Effects of Blended NPSB Fertilizer Rates on Yield and Yield Related Traits of Bread Wheat (Triticum aestivum L.)Varieties in Kedida Gamela District, Southern Ethiopia

Bread wheat is one of the major crops in the study area cultivated both for home consumption and market purposes. However, its productivity is mainly constrained by poor soil fertility and lack of site specific fertilizer (NPSB) recommendation. Therefore, field experiment was carried out to assess the effect of blended NPSB fertilizer rates on yield, and yield related traits on selected bread wheat cultivars during the 2018/2019 cropping season on farmer training center (FTC) in Kedida Gamela District, southern Ethiopia. Factorial combinations of blended five NPSB fertilizer levels (0, 50,100, 150 and 200 kg ha-1) with three bread wheat varieties (Ogolcho, Hidase, and Shorima) were laid out in a randomized complete block design with three replications. Analysis of the results revealed that the days of 50% heading, days to 90% physiological maturity, plant height, spike length, number of kernels per spike, aboveground dry biomass yield, grain yield, and straw yield were significantly (P < 0.01) affected by main effect of NPSB fertilizer rate as well as by the main effect of varieties while thousand kernels weight and agronomic efficiency were affected by the main effects of blended NPSB fertilizer only. The highest days of 50% heading (59.44 days), days to 90% physiological maturity (102.00 days), plant height (82.38cm),spike length (9.36cm), number of kernels per spike (58.3), total dry biomass yield (12927 kg ha-1), grain yield (5586kg ha-1), and straw yield (7663 kg ha-1) were obtained at, NPSB rate of 200 kg ha-1 . With regards to the main effects of varieties, variety Shorima recorded the highest days of 50% heading (58.27), days to 90% physiological maturity (102.13), number of kernels per spike (54.25), aboveground dry biomass yield (9967 kg ha-1), grain yield (4325 kg ha-1), straw yield (5769 kg ha-1) and variety Hidase recorded the highest plant height (82.94cm ), and variety Ogolcho recorded the highest spike length (9.431cm). The maximum agronomic efficiency (18.59 kg grain per kg NPSB) was recorded at 150 kg NPSB ha-1. Interaction of blended NPSB rate with varieties significantly affected the number of total tillers and productive tillers where highest total tillers (441.7 per m2) and productive tillers (390.0 per m2) were recorded at the combination of 200 kg NPSB ha1 with variety Shorima. The economic analysis revealed that variety Shorima with the application of 200kg NPSB ha-1 gave the highest net benefit of 62848.2 birr ha-1 with marginal rate of return of 739.7%. Therefore, from the result of present study that the application of the 200 kg ha-1 blended NPSB fertilizer with Shorima variety can be tentatively recommended for farmers for production of wheat in the study area and other areas with similar agro-ecological conditions