Determination Time of Nitrogen Fertilizer Top Dressing for Teff Grown on Vertisols in the Northern Part of Ethiopia

Teff is a highly valued crop in more than 50-million Ethiopian people. However low plant available soil nitrogen due to depleting soil organic matter content and high leaching losses of mineralized nitrogen during the growing rainy seasons is one of the constraints listed for its low production and productivity in the country. The nationwide N fertilizer Recommendation for heavy soils (including Vertisols) was 60 kgha-1 and this rate most of the farmer were recommended to apply at 50% one week after emergence and 50% at 35-40 days after planting that is without any application of nitrogen at sowing/planting. Therefore, a field experiment was carried out during 2012 and 2013 main cropping season from July to November in Tahtay Machew district of central zone of Tigray region, Ethiopia. The objectives was to determine the most effective time of nitrogen fertilizer application for tef production in the study area, effect on yield and yield components of teff and Total nitrogen uptake by the plant.. The treatments were T1: (100% applied at Planting) Control, T2: (100% applied at Emergence), T3: (100% applied at Tillering), T4:(75% at Planting and 25% at Tillering), T5: (75% at Emergence and 25% at Tillering), T6: (75% at tillering and 25% at Emergence, T7: (50% at Planting and 50% at Tillering), T8: (50% at, Emergence, 25% at Tillering 25% at planting), T9: (50% at Tillering and 50% at Emergence), T10: (25% at Planting and 75% at Tillering), T11: (25 % at emergence, 50% at tillering and 25% at planting), T12: (25% at tillering, 25 % at Emergence and 50% at planting. The experiment was laid out as a randomized complete block design with four replications. All the parameters collected were computed using Gen-Stat 13th edition statistical software. The parameters were: days to panicle emergence, days to maturity, plant height, panicle length, lodging percentage, grain yield, biomass yield, harvest index and total Ni uptake by the plant. In general the highest panicle length, plant height, lodging percentage, grain yield, biomass yield, harvest index and total nitrogen was recorded when the recommended N is applied 25% at planting and 75% at tillering as compare to other treatments. Thus in heavy soils, where by the recommendation rate of 60-kgha-1 should be applied at a time of 25% at planting and &75% at tillering. Keywords: Tillering, Lodging percentage, Grain yield, Total N Uptake