Effects of zinc application rate and zinc distribution relative to root distribution on grain yield and grain Zn concentration in wheat

Zinc (Zn) nutrition affects wheat yield and the health of humans who consume wheat grain. This study determined: 1) how distributions of roots and available Zn (DTPA-Zn) in soil affect the Zn content of wheat plants; and 2) the concentrations of shoot Zn and soil DTPA-Zn needed to obtain high yields and the target value of grain Zn biofortification (45 mg kg(-1)). Zn application rates were investigated in a field experiment, and Zn location relative to root location in the soil profile was investigated in a pot experiment. In the field, wheat yield and tissue Zn levels increased with Zn application rate. High yields required 29.4 mg Zn kg(-1) in shoots and 1.98 mg DTPA-Zn kg(-1) in soil. The target value of Zn biofortification of grain was obtained with 31.6 mg Zn kg(-1) in shoots and 4.09 mg DTPA-Zn kg(-1) in soil. In the pot experiment, Zn application at 0-15/0-30 cm soil layers showed the most improvement with tissue Zn levels. Increasing soil available Zn and matching its distribution with that of roots can increase Zn uptake by wheat, yield, and the Zn concentration in grain.