Majority of farmers in upper Eastern region of Kenya mainly apply chemical fertilizers to boost crop yields. Continuous use of chemical fertilizers causes several adverse effects such as P-fixation, volatilization of essential nutrients and leaching that affect safety of groundwater and agricultural environment. Hence, the effects of goat manure-based vermicompost on soil chemical properties under garlic were evaluated in PCEA Nkio secondary school farm-chuka, Meru South sub-county and KALRO Embu horticultural field, Manyatta sub-county; from December 2018 to March 2019. The experiment was laid out in a randomized complete block design and replicated thrice. The treatments were; goat manure-based vermicompost applied at five levels (0, 5, 10, 20 and 30 t ha-1), NPK 17-17-17 at 200 Kg ha-1 and goat manure (30 t ha-1). The treatments were randomly assigned to experimental plots. Soil sampling and analysis were done before planting and after harvesting of garlic on each experimental plot. The results showed that application of goat manure-based vermicompost had statistically significant difference (p ≤ 0.05) on soil chemical properties. Application of 30 t ha-1 goat manure-based vermicompost showed significantly (p ≤ 0.05) higher soil pH (8.00), total N (0.606%), available P (21.933 ppm) and exchangeable K (0.863 Cmol Kg-1) than control treatment that had pH (6.59), total N (0.043%), available P (4.67 ppm) and exchangeable K (0.456 Cmol Kg-1) at Chuka. A similar trend was observed in Embu where goat manure-based vermicompost gave significantly higher soil pH (7.91), total N (0.563%), available P (21.053 ppm) and exchangeable K (0.71 Cmol Kg-1) compared to control which had pH (6.54), total N (0.03%), available P (4.6 ppm) and exchangeable K (0.34 Cmol Kg-1). Hence, the results of this experiment revealed that addition of goat manure-based vermicompost enhanced soil chemical properties leading to improved garlic productivity.
Keywords: Garlic, Goat manure-based vermicompost, Soil chemical properties