Multi-site evaluation of plastic film mulch and nitrogen fertilization for wheat grain yield, protein content and its components in semiarid areas of China

Abstract

High crop yield and high quality are the primarily targets in intensive crop production. Although the plastic film mulch (PFM) approach has been well established for high-yielding wheat production in dryland, effects of PFM on wheat grain quality is still poorly understood. Therefore, multi–site and fixed location field experiments were conducted to investigate effects of PFM on grain yield, protein content and its components content of dryland winter wheat in 2014–2016 in the Loess Plateau of China. Compared with no mulch (NM), PFM increased the grain yield, structural protein contents and the ratio of gliadin/glutenin by 634 kg ha−1, 11.3%–30.8% and 15.1%, respectively, but reduced the total protein and its gluten contents by 7.8% and 3.4%–15.1%. Furthermore, PFM significantly increased the proportion of albumin, globulin and gliadin to total protein by 22.3%, 44.2% and 5.5%, respectively, but decreased the proportion of glutenin by 7.4%, compared to NM. The highest grain yield, albumin and glutenin content were attained when the critical N rates were 146 kg N ha−1, 167 kg N ha−1 and 100 kg N ha−1, respectively. Moreover, for every 100 kg ha−1 increase in N fertilizer, the globulin content increased by 0.11%, but the ratio of gliadin/glutenin decreased by 0.12%. In summary, PFM did not show any benefit for gluten, while precise N fertilizer management provided an opportunity for improving grain processing quality of dryland wheat. In order to tradeoff between grain yield and its processing quality, the optimal N application rate (146–167 kg N ha−1) should be considered under PFM. These findings suggest that optimal N management serves as a basis for further investigation and regulation of grain protein components of wheat under PFM in the semiarid area of China and similar cropping system around the world.