施氮量对高粱产量、品质及氮利用效率的影响

为了更好地对高粱进行氮素管理,采用盆栽试验研究了施氮量对高粱生长、籽粒产量及品质、氮素累积及转运利用的影响。选取肥力较低的土壤,设6个氮水平：0（N0）、0.05（N1）、0.1（N2）、0.2（N3）、0.4（N4）和0.6g/kg（N5）（风干土）。结果表明,N3处理干物质累积量、叶片SPAD值、籽粒产量、穗粒数及收获指数均显著高于N0和N5处理;N3处理籽粒淀粉含量低于N1处理,但淀粉产量最高;随施氮量的增加籽粒单宁含量降低,蛋白质含量增加,蛋白质总产量以N3和N4最高。随施氮量的增加叶鞘中NO₃^--N含量增加,N3处理挑旗期和穗花期叶鞘中NO₃^--N含量明显高于N0、N1和N2,但在灌浆期N0~N3处理间硝态氮含量没有显著差异;N3处理从茎叶向籽粒的转运率最高,达到76.76%。综上,适宜的施氮量有利于高粱生长及产量的提高,且在生长前期提高了叶鞘中硝态氮累积,能协调籽粒产量和功能成分的关系,获得较高的淀粉和蛋白总产量。

Effects of Nitrogen Fertilization on Yield,Quality and Nitrogen Utilization Efficiency of Sorghum

To establish the nitrogen management practice for grain sorghum, a pot experiment was conducted to investigate the effects of nitrogen application rate on its growth, grain yield and quality, N accumulation and translocation. Less fertile air-dried soil was selected with six nitrogen levels, 0 (N0), 0.05 (N1), 0.1 (N2), 0.2 (N3), 0.4 (N4), and 0.6 (N5) g/kg. The results showed that dry matter accumulation, leaf SPAD value, grain yield, number of grains per panicle, and harvest index under N3 treatment were significantly higher than those under N0 and N5 treatments. The starch content in N3 treatment was lower than that in N1 treatment, but the starch yield of N3 was the highest. With the increase of nitrogen fertilization, the grain tannin content decreased and protein content increased, and the total protein output was the highest in N3 and N4. High NO₃^--N concentration of leaf sheath was induced by high N fertilization intensity. It is worthy of mentioning that NO₃^--N concentration of leaf sheath of N3 treatment was significantly higher than those of N0, N1, and N2 at flag leaf and anthesis stages. However, there was a similar value of NO₃^--N concentration of leaf sheath for these four treatments at filling stage. N3 treatment induced the highest percentage of N translocation from shoot to grain, which was 76.76%. In conclusion, appropriate nitrogen fertilization was beneficial to the growth and yield of sorghum, and increased NO₃^--N accumulation in leaf sheath at the early stage of growth, which could coordinate the relationship between grain yield and functional components and obtain higher total starch and protein yield.