BREAD WHEAT (Triticum aestivum L.) RESPONSE TO POTASH FERTILIZER APPLICATION IN SIYA DEBIRINA WAYU DISTRICT, AMHARA NATIONAL REGIONAL STATE, ETHIOPIA

Abstract

Potassium (K) status of agricultural soils in Ethiopia is repeatedly reported as adequate for crop production and most Ethiopian farmers have not been using K fertilizers. However, recent researches showed a positive response of crops to applied K fertilizers where determining optimum rate with economically feasible level is urgently needed. Hence, an experiment was conducted on Vertisols of Sidebrena Wayu district on farmers’ field with six levels of K fertilizer (0, 40, 80, 120,160 and 200 of K kg/ha) as KCl at Wele Deneba and Ejersa-Kubetin experimental sites on bread wheat variety Danda’a. Treatments were arranged in RCBD with three replications. Pre-sowing and post-harvest soil analysis was done as well as consecutive agronomic data was recorded from emergence to harvesting. Besides, NPK concentrations in grain and straw were analyzed after harvest based on standard procedures. Soil analysis results before sowing revealed that the soil was slightly acidic and clay texture with medium available P and organic matter. CEC and K values of soils was in high rate whereas the area has low N. In post-harvest soil analysis, generally, the highest accumulation of available K was found at higher levels of K and lowest value was recorded at control plot. Regarding the agronomic attributes, days to 50% emergence, days to 50% heading, days to 75% grain-filling period were not significantly affected by applications of K fertilizer. Vegetative growth attributes and yield components such as number of tillers, plant height, spike length, number of grain per spike and thousand seed weight were affected due to application of K. Grain yield, biological and harvest index were significantly influenced by different rates of K at Wele-Deneba experimental site.Whereas,in Ejersa-Kubetin experimental site only grain yield and harvest index was remarkably influenced by rates of K. Applications of different rates of K had shown significant influence on N, and K concentration of the grain and straw but not phosphorus. Lowest K uptake by straw and total plant uptake was recorded from control treatment where accumulation of K in grain was statistically in par in both experimental sits. Application of K fertilizer resulted in increasing total N uptake by grain, straw as well as by the whole plant as compared to the control except in Wele-Deneba where grain TN uptake was statistically non-significant. Generally, applications of K fertilizer at 160 kg/ha had shown positive yield and yield attributes in both experimental sites. Agronomic use efficiency and Apparent K recovery were significantly higher at 160K kg/ha and 200K kg/ha, respectively in both experimental sites. However, K harvest index and was not shown significant variation due to applied K rate. Partial budget analysis results also shown that application of 160 K kg/ha at Wele-Deneba and Ejersa-Kubetin experimental sites had the highest yield with an acceptable marginal rate of return 895% and 805% respectively, which can be a tentative recommendation. However, it is vital to verify these results in multilocation with diverse soil type and many years for complete applications of these results