Effects Of Selenium And Zinc On Yield And Mineral Nutrition Of Main Crops On Dryland

Maize and wheat are the major food crops for residents living in northern China, and alsois the main source of essential mineral elements, such as Se, and Zn. On the arid LoessPlateau in China, Se and Zn deficiencies not only affects crop yields, but also causes Se andZn deficiencies of agricultural products, sequentially affects human health. Thus, it is veryimportant to investigate biofortification effect of Se and Zn for improving crop yield andnutrition quality; In order to meet needs of human on Se and Zn, three years of fieldexperiments were conducted to investigate the effects of both soil and foliar application ofselenium (Se, applied as Na2SeO3), and zinc (Zn, applied as ZnSO4·7H2O) fertilizers, theircombination, different rates, and foliar application time on the yield and mineral nutrient,especially grain Se and Zn concentrations of maize and wheat. The main results are asfollows:1. Both soil and foliar application of Se and Zn showed no significant impact on thegrain yield and biomass of maize and wheat， and also no significant effect on theconcentration of N, P, K, Ca, Mg, Fe, Mn, Cu in the grain of maize and wheat, but a trend toincrease the concentration of N and K in maize grain with soil Se application and increase theFe concentration in maize grain with foliar Zn application.2. Soil Se application significantly enhanced the Se concentration in maize and wheatgrain, and a significant linear correlatin was found between the grain Se concentration inmaize and wheat and the rates of soil-applied Se. One g Se ha-1applied as Na2SeO3to soilincreased the grain Se concentration by0.1-0.3μg kg-1in maize and0.5μg kg-1in wheat.Thus in the Loess Plateau areas, the soil application of300-835g Se ha-1and180g Se ha-1could elevate the grain Se concentration in maize and wheat to100μg kg-1.3. Foiliar Se application significantly enhanced the Se concentration in maize and wheatgrain, and also a significant linear correlatin was found between the grain Se concentration inmaize and wheat and the rates of foliar-applied Se. One g Se ha-1applied as Na2SeO3by foliarapplication increased the grain Se concentration by8μg kg-1in maize, and One g Se ha-1applied as Na2SeO3by foliar application at heading stage and filling stage improved the grainSe concentration in wheat by5-7μg kg-1and16μg kg-1, respectively. Thus, in the Loess Plateau areas, the foliar application of14g Se ha-1could elevate the grain Se concentration inmaize to100μg kg-1, while the foliar application of14g Se ha-1at heading and2g Se ha-1atgrain filling stage could elevate the grain Se concentration in wheat to the same level. Foliarapllication of Se are therfore the effective and economical method to increase Seconcentration in maize and wheat grain.4. Soil Zn application had no significant effect on the grain Zn concentration andaccumulation, grain Zn recovery, and total Zn recovery in the above ground parts of maizeand wheat, but showed a trend to increase them compred to the control. The grain Zn recoveryin maize is very low as3‰, and both the grain Zn recovery and total Zn recovery of winterwheat are also very low, not more than1.5‰and6‰.5. Foliar Zn application caused evident increase in grain Zn concentration of maize andgrain, and the increase is more noticeable when applied at filling than that at heading stage forwheat. Compared to soil Zn application, foliar Zn application had higher grain Zn recoverywith the maximum of58‰. On the Loess Plateau, foliar Zn application is an effective methodto raise the grain Zn concentration of maize and wheat.6. Neither soil Se application nor soil Zn application alone or coordinate with each otherdistinctly affected the grain yield, biomass, and also the concentration of N, P, K, Ca, Mg, Fe,Mn, Cu in the edible parts of potato, cabbage, soybean, maize and wheat. Soil application ofSe alone or combined with Zn significantly elevated the Se concentration in the edible part ofall tested crops, while soil application of Zn alone or combined with Se significantlyimproved only the Zn concentration in cabbage leaf. The raise of Se and Zn concentrationcaused by their application was not affected by seperate or combined application.7. Neither seprate or combined foiliar application of Se and Zn application haddistinguished effect on grain yield, biomass, and also the concentration of N, P, K, Ca, Mg, Fe,Mn, Cu in maize grain. Foliar application of Se alone or combined with Zn significantlyincreased the Se concentration in maize grain, and foliar application of Zn alone or combinedwith Se significantly increased the Zn concentration in maize grain. The increase of grain Seand Zn concentration caused by their application was not affected by seperate or combinedapplication.