Economically Optimal Rate for Nutrient Application to Maize in the Semi-deciduous Forest Zone of Ghana

Abstract

Low inherent nitrogen (N), phosphorus (P), and potassium (K) contents of smallholder farms limit maize grain yield. Maize grain yield response to N, P, and K mineral fertilizer application and economically optimal rates for nitrogen (EOR N), phosphorus (EOR P), and potassium (EOR K) were evaluated on a Ferric Acrisol within the semi-deciduous forest zone of Ghana. The nutrient rates evaluated were N (0, 30, 60, 90, and 120 kg N ha −1), P (0, 30, 60, and 90 kg ha −1 P 2 O 5), and K (0, 30, 60 and 90 kg ha −1 K 2 O). The treatments were arranged in a randomized complete block with three replications using an incomplete factorial design. Nutrient responses were determined using asymptotic quadratic-plus plateau functions. The best nitrogen rate for all P and K levels was 60 kg ha −1 , which gave grain yield of 5 t ha −1. Nitrogen uptake, N agronomic and N recovery efficiencies peaked at 60 kg N ha −1 while N partial factor productivity declined with increasing N application rate. Cost to grain price ratios (CP) were 1.29, 1.65, and 1.65 for N, P, and K, respectively. The EOR N was 61 kg ha −1 , 32% less than the recommended 90 kg N ha −1 for maize production in the semi-deciduous forest zone of Ghana. Nitrogen application had the lowest CP ratio, making its application economically profitable than P and K. The findings suggest that the application of N at 61 kg N ha −1 to maize is economically profitable than at higher application rates. However, further studies should be conducted on farmers' fields to validate the results obtained.

Soybean (Glycine max L. Merrill) responds to phosphorus application and rhizobium inoculation on Acrisols of the semi-deciduous forest agro-ecological zone of Ghana

“…Even though the residual effect of the treatment on maize was not significant, the yields produced were comparable to yields obtained under mineral and organic fertilizer trials ( Essel et al, 2020 ) and about double the current national average yield of 2.26 t ha −1 ( Ministry of Food & Agriculture, 2018 ). This indicates that the yield cannot be attributed to the treatment effects alone.…”

Reducing Topdressing N Fertilization with Variable Rates Does Not Reduce Maize Yield

“…In the present case study, located in eastern Lombardy (Italy), maize production is experiencing relevant variability, being caused mainly by the low price on the market and pest control regulations and limits, which results in increased imports from countries outside the EU [31]. It was observed that dairy farmers hardly adhere to the organic recommended fertilizer application rates due to the high availability of manure and slurry [28,[32][33][34][35][36]; however, to ensure high crop yields, topdressing mineral N is used despite the purchase and environmental costs [37]. Even considering the current subsidized rates, mineral fertilizers still represent a substantial budget item in European farms [38].…”

Productivity of Rainfed Winter Wheat with Direct Sowing and Economic Efficiency of Diversified Fertilization in Arid Region of South Kazakhstan

“…An important factor for increasing the efficiency of zero-till technology is an optimization of plant nutrition [25][26][27][28][29]. The balanced fertilization implies that crops are adequately supplied with nutrients at every stage of growth and development.…”