Comparative economic assessment of the effect of selected fallow species for soil amendment on the yield of sweetpotato (Ipomoea batatas) alley in the Guinea savannah of Nigeria
The study focused on the comparative economic assessment of the effect of selected fallow species for soil amendment on the yield of sweetpotato (Ipomea batatas) alley in the Guinea Savannah of Nigeria. As a result of the increasing cost and scarcity of inorganic fertilizers, sweetpotato production has been on the decline in recent times. Part of the intensive efforts being made by farmers to resuscitate the declining soil fertility so as to meet the challenge of providing food for the increasing population, is the use of cheap and available fallow species in a sweetpotato alley. Therefore, sweetpotato (Ipomea batata) vines (30cm long) of the variety, Ex- Igbariam were used in a three year alley cropping system using different combinations of the selected fallow species. These include; 100% Moringa alley, 50% Moringa + 50% Leucaena leucocephala alley, 50% Moringa + 50% Glaricidia septum alley, 100% Leucaena leucocephala alley, 100% Gliricidia alley, 50% Leucaena + 50 % Glaricidia alley, N.P.K. (15:15:15) fertilizer (200kg ha-1) and Control. Mean yield of sweatpotato from plots treated with the different fallow species were separated using analysis of variance (ANOVA) to determine if statistical difference existed among the values. The economic analysis was done by simple gross margin analysis. The result showed that alley cropping with all the fallow species used in the trial, increased yield of sweetpotato progressively, with 50% Moringa + 50% Leucaena leucocephala alley, giving the highest average yield of 17.2 tons/ha and highest value of output ₦111,000 with a returns to investment of 1: 3.79. Also, the application of 100% Leucaena leucocephala alley and any other mixture of leuceana had yield advantage over the other fallow species used in the experiment. It was therefore concluded that alley cropping of sweetpotato with the selected fallow species, progressively increased yield and reduced cost of sweetpotato production in the Federal Capital Territory Abuja, Nigeria.
Keywords: Sweetpotato, Fallow, Species, Alley, Cropping, Economic, Yield