Ethiopia is the only country that produces teff (Eragrostis tef) in the world, but the production of teff is still low compared to other cereal crops. The main purpose of this study was to evaluate the impacts of organic and inorganic fertilizers on teff yield between 1995 and 2017 using an autoregressive distributed lag with co-integration approach. The Phillips Peron test and the Augmented Dickey-Fuller test for time series stationary checking and capturing serial correlation were used, whereas the Breusch Godfrey Lagrange multiplier and the cumulative sum test were used for determining the autocorrelation of residuals and the stability of coefficients. The result showed that the average yield of teff was 11.25 quintals per hectare, and the bounded F-test for co-integration among the variables does not show evidence of a long-run relationship between fertilizers applied and teff yield per hectare. The quantity of urea applied had a positive and significant impact on the yield of teff, and the quantity of di-ammonium phosphate (DAP) application had a negative impact in the short run. In conclusion, there was no co-integration between the yield of teff crops and fertilizer types such as urea and di-ammonium phosphate, which indicates that the quantity of urea fertilizer used for the production of teff has a positive relationship while the quantity of DAP fertilizer had an indirect relationship. Hence inorganic fertilizer like DAP is negatively correlated with the production of teff while organic fertilizer (urea) is positively correlated.

Potato is important for food security in developing countries such as Ethiopia. The purpose of this study is to evaluate the contribution of varied fertilizers to potato yields at Basketo Special Woreda, Gamogofa Zone, Ethiopia. To attain this objective, a generalized linear mixed model was used to differentiate the factors that affect the marketable yield of potatoes by considering variability within three replications. In addition, this study used the Kolmogorov-Smirnov test to check the goodness of fit tests of normal distribution. The collected data were analyzed using statistical software, SAS version 9.4. The mean of plant tallness, number of plants per plot, number of plants per slope, and number of tubers per slope were 73.65 (SD = 12.2), 155.2 (SD = 112.2), 3.23 (SD = 1.31), and 10.91 (SD = 3.15.2), respectively. The result reveals that 6% of variation existed in potato yield between plots, and the remaining 94% existed within plots. Apart from a linear mixed model, a random intercept model was applied to this data. The findings reveal that fertilizer types, number of plants per plot, and numbers of tubers per hill were significant at 5% level of significant. Thus, the expected marketable yield of potatoes decreased by 0.7819 tons/hectare when the number of tubers per hill increased by 1 unit. On the other hand, the expected marketable yield of potatoes has increased by 0.0175 tons/hectare when the number of plants per plot increased by 1 unit.

Phosphorus is the second most important nutrient for plant growth, but its availability is very low in the soil. This study was designed to identify phosphate-solubilizing Rhizobia from rhizosphere soil in Gorogutu and Deder districts of Ethiopia. The study evaluates the effects of phosphate-solubilizing Rhizobia on Teff (Eragrostis teff) growth under greenhouse conditions. The greenhouse experiment was assembled in a completely randomized design with 5 treatments including the control with three replications. A total of 30 Rhizobia isolates were obtained from rhizosphere soils in two districts (Gorogutu, and Deder) and screened for phosphate solubilization using Pikovskaya’s Agar. Based on their phosphate solubilization indices, 4 potential isolates (PS-6, PS-22, PS-27, and PS-30) were selected for further study in the greenhouse. Phosphate solubilizing isolates in pot experiment under greenhouse were applied at a rate of 0.5 g per pot and Teff disinfected seeds were suspended in 30 ml thick cell suspension of phosphate solubilizing Rhizobia (1012 cells/ml) in the presence of 0.5% peptone (antidiuretic hormone for 30 minutes), but not the control. The result showed that almost all inoculants, after 30- and 90-days inoculation, have significantly improved the growth parameters of Teff (Eragrostis teff) under greenhouse conditions. Moreover, all the isolates showed a positive impact on all the growth parameters. The results from this experiment are useful in Ethiopia for biofertilizer development and for teff growth under organic farming systems. Therefore, isolates PS-6 and PS-22 are highly recommended to be prospective commercial biofertilizers at field conditions in different teff agroecologies.