Leaching losses of nutrients in oil palm plantations determined by tension lysimeters

Summary

The leaching losses of both native and applied fertilizer nutrients in young and adult oil palm plantations on an acid sand soil at the NIFOR Main Station in Central-Southern Nigeria were studied using alundum tension lysimeters placed at 60- and 150-cm depths. There were no significant differences in the leaching of the applied fertilizers between the young and adult plantations. Under an annual rainfall of 1923 mm, the average leaching losses of the applied fertilizer nutrients from both plantations were 11 kg N (34%), 10 kg K (18%), 43 kg Ca (172%), 14 kg Mg (60%), 12 kg SO₄-S (14%) and 77 kg Cl (141%) per hectare. The average losses of the native nutrients were 43 kg N, 16 kg K, 144 kg Ca, 32 kg Mg, 67 kg SO₄-S and 142 kg Cl. Although large, the annual losses of the native N, K, Ca and Mg represented only 6, 15, 4 and 3 per cent respectively of the total initial amounts (total N and exchangeable cations) of these elements in the soil to a depth of 60 cm. Compared with losses under annual crops in areas of West Africa with much lower rainfall, the losses of the applied N, K and S are moderate. The leaching losses are discussed in relation to the current fertilizer practice and annual nutrient removal of the oil palm for vegetative growth and bunch production.