淮北地区麦茬机插优质食味粳稻氮肥减量的精确运筹

Abstract

<p id="C3">At present, “nitrogen reduction” has become one of the planting measures for good eating quality<italic> japonica</italic> rice, but the scientific management plan of nitrogen fertilizer after nitrogen reduction is unclear and further studies are needed. From 2018 to 2019, good eating quality<italic> japonica</italic> rice varieties including Nanjing 505 and Nanjing 2728 were planted as materials, and four ratios of basic and tillering to panicle fertilizer including 5:5, 6:4, 7:3, and 8:2 were arranged with nitrogen application 20% less than conventional nitrogen application (CK) for mechanical transplanting rice under wheat straw returning. Yield, rice quality, and nitrogen utilization were investigated to determine the effects under nitrogen reduction for good eating quality<italic> japonica</italic> rice. The results were as follows: With the increase of the proportion of the basic and tillering fertilizer in the total nitrogen application, the yield increased first and then decreased. The 7:3 treatment had the highest yield, reaching 11,134.80-11,280.19 kg hm ^-2 for two years. Compared with CK, the yield increased by 1.23%-2.54% and there was no significant difference. The 7:3 treatment group could obtain sufficient population spikelet, higher seed-setting rate, and 1000-grain weight. With the increase of the proportion of nitrogen application in the previous period, the dry matter weight of the population at (N-n) stage and jointing stage displayed an increasing trend, while the dry matter weight at heading stage and maturity stage, the dry matter accumulation from heading to maturity, the final nitrogen accumulation and the nitrogen efficiency increased first and then decreased, and reached a peak in the 7:3 treatment. Compared with CK, nitrogen reduction treatment could ensure higher dry matter accumulation of the population at the later stage by increasing the proportion of nitrogen fertilizer application (7:3) at the early stage, which significantly improved nitrogen absorption and nitrogen use efficiency of the population by 14.10%-15.48%, and significantly higher than CK. For eating quality of<italic> japonica</italic> rice under nitrogen reduction, the processing quality deteriorated with the increase proportion of basic and tillering nitrogen, the appearance quality became better, the cooking and eating quality improved, and rice RVA profile was optimized. Under the condition of the whole wheat straw to the field, nitrogen was reduced by 20% compared with conventional fertilization. To achieve the comprehensive planting goal of high-yield, high-quality, and high-efficiency for good eating quality rice to a certain extent, nitrogen application with the ratio of basic and tillering fertilizer to panicle fertilizer 7:3 could stabilize or slightly increase the yield of good eating quality<italic> japonica</italic> rice, greatly increase nitrogen use efficiency, and improve the appearance and taste quality in rice.