Influence of different weed control methods on weed biomass, growth and yield of mango ginger (Curcuma amada Roxb.) in forest savannah transition agro-ecological zone of Nigeria

Field trials were conducted in the early cropping seasons of 2016 and 2017 at the Teaching and Research Farm of the Federal University of Agriculture Abeokuta (07° 20ʹN , 3° 23ʹE 159 m above sea level) in the forest – savannah transition agroecology of South-western Nigeria to evaluate the effect of weed control methods on weed biomass, growth and yield of mango ginger. Ten weed control methods were evaluated and laid out in a randomized complete block design with three replications. Data were collected on weed biomass, crop vigour score, stand count, number of rhizomes and rhizome yield. Results on weed biomass at 8 WAP showed that plots treated with different rates of pre emergence herbicide gave lower weed biomass than plots hoe weeded plots. Also at 24 WAP, plots treated with pre emergence herbicide followed by different post emergence treatments gave lower weed biomass than plots when only pre emergence herbicide was applied. In both years, plots hoe weeded five times at 4, 8, 12, 16 and 20 WAP gave the highest rhizome yield. Application of only pre emergence herbicide throughout crop life cycle irrespective of the rate resulted in 60.7 to 62.0 % reduction in rhizome yield relative to the maximum across the two years. Uncontrolled weed interference resulted in 91.9 and 92.1 % rhizome yield reduction in 2016 and 2017, respectively. This study reveals that, mango ginger being a long seasoned crop should be kept weed free beyond 12 WAP for acceptable yield.