Response of tef [eragrostis tef (zucc.)trotter] to time of nitrogen application and variable seed rates at dilla district, southern Ethiopia

A field experiment was conducted at Dilla district, Gedio Zone Southern Ethiopia during the 2014 main cropping season under rain-fed condition, to study the effects of variable seed rates and time of nitrogen fertilizer application on yield and yield components of tef. A factorial experiment with three variable seed (15, 25 and 35 kg ha-1) and four timing of applications (full dose at sowing, full dose at tillering, ½ dose at sowing + ½ dose at tillering, ¼ at sowing+ ½ after 30 days of sowing+ ¼ after 60 days of sowing) were used in Randomized Complete Block Design (RCBD) with three replication. Nitrogen fertilizer at recommendation rate of 46 kg N ha-1 was applied by broadcasting urea. Phosphorus was applied to all plots equally at the blanket recommendation rate of 46 kg P205 ha-1 as TSP (Triple- supper phosphate). The tef variety used for the study was, Kuncho (DZ-CR 387 RIL 355). Both seed rates and time of nitrogen application significantly affected days to heading, physiological maturity, plant height, panicle length, straw yield, above-ground biomass, grain yield and harvest index. The treatment interaction significantly (P<0.001) affected plant height and lodging index of tef. Low seed rates delayed days to panicle initiation and days to physiological maturity of tef plants. Seed rate at 15 kg/ha increased above ground biomass yield by 4.65% over seed rate at 35 kg/ha. Application of the recommended rate of nitrogen 1/2 dose at sowing and 1/2 dose at tillering also increased total aboveground biomass yield and straw yield of tef as compared to other treatments. Application of the recommended rate of nitrogen half dose at sowing and half dose at tillering gave significantly higher (2308.96kg/ha) grain yield than the rest of the treatments. Significantly higher (2000.24 kg/ha) grain yield was also recorded under low seed rates. Hence, reducing seed rates and using application of the recommended rate of nitrogen half dose at sowing and half dose at tillering considerably increased the growth, yield and yield attributes of tef and can be suggested for higher tef production in the study area.