Characteristics of Phosphorus Sorption Capacity of Hevea Supporting Soils in Southern Region of Nigeria

 

Abstract

Phosphorus (P) is a macronutrient element that plays a number of irreplaceable roles in Hevea brasiliensis (natural rubber), most especially –in the  improvement of latex yield and quality. Thus, a study of the relevant indicator of P sorption across depth of rubber supporting soils is necessary. The study evaluated – the P sorption of soils under rubber plantation. Soil samples were collected from the profile pit in the soil mapping unit of ‘Kulfo’ series from each horizon and analyzed for physic-chemical analysis and P sorption studies.  The P concentrations differential of 53.28, 85.61, 120.89, 173.06 and 216.49 mg/l from 1M KH₂PO₄ were used as P added. The sorption data were fitted into the Isotherm models of Freundlich, Langmuir and Temkin and their indices used to correlate the physical and chemical characteristics of the soils. The results showed that the soil horizons exhibited different affinity to sorption of P. Horizons with higher clay and organic carbon content showed higher and lowest mean P sorption values of 106.33 in the Bt₂ horizon (148 – 183 cm) and 50.34 in the A₁ horizon (0 – 18 cm) respectively.  Freundlich model best describes P sorption capacity of the soil series based on the smallest root mean square error (RMSE) values recorded when compared to the other models. However, the correlation showed both positive and negative correlation of r = 0.538<0.05 with clay, -0.680<0.05 with organic carbon and 0.103<0.05 in A_l respectively. In conclusion, P sorption been quantified by the isotherm model gives an insight into the proper phosphorus management program for an efficient and effective fertilizer use in the study area for optimum rubber development.