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 = ⅓ N at sowing + ⅓ N at first irrigation + ⅓ N at second irrigation; NS4 = ¼ N at sowing + ¼ N at first irrigation + ¼ N at second irrigation + ¼ 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.