AVAILABLE PHOSPHORUS FRACTIONS IN SOILS FROM DORO, KATSINA STATE, NIGERIA

Abstract

Sustainable crop production in the Nigerian Sudan Savanna biome requires a good understanding of the fertility status of the soil for appropriate nutrient management strategies, yet phosphorus (P) reserves are rapidly being depleted. Agricultural soils, especially in the region are inherently poor in basic nutrients, including P. Field sampling was conducted to assess the phosphorus status of soils from Doro, Katsina State in the Northern Nigerian Sudan Savanna area. The sampled field was dominated by sand with a mean value of 62.66 % followed by clay (17.34 %) and silt (20.00 %). The soil was classified as sandy loam, with basic soil nutrients (organic C, total N, exchangeable cations and ECEC) within low to very low fertility classes. The soil was slightly acidic (pH 6.8) in reaction with total P (TP) of 97.89 mg kg-1. Available (Bray’s) P of 4.82 mg kg-1 and the Olsen extracted P (1.27 mg kg-1) were far too low compared with TP. These low available P values are indicative of soil nutrient depletion and degradation. Therefore, maintenance of soil P at a target value through application of P fertilizers, periodic incorporation of crop residue and organic manures would be very essential for soil P restoration and fertility management.