The Search In Fixed Ammonium Of Some Typical Soil In Jilin Province

The supply condition of nitrogen is one of the important targets to judge the fertility in soils.The supply condition of'nitrogen,the different forms of nitrogen and their transformation,the fixation and adsorption of ammonium are important parts of nitrogen recycle in soils,keeping and improving soil fertility.and using nitrogenous fertilizer in reason according as them.The research by using the method of chief of field sampling, laboratory incubation and analyses to investigate the different forms of nitrogen,the content of fixed ammonium,capacity of fixing-ammonium in different types of soils.,they are wind sandy soil,black calcium soil,dark brown soil,white bentonite soil,black soil.The maximum capacity of fixing-ammonium and their affect factors,kinetics of soils ammonium fixation and release of fixed ammonium,ammonium adsorption and desorption in order to definite characteristics of Ammonium Fixation and adsorption of the five kinds of soils in Jilin province and realize the reserves of fixed ammonium,the capability of the fix nitrogen fertilizer, ammonium fixation and release of fixed ammonium.Consequently forecast the capacity of keeping nitrogen to the purpose of affording guidance to utilize fertilizer availability.The main results were as follows:1.The total N of cultivated horizon in these five different soils average is balck soil 0.434%,black calcium soil 0.545%,dark brown soil 0.475%,white bentonite soil 0.19%,wind sandy soil0.047%.Nitrate nitrogen's average in order with 22.86mg/kg,18.40mg/kg,11.18mg/kg,4.63mg/kg,6.04 mg/kg,Fixed ammonium content in soil samples studied in five types of soil in order with245.40 mg/kg,204.53 mg/kg,185.66 mg/kg,213.96 mg/kg,67.64 mg/kg。-which accounted for 4.06%-13.78%of the total N and accounted for 55.12%-81.85%of abio-nitrogen.The soil factors affecting fixed ammonium content in different types of soils tested were mainly parent material except wind sandy soil,soil clay composition,the content of clay(＜0.01 mm) and CEC.2.Five different soil type's soil particle composition differences are in evidence.In the wind sandy soil, the sand grains content is highest,the silt next,the clay is lowest.But in other soil types,the silt is highest, the sand grains next,the clay is least low.After the relevant analysis,the soil particle composition and the solid state ammonium's relations are decided by the grain size.The small grade and the solid state ammonium has the correlational dependence,big grade is different.The solid fixed ammonium and the physical sand grains are inverse correlations;Is being related with the physical clay.Except wind sandy soilother soil types, assumes remarkable or the extremely remarkable relevance with the silt and the clay,but the wind sandy soil has only presented the relations which is related.3.In the determination of fixed ammonium content in sand grains,the silt and the clay solid indicated that in clay solid fixed ammonium quantity is biggest,the next best silt,the sand grains are lowest.The wind sandy soil occupies the three clay content sums is 60%,other four types of soils account for 50%.But the silt content occupies three sums 29%-38%,the sand grains are very low,occupy three sums 12%-21%.According to the computation,had proven it has good uniformity with between each grade and sum of the solid fixed ammonium product and fixed ammonium.4.In five different types of soil,the most greatly fixed ammonium capacity is black soil,which is 484.03mg/kg equally,most lowers for the wind sandy soil,which is 386.70mg/kg.The highest capacity of fixed ammonium is also black soil,which is 245.40mg/kg,the lowest wind sandy soil is 59.83mg/kg.Most greatly of capacity of fixed ammonium and the cation exchange quantity assume the extremely remarkable correlational dependence.5.The fixing quantity of ammonium in these five types of soil increased with the increasing of the fixation time,and the fixation rate was the largest at the beginning several hours.The releasing amount of fixed NH₄⁺ -in soils tested increased with the incubation time,and the velocity of fixed NH₄⁺ -release was very slow.The release of fixed ammonium still continued at the reaction time of 42 days.Both first-order equation and parabolic diffusion law equation were the most adaptable to describe the NH₄⁺-fixation and fixed NH₄⁺-release6.In the adsorption of NH₄⁺,from the adsorption-desorption data we could learn that capacity of adsorption mainly increase with the concentration of ammonium.when the concentration of ammonium arrive at a fixed value,.the rate of increase become slow.the capability of adsorption wear off.At last,the quantity of adsorption of wind sandy soil,black calcium soil,dark brown soil have descend direction.The characteristics of ammonium adsorption-desorption were conducted to find out the best equation for the tested soil.It was shown that Freundlich equation was the best one.Freundlich and Langmuir equation describe the sorption date judged by their very significant correlation coetffcients.