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Fertilizer Microdosing in the Humid Forest Zone of Ghana: An Efficient Strategy for Increasing Maize Yield and Income in Smallholder Farming

Chinyere B. Okebalama, Ebenezer Y. Safo, Edward Yeboah, Robert C. Abaidoo, Vincent Logah
Soil Science Society of America journal 2016 v.80 no.5 pp. 1254-1261
Acrisols, NPK fertilizers, Vigna unguiculata, Zea mays, corn, corn stover, cowpeas, cropping systems, crops, economic impact, fertilizer rates, field experimentation, grain yield, income, limited resource farmers, nitrogen, phosphorus, potassium, rain forests, small-scale farming, Ghana
High fertilizer costs pose a challenge in smallholder farming; optimizing fertilizer recommendations that are affordable to resource-poor farmers could increase crop yield and income. The study aimed to determining the yield and economic effects of N–P–K fertilizer microdosing on maize (Zea mays L.) crops on Gleyic Plinthic Acrisol (GPA) and Plinthic Acrisol (PA) in the semideciduous rainforest zone of Ghana using a split-plot randomized complete block design with three replications. The field trial included two cropping systems (continuous maize cropping [CMC] and cowpea [Vigna unguiculata (L.) Walp.]–maize rotation [CMR]) as main plots with four treatments (N₀P₀K₀, N₀P₂₀K₂₀, N₀P₄₀K₂₀, and N₂₀P₄₀K₂₀) and the recommended fertilizer rate (N₉₀P₆₀K₆₀) as subplots. Fertilizer treatment effects on maize stover and grain yields were assessed. The microdose treatments increased maize yields by 32 to 99% across cropping systems and soil types. Maize grain yield increase was higher on the GPA than on the PA. The N₉₀P₆₀K₆₀ and N₂₀P₄₀K₂₀ treatments resulted in higher grain and stover yields than the other treatments across cropping systems and soil types. Among the treatments maximum grain yield increases of 76 and 99% were obtained with N₂₀P₄₀K₂₀ on the PA and the GPA, respectively, under CMC. Under CMR, grain yield increased by 46% with N₀P₄₀K₂₀ (PA) and 74% with N₀P₂₀K₂₀ (GPA). The largest net return was obtained with N₂₀P₄₀K₂₀ under CMC across both soil types and with N₀P₂₀K₂₀ (GPA) and N₀P₄₀K₂₀ (PA) under CMR. These fertilizer microdoses can be considered appropriate for increasing maize yield and the income of smallholder farmers.