The influence of Potassium Fertilizer on the Production of Potato (Solanum tuberosu l.) at Kembata in Southern Ethiopia

An experiment was conducted at Angacha Research Station in Kembata Tembaro Zone of Southern Ethiopia to evaluate the response of potato (Solanum tuberosum L.) to potassium fertilizer. Increasing rates of K (0, 40, 80, 120, 160, 200, 240, 280, and 320 kg ha-1 as KCl) in RCBD with four replications were used in the experiment. Recommended rates of N and P, 111 and 39.3 kg ha-1, respectively were applied to all treatments. Urea (46-0-0) and DAP (18-46-0) were used as sources of N and P. N was applied in split at planting and after tuber initiation (as side dressing). The composite soil sample contains moderate organic carbon (1.6%), whereas the total N (0.26%), available P and K contents are high. The potato tuber yield ranged between 43.97 t ha-1 at application of 200 kg K ha-1 and 53.33 t ha-1 at application of 280 kg K ha-1. Application of K did not significantly influence potato tuber yield, N, P and K concentrations both in leaf and tuber, exchangeable and available potassium in the soil. However, a yield advantage of 11.4% (5.47 t ha-1) was obtained from the application of 280 kg K ha-1 over the control, although the difference is not statistically significant. These parameters neither showed increasing or decreasing pattern with increased K application. Based on the current finding, application of K for potato at Angacha is not required. However, as potato is highly K demanding crop, periodic checking of the K status of the soil and crop response to it is important. Key words: Potassium fertilization, Potato tuber yield, Exchangeable potassiu