The Enhancement Of Wheat Zinc By Residual Zn Fertilizer And Green Manure

Zinc?Zn?deficiency in the human body can cause a series of serious health problems.Insufficient daily dietary zinc intake the main cause of zinc deficiency for human.Wheat is the main food crop in northern China,but most of the main wheat producing areas in China are calcareous soil areas,which limited the wheat Zn uptake making it difficult to meet the human body's nutritional needs for zinc.Therefore,it is of great significance to investigate agronomic bio fortification methods to improve wheat Zn uptake and tacking Zn deficiency problem of human.Field experiments were conducted on zinc-deficient soils in Weibei Dry Highland from 2017 to 2018 to study the effects of residual zinc fertilizer and green manure?Black kidney bean BK,Gaodan grass GG,Mung beans MB and Buck Wheat BW?on succeeding wheat and soil nutrients concentration,dissolved organic carbon and pH,for the purpose of providing guidance to solve wheat zinc deficiency problem in Weibmei dryland on loess plateau in China.The main results were as follows:?1?Compared with summer fallow?SF?treatment,different green manure rotation treatments reduced the grain yield and shoot biomass of the wheat regardless of zinc rates.Wheat grain yield and shoot biomass with Zn fertilizer were higher than those without zinc application with an increase of 7.5%and 7.7%,respectively.?2?Regardless of Zn fertilization treatments,different green manure rotation treatments increase the wheat Zn concentration.Compared with SF,the GG,BK,MB and BW increased by 17.5%,38.3%,29.5%and 19.1%without Zn fertilizer;the increase with zinc fertilization were 34.6%,40.1%,30.9%and 4.1%.BK significantly increased the wheat stems and glumes zinc concentration with Zn fertilization.And there were no significant difference among green manure rotation and SF treatments without zinc application.Zinc fertilization treatments averagely increase wheat grain Zn and shoot Zn uptake by 48.4%,20.4%and 45.5%.?3?Regardless of Zn fertilization,BK and MB treatments significantly increased wheat grains concentration and content.Without Zn fertilization,compared with SF,the BK and MB significantly increased wheat grain and shoot zinc content by 27.2%,27.5%and 20.9%,23.8%respectively.Under zinc application conditions,compared with SF,GG,BK and MB treatments increased grain Zn content by 27.1%,21.9%and 21.7%and increased the wheat shoot zinc content by 25.1%,20.0%and 25.3%.The shoot Zn content and grain Zn content were 59.2%and 53.7%higher with Zn than those without Zn fertilization,respectively.?4?Regardless of Zn fertilization,the BK significantly increased wheat grain nitrogen concentration.Compared with SF,zinc application increased wheat grain N by 4.7%,and increased by 8.0%without zinc application.There were no significant effect on grain P and grain K concentration among green manure different rotation treatments.?5?BK treatments increased Soil DTPA-Zn concentration by 40.4%at GM harvest stage and by 10.1%wheat maturing stage with zinc fertilization.There were no significant difference among soil DTPA-Zn concentration at either stage with different green manure treatments without Zn fertilization.The soil DTPA-Zn was significantly higher with Zn fertilization than that of treatments without zinc fertilization.BK treatment increased soil NO^3--N concentration at wheat maturing stage by 36.7%compared with SF without zinc application,and increased by 26.8%with zinc application.There were no significant difference among either soil available P or K of all treatments.The soil dissolved organic carbon of BK treatment at green manure harvest stage was 17.0%higher than that of SF without zinc application,and 6.7%higher than that in the fallow condition with zinc application.At the green manure harvest stage and wheat maturing stage,BK treatment treated reduced soil pH was by 0.05 units compared with that of SF.Pared with other green manures,Black kidney bean excells in reducing soil pH,increasing soil NO^3--N,soil DOC and soil DTPA-Zn concentration,which may be the main reasons for continuously increasing suceeding wheat Zn concentration.