Deep mechanized application of super rice special fertilizer increasing soil fertility and yield of super rice

Abstract: In China, the fertilizer use rate of planting rice is 30%, and the application of large amounts of chemical fertilizer not only increases the cost, but also makes the soil physical and chemical characteristics and soil fertility decline, and causes serious environmental pollution. Increasing the utilization rate of chemical fertilizer mainly has two methods, one is to change the method of application of fertilization, through deep fertilizer application that reduces fertilizer volatilization and loss, the second is the application of organic fertilizer, rice special fertilizer, and slow-release fertilizer that can improve the utilization rate of fertilizer and soil physicochemical properties and rice yield. Super rice specialized fertilizer based on super rice growth characteristics, can provide the necessary nutrients and increase the content of organic matter in soil. The rice precision dry direct seeding machine with synchronous ditching ridging fertilizer application can complete the ditching, ridging, fertilization, mulching, and sowing work synchronously, which solved the problem of the deep application of fertilizer in rice cultivation. In order to investigate the function on increasing soil fertility and super rice yield of deep mechanized application of the super rice specialized fertilizer, the effects of deep mechanized application of super rice specialized fertilizer of 900 kg/hm2, deep mechanized application of super rice specialized fertilizer of 1200 kg/hm2 and manual broadcast application of the super rice specialized fertilizer of 1200 kg/hm2 on soil nutrients and soil physicochemical properties and super rice yield were studied by using field experiments. The results showed that the contents of soil nutrients and macro-aggregate of two deep mechanized application of super rice specialized fertilizer were increased, and the activity of the soil enzyme and yield of super rice were raised significantly comparing with a manual broadcast application of the super rice specialized fertilizer (P<0.05). Organic matter, total nitrogen, available nitrogen, total phosphorus, available phosphorus, total potassium, and available potassium ware increased by 5.11%-6.34%, 4.45%-5.13%, 5.37%-5.95%, 3.82%-4.51%, 5.34%-6.12%, 3.18%-4.20% and 6.14%-7.12% on average, respectively. Furthermore, the content of soil macro-aggregate with the diameter over 0.25 mm was increased by 13.12%-17.36% on average. On top of that, the activity of urease, catalase, and sucrase was promoted after a deep mechanized application of super rice specialized fertilizer treatments by 5.16%-6.21%, 8.64%-9.25% and 10.13%-11.04%, respectively. Yield of two super rice varieties ware increased by 3.8%-5.6% and 8.4%-10.0% on average, respectively, their effective panicles, grains per panicle, and seed setting rate ware increased by 5.0%-12.4%, 2.8%-8.8%, and 1.8%-4.7%, respectively. Improving functions on the physical and chemical properties of soil and super rice yield were not significantly different between two deep mechanized applications of super rice specialized fertilizer (P＞0.05). The amount of fertilizer of the deep mechanized application of super rice specialized fertilizer of 900 kg/hm2 was reduced by 25% under that of a deep mechanized application of super rice specialized fertilizer of 1200 kg/hm2, the former had obvious advantages, low input but high output and was more suitable for application in super rice production.