Evaluation of mustard meal as organic fertiliser on tef (Eragrostis tef (Zucc) trotter) under field and greenhouse conditions

Experiments were conducted to evaluate the potential use of mustard meal as organic fertiliser on tef ( Eragrostis tef ( Zucc) Trotter). Mustard meal is a high quality nutrient source with 6.35% lignin, 2.1% total extractable polyphenol, C to N ratio of 14 and lignin to N ratio of 1.1. Under field conditions the effect of tef on Nitosol was studied in a split plot design with three replications. Grain yield increases due to increased mustard meal N rate varied from 2 to 116% over the control. The agronomic efficiency was 3.0, 8.3 and 13.5 kg when N was applied at 15, 23 and 31 kg ha(-1), respectively. The mustard meal N use efficiency was 7.6, 20.6 and 33.7% for the above-indicated N rates. Application of mustard meal in powder form was more effective than granular. In the greenhouse, the effect of mustard meal and urea N mixed in different quantity was studied with 15 N technique. The N derived from fertiliser was lowest ( 3.5%) when 20 mg pot(-1) from urea was combined with 100 mg pot(-1) from mustard meal and highest ( 11%) when 67 and 33 mg pot(-1) as urea and mustard meal were combined, respectively. The N derived from mustard meal was lowest ( 3.3%) when mustard meal and urea N were combined at 50 mg N pot(-1) each, and highest ( 8.9%) when combined at 20 and 100 mg N pot(-1), respectively. The urea and mustard meal N yields significantly varied between the treatments. The N use efficiency from urea ( FNUE) varied from 38.4 to 43%. Combining urea and mustard meal N at 50 mg N pot(-1) each has decreased FNUE to 4.4% compared to the urea N applied alone at 50 mg N pot(-1). N use efficiency ( NUE) from mustard meal was highest ( 38.4%) when mustard meal and urea N were combined at 33 and 67 mg N pot(-1), respectively, and lowest when it was combined at 67 and 33 mg N pot(-1).