Evaluation of Agronomic Practices for Striga Controlling Management on Sorghum (Sorghum Bicolor L.) Crop Yield in Raya valley, Northern Ethiopia

摘要

Striga hermonthica (Del.) Benth ( Scrophulariacae ), which is aggravated by the inherent low soil fertility, recurrent drought and continuous cereal monoculture, is one of the major production constraints in the sorghum growing regions of Ethiopia. Thus, an experiment on evaluation of agronomic practices for Striga controlling management on sorghum was conducted in 2016 and 2017 cropping seasons to determine the appropriate Striga controlling management practice under rain fed conditions. Treatments (T) comprised (T1) farmers’ practice (no fertilizer and intercropping) as a control; (T2) compost (at10 ton ha -1 ); (T3) intercropping with Mungbean variety (N-26); (T4) inorganic fertilizer (at 41kg N ha -1 and 46 kg P 2 O 5 ha- 1 ); (T5) 50% compost + 50% inorganic fertilizer; (T6) 50% compost + intercropping; (T7) 50% inorganic fertilizer + intercropping; (T8) 50% compost + intercropping + 50% inorganic fertilizer rate; (T9) Striga resistant sorghum. These treatments were laid out in Randomized Complete Block Design (RCBD) with three replications. According to the current results, the maximum average grain yield (4640.40 kg ha -1 ) and total biomass (10879.60 kg ha -1 ), head weight (93.54 g), and plant height (164.16 cm) were recorded prominently in plots treated with inorganic fertilizer. The combination of compost and inorganic fertilizer also gave remarkable grain (4537.80 kg ha -1 ) and biomass yields (10592.60 kg ha -1 ). Moreover, Striga population reduced due to application of inorganic fertilizers (0.95 Striga m -2 ). A significant reduction was also observed when plots were treated with the combination of compost and inorganic fertilizer (1.17 Striga m -2 ). Similarly, as compared to farmers’ practice (2.37 Striga m -2 ), low number of Striga m -2 (1.24) was recorded from resistant sorghum variety (Gubiye). Based on economic analysis, application of 50% compost + 50% inorganic fertilizers gave optimum marginal rate of return (MRR) (165.66%), which was above the minimum rate of return (100%). Generally, this experiment showed that productivity of sorghum is considerably higher when farmers use integrated soil fertility management options. This is, therefore, integrated use of 50% compost and 50% inorganic fertilizers should be recommended for farmers as they were affordable options for increasing sorghum yields with improving soil fertility in the small-scale farming systems of the study area. Furthermore, integrated use of organic and inorganic fertilizers proved to be highly effective in terms of reducing Striga incidence both in terms of reduced seed density in the soil and decreased infection in sorghum.