Evaluation of a chemical extraction procedure for estimating potentially available nitrogen in manure-amended soil.

摘要

This thesis is an investigation of a chemical extraction procedure using 0.01M CaCl₂ for the determination of potentially available nitrogen in manure amended soil. The ability to predict the amount of nitrogen available for crop production on farms that use manure is viewed as a step towards achieving manure resource use efficiency. The index of nitrogen availability determined using CaCl₂ was compared with a biological index of available nitrogen determined in an incubation of soil manure mixtures. The CaCl₂ index was significantly related to the biological index, however, the index did not adequately account for all the variability in available nitrogen. The CaCl₂ index was evaluated as an index of nitrogen availability to silage corn in a field experiment. A lack of yield response to applied N prevented this evaluation. The index value was used to estimate potential nitrogen losses, which were comparable with losses estimated from a nutrient balance.