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西北农林科技大学 (2017)

Reasons for Wheat Grain Zinc Difference among Fields in Dryland Areas


Titre : Reasons for Wheat Grain Zinc Difference among Fields in Dryland Areas

Auteur : 佘旭;

Grade : Master’s Theses 2017

Université : 西北农林科技大学

Loess Plateau is one of the important winter wheat production areas in China.However,wheat grain zinc concentrations were commonly low with wide variation,which was associated with soil and climate factors.Based on the difference of soil characteristics and field management measures in this area,the investigation was conducted to study the relationships of grain zinc concentration to soil characteristics,wheat grain yield,shoot biomass,yield components,zinc uptake and utilization by questionnaire survey and sampling of soil and plant in 2015 and 2016.Results are showed below:1.In dryland areas of Loess Plateau,winter wheat grain zinc concentration is commonly low but with large variation in different sampling sites and fields,while the difference between years was low.Wheat grain zinc concentrations ranged from 12.2 mg kg-1 to 50.7 mg kg-1 with 4.2 fold variation,and the mean zinc concentrations among all research sites ranged from 19.6 mg kg-1 to 37.6 mg kg-1.Average grain zinc concentrations were 29.0 and 28.1 mg kg-1 in 2015 and 2016,respectively.Even located in the same area,the difference of grain zinc concentration was still existed,with a range of 15.8 to 30.0 mg kg-1.2.Soil moisture,pH,soil nitrate-N,Oslen-P,available potassium and DTPA-extractable Fe,Mn,Cu,Zn were the major soil factors caused the wide variation of grain zinc concentrations.Soil moisture,pH,Oslen-P,DTPA-Fe,Mn,Cu at wheat harvest were negatively correlated with grain zinc concentrations,while soil nitrate-N,available potassium and DTPA-Zn was positively correlated with grain zinc concentrations.3.Higher wheat grain yield had the “dilution effect” to grain zinc concentration.Grain zinc concentration was significantly and negatively correlated with yield of grain,chaff and straw,shoot biomass,grain numbers per spike,thousand kernel weight,and harvest index.Grain yield ranged from 1.1 to 9.2 t ha-1,with an average of 4.3 t ha-1.With 1 t ha-1 increase of grain yield and shoot biomass,the average decrease of grain zinc concentration was 1.4 and 0.6 mg kg-1,respectively.4.Wheat grain zinc was positively correlated with the amount of grain zinc uptake,while it ?s not correlated with zinc distribution in the aboveground part of wheat.With grain zinc yield increase of 100 g ha-1,grain zinc concentration increased about 6.7 mg kg-1.However,no difference of zinc harvest index was observed among the low,middle and high zinc groups.5.Appropriate water and nutrients management play important roles in the wheat production and grain zinc nutrition improvement in the dryland.Increased the soil water utilization by farming practices,elevated N and K application rates and lowered P rates based on yield and nutrients balance simultaneously,and foliar application of zinc fertilizer are key practices for biofortification of wheat grain zinc in Loess Plateau.

Mots clés : dryland; wheat; soil; zinc; yield;

Présentation (CNKI)

Page publiée le 22 février 2018