Effects of pine growing on soil nutrients and chemical properties of soil at Kikonda forest reserve, Kyankwazi district

Abstract

Many commercial tree growers and organizations in Uganda are growing exotic tree species for their fast growing rate which yields timely outputs. Pinus caribaea is one of the widely planted tree species for the production of timber or wood for general use. For example, production of construction materials, fuelwood, pulp and paper, ply wood, resin, biomass production, and to help reduce the global effects of climate change. The accumulation of deep litter under pine plantation in Kikonda forest reserve may alter some chemical properties which may either booster or lower soil fertility. To test this hypothesis, the of concentration of sodium, nitrogen, potassium, phosphorous, soil pH, organic matter content and organic carbon content were compared between the pine plantation soils and adjacent open grassland soil. Soils were dug from a depth of 0 – 20 cm down the ground from about 180 sampling points within the 36 established plots within those plantations. Soil samples were prepared and taken for soil laboratory analysis. The concentrations of the chemical properties tested were high under pine plantations than the open grassland. No negative effects of pine plantations on soil chemical properties was observed but instead pine improves soil chemical properties which boosts soil fertility. There was no negative impact of pine plantations on soil chemical properties. Soils under pine plantations had higher nutrient returns than open grassland soil. The concentrations of all nutrients tested were high under pine plantation but only potassium and nitrogen concentration were significantly high. The concentrations of soil organic carbon content and soil organic matter content were high under all pine plantations but only significantly high under the 15 year old pine plantation. Pinus caribaea can perform well on Kikonda forest reserve soil and the neighboring areas thus, growing it on marginal lands and on agricultural lands which are not in use would be a great idea because growing this tree species contributes to the improvement of most chemical properties of soil.