Effects of Nitrogen Application on Exchangeable Acidity and Base Saturation in Purple Soil

The factors including different application levels of nitrogen fertilizer and different types of nitrogen fertilizer that influenced the exchangeable acidity(EA)of purple soil and base saturation(BS)were studied through soil column leaching simulations.Results showed that:(1)The pH of purple soil decreased through the leaching of nitrogen fertilizer and the pH and levels of nitrogen fertilizer were inverse ratio.Moreover,the decrease of pH manifested as thiaminenitramineurea under the same nitrogen rate.(2)The content of exchangeable H+and exchangeable Al 3+changed with the types of nitrogen fertilizer,and the decrease of pH manifested as thiaminenitramineurea under the same nitrogen rate,what's more,there was a positive correlation between the decrease of pH and the amount of nitrogen in the same application levels of nitrogen.(3)With the increase of exchangeable acidity,the content of exchangeable H+and Al 3+increased.When applied urea and nitramine,the exchangeable acidity in soil mainly depended on exchangeable Al.While thiamine was used,the exchangeable acidity hinged on both exchangeable H+and Al 3+.(4)As applying nitrogen fertilizer,the amount of exchangeable bases in soil was lower than that in the original clays,the content was characterized by Ca2+ Mg2+K+Na+,the base saturation decreased and there was a negative correlation between base saturation and the application content of nitrogen.When applied different types of nitrogen fertilizer under the same application levels of nitrogen,the regulation was ureanitraminethiamine.(5)For purple soil,the pH decreased while the EA increased,but the pH increased with the increase of exchangeable base cations(EB),of the both,EA played a dominant part in the change of soil pH.