Grain zinc concentration and its relation to soil nutrient availability in different wheat cropping regions of China

Abstract It is useful to understand soil nutrients responsible for grain zinc (Zn) variation of winter wheat ( Triticum aestivum L.) in different cropping regions, in order to adopt appropriate soil management measures to improve grain Zn nutrition and alleviate human Zn malnutrition. A total of 599 wheat plant and corresponding soil samples were collected from farmers’ fields in three typical wheat cropping regions of China in 2015 and 2016, to determine the dominant soil nutrients related to high grain Zn concentration. Obtained results showed that a large variation in grain Zn existed within different regions, with 8%, 9% and 16% of grain samples reaching the recommended level of 40 mg kg −1 in the single wheat, wheat-maize and rice-wheat regions, respectively. In the single wheat region, grain Zn was positively correlated with soil available potassium (K) and Zn, and negatively correlated with available iron (Fe) ( P −1 , Zn 0.64 and 0.46 mg kg −1 , and Fe 3.3 and 5.2 mg kg −1 for the high and low Zn groups, respectively. In the wheat-maize region, grain Zn was positively correlated with soil available Zn, while negatively correlated with available phosphorus (P) ( P −1 , and P 24 and 25 mg kg −1 for the high and low Zn groups, respectively. In the rice-wheat region, grain Zn was positively correlated with soil ammonium nitrogen (Amon-N) and available Zn ( P −1 , and available Zn 1.9 and 1.2 mg kg −1 for the high and low Zn groups, respectively. Therefore, it is possible to produce wheat with grain Zn higher than 40 mg kg −1 in farmers’ fields, and apart from available Zn, soil available K and Fe in the single wheat region, available P in the wheat-maize region, and Amon-N in the rice-wheat region should also be considered for the purpose of grain Zn improvement.