Effects of Vermicompost and Inorganic NP Fertilizers on Growth, Yield and Quality of Garlic (Allium sativum L.) in Enebse Sar Midir District, Northwestern Ethiopia

Abstract

Garlic (Allium sativum L.) is an important vegetable crop in Ethiopia. However, the yield of the crop is often constrained by low and imbalanced nutrient supply in the soil. Therefore, a field experiment was conducted at Mertule Mariam ATVET College to study the effect of vermicompost and inorganic NP fertilizers on growth, yield and quality of garlic (Allium sativum L.) during 2013 main rainy season. A locally grown garlic cultivar called Tsedey 92 (G-493) was used for the study. The treatment consisted of three levels of nitrogen (0, 23 and 46 kg ha^-1), three levels of phosphorus (0, 46 and 92 kg P₂O₅ ha^-1) and three levels of vermicompost (0, 2.5 and 5 t ha^-1). The experiment was laid out as a randomized complete block design (RCBD) in a factorial arrangement, and replicated three times. Data were collected on phenology, plant growth, bulb yield, and quality of the crop. The results revealed that the main effects of phosphorus and vermicompost significantly (P < 0.05) affected days to emergence whereas nitrogen had no significant effect on days to emergence. The main effects of nitrogen, phosphorus and vermicompost also significantly (P < 0.05) influenced days to maturity, leaf number, leaf area index, mean clove weight, mean bulb weight, fresh biomass yield, total bulb yield, dry matter percent and total soluble solid. The highest total bulb yield 7.96 t ha-1 was recorded at 92 kg P₂O₅ ha^-1. At lone application of 46 kg N ha^-1 and 92 kg P₂O₅ ha^-1, similar amount of maximum total soluble solid 5.79^oBrix was recorded. Conversely, the interaction effects of nitrogen, phosphorus and vermicompost significantly (P < 0.05) influenced plant height. The interaction effects of nitrogen and phosphorus and the main effect of vermicompost significantly (P < 0.05) affected marketable and unmarketable bulb yield, and mean clove number. The highest marketable yield 7.87 t ha^-1 and 6.99 t ha^-1 were recorded from combined application of 46 kg N ha^-1 and 92 kg P₂O₅ and sole application of 5 t vermicompost ha^-1 respectively. Harvest index was also significantly (P < 0.05) affected by the interaction effects of nitrogen and phosphorus. The maximum harvest index 68.36% was also recorded at combined application of 46 kg N ha^-1 and 92 kg P₂O₅ ha^-1. The highest benefit (280542.00 ETB ha^-1) in the partial budget was recorded at 5 t ha^-1 vermicompost followed by (172569.00 ETB ha^-1) at combined application of 46 kg N and 92 kg P₂O₅ ha^-1.  It can, thus be concluded that, lone application of 5 t ha^-1 vermicompost or combined application of 46 kg N ha^-1 plus 92 kg P₂O₅ ha^-1 led to the maximum growth, yield and quality of the garlic crop.

Keywords: vermicompost, garlic, organic fertilizer, inorganic fertilizer, earth worm, Eisenia foetida