On-farm Verification of Potassium Fertilization for Major Cereal Crops under Balanced Fertilizers in North Shew Zone of Amhara Region, Ethiopia

The present study was conducted to investigate the response of major cereal crops to application of potassium with balanced fertilizers as well as to validate newly released soil fertility map of Amhara Region. A field experiment was carried out with different districts of North Shewa of Amhara region: Kewet (Sorghum), Basona warana (Food Barley) Moretena jiru and Mojana wedera (Bread wheat. A randomized complete block design was used, with three replications. The treatments were consisted of NPS, NPS+K, NPSBZn, and NPSBZn+K. The required amount of nitrogen and phosphorus were adjusted to crop and site specific recommendation. The rate of K was 150 kg ha -1 K 2 O and applied as a straight fertilizer at planting in the form of potassium chloride (KCl).The highest grain yield of sorghum (4301.9 kg ha -1 ) was recorded under the treatment of NPSBZn and followed by NPS fertilizer application respectively, while lower grain yields (3017.7 and 3186.9 kg ha -1 ) were recorded under the treatments of NPSBZn and NPS with potassium fertilizer application. Even though statically insignificance both NPS and NPSBZn, application of NPSBZn had gave 5.3% of sorghum grain yield advantage as compared to sole NPS and N fertilizer application. The highest grain yield of barley (4411 kg ha -1 ) also was recorded under the treatment of NPS and followed by NPS+K respectively, while lower grain yield (3960.6 kg ha -1 ) was recorded under the treatments of NPSBZn. Grain yield of bread also showed similar trend as grain yield of food barley at Moretena jiru and Mojana wedera districts. Generally the results of this experiment did not showed agronomical viable options due to utilization of potassium with recommended NP nutrient sources and micronutrients. The soil was deficient in organic matter, total nitrogen, and available phosphorus and adequate in available potassium. Thus it can be concluded that potassium is not a yield limiting nutrient but soil nitrogen and phosphorus management need especial attention.