Quantifying nutrient stoichiometry and radiation use efficiency of two maize cultivars under various water and fertilizer management practices in northwest China

Precise nutrient diagnosis is the basis of accurate simulation of maize (Zea mays L.) grain yield and high-efficient utilization of resources under the changing climate. However, the combined effects of supplementary irrigation and fertilizer application on plant stoichiometry of various maize cultivars in water-limited and nutrient-deficient regions are still poorly understood. A three consecutive year field experiment (2015-2017) was conducted on two maize cultivars (QL14 and ZD958) in northwest China, with two irrigation treatments (RF: rainfed and DI: drip irrigation) and two fertilization treatments (F0: no fertilization and F1: local fertilization practice). The results showed that the radiation use efficiency for biomass yield of QL14 with fertilization under drip irrigation was increased by 7.39% than that of ZD958. DI (70.19 kg kg(-1)) and ZD958 (68.55 kg kg(-1)) obtained significantly higher physiological efficiency of nitrogen fertilizer than RF (59.52 kg kg(-1)) and QL14 (61.17 kg kg(-1)), respectively. Both plant and grain N:P ratios under F1 were higher than those under F0. QL14 had significantly higher grain N:P ratio (4.64) than ZD958 (4.26) under DIF1. Grain yield was increased obviously when grain N:P ratio and plant N:K stoichiometry were greater than 4.0 and 1.2, respectively. The newly released maize cultivar (QL14) was highly recommended as forage and cereal crops, since QL14 obtained significantly higher leaf and stem dry matter even under severe drought and low soil fertility conditions. Our study provides an opportunity to achieve high-yielding maize systems in northwest China and maybe other regions with similar environments, and the data will help inform policies and strategic plans for the effective use of water and fertilizer resources.