Effects Of Reduced Solar Radiation And Enhanced O3on Soil Property And Nitrogen And Phosphorus In Winter Wheat Plant

In recent years, the weakening of the surface solar radiation and elevated O3showed an increasing trend, the decreased solar radiation and increased O3will affect crop growth and absorption of N, P elements. In this paper, we simulated the enhanced O3concentration and reduced solar radiation by using open-top chamber (OTC) and black shade nets, set up9experimental treatments:CK1(field cornfield group, completely natural environment); S1(solar radiation attenuated by20%); S2(solar radiation weakened40%); S3(solar radiation weakened60%); CK2(only add the chamber without ozone aeration and shading); T(O3concentration of100±8n1·L-1); TS1(T and S1composite), TS2(T and S2composite), TS3(T and S3composite). Research was conducted comprehensive under the reduced solar radiation and enhanced O3conditions to detect the regularity of N、P concentration in different organ of winter wheat plants (Triticum aestivum L, Yang Mai13), cornfield topsoil physicochemical properties and soil enzyme activity. The main results indicated as follows:(1) The treatments of decreased solar radiation (S1, S2, S3) was increased soil moisture, increased the concentration of soil total N and available K, decreased soil available P concentration; The shading treatments increased the concentration of N, P in root, stem, leaf and vegetative organ, and N、P concentration in root, stem and nutritorium and the sun radiation abate strength was showed a significant positive correlation, the decreased solar radiation treatments reduced N, P cumulant and distribution rate of root, increased N and P cumulant of leaf, reduced the total transfer volume and transfer rates of N and P in the nutritorium.(2) The treatments (T) of single increasing O3concentration was reduced soil catalase activity, increased urease activity and concentration of soil available P, K and total P, K; increased N, P concentration in the various organs of winter wheat and N, P total transfer rates of nutritorium, reduced translocation amount of N, P of leaf, reduced the cumulant of P in various organs of winter wheat, reduced the stage accumulation of N, P in root, stem and leaf in the seeding stage-heading stage, reduced the stage accumulation of P in spike and the phase output of P cumulant in root, stem and leaf during the heading stage and the maturity stage, increased output of N cumulant in root, stem and vegetative organ in the heading stage-mature stage.(3) The treatmens of increased O3under different levels of reduced solar radiation conditions (TS1, TS2, TS3) increased canopy air relative humidity, reduced the daily average temperature of canopy air, promoted N and P concentration in different organs of winter wheat plant, reduced the total N cumulant of nutritorium and the P cumulant in winter wheat plant, decreased N, P transfer amount in root, leaf and nutritorium, reduced P cumulant and distribution rates in spike, decreased the stage accumulation of N, P in stem and leaf during seeding stage and heading stage, reduced N, P phase output of stem, leaf and P cumulated absorption of spike in the heading stage-mature stage, and the N, P transfer amount was reduced as the weaken intensity of solar irradiance.(4) The soil moisture and N, P concentration in various organs of winter wheat was showed a significant positive correlation, showed a significant negative related with N, P cumulant in the different organs, soil pH was significant negative correlated with N, P concentration in various nutrient organs. Path analysis showed that soil moisture increases promoted N, P concentration in nutritorium of the largest direct role, but produced direct impediment on N, P total cumulant in nutritorium to some extent, daily average solar instantaneous radiation intensity had the largest role in direct promoting N, P total cumulant in nutritorium of winter wheat.