EFFECT OF LAND-USE PATTERN ON PHOSPHORUS AND POTASSIUM FIXATION AND MAIZE PERFORMANCE

Abstract

The effect of three different lands-use types for ten years on Phosphorus and Potassium Fixation and maize performance were studied at University Teaching and Research Farm.  Soil samples were collected from the different land-use systems; continuous cultivation of arable crops without fertilizer (CC-F), continuous cultivation of arable crops with fertilizer (CC+F), and Fallow. 

The samples were subjected to routine analysis and fixation studies in the laboratory.  Greenhouse investigation was also carried out for six weeks to evaluate maize performance in the three different land use systems. Data were subjected to analysis of variance. CC+F released the highest amount of Phosphorus (P) while the fallow released more Potassium (K).  The K released was a reflection of its high organic matter (4.5%).  The continuously cultivated soil without fertilizer (CC-F) had the highest P and K fixation capacity and therefore would require the largest amount of P and K fertilizer for optimum yield than CC+F and Fallow. Dry matter yield of maize correlated with soil organic matter; root weight; Nitrogen (N). P and K uptake; and P and K in solution at zero addition.  Significant correlation was only found between yield and organic matter and N uptake for all the soils indicating the importance of these two related parameters for good crop performance. Also significant correlation between yield and root weight was only found in Fallow and not in the cultivated soils since root impedance caused by high bulk density and gravel content probably occurred in the cultivated soils. A continuously cultivated soil thus have high nutrient fixing capacity since continuous cropping rapidly depletes the nutrients on the exchange sites or nutrient reserves of soils and when fertilizer is added to the soil it first replenishes it exchange sites before meeting the needs of crops.  Cropping practices therefore play a vital role in determining yield and nutrient release capacity of soil in conjunction with the soil characteristics.