Nitrogen fertilizer and high-protein varieties work together to increase wheat grain protein concentration and yield

Context

Meeting humanity's growing grain protein needs is the top priority for food production, and although the formation of grain protein in plants is a complex and integrated process, some specific crop management practices may play a dominant role. Few studies have been data-driven to quantitatively assess the benefits of crop management practices on wheat grain protein on a national scale.

Objectives

To fill this gap, we quantified the total national benefits of crop management practice on wheat grain protein and estimated for the first time the productivity of China's wheat grain protein in 2030.

Methods

A meta-analysis was performed by compiling 5819 pairs of observations related to crop management practices and wheat grain protein, and a large-scale farmer survey was conducted from 2010 to 2020 to understand the current status of smallholder wheat production and to predict further trends using the Random Forest model.

Results and conclusions

Results showed that the concentration and yield of grain protein increased by 2.6–6.9 % and 9.4–13.2 % for topdressing, and 9.1 % and 6.7 % for high-protein variety, but decreased by 5.3 % and 8.5 % for optimized nitrogen (N) fertilizer rate, respectively. The RF model showed that eleven key predictors from crop management practices and soil-climate factors accounted for 84 % of the effect on wheat grain protein, with N fertilizer management and wheat varieties making the largest contributions. Using this data-driven approach, we estimated that China's grain protein production would increase from 18.6 to 19.8 Mt. with a 14 % reduction in N use through optimized N fertilizer management and the use of higher gluten wheat varieties under future climate change. Optimized N fertilizer management and the adoption of high-protein variety are the most important approaches to simultaneously improve grain yield and protein concentration.

Significance

Our findings fill a gap in national estimates of wheat grain protein production and highlight the importance of strategic crop management practices for nutritional security.