Evaluation of Fertilizer Rates and Weed Infestation on Yield and Economic Return of Cassava-Maize Intercrop in Savanna Ecology of Nigeria

The low yields of maize-cassava intercrop in sub-Saharan Africa are due to some identified constraints like the poor density of component crop(s), inappropriate application of fertilizer and weed infestation among others. This study was conducted in Otukpo and Igbariam in the Derived Savanna ecology of Nigeria during the 2018 and 2019 cropping seasons to determine the impact of fertilizer rates on weed growth and yield of cassava/maize intercrop. The trials were laid out as a Randomized Complete Block Design with four replications. Cassava (TME 419) was planted as 1 m x 0.8 m (12,500 plants ha-1) while maize (SAMMAZ 35) was sowed using two different spacing 1 m x 0.5 m and 1 m x 0.25 m to give an approximately plant population of 20,000 plants/ha and 40,000 plants/ha, respectively. 

 

 NPK-fertilizer was applied as 90:20:40 kg/ha and 75:20:90 kg/ha. Data collected on weed density and weed biomass, maize grains yield and cassava root yield were subjected to analysis of variance at P ≤ 0.05. The benefit-cost ratio also was calculated. Results showed that weeds emerged throughout the growing season with a peak at 8 weeks after planting (WAP). Ageratum houstonianum, Cyperus rotundus, Digitaria horizontalis, Lindernia crustacea, Stachytapheta jamaicensis and Oldenlandia corymbosa were the most prevalent weed species. Intercropping cassava at 12,500 plants/ha and maize at 40,000 plants/ha with 90:20:40 kg/ha of NPK gave the highest economic return of ₦ 535,064.00 – 618,614.00 (US$ 1,301.95 - 1,505.21) and production efficiency of 28 - 31% per hectare. This study concludes that intercropping 12,500 plants/ha of cassava and 40,000 plants/ha of maize with the application of 90:20:40 kg/ha of NPK relatively reduces weed growth and gives a higher intercrop yield with good economic returns in the derived savannah ecology of Nigeria.