Phosphorus distribution in five highly weathered Alabama soils

• Published in: Communications in soil science and plant analysis 2003-01, Vol.34 (1-2), p.97-109
• Main Authors: Senwo, Z.N, Taylor, R.W, Sistani, K.R
• Format: Article
• Language: English
• Subjects: agricultural soils; Agronomy. Soil science and plant productions; Alfisols; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; clay fraction; clay minerals; Fundamental and applied biological sciences. Psychology; Mineral components. Ionic and exchange properties; nutrient availability; phosphorus; Physics, chemistry, biochemistry and biology of agricultural and forest soils; soil fertility; soil inorganic phosphorus; Soil science; soil test values; soil weathering; Ultisols
• ISSN: 0010-3624; 1532-2416
• DOI: 10.1081/CSS-120017418

A major nutritional problem to crops grown in highly weathered Alabama soils is phosphorus (P) deficiency linked to their low availability and the capacity of the soils to fix P in highly insoluble forms. This work, examines factors that might influence the distribution, availability, and adsorption of P in five typical highly weathered Alabama soils. The total P contents range from 199 to 543 mg P kg −1 soil. Soil inorganic P fractions were determined by a sequential-fractionation procedure (NH 4 Cl-P, NH 4 F-P, NaOH-P, CDB-P, and H 2 SO 4 -P). The comparative rankings of the various inorganic P fractions on the average were in the order: NaOH-P>NH 4 F-P>H 2 SO 4 -P>NH 4 Cl-P>CDB-P. Most of the inorganic P occurred in the least available NaOH-P form. The following soil test P on the average, extracted P in this order: Mehlich 3 (16.78 mg kg −1 ), Bray 1 (14.72 mg kg −1 ), Mehlich 1 (9.01 mg kg −1 ), Olsen (8.09 mg kg −1 ), H 2 O (1.55 mg kg −1 ), and CaCl 2 (0.39 mg kg −1 ). The correlation results suggest that the extractants removed easily soluble P as well as P from Al oxides. The P adsorption rate coefficient (k d ) obtained, correlated with the clay content ( r=0.77;p