Persistence of Manure Phosphorus Availability in Calcareous Soil1
- J. L. Abbott and
- T. C. Tucker2
Reappraisal of animal manure as fertilizer has shown manure to be an effective P source in calcareous soils. Correlations for data from cotton (Gossypium hirsutum) and barley (Hordeum vulgare) experiments indicated manure benefits to be largely the result of providing available P to the crop. Residual effects of manure P were measured by alfalfa (Medicago sativa) P uptake, yield and soil analyses following 4 years of cropping to cotton and 1 year of barley. Soluble P in Mohave clay loam manured at 22 metric tons/ha 4 years before sampling was above that of unmanured soil. Manuring at 2- or 3-year intervals at 22 metric tons/ha appears to assure adequate P availability, while P availability from phosphate fertilizers may be negligible over the same period. The stable nature of manure organic matter, stimulation of microbiological activity and association of P with organic components of the soil may account for the resistance of manure P to processes removing phosphate fertilizer P from available forms.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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