Optimizing sulfur fertilizer application rate for profitable maize production in the savanna agroecological zones of Northern Ghana

• Published in: Journal of plant nutrition Vol. 45; no. 15; pp. 2315 - 2331
• Main Authors: Agyin-Birikorang, Sampson, Tindjina, Ignatius, Fugice, Job, Dauda, Haruna W., Issahaku, Alhaji Rahman, Iddrissu, Mumuni, Singh, Upendra
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 15.07.2022; Taylor & Francis Ltd
• Subjects: Apparent nitrogen recovery efficiency; apparent sulfur recovery efficiency; Corn; Crop production; Crop yield; economically optimum fertilizer rate; Economics; Fertilizer application; fertilizer rates; Ghana; Grain; grain yield; maize yield; Mitscherlich equation; Optimization; plant nutrition; Plant tissues; Productivity; Profitability; Savannahs; savannas; soil; Soils; Statistical analysis; Sulfur; sulfur fertilizers; tissue sulfur concentration; Ghana
• DOI: 10.1080/01904167.2022.2063740
• ISSN: 0190-4167; 1532-4087

Although several studies have established the importance of sulfur (S) in increasing maize productivity in the savanna agroecological zones (AEZs) of northern Ghana, the economically optimum S application rate is still unknown. In a two-year study at eight locations across the AEZs, we determined the economically optimum S application rate for S-deficient soils. We compared eight S application rates, ranging from 0 to 70 kg ha −1 at 10 kg intervals, for optimal maize productivity and profitability. The study identified 30 kg S ha −1 as the minimum rate that resulted in a plant tissue S concentration above the critical level of 0.15%. Although increasing the S application rate resulted in increases in maize grain yield, application of S beyond a rate of 30 kg ha −1 resulted in increases in maize grain yield that were not statistically significant and leveled off at 50 kg S ha −1 . Application rates ≥50 kg ha −1 resulted in a high proportion of the applied S not taken up by the plant and, thus, subject to losses from the soil. Based on agro-input prices at the local level and the farm-gate prices of maize, the greatest potential profit resulting from S application was observed at 30 kg S ha −1 , with a projected average maize yield of between ∼4.2 and 5.3 Mg ha −1 , representing >90% of the observed yield with the highest S application rate of 70 kg ha −1 . Thus, we conclude that, for sustainable and profitable maize production in S-deficient soils of the savanna AEZs of northern Ghana, an S applications rate of 30 kg ha −1 is economically justified.