THE EFFECT OF CATTLE FEEDLOT MANURE AND INORGANIC FERTILIZER ON THE IMPROVEMENT OF SUBSOIL PRODUCTIVITY OF IWO SOIL

Abstract

Maize (Zea mays L.) was grown in greenhouse soil pot cultures to evaluate the effect of cattle feedlot manure and NPK fertilizer on the improvement of the yield capacity of the Iwo subsoil in Western Nigeria. Manure was applied at 0, 3, and 6 percent rates, and fertilization levels were zero and complete, complete fertilization consisting of 100 micrograms of nitrogen, 40 micrograms of phosphorus, and 100 micrograms of potassium per gram of soil. Subsoil treatments were evaluated against corresponding topsoil that was under 25-year bush fallow. A combination of NPK fertilization and manure applied at the rate of 6 percent (of dry soil) produced dry matter yields on the subsoil equivalent to those on the topsoil. The effect of adding manure alone on yield from the topsoil was comparable to that resulting from fertilization. Root growth generally reflected a large complementary effect of manure and fertilization. Recovery of nutrient elements, expressed as a percentage of applied nitrogen, phosphorus, and potassium, was explained in terms of their uptake by plants. Manure addition resulted in substantially high phosphorus uptake, and potassium concentrations in roots and shoots were consistently high and not as limiting as nitrogen and phosphorus in the subsoil.