The use of right amount of fertilizer based on crop requirement has a significant importance for sustainable crop production. Study was undertaken to investigate the effects of NPSZnB blended fertilizer for maize yield production at Laelay Adiyabo and Medebay Zana districts. Seven treatments were used for the field experiment. Treatments were without fertilizer, blanket recommended NP (64 kg N ha -1 +69 kg P 2 O 5 ha -1 ) and five treatments of blended fertilizer rates (150, 200, 250, 300, and 350 kg NPSZnB ha -1 ). Treatments were laid out in RCBD design with three replications. The results revealed that among fertilizers rates significantly (P ≤ 0.05) affected almost all the maize traits tested except tasseling, silking and maturity in Laelay Adiyabo district. However, in Medebay Zana district except tasseling, silking and maturity, plant height and thousand seeds weight, the rest parameters of above ground biomass yield, stover yield grain yield and harvest index were found significantly (P<0.05) affected by the fertilizer treatments. Highest stover yields (11.12 and 11.76 t ha -1 ) were obtained from application of 150 and 250 kg NPSZnB ha -1 for Laelay Adiyabo and Medebay Zana districts, respectively. At both districts of Laelay Adiyabo and Medebay Zana areas the highest grain yields (3.20 and 2.97 t ha -1 ) were obtained, respectively from application of NPSZnB fertilizer at the rate of 300 kg ha -1 , while the minimum grain yields of both districts were obtained from the control checks. The highest marginal rate of returns of 242 and 255% were obtained from application of 150 kg NPSZnB ha -1 in both Laelay Adiyabo and Medebay Zana districts, respectively. Therefore, based on the result obtained from this study 150 kg NPSZnB ha -1 can be recommended as profitable for the production of maize at both districts of the study areas.

Study was carried out to evaluate the supplementary nitrogen requirement of tef to enhance nitrogen use efficiency of tef grown under chickpea-tef rotation cropping. On-farm, experiment was conducted during the 2015 main cropping season at Tahtay Koraro District of the Tigray regional State, Ethiopia on tef after preceding chickpea. The experiment was set in a randomized complete block design with three replications. Seven treatments: Six N levels (0, 11.5, 23, 34.5, 46, and 69 kg N ha-1) under the chickpeatef rotation and the seventh one negative control (0 kg N ha-1) under the continuous tef cropping were tested. Surface soil samples were collected before tef sowing and after harvesting. They were analyzed for selected soil properties. Clay sized particles dominate the soil of the experimental site and the textural class of the soil is clayey. There was a difference in the bulk density of the same soil between the chickpea-tef and tef-tef sequence. Nitrogen and organic carbon were higher in soil under chickpeatef cropping sequence than in soil under continuous tef cropping. Application of different N rates under chickpea-tef rotation statistically significantly affected grain (GNU), straw (SNU) and total nitrogen uptake (TNU) (kg ha-1). The highest total tef nitrogen uptake (59 kg N ha-1) was obtained in response to application of 34.5 kg N ha-1. The highest apparent nitrogen recovery (81%), agronomic efficiency (10.48 kg kg-1) and physiological N use efficiency were obtained in response to the lower N rate (11.5 kg N ha-1), 23 kg N ha-1 rate and 34.5 kg N ha-1 respectively. The highest grain protein content (7.78%) was recorded for grain harvested from plots fertilized with 23 kg N ha-1. Hence, it could be concluded that, under chickpea-tef rotation cropping system some supplementary nitrogen is needed to fulfill the nitrogen requirement and nitrogen use efficiency of tef crop at the study area.

Summary Nutrient deficiency is a major constraint in tef (Eragrostis tef (Zucc.) Trotter) production in Ethiopia. In the past, a blanket recommendation of nitrogen (N) and phosphorus (P) fertilizers has been applied regardless of the diversity of agroecological zones and soil types. As crop responses declined with widespread deficiencies of nutrients, farmers have lost interest in applying the recommended fertilizer rates. The present study was conducted with the objective of quantifying the response of tef to different rates of N, P, potassium (K) and sulphur (S) fertilizers under balanced application of the nutrients other than the one under investigation. In each region, the same set of trials was implemented on farmers’ fields for three years. All trials were implemented on Vertisols across four agroecological zones (AEZs). The treatments were seven rates of N, six rates each of P and S and eight rates of K with a basal application of zinc (Zn) and boron (B). The results showed that the most limiting nutrient is N followed by P in each agroecological zone on the Vertisols. There was clear evidence of increases in grain yield with increasing rates of N and P, but the responses to K and S rates did not follow clear trends across AEZs. With balanced application of the other nutrients, 23–92 kg N ha−1 increased grain yield by 11–92%, while 10–40 kg P ha−1 increased yields by 12–33% over the control in the different AEZs. Based on results from dose–response models, it is concluded that the agronomic optimum rates for tef production are 69 kg N, 20 kg P, 30 kg K and 10 kg S ha−1 in the cool sub-moist mid-highlands and the tepid sub-humid mid highlands; 92 kg N, 30 kg P, 15 kg K and 10 kg S ha−1 in tepid moist mid highlands but 69 kg N, 10 kg P, 15 kg K and 10 kg S ha−1 in the tepid sub-moist mid highlands. On Vertisols not covered by this study, these recommendations should be subject to appropriate soil and plant analysis. We also recommend further studies on the nutrient requirement of tef on other soil types and AEZs.

Tef is a stable crop in Ethiopia in which its yield is constrained by poor soil fertility management. Therefore, a field experiment was conducted for two consecutive years during 2016 and 2017 on clayey textural soil to assess the effect of vermicompost and inorganic fertilizer rates on yield and yield components of tef. Accordingly, field experiment with four levels of vermicompost (0, 2, 4 and 6 t ha -1 ) and four levels of NPS (0, 100, 150 and 200 kg ha -1 ) were arranged in randomized complete block design (RCBD) in a factorial combination with three replications. A tef variety, qunco was used as test crop. Analysis of the data revealed that highest grain yield (2269.80 kg ha -1 ) was obtained from the treatment of 4 t vermicompost ha -1 + 150 kg NPS ha -1 . Significantly highest straw yield (6480.60 kg ha -1 ) was obtained from the treatment of 6 t vermicompost ha -1 +200 kg NPS ha -1 , but statistically similar with 4 t vermicompost ha -1 +150 kg NPS ha -1 . To evaluate the feasibility of the treatments with view of farmers' practices, a partial budget analysis was conducted on straw and grain yield of tef and accordingly the highest marginal rate of return 4184% were obtained from combined fertilization of 4 t vermicompost ha -1 and 150 kg NPS ha -1 . Therefore, based on the data obtained from this study application of 4 t vermicompost ha -1 and 150 kg NPS ha -1 will be recommended as profitable for the production of tef at Beles kebelle Tahtay Koraro district.

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