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Publication Date
1993
Location
New Zealand
Description
A relationship is developed between the substitution value of reactive phosphate rock (RPR) relative to triple superphosphate (TSP), both applied annually to pasture, and the dissolution rate of the RPR. The residual effect of dissolved phosphate is included. Residual RPR is calculated from the dissolution rate of the RPR in the soil, while residual phosphate from TSP or dissolved RPR is taken as a constant fraction of the value in the previous year. Calculations including the residual effect of dissolved fertiliser produce smaller substitution values and longer lag times for RPR than when the effect is omitted. The relationship derived from RPR dissolution rate constants was consistent with available experimental data from dry matler.
Citation
Watkinson, J H. and Perrott, K W., "Estimating Fertilizer Substitution Values from the Dissolution Rates of Reactive Phosphate Rocks in New Zealand Pastoral Soils" (1993). IGC Proceedings (1985-2023). 25.
(URL: https://uknowledge.uky.edu/igc/1993/session40/25)
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Estimating Fertilizer Substitution Values from the Dissolution Rates of Reactive Phosphate Rocks in New Zealand Pastoral Soils
New Zealand
A relationship is developed between the substitution value of reactive phosphate rock (RPR) relative to triple superphosphate (TSP), both applied annually to pasture, and the dissolution rate of the RPR. The residual effect of dissolved phosphate is included. Residual RPR is calculated from the dissolution rate of the RPR in the soil, while residual phosphate from TSP or dissolved RPR is taken as a constant fraction of the value in the previous year. Calculations including the residual effect of dissolved fertiliser produce smaller substitution values and longer lag times for RPR than when the effect is omitted. The relationship derived from RPR dissolution rate constants was consistent with available experimental data from dry matler.
