Photosynthetic characteristics and productivity in a wheat–maize system under varying zinc rates

Abstract

AbstractThe photosynthetic rate (Pn) and leaf area index (LAI) play an important role in dry matter production. To understand the role of Zn fertilizer in increasing the yield of winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) by regulating Pn and LAI, a field experiment with six Zn rates (0, 2.3, 5.7, 11.4, 22.7, and 34.1 kg Zn ha−1) was conducted from 2013 to 2015 on a calcareous soil. Zinc application increased wheat and maize yield by 4–19% and 4–13%, respectively, across the 2 yr. The aboveground biomass, Pn, and LAI of both wheat and maize also significantly increased with increasing Zn rates. Structural equation modeling showed that the yield increase of wheat mainly depended on the Pn and LAI, whereas that of maize mainly depended on the Pn. The relationships of the Pn and LAI with shoot Zn concentrations followed a linear‐plateau trend for wheat and linear for maize. The optimal shoot Zn concentrations to obtain the maximal Pn and LAI of wheat were determined to be 46–49 mg kg−1. Zinc application at 11.4 kg Zn ha−1 was an optimal rate to guarantee yield attainment and Zn biofortification. The results of this study are useful for farmers to optimize their Zn fertilizer management in agricultural systems to obtain high yields.