Soil Chemical Properties and Plant Nutrient Status as Influenced by Application of Lime, Phosphorus and Compost

Declining soil fertility along with soil acidity are major soil degradation problems affecting crop production in Ethiopian highlands. However, little effort has been done to investigate different soil amendment measures on soil chemical properties and nutrient status of common bean crop on acid soils of Areka. Therefore, field studies were conducted with the objective of investigating the effects of combined application of compost, lime and P-fertilizer on selected soil chemical properties and plant nutrient concentration of common bean at Areka area of southern Ethiopia. Treatments, consisted of factorial combinations of three rates of compost (0, 5 and 10 t ha-1), lime (0, 0.64 and 1.28 t ha-1) and phosphorus (0, 23 and 46 kg P2O5 ha-1) were laid out in a randomized complete block design with three replications. Data on several soil chemical properties and tissue nutrient status were collected. The results revealed that relative to the control treatment, the application of 10 t ha-1 of compost alone increased soil pH and nitrogen by 7 and 68% in Belg and 7 and 77% in the Meher seasons, respectively. Similarly, sole application of lime increased soil pH by 20 and 10% in Belg and Meher seasons, respectively. The application of compost at the rates of 5 t ha-1 also resulted in increase in leaf tissue N concentration during Belg and Meher seasons. Further significant interaction effects of compost × lime × phosphorus were found for soil available P and tissue P concentration in both seasons. Combined application of compost, lime and P at their highest rates resulted in an increase in available P by 221% in belg and 144% in meher seasons compared to the control treatment. In conclusion, separate as well as combined application of compost, lime and P in both seasons can improve the fertility of the soil in the study area.