ISSN:
1432-0789
Schlagwort(e):
Urea
;
Ammoniacal fertilizers
;
Ammonia volatilization
;
Sandy soils
;
pH
;
Ammonia loss model
;
Air flow
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Geologie und Paläontologie
,
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
Notizen:
Abstract NH3 volatilization from surface-applied urea, diammonium phosphate (DAP), and calcium ammonium nitrate (CAN) was measured with chambers through which air was drawn continuously. Two sandy soils and two sandy loam soils, which had been treated with and without time for the last 25 years, were used for the experiments. The accumulated NH3 loss from CAN applied to an unlimed sandy soil was linearly related to time. For the other treatments the accumulated loss was exponentially related to time. The NH3 loss was exponentially related to the maximum soil pH of the fertilizer-amended soil, and was inversely related to the content of exchangeable H+. Due to the low cation exchange capacity of these light-textured soils the NH3 loss was not reduced as the soil CEC increased. The maximum pH after soil amendment was related to soil pH. Therefore, a model is proposed that relates the NH3 loss solely to fertilizers and soil pH. The NH3 loss was less than 5% from CAN, about 20% from DAP, and about 30% from urea, with the insignificant loss from urea applied to the unlimed sandy soil excluded. The NH3 loss from surface-applied DAP was related to the air flow rate and a transfer coefficient (K a) was estimated. K a increased exponentially with the flow rate. At a flow rate above 3.9 liters min−1 (20 volume exchanges min−1) no further increase was seen.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00335993
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