Effects of Goat Manure-Based Vermicompost on Soil Chemical Properties, Growth and Yield of Garlic in Meru South and Manyatta Sub Counties, Kenya

Abstract

Garlic (Allium sativum L.) is a bulb vegetable that is gaining prominence among small-scale and commercial farmers in Eastern Kenya due to its reported high returns and the readily available market. It is used as food and for medicinal purposes. Most of farmers growing garlic in Kenya, apply chemical fertilizers alone during the growth of this crop. Overutilization of chemical fertilizers has caused several adverse effects to the environment and human health, besides being costly hence limiting optimization of garlic production. Moreover, there is increase in the number of customers preferring organically produced agricultural products. This study aimed to determine the effects of different rates of goat manure-based vermicompost on soil chemical properties, growth and yield of garlic. The study was conducted in PCEA Nkio secondary school farm and KALRO Embu horticultural field in 2018 to 2019. The experiment was laid out in a randomized complete block design and replicated three times. The treatments consisted of goat manure-based vermicompost which was applied at five levels (Control treatment (0), 5, 10, 20 and 30 t ha-1), inorganic fertilizer (NPK 17-17-17) at the recommended rate of 200 Kg ha-1 and goat manure (30 t ha-1). Data collected included soil pH, total nitrogen, available phosphorous, exchangeable potassium, plant height, number of leaves, stem diameter, leaf length, leaf width, bulb fresh weight, bulb diameter, bulb length, bulb dry weight, number of cloves per bulb and bulb yield per hectare. The data obtained were subjected to ANOVA using SAS and significantly different means were separated using least significance difference at α = 0.05. Application of 30 t ha-1 goat manure-based vermicompost showed significantly (p < 0.05) higher soil pH, total N, available P and exchangeable K compared to control treatment at Chuka and Embu. Application of 30 t ha-1 goat manure-based vermicompost showed significantly (p < 0.05) higher plant height, number of leaves, stem diameter, leaf length and leaf width than control treatment at Chuka and Embu. Application of 30 t ha-1 goat manure-based vermicompost showed significantly (p < 0.05) higher bulb fresh weight, bulb diameter, bulb length, number of cloves per bulb, bulb dry weight and bulb yield per hectare than control treatment at Chuka. A similar trend was observed in Embu where goat manure-based vermicompost gave significantly (p < 0.05) higher bulb fresh weight, bulb diameter, bulb length, number of cloves per bulb, bulb dry weight and bulb yield per hectare compared to control treatment. Hence the most appropriate recommended rate of application is 30 t ha-1 of goat manure-based vermicompost in the organic production of garlic. This study, therefore, provides valuable information on the utilization of goat manure-based vermicompost in organic production of garlic.