Sustaining yam yields amidst climate threat in the forest – savannah transition zone of Ghana

Abstract

With about 70% of yam tuber been water, yield is critically affected during bulking as a result of onset of temporal drought. As a consequence of climate change, farmers who are into Dioscorea rotundata (white yam) production for local and international market lose their investments mainly due to erratic precipitation, drought spells culminating into low yields of just 12t/ha compared to the potential of about 22-49t/ha depending on the variety. Innovative land uses technologies with higher and sustained productivity for yam production are imperative. This study verifies improved agronomic package for sustainable yam production in yam growing areas in the forest – savannah transition zone of Ghana during the 2015 and 2016 cropping seasons. The improved agronomic package included use of ridging as seedbed, seed treatment before planting, fertilizer application at a rate of 30:30:36 N:P₂0₅:K₂0 kg/ha plus 15 kg/ha Mg and 20 kg/ha S as MgSO₄ and the use of minimum stakes (trellis; 30-50% less number of stakes used by farmers staking). This was compared with farmers’ practice which consisted of mounding, no fertilizer application and no seed treatment. The results revealed significant (P ≤ 0.01) yam yields of more than 60% difference between the improved agronomic practice and farmers’ practice from Ejura, Atebubu and Kintampo yam growing communities. Adoption of improved agronomic practices does not only sustain yam production and address deforestation but also provide higher returns on investments promoting climate resilience by small holders.