Effects Of Slow-release Fertilizer Application On Grain Yield And Nutrient Utilization Of Maize

The experiments were conducted in Experimental Farm of Yangzhou University in 2013-2015. The trial of different slow-release fertilizer amounts was conducted in 2013 using two maize hybrids (Suyu29 and Suyu30) as materials. Based on the results of the trial, the conventional nitrogen (N) application was added in the experiments in 2015. The effects of slow-release fertilizer application on grain yield and nutrient utilization of normal maize were clarified. The main results were as follows:1. Effects of slow-release fertilizer application on the yield formationThe grain yield was significantly different among different slow-release fertilizer treatments, between two varieties and two sowing dates. The grain yield rose first and fall later and peak at N 405 kg/ha for both varieties. The yield of Suyu29 and Suyu30 were 15965 and 13702 kg/ha for summer sowing and were 13896 and 12616 kg/ha for spring sowing, respectively. The fitted equation based on N amount and yield indicated that the optimum N application of Suyu29 and Suyu30 were 412.8 and 407.7 kg/ha for spring sowing and were 432.4 and 420.4 kg/ha (average of two years) for summer sowing, respectively.2. Effects of slow-release fertilizer application on population quality indexThe dry matter accumulation amounts were peaked at N 405 kg/ha for all years and sowing dates. The results of correlation between dry matter accumulation amount at different growth stages (sowing-jointing stage, jointing-flowering stage, and flowering-maturity stage) and grain yield indicated that increase the dry matter accumulation after flowering is key for the increase of grain yield. The leaf area index (LAI) rose first and fall later and peaked at flowering stage, the lower decrease rate after flowering increased the dry matter accumulation during grain filling, which led to the higher yield.3. Effects of slow-release fertilizer application on absorption and utilization of NIncrease the N accumulation amount, utilization rate and translocation rate were favored to increase grain yield. Among different years and sowing dates, the N accumulation amount and use efficiency rose first and fall later and peaked at N 405 kg/ha with the increase of N application amount, both parameters were 458.4 kg/ha and 48.8% for Suyu29 and were 345.5 kg/ha and 35.3% for Suyu30, respectively. The results indicated the moderate N application could increase the absorption and utilization of N in maize plants. The N use efficiency was higher for Suyu29 than for Suyu30, the value in summer sowing treatments in 2013 ranged from 13.0% to 48.8% for Suyu29 and from 2.1% to 35.3% for Suyu30, respectively, and the change tend in summer sowing treatments in 2015 was similar to 2013. The N use efficiency in spring sowing treatments in 2015 ranged from 22.9% to 43.8% for Suyu29 and from 22.5% to 46.6% for Suyu30, respectively. The results of regression analysis based on the N distribution rate among different organs at maturity and yield indicated that high rate in sheath and bract and low rate in cob were favored to increase yield for Suyu29, and high rate in stem was favored to increase yield for Suyu30, respectively. The translocation amount for both varieties in 2015 rose first and fall later and peak at N 405 kg/ha, which indicated that application N more or less could reduce the N translocation amount. The values for Suyu29 and Suyu30 were 88.7 and 80.3 kg/ha under spring sowing and were 50.6 and 77.6 kg/ha under summer sowing treatments, respectively. In 2013, the N translocation rate of Suyu29 and Suyu30 at highest yield treatments (N 405 kg/ha) were 8.7% and 19.5% higher than blank. The change tend of N translocation rate in 2015 was similar to 2013, while the response of N translocation rate to N application amount were higher in spring sowing maize.4. Effects of slow-fertilizer application on the absorption and utilization of phosphorus (P) and potassium (K)With the increase of N application amount, the P accumulation amount and use efficiency for both varieties rose first and fall later and peaked at N 405 kg/ha, the two parameters under summer sowing treatments were 55.7 kg/ha and 20.9% for Suyu29 and were 50.7 kg/ha and 11.5% for Suyu30, respectively. The change tend under spring sowing treatment was similar to summer sowing, which indicated that moderate N application could increase the P absorption and utilization for maize plants. Similar to P, the K accumulation amount and use efficiency for both varieties rose first and fall later and peaked at N 405 kg/ha, the two parameters under summer sowing treatments were 225.5 kg/ha and 33.1% for Suyu29 and were 194.9 kg/ha and 22.6% for Suyu30, respectively. The results of regression analysis based on the P and K distribution rate among different organs at maturity and yield indicated that increase the K rate in leaf and stem and decrease the P rate in sheath and tassel were favored to increase the grain yield of Suyu29, and increase the P rate in cob and decrease the P rate in tassel and K rate in sheath were favored to increase the grain yield of Suyu30, respectively.5. Comparison of slow-release fertilization to conventional fertilization patternUnder the N 405 kg/ha level, the grain yield were 11655 and 9757 kg/ha, and dry matter accumulation amount were 15242 and 13652 kg/ha for Suyu29 and Suyu30, respectively, both values were significantly lower than slow-release fertilization pattern. Compared to conventional fertilization pattern, application slow-release fertilizer increased the N use efficiency, which was increased 13.3% and 11.3% for Suyu29 and Suyu30 under summer sowing treatments, respectively. No difference was observed under spring sowing treatments. The P use efficiencies for Suyu29 and Suyu30 were increased 3.6% and 7.2% under spring sowing treatments and increased 1.7% and 1.4% under summer sowing treatments, respectively. The K use efficiency between two fertilization patterns was not different for Suyu30, which the value was increased 12.2% and 10.7% by slow-release fertilization pattern under spring and summer sowing treatments for Suyu29, respectively. The results indicated that application of slow-release fertilizer could increase grain yield, dry matter accumulation amount, N use efficiency for summer maize, P use efficiency for spring maize, and K use efficiency for Suyu29.