Effects of fresh soil samples and modified ASI extractant on soil available nutrient determination

In order to meet require of pre-treatment of soil samples before measurement in soil nutrient testing for vehicle application, soil available nutrient determinations based on fresh soil samples and modified ASI (Agro Services International Inc., ASI) extractant were explored and compared with that based on air-dried soil samples and ASI extractant. In the soil available nutrient determinations based on ASI extractant for fresh and air-dried soils (fluvo-aquic soil) collected in Beijing, there are significant linear correlations between the available nutrient contents of NO3--N, NH4+-N, P, K, Ca, Mg, Cu, Fe, Mn and Zn, organic matter, and pH value under the treatments of fresh and air-dried soils, and the relative errors are less than 5%9%. In the soil nutrient determinations based on fresh and air-dried soils for modified ASI and ASI extractants, there are significant linear correlations between the available nutrient contents of NH4+-N, P, K, Ca, Mg, Cu, Fe, Mn and Zn, and he relative errors are less than 5-8%. Therefore, the soil nutrient determination based on fresh soil sample and modified ASI extractant is an available way for supplying a suitable soil pre-treatment method in vehicle soil nutrient testing.