氮素运筹对皖草2号和墨西哥玉米吸收Fe、Mn、Cu、Zn的影响

Effect of nitrogen application on the absorption of iron,manganese,copper and zinc in Wancao 2 and Zea mexicana

为明确氮素运筹对皖草2号和墨西哥玉米吸收矿质元素的影响,本研究分析了两者茎、叶及整株的Fe、Mn、Cu、Zn元素含量、累积量以及产量的变化情况。结果表明,皖草2号和墨西哥玉米植株中,Fe的含量最高,且叶片中的Fe含量明显高于茎;皖草2号的Mn、Cu、Zn含量高于或显著高于墨西哥玉米,但Fe含量显著低于墨西哥玉米。不同氮素运筹比较,一次性施肥处理中,2种牧草均以300 kg/hm2(N1)处理的Fe含量最高;而分次施肥处理中,Fe含量有随施氮量的增加而增加的趋势;皖草2号的Mn含量以N1处理最高,Cu、Zn含量以低施氮量处理较高;而墨西哥玉米的Mn含量随施氮量的增加而增加,Cu、Zn含量均以底肥一次性施入的含量较高。N1处理的Fe、Mn、Cu、Zn累积量和产量最高,且墨西哥玉米的累积量和产量显著高于皖草2号。不同器官中4种元素的累积量和产量不同,皖草2号叶片中Fe的累积量和产量高于茎,而Mn、Cu、Zn的累积量和产量低于茎;墨西哥玉米叶片中Fe、Mn、Cu、Zn的累积量和产量均显著高于茎。刈割次数对2种牧草吸收4种元素的影响也不同,皖草2号的Fe、Mn、Zn含量以头茬草最高,而Cu含量以第3次刈割草的含量最高;墨西哥玉米则以头茬草的Mn、Cu含量和第3次刈割草的Zn含量最高。2种牧草再生草中4种元素的累积速率表现为Fe>Mn>Zn>Cu,且均呈逐渐下降的趋势,墨西哥玉米的降低幅度大于皖草2号。综合分析认为,生产上选择皖草2号牧草类型,采取一次性施入氮肥300kg/hm2的管理措施,可以获得矿质营养较高的优质牧草,且要重视头茬草的产量。

T o study the effect of nitrogen application on the absorption of mineral elements in Wancao 2 and Zea the contents, amount accumulated and output of iron （Fe）, manganese （Mn）, copper （Cu） and zinc （Zn） in the stem, leaf and whole plant were analysed. Fe content was the highest of the four elements in Wancao 2 and Z. mexicana, and it was higher in leaves than in stems. The contents of Mn, Caa and Zn were higher or significantly higher in Wancao 2 than in Z. mexicana, but Fe content was significantly lower. Fe content was the highest in both species after 300 kg/ha nitrogen （N1） was applied once. In the treatments with N fertilizer applied separately, there was a trend for Fe content to increase with an increase in the nitrogen plication rate. For Wancao 2, Mn content was highest in the N1 treatment, but Cu and Zn contents were hi ap gh er in treatments with less nitrogen fertilisation. For Z. mexicana, Mn content increased with an increase in the nitrogen rate, and the contents of Cu and Zn were higher in all treatments where nitrogen was used as a base fertiliser. The accumulation amount and output of Fe, Mn, Cu and Zn were highest in the N1 treatment, and were higher in Z. mexicana than in Wancao 2. The accumulation amount and output of the four elements showed different variations in different organs accumulation amount and output of Fe were hi of gh Wancao 2 and Z. rnexicana. In the leaves of Wancao 2, the er, while those of Mn, Cu and Zn were lower compared with those in the stem. However, in Z. mexicana, the accumulation amount and output of the four elements in the leaves were significantly higher than those in the stem. Harvest time also had different effects on the absorp tion of the four elements in Wancao 2 and Z. mexicana. For Wancao 2, the contents of Fe, Mn and Zn were the highest in the first harvest of the grass, while Cu content was the highest in the third harvest. For Z. mex icana, the first harvested grass had the highest contents of Mn and Cu, while the third harvested grass had the highest contents of Fe and Zn. The accumulation rate of the four elements in the regrowth tissues of Wancao 2 and Z. mexicana was in the order of Fe〉Mn〉Zn〉Cu, and all showed a declining trend. The reduction in Z. mexicana was more serious than that in Wancao 2. In conclusion, selecting Wancao 2 and using 300 kg/ha nitrogen as base fertilizer was beneficial for obtaining herbage with higher mineral contents. The yield of first harvested herbage should be paid more attention.