A THESIS SUBMITTED TO THE DEPARTMENT OF PLANT SCIENCE, SCHOOL OF GRADUATE STUDIES, COLLEGE OF AGRICULTURAL SCIENCES, ARBA MINCH UNIVERSITY

Abstract

Oat (Avena sativa L.) is the most important cereal crops in Ethiopia. However, the productivity of the crop is affected due to varieties commended along with rates of blended NPSB fertilizer and seeding rate. Therefore, a field experiment was conducted at Chencha, Southern Ethiopia Regional State during 2023 cropping season. The experiment consisted of three seeding rates (70, 100 and 130 kg ha-1) combined with two oat varieties ( Souris and Goslin ) and four levels of blended NPSB fertilizer rates (0, 50,100 and 150 kg ha-1) and laid out in factorial arrangement in split plot design with three replications. The seeding rates combined with oat varieties were assigned as main plot, and the blended NPSB fertilizer rates were assigned in a subplot. Data on crop phenology, growth, yield and yield components were collected and subjected for analysis. The results showed that, plant height, spike length, biomass yield, number of grains spike-1, grain yield, thousand seed weight and harvest index were significantly (p≤0.05) affected by variety combined with seeding rate and blended NPSB fertilizer rates. The maximum grain yield of 3589.5 kg ha-1 was recorded from variety Souris combined with seeding rates of 100 kg ha-1 and with blended fertilizer application rate of 100kgha-1. But the minimum grain yield of 1495 kg ha-1 was recorded from oat variety Goslin combined with seeding rate of 130 kg ha-1 and blended fertilizer application rate of 0 kg ha-1. The maximum biomass yields 21,348.3kg ha-1 was recorded from variety Souris combined with seeding rate of 130 kg ha-1 and with blended NPSB fertilizer application rate of 100 kg ha-1. However, the minimum biomass yield of 9927.5 kg ha-1 was recorded from oat variety Goslin combined with seed rate of 100 kg ha-1 and blended NPSB fertilizer rate of 0 kg ha-1. From partial budget analysis of the highest net benefit and MRR 214,466.1 birr was obtained from V1SR2 and 100 kg ha-1 of blended NPSB fertilizer rate and the lowest net benefit and MRR of combined mean effect of variety seed rate and blended NPSB 124,337.05 birr was obtained from V2SR3 and 150 kg ha-1 of NPSB fertilizer rate. Therefore, oat variety Souris when combined with the seed rate of 100 kg ha-1 and blended NPSB fertilizer rate100kgha-1was found to be important for oat growth and yield at Chencha. However, further study needs to be done under different seasons and locations to utilize the recommendations of the present study.