Wheat p requirements on calcareous Morrocan soils: III evaluation by isotherms compared to Olsen extractable P*
作者:
Abdelmalek Azzaoui,
R. G. Hanson,
P. N. Soltanpour,
期刊:
Communications in Soil Science and Plant Analysis
(Taylor Available online 1989)
卷期:
Volume 20,
issue 7-8
页码: 909-922
ISSN:0010-3624
年代: 1989
DOI:10.1080/00103628909368124
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Phosphorus fertilizer recommendations were compared by interpretations from P isotherms, Olsen extractable P and the Mitscherlich‐Bray model based on the Olsen method for 15 soils from the Chaouia (dryland) region of Morocco. The P isotherms were fit to straight line and second degree polynomial equations. The P buffer indexes (PBI) derived from the isotherms were not significantly correlated to P buffer capacities as measured by a single P buffer capacity index, but negatively correlated to Olsen P (r = ‐0.63), relative yield (r = ‐0.76) and P uptake (r = ‐0.66). Phosphorus in solution was a quadratic function of P added in 0.01 M CaCl2equilibrium solution. The P fertilizer recommendations to maintain soil solution P concentrations at 0.01, 0.12 and 0.20 mg P L‐1were higher than recommended by direct interpretation of plant response to Olsen extractable P and the quantity based on the Mitscherlich‐Bray model as calculated from Olsen available P values. The P fertilizer recommended to maintain soil solution P of 0.10 mg P L‐1was significantly correlated with Olsen P (r = 0.71) as was that recommended Mitscherlich‐Bray log transformation model (r = 0.81), and nonlinear least square estimation (r = 0.78). Field research will be needed to evaluate if the P fertilizer recommended to maintain this solution P concentration is adequate for maximum economic wheat grain yield under field conditions
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