Effects Of The Combined Application Of Controlled-Release Urea And Urea On Nitrogen Metabolism And Yield Formation Of Maize In The Middle Of Sichuan Hilly Basin

In this research, maize was cultured in field, common urea and controlled-release urea (CRU) were the fertilizers tested. Under the same nitrogen fertilizer rate, the effects of the combined application of controlled-release urea and common urea under different fertilizer applied conditions(single basal application of fertilizer and the secondary) on growth of maize, dry matter accumulation and distribution, N absorption and utilization, the key nitrogen mechanism enzymes and yield were mainly researched. The main results obtained were as follows:1?The single basal application of fertilizer could promote growth of maize at early stages, increased height and leaf area at jointing stages, especially in height. With the increase of CRU ratio, the height and leaf area were decreasing at jointing stages, while the trend were increased first and decreased afterwards at silking stage, the proportion of 75% of controlled-release urea was the highest, the single basal application fertilizer was consistent with the secondary.2?The single basal application of fertilizer could promote dry matter accumulation at jointing stages, the secondary could increased dry matter accumulation to a certain extent after silking, especially urea, the difference of dry matter accumulation of CRU in different applications were smaller than common urea in each growth stage; either single basal application or the secondary, with the CRU ratio was increased, the dry matter accumulation in mature and it's distribution rates of grain were increased first and decreased afterwards, the proportion of 75% of controlled-release urea was the highest. Show that the combined application of common urea and controlled-release urea could not only increased the dry matter accumulation in late growth stages, it was also beneficial to the dry matter transportation, improved harvest index, two year were basically the same.3?The single basal application of fertilizer could promote N accumulation before silking, especially at jointing stages, the secondary could increased N accumulation after silking, especially in 2014; with the CRU ratio increased, the N accumulation were increased first and decreased afterwards in maturity. The nitrogen fertilizer agronomic efficiency of common urea of single basal application was lower than the secondary, the nitrogen fertilizer agronomic efficiency of controlled-release urea and the combined application of controlled-release urea and common urea of the single basal application were higher than the secondary;compared with the single basal application, the secondary had a trend to improve the nitrogen apparent recovery efficiency, particularly common urea and the lower of CRU ratio; with the CRU ratio increased, the nitrogen fertilizer agronomic efficiency and the nitrogen apparent recovery efficiency were increased first and decreased afterwards, nitrogen harvest index and soil nitrogen dependent rate were declining.4? Different fertilizer treatments (fertilizer application frequency and CRU ratio) had a certain impact on key enzymes activities of nitrogen metabolism of the function leaf of maize during each period, particularly in GS and GOT activity. Overall, the key enzymes activities of nitrogen metabolism of the function leaf of single basal application was higher than the secondary at jointing stage, especially in GS and GOT activity, the key enzymes activities of nitrogen metabolism of the secondary was higher at silking stage, especially in GOT activity, the GS and GOGAT activity of single basal application was higher in milk stage, and GOT and GDH activity of the secondary was higher; with the CRU ratio increased, the key enzymes activities of nitrogen metabolism of ear leaf were increased first and decreased afterwards at silking and milk stage (except the GS of single basal application of milk stage), the proportion of 75% of controlled-release urea was the highest. The Chlorophyll content of single basal application was higher at jointing stage, the difference between the single basal application and the secondary was no significant at milk stage. With the CRU ratio increased, the Chlorophyll content was increased first and decreased afterwards after silking, and the proportion of 75% of controlled-release urea was the highest(the proportion of 100% of controlled-release urea of single basal application was the highest at milk stage).5?The yield of common urea of single basal application was less than the secondary, and while blending a certain percentage of controlled-release urea, the yield of single basal application and the secondary were not significant different, whether it is administered single basal application or the secondary, with the CRU ratio increased, the yield of maize was increased first and decreased afterwards, and the proportion of 75% of controlled-release urea was the highest. All treatments mainly through the influence of spike length and spike diameter, thereby affecting kernel number and 1000-kernel weight and yield.