Nutrients Limiting Tef [Eragrostis tef (Zucc.) Trotter] Crop Yield on Vertisols in Yilmana Densa, Upper Blue Nile Basin of Ethiopia

Currently, the government of Ethiopia is supplying fertilizers containing N, P, S, Zn & B. However, many researchers argued that N and P are the only yield-limiting nutrients. The current study was conducted to identify yield-limiting nutrients for tef and to assess the inherent nutrient supplying status of Vertisols. The experiments were carried out during the 2020/2021cropping season under screen house, on-station, and on-farm conditions at Yilmana Densa district of Amhara region, Ethiopia. Tef (Quncho variety) was used as a test crop. This trial contained ten treatments including: control, PKSZnB, NKSZnB, NPSZnB, NPKZnB, NPKSB, NPKSZn, NPKSZnB, NP, and NPS. Each pot with a height of 0.185 m and volume of 0.186 m 3 was filled with 5 kg of soil which was taken from 0 to 20 cm depth by auger. The pot trial was laid out in a completely randomized design (CRD), while the field trials were laid out in a completely randomized block design (RCBD) with three replications. The gross plot area was 7.5 m 2 for field experiments. Yield-limiting nutrients were identified through a nutrient omission trial. The data were analyzed using SAS version 9.0, and significant treatment means were separated by using LSD at P ≤ 0.05. The nutrient contents of the soils determined from the composite samples collected before planting indicated that TN (0.126% on-station and 0.125% on-farm) was low. The Av.P (3.89 mg kg −1 on-station and 4.24 mg kg −1 on-farm) content of the soil was also very low. The result revealed that omission of N and P highly significantly ( P