An individual-tree linear mixed-effects model for predicting the basal area increment of major forest species in Southern Europe

摘要

Soil acidity and phosphorus deficiency is a major constraint to increase crop yields in tropical andsubtropical regions. Phosphorus must be added to the soil plant system as mineral fertilizer to replenish whatis removed by harvested crop parts. Efforts to ameliorate the deleterious effects of soil acidity mustaccompanied by appropriate rate of lime and P fertilizer. Therefore, this investigation was undertaken to studyyield response of bread wheat to lime and P fertilizer for better yield. The experiment was conducted in 2018 atHoleta Agricultural Research Center (HARC), Robgebeya (RG) and Watabacha Minjaro (WM) sites in WelmeraDistrict of Oromia Regional National State. Acidic fields that were not reclaimed with lime for the last five yearswere selected and sampled. The experimental treatments comprised six rates of lime (0, 1.56, 2.34, 3.12, 3.9 and4.68 t ha ) and three rates of P (0, 16.5 and 33 kg ha ) arranged in factorial randomized complete block design 1 1(RCBD) in replications. Soil and agronomic data were collected and analyzed following standard procedures.The soil pH increased and exchangeable acidity reduced after amending the soil with lime. Interaction oflime (t ha ) by P (kg ha ) for grain yield of bread wheat at the rate of 3.12/16.5 yielded 3.86 t ha at HARC and 1 1 15.39 t ha at WM; and 3.12/33 yielded 3.61 t ha at RG. Some of the growth parameters of bread wheat 1 1increased with increased application of lime. Therefore, it is recommended that, 3.12 t ha lime by 16.5 kg ha 1 1P fertilizer are good combination for production of bread wheat in Welmera District. However, this work needsto consider economic feasibility of the finding before taking the result to end users.