Growth and yield of carrots affected by integrated nutrient management of organic and inorganic fertilizers

Two experiments were conducted at the Multipurpose Crop Nursery Research fields of the Akenten Appiah-Menka University of Skill Training and Entrepreneurial Development (AAMUSTED), Mampong-Ashanti during the 2018 major (March-July) and minor (September-December) seasons to assess the effect of organic and inorganic fertilizers and their combinations on the growth and yield of carrot. Four organic manures [cattle dung (CD), poultry manure (PM), Gliricidia sepium prunnings (GP) and Leucaena leucocephala prunnings (LP)] at 10 t/ha, NPK 15-15-15 at 300 kg/ha, their combinations (at ½ full) and no amendment (control) were arranged in a randomized complete block design with four replications. Combining organic manures and inorganic fertilizers increased the growth and yield of carrot greater than the control and sole fertilizers. Plant height and canopy width were greatest for the 5 t/ha CD + 5 t/ha PM and 5 t/ha PM + 5 t/ha GP in both seasons. Carrot root yields in both seasons for the organic and inorganic combinations ranged from 24.3-54.2 t/ha, which was 9-14% and 25-95% greater than the sole fertilizers (22.2-47.6 t/ha) and control (19.4-27.8 t/ha), respectively. Root yields in the major and minor seasons were highest for 5 t/ha CD + 5 t/ha GP and 5 t/ha CD + 5 t/ha PM, respectively.