| Autor: |
T.M. Egelkraut, D.E. Kissel, M.L. Cabrera, W. Adkins |
| Zdroj: |
Nutrient Cycling in Agroecosystems; May2003, Vol. 66 Issue 1, p1-12, 12p |
| Abstrakt: |
The N mineralized from soil organic matter provides an important portion of N available for crop production. The objective of this study was to determine the amount of spatial variability in N mineralization potential in a field and to evaluate three different methods that might be used to estimate this variability. The three methods tested included predicting the N mineralized from surface soil properties as well as from a biological and a chemical procedure. Three soils varying in N mineralization potential were selected for the study from a field in the Georgia Coastal Plain. The N mineralized from these soils was determined by an N balance of unfertilized and cropped plots. The amount of N mineralized could not be reliably predicted from surface soil organic C, although surface soil clay concentration was positively correlated with the N mineralized. The N mineralized that was predicted using mineralization parameters determined by aerobic incubation, adjusted daily for soil water content and temperature, was approximately 50% of the field measurements of N mineralized. The values of NH4-N extracted with hot 2 M KCl were related significantly to N mineralized in the field (r2= 0.60) and also to the zero order rate constant of mineralization, k0 (r2= 0.77), determined from the N mineralized in the aerobic laboratory incubation. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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