the field trial. The maize grain yield of BCRF treatment increased by 8.36 percent, 13.34 percent, 25.24 percent more than that of WCCF treatment, NCCF treatment and single urea treatment, respectively in the barrel experiment, while, by 5.13 percent, 14.18 percent, 27.9 percent correspondingly in the field trial. The results showed that yield difference was significant or extremely significant among different treatments. In addition, the grain number per spike and the 100 kernel weight had a significant increase as result of application of BCRF both in barrel and in field growing.3. In all treatments, the nitrogen use efficiency (NUE) of BCRF was the highest under the barrel grown condition. The results of the treatment BCRF,WCCF, NCCF were 47.08 percent, 37.38 percent,32.08 percent, respectively. There were similar results in barrel and in field experiment.4. The experiment results indicated that BCRF had positive effects on photosynthetic rate , the amount of CHL, the LAI and root activity, especially in the late stage. The decrepit of roots and leaves were postponed ,the functional period of them was prolonged and the higher level of photosynthetic rate was remained in the post stage of summer maize, -thus caused the increase of grain yield.5. The application of BCRF not only promoted maize growth and increased its economic yield, but also had a less influence on the deep layers of soil body. Under the barrel grown condition, the total NO-3-N left in the 1 m soil body were in the order of urea>NCCF>WCCF>BCRF at the harvest stage.6. From the economic analysis, besides applying conveniently with less labor input, the net gain of BCRF treatment could increased by about 1247 yuan / ha , 2188 yuan /ha more than that of NCCF and single urea treatment.