Article ID Journal Published Year Pages File Type
6374910 Field Crops Research 2015 12 Pages PDF
Abstract
Eleven field trials of wheat (Triticum aestivum) in Yongshou County, Shaanxi Province and seven in Luoyang District, Henan Province were conducted with two treatments (without N as control and with 150 kg N ha−1 addition). Soil nitrate N and ammonium N concentrations were determined in five layers from 0 to 100 cm depth at each site. Results showed that soil ammonium concentrations were very low and concentrations and cumulative amounts had no relations with wheat yield and yield increase by N applications. Nitrate N concentrations, in contrast, were high and correlated with seed (grain) and biomass yields of wheat without added N, and with yield increase by N addition in some layers. The cumulative nitrate N in 0-20 cm layer plus other layers to different depths was significantly or very significantly correlated with control yield and yield increase by N addition. The cumulative nitrate N in 0-80 cm depth explained 70% of seed yield, and that in 0-100 cm 72% shoot variation and over 55% yield increases. Nitrate N occupied 88% of the total amount of ammonium N and nitrate N, and had the same trends as the total in reflecting soil N supplying capacity. Wheat mainly depended on 0-20 cm layer nitrate N at over-wintering stage, 0-40 cm at reviving, 0-60 cm or deeper at elongation stages, and at maturity, the correlation of cumulative nitrate N in 0-100 cm layer was highest with biomass and biomass increase by N addition. The control wheat in Yongshou County absorbed 107.4 kg N ha−1 from soil on average, equivalent to 72% of the cumulative nitrate N or 65% of the total mineral N in 0-100 cm layer. After wheat harvest, the concentration of ammonium N was not significantly different from the initial while that of nitrate N greatly decreased.
Related Topics
Life Sciences Agricultural and Biological Sciences Agronomy and Crop Science
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