Resource Use Efficiencies of C₃ and C₄ Cereals under Split Nitrogen Regimes

Resources are limited, thus improving resource use efficiency is a key objective for cereal-based cropping systems. This field study was carried out to quantify resource use efficiencies in selected C₃ and C₄ cereals under split nitrogen (N) application regimes. The study included the following treatments: six cereals (three C₃: wheat, oat, and barley; and three C₄: maize, millet, and sorghum) and four split N application regimes (NS₁ = full amount of N at sowing; NS₂ = half N at sowing + half N at first irrigation; NS₃ =¹₃ N at sowing +¹₃ N at first irrigation +¹₃ N at second irrigation; NS₄ =¹₄ N at sowing +¹₄ N at first irrigation +¹₄ N at second irrigation +¹₄ N at third irrigation). Results revealed that C₄ cereals out-yielded C₃ cereals in terms of biomass production, grain yield, and resource use efficiencies (i.e., radiation use efficiency (RUE) and nitrogen use efficiency (NUE)), while splitting N into three applications proved to be a better strategy for all of the selected winter and summer cereals. The results suggest that C₄ cereals should be added into existing cereal-based cropping systems and N application done in three installments to boost productivity and higher resource use efficiency to ensure food security for the burgeoning population.