Efficiency of nitrogen fertilization in sweet sorghum
作者:
C. A. Rosolem,
J. R. Machado,
期刊:
Communications in Soil Science and Plant Analysis
(Taylor Available online 1985)
卷期:
Volume 16,
issue 7
页码: 693-706
ISSN:0010-3624
年代: 1985
DOI:10.1080/00103628509367638
出版商: Taylor & Francis Group
关键词: Sorghum bicolor;Nitrogen rates;Method of N application
数据来源: Taylor
摘要:
In spite of a high N requirement, sweet sorghum hasn't shown a consistent response to N fertilization. This research was designed to study the effect of N fertilization on sweet sorghum as affected by rates and time of N application. Five experiments were conducted under field conditions, where 0, 50, 100 and 150 kg N/ha were applied at sowing, and 35, 40, 55, 60 and 80 days after plant emergence. The soil had textures varying from sandy loam to clay, and organic matter contents from 0.67% to1.9%.The highest yields were observed when N was applied early in the season, showing that for sweet sorghum, sidedressing with N is not necessary. All the N can be applied at planting time, which allows the highest fertilizer use efficiency. On the other hand, late applications of N fertilizer (after 40 days), when the floral primordia is already visible, has little effect on stalk or grain yield. In this situation, a double or triple rate had to be applied to overcome the low efficiency of N utilization. There was no great advantage in splitting the sidedressed N rate. On the other hand, it was impossible to link the response to N to soil analysis as performed in most of Brazilian laboratories.
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