Changes in the relationship between both arsenic and selenium content of sunflower and maize plants and their spectroradiometer reflection values at different irrigation levels

In this study, it was investigated that how relationship changes, depending on irrigation levels, between arsenic and selenium content and spectral reflection data of sunflower and maize leaves. Plants were grown in a clay loam texture soil contaminated with sodium selenite (Na2SeO3) and sodium arsenate heptahydrate (Na2HAsO4.7H2O). In the experiment four different irrigation levels were used such as S1 (control), S2 (0.90 S1), S3 (0.80 S1) and S4 (0.70 S1). Control application was based on 50% of available moisture consumed up to field capacity level. Spectral reflectance of the leaves was measured by the ASD FieldSpec HandHeld spectroradiometer with plant probe in two different periods and As, Se content of these leaves were determined by using microwawe and ICP-OES. While As and Se content of sunflower leaves were found ranging from 3.537- 3.973 mg kg-1 and 7.610- 9.030 mg kg-1 during I. period and these values at II. period ranged from 10.173- 11.790 mg kg-1, 6.278- 9.959 mg kg-1. While As and Se content of maize leaves were found ranging from 1.288-1.890 mg kg-1 and 3.443- 4.272 mg kg-1 during I. period, at II. period ranged from 2.109-2.923 mg kg-1and 3.459- 4.663 mg kg-1. The changes in the As content of sunflower and maize leaves betwen periods were statistical significant (P<0.01). In addition the changes in Se content of maize leaves were also found significant depending on irrigation levels. Maize leaves Se content was statistically significant according to application of different irrigation levels (P<0.05).Irrigation levels on the same wavelength reflectance values for sunflower plants were found specific differences between the periods on visible region (400-700 nm) that was not very clear in S4 compared to other applications. In the near-infrared region (700-1000 nm), reflectance values between periods the differences between the S3 and S4 applications were quite apparent. For maize plant, irrigation levels, visible and near-infrared region as the differences between the periods, S2 was found to be more prominent than the other irrigation applications. Depending on their level of irrigation with As and Se content of leaves. The relationships between spectral reflectance data and the accuracy were investigated by using multivariate regression analysis and determination coefficient (R2) was high and finally the mathematical prediction models were constructed.