IInvestigating the Effect of Nano-Clay Particles and Biochar on Nitrate Leaching and Soil Aggregate Stability

Nitrogen is the nutrient in plants production which usually can be added as a fertilizer into the soil. Nitrate is one of the pollutants which is mainly caused by agricultural activities which contaminants groundwater and surface water and threatens human health. Investigating an effective factor on water and minerals movement in soil and applying the new modifiers such as inorganic nanoparticles and biochar might be useful in reducing nitrate leaching and avoiding underground waters pollutions. Due to this difficulty, some situations to preserve nitrogen in the upper layers of soil such as increasing the absorbent surfaces for minerals, zeolite modifier, and biochar are considered by researchers. As many research have been conducted on using biochar in agricultural systems in terms of organic carbon sequestration in soil and reducing the greenhouse gases, its influence on other processes such as nitrate leaching has been considered as well. The purpose of this study was to investigate the effect of mineral nano-particles and biochar on nitrate leaching in soil and aggregate stability.

This study had been conducted in the laboratory in faculty of natural resources and geology science, Shahrekord University. Treatments in this study included zeolite, cloisite, and biochar at three levels. PVC pipes with 3 cm in diameter and 40 cm in height were used for the soil columns. Urea fertilizer included 46% pure nitrogen was applied to the soil columns. The amount of the Urea fertilizer was employed as an applied fertilizer for corn plants (200 g Nitrogen per hectare). Urea fertilizer was added as a solution to the soil in irrigation 1, and 5 from irrigation events. At the end of each irrigation event, nitrate effluent was measured using Spectrophotometry method.

The results showed a significant reduction of nitrate leaching in treatments, 1g biochar, 1g zeolite, and 1g cloisite compared to the control treatment. There was no significant difference between reduction of nitrate leaching in the three treatments, 1g biochar, 1g Zeolite, and 1g cloisite. Furthermore, nitrate leaching in treatments, 5g biochar, 5g zeolite, and 5g cloisite compared to the control treatment was decreased significantly. In all irrigations, 5g biochar had the smallest amount of nitrate leaching comparing 5g zeolite, and 5g Clozite. In general, the results showed that nitrate leaching would be decreased significantly by adding biochar and mineral nano-particles (5%) into the soil. According to the present results and previous findings, it can be mentioned that adding biochar into the soil will cause improving the soil physical properties and reducing nitrate leaching. Thus, we show here, that biochar and nano-particles soil application decreased nitrate leaching and enhanced soil aggregate stability.