Integrated nitrogen amount and sources maximize maize nitrogen efficiency in the saline soils

Abstract

AbstractAlthough efficient N fertilization has become widely accepted for sustaining or improving N use efficiency (NUE), many existing N fertilizer recommendations seldom consider N sources during implementation. To investigate the effect of N rates and sources on maize (Zea mays L.) production efficiency, soil quality, and economic benefits, a field experiment was conducted in the coastal saline area of China. The optimal N rate (ONR) treatment based on in‐season root‐zone N management reduced N application amount by 44% without grain yield losses and decreased the apparent N losses by 144 kg N ha–1 compared with the local N management practice of farmers. Furthermore, the ONR treatment with ammonium sulfate (ONR‐AS) or calcium ammonium nitrate (ONR‐CAN) had higher maize grain yield and NUE than the ONR with urea (ONR‐urea) treatment. Compared with ONR‐urea, treatment with ONR‐AS or ONR‐CAN increased Ca2+ content, decreased soil pH and Na+ content, and thus imporved maize yield and NUE. Among the ONR treatments, the ONR‐AS treatment increased economic gains compared with the ONR‐urea treatment. This study suggests that an integrated N management can increase maize yield, NUE, and economic benefits and improve soil quality in the coastal saline soils.