Comparative performance of summer cereals under limited water and fertilizer inputs

Abstract

Optimizing cereal production under limited water and nitrogen availability is crucial for sustainable agriculture. This study evaluates the effects of three planting densities (D1: low, D2: medium, D3: high) and input levels on the yield, resource use efficiency, and economic performance of three summer cereals: maize, pearl millet, and sorghum. A split-split plot design with three replications was used. Statistical analysis revealed that pearl millet exhibited the highest leaf area under D1 (low planting density) with optimum inputs. It also had the maximum ear/panicle number (35 m−2), while D2 (medium density) and D3 (high density) resulted in a higher ear/panicle count. Maize produced the longest (17.1 cm) and heaviest (91 g) ears under D2 planting density. Among the three cereals, maize had the highest grain yield (2695 kg ha⁻1). Across all planting densities, D2 (medium density) resulted in the highest yield (2434 kg ha⁻1). Additionally, optimum input levels significantly improved grain yield, reaching 2467 kg ha⁻1. Water use efficiency (WUE) and nitrogen use efficiency (NUE) varied significantly, with sorghum showing the highest WUE (5.93 kg m−2) and maize showing the highest NUE (19.4 kg kg−1). Constrained inputs led to higher NUE (20.1 kg kg−1) and WUE (5.77 kg m−2). Quality analysis indicated sorghum had the highest grain protein content (9.4%), while pearl millet showed the highest root and shoot dry weights. Principal component analysis revealed strong associations between specific yield attributes and each cereal, with D2 planting density showing the strongest overall associations. Economic analysis highlighted that sorghum under D2 density with optimum inputs yielded the highest gross return (858.0 USD ha−1), while sorghum at D3 density with constrained inputs achieved the highest net benefit (711.6 USD ha−1) and benefit–cost ratio (5.9). To maximize production, D2 planting density is recommended. Optimizing input management can enhance productivity, while sorghum cultivation under constrained input offers the highest economic returns.