追施氮肥对苏丹草农艺性状、种子产量及氮肥利用效率的影响

Effects of Topdressing Nitrogen Fertilizer to Sudangrass in Agronomic Traits Seed Yield and Nitrogen Use Efficiency

以‘新苏2号’苏丹草(Sorghum sudanense‘Xinsu No.2’)为试验材料,在拔节、抽穗和灌浆期以固定比例追施氮肥,研究追施氮肥对苏丹草农艺性状、种子产量、产量构成因素及氮肥利用效率的影响,结果表明,追施氮肥能够促进株高生长,增加叶片长度和宽度,减缓叶片衰老速度,提高叶面积指数。适量追施氮肥显著增加了苏丹草种子千粒重及一级穗柄数,并极大提高了每穗粒数,最终获得较高的种子产量,追氮600kg·hm-2时可获最大种子产量3815kg·hm^(-2)。灌浆期随追氮量增加各器官全氮含量增加,追氮750kg·hm-2时,茎秆和穗粒部全氮含量最高,追氮600kg·hm^(-2)时,叶片全氮含量最高,且同一追肥处理:穗粒部>叶片>茎秆;随追氮量增加,氮肥农学利用率以及氮肥利用效率呈下降趋势。综合考虑追施氮肥对苏丹草农艺性状、种子产量、产量构成因素及氮肥利用效率的表现情况认为,本试验条件下,追施氮肥600kg·hm^(-2)表现最优。

Based on ＇Xinsu No. 2＇, a Sorghum Sudanese variety, a serial ratio of nitrogen fertilizer as topdressing in jointing, heading and filling stage were applied to analyze the relationship of different dose of nitrogen fertilizer with agronomic traits, seed yields, yield components and nitrogen fertilizer use efficiency in this study. The results showed as below, nitrogen fertilizer input as topdressing could increase the stem length, leaf length and width and leaf area index and decreased the speed of leaf senescence. On a suitable input level of nitrogen fertilizer as topdressing could increased the TKW（thousand kernel weight） and number of primary pedicel of ＇Xinsu No. 2＇ significantly and could increase the number of grains per ear on a extreme outstanding level, also induced the relatively higher seed yields, when the input dose of nitrogen fertilizer was 600 kg ·ha-1 , the seed yields could be up to 3815 kg · ha-1 , the highest appearance in this study; during filling stage of sudangrass, the N contents of different organism in total plant were increased following the input increasing of nitrogen fertilizer. When the topdressing dose of nitrogen fertilizer was up to 750 kg · ha-1 , the N content of stem and spike were on the highest level; when the topdressing dose of nitrogen fertilizer was up to 600 kg · ha-1 , the N content of leaf was highest among other treatments. In anyone treatment, N content of different organism were sequenced as spike〉 leaf 〉 stem; followed the input of nitrogen fertilizer increasing, the agronomic nitrogen fertilizer use efficiency and nitrogen fertilizer use efficiency showed a decrease trend. Compared to all the investigated agronomy traits and topdressing dose of nitrogen fertilizer overall, 600 kg · ha-1 was the most efficient input of nitrogen fertilizer in sudangrass cultivation in this study.