关键词: 夏玉米, 氮素形态, 产量, 籽粒灌浆特性, 籽粒品质

Abstract:

【Objective】 The effects of different nitrogen forms on filling characteristics, grain quality and yield of summer maize were studied, so as to provide the scientific basis for selecting suitable nitrogen fertilizer types and improving the yield and grain quality of summer maize. 【Method】 The experiment was conducted in Taian, Shandong Province from 2022 to 2023. Denghai 605 (DH605) was selected as the experimental material, with a nitrogen application rate of 210 kg N·hm^-2. The experiment included five treatments: amide nitrogen (Urea, UREA), nitrate nitrogen (Calcium nitrate, NN), ammonium nitrogen (Ammonium chloride, AN), co-application of nitrate and ammonium nitrogen (1:1, HH), and urea ammonium nitrate solution with a blend of amide nitrogen, nitrate nitrogen, and ammonium nitrogen (2:1:1, UAN). The effects of different nitrogen forms on the yield and quality of summer maize were investigated by determining the grain filling characteristics, grain quality characteristics and grain capacity of summer maize. 【Result】Compared with the conventional application of amide nitrogen in UREA, both the maize yield and grain quality under NN decreased. The maize yield under AN increased, but the grain quality decreased. HH significantly increased maize yield without affecting grain quality. UAN significantly increased maize yield and improved grain quality. Over the two years, the highest maize yield achieved with the co-application of the three nitrogen forms, significantly increasing by 13.7% to 16.3% compared with UREA. The Next the highest maize yield were from AN and HH, which significantly increased maize yield by 5.2% to 6.8% and 7.3% to 10.6%, respectively, compared with UREA. The maize yield under NN decreased by 5.4% to 5.8% compared with UREA. Compared with UREA, the growth amount at the maximum filling rate (W_max) under UAN was enhanced by 6.3% to 9.7%, and the active filling period (D) was extended by 7.7% to 10.9%. Both AN and HH increased W_max and prolonged D, thereby promoting the accumulation of grain weight and increasing yield. The W_max, D, grain filling rate, and dehydration rate of NN were significantly lower than those in the other treatments. The crude protein content was lower with NN and AN, decreasing by 20.6% to 22.0% and 15.2% to 17.4% than that under UREA, respectively. The rude fat content with NN was significantly higher than that of other treatments, increasing by 23.6% to 30.9% than that under UREA. Compared with UREA, UAN improved grain quality, with total starch and amylopectin content increasing by 4.9% to 5.2% and 11.7% to 14.4%, respectively, compared with UREA, and the ratio of amylopectin to amylose increased by 31.0% to 39.1%. The amylose content decreased by 14.1% to 16.8%. The crude protein content of UAN increased by 11.7% to 24.1%. The grain bulk weight under UAN was significantly higher than that under other treatments. 【Conclusion】Compared with the conventional application of amide nitrogen, the treatment with nitrate nitrogen inhibited grain filling, reduced grain weight, and decreased yield. In contrast, ammonium nitrogen or the co-application of multiple nitrogen forms enhanced the grain filling process, increased grain weight, and thereby improved yield. Furthermore, compared with the application of a single nitrogen form, the co-application of three nitrogen forms could achieve a synergistic improvement in both yield and grain quality.

Key words: summer maize, nitrogen forms, yield, grain filling characteristics, grain quality