Growth and Yield Response of Onion (Allium cepa L.) to Different Rates of Soil Amendments and Plant Spacing.

Abstract

Two field experiments were conducted at the multipurpose research station of the College of Agriculture Education, University of Education Winneba-Mampong Campus, in the Ashanti Region of Ghana from October to December, 2019 and March to May, 2020, to determine the effects of different rates of soil amendments and plant spacing on growth and yield of onion. The experimental design used was a 5 x 3 factorial arranged in a randomized complete block design (RCBD) with three replications. The treatments consisted of five levels of soil amendments and three plant spacings. The five levels of soil amendments were; Control, 10 t/ha chicken manure, 15 t/ha chicken manure, 20 t/ha chicken manure and 300 kg/ha NPK (15-15-15). The three (3) plant spacings were; 10 cm × 10 cm, 15 cm × 10 cm and 15 cm × 15 cm. Data were collected on vegetative growth characteristics, yield and yield components. Significantly taller plant height was obtained at the plant spacing of 15 cm × 15 cm and 20 t/ha CM of soil amendment rate. The highest mean bulb weight and bulb diameter were produced at treatment combinations of the 15 cm × 15 cm and 20 t/ha CM of soil amendment. The highest marketable bulb yield and total bulb yield were produced at treatment combinations of 10 cm × 10 cm plant spacing with soil amendment rate of 15 t/ha CM. Significantly, the highest value of unmarketable bulb yield was produced at no soil amendment rate (control) and 10 cm × 10 cm of plant spacing. The partial budget analysis indicated the highest net benefit: cost ratio were obtained from the application of 15 t/ha CM and 10 cm × 10 cm plant spacing. The 15 t/ha CM and 10 cm × 10 cm plant spacing could be recommended for possible adoption.