Comparative Study on the Effect of Applying Biogas Slurry and Inorganic Fertilizer on Soil Properties, Growth and Yield of White Cabbage (Brassica oleracea var. capitata f. alba)

Abstract

The use of locally available, nutrient rich organic sources is an effective means for improving soil fertility and increasing crop yield in view of the escalating cost of inorganic fertilizers and low fertilizer use efficiency of crops in Ethiopia. This study was conducted in Sebeta Hawas Woreda with the objective of comparing the effectiveness of bio-slurry and inorganic fertilizer on soil properties, growth and yield of white cabbage. Laboratory analysis and field experiment were done on bio-slurry in liquid and composted form to determine the nutrient content and effect of bio-slurry and inorganic fertilizer on  plant height, number of leaves, head yield and nutrient content of  cabbage as well as physical and chemical properties of  the soil. The maximum plant height (cm) was obtained from T6 (recommended dose of inorganic fertilizer (RDIF) + biogas slurry compost (BGSC) at (8ton/ha), while the lowest plant height (cm) was recorded in T1 (control). Cabbage plants treated with T7 ( (1/2 RDIF) + (½ BGSC )), T6 ( (RDIF) + BGSC at  8ton/ha),T5 (BGSC at (8ton/ha)) and T6  showed the highest number of  leaves at 2,4,6 and 8 weeks after planting respectively. With regard to fresh weight of individual head, T6 showed the highest value for fresh weight of individual head. Considering major nutrient content of white cabbage, it can be inferred that bio-slurry and inorganic fertilizer showed no significant effects on leaf phosphorous and potassium value but bio-slurry applied in combination with inorganic fertilizers has positive influence on nitrogen content. The study also revealed that there was significant contribution of bio-slurry to increase organic carbon, phosphorus and cation exchange capacity of soil.

Keywords: Growth, head yield, soil properties, bio-slurry, fertilizer