Response of maize (zea mays l.) To omission of nutrients At kersa district, jimma zone, south western Ethiopia

Abstract

Appropriate fertilization practices based on actual limiting nutrient and crop requirement for a given crop is economic and judicious use of fertilizers for sustainable crop production. Balanced nutrition must be achieved to optimize maize productivity. A field experiment was conducted with an objective to identify which of macronutrients N, P and K are limiting maize grain and yield components in the study area during 2017/18 cropping season. The experiments were laid out in a completely randomized block design with six treatments replicated across six farmers’ fields in Kersa district, Jimma zone, south western Ethiopia. The trial consisted of six treatments, which include; control, PK (-N), NK (-P), NP (-K), NPK and NPK+ CaMgSZnB. Among the six treatments, -N, -P, and -K were set to estimate the inherent N, P and K supplying capacity of soil respectively. The yield and soil fertility gap between a full NPK fertilizer plot and a fertilizer omission plot was used as a good diagnostic tool to assess the extent of macronutrient limitations. Average maize yields were the highest in the NPK treatment, followed by those in the NPK+CaMgSZnB plots among all treatments. Maize yield, a significantly increasing trend over time was found in the NPK-treated plots and a decreasing trend in the PK and NK-treated plots. In the absence of N or P, maize yields were significantly lower than those in the NPK treatment. A balanced use of NPK has a remarkable influence on maize growth and yield. Among different treatments NPK combinations, provided the highest grain yield of 9185 kg ha-1 andthe lowest (1861.3 kg ha-1 ) was obtained from control plots. Nitrogen, Phosphorus and Potassium are macronutrients that play a major role in plant growth and crop yields. Yield responses to fertilization were ranked NPK > NPK+CaMgSZnB >NP>PK>NK, illustrating that N deficiency was the most limiting condition in maize production, followed by P and K deficiencies. As compared with the NP treatment, the NPK treatment was significantly increased maize yields by 15.4%. However, maize yields under the NPK treatments were statistically better than those in the NPK+CaMgSZnB treatment. Based on the results, it was concluded that the inherent N, P and K supplying capacity of soil is very low. Therefore, use of appropriate balanced fertilizers should be used for efficient nutrient uptake which ultimately increases maize productivity.