Effects Of The Law Of Micronutrient Absorption Of Soil Aggregates Under Different Long-term Fertilization

This experiment was carried out in a long-term experimental location of brown soil fertilizer.The site has a history of 41 years since 2019,with a total of 15 treatments,it was divided into three areas,namely,fertilizer area(N1P,N1 PK,N1,N2,CK),low-level organic fertilizer area(M1N1P,M1N1 PK,M1N1,M1N2,M1),high-content organic fertilizer area(M2N1P,M2N1 PK,M2N1,M2N2,M2).In this experiment,the content of total and continuous extractive trace elements in 1mm-2mm,0.5mm-1mm,0.25-0.5mm,0.053-0.25 mm,<0.053 mm five grades in 0-20 cm and 20-40 cm soil layers during the 2017 harvest period was determined.The effects of long-term fertilization on the continuous extraction of trace elements in soil were studied.The changes of continuous extracting trace elements in soil under different fertilization conditions and the relationship with fertilization were discussed to provide a basis for rational application of trace element fertilizers in agriculture.The research results are as follows:Fe and Mn in the 1-2mm are mainly in the Fe-Mn oxides state.Second is the Organic binding state,And Cu,Zn are mainly in the Organic fraction,second is the Fe-Mn oxides state,about 90% of the sum of the five forms.There is no obvious law on the effect of fertilization on Fe and Mn content.Fertilizer application reduced the Fe-Mn oxides and Carbonate-bound state Cu and Zn contents in the soil,and the application of organic fertilizer increased the Cu and Zn contents of this two forms.Fe and Mn in the 0.5-1mm are mainly in the Organic binding state,second is the Fe-Mn oxides state and Carbonate-bound state(Mn).Cu,Zn are mainly in the Fe-Mn oxides,second is the Organic binding state,carbonate-bound and Exchangeable state.The application of organic fertilizer significantly increased the content of Organic binding state Fe and Mn in 20-40 cm soil layer,increasing the content of Cu and Zn in all forms of 0-20 cm and 20-40 cm.Fe and Mn in the 0.25-0.5mm are mainly in the Organic binding state,second is the Fe-Mn oxides state,all fertilization treatments can increase the content of Organic binding state Fe.Organic binding state,Fe-Mn oxides state,Carbonate-bound state,Exchangeable state Mn are distributed.Except for M1M2 treatment,other fertilization treatment increased the Exchangeable state content of Mn in 0-20 cm soil layer.Application of organic fertilizer(except for individual treatment)increased the content of Cu and Zn in different forms of 0-20 cm and 20-40 cm soil layers.Fertilizer application has no such effect.Fe in the 0.053-0.25 mm of 0-20 cm soil layers is mainly in the Fe-Mn oxides state,second is the Organic binding state.Mn is mainly in the Fe-Mn oxides,second is the Organic binding state and Exchangeable state,less carbonate-bound content.The content of Organic binding state Fe,Mn in the 20-40 cm soil layer is more than 0-20 cm.Fertilization treatment has no obvious effect on the Fe and Mn content of each form in these two soil layer.The Cu,Zn contents of the two soil layers in this grade are similar.Application of organic fertilizer(except for individual treatment)increased the content of each forms of Cu,Zn in 0-20 cm and 20-40 cm soil layers.Fertilizer application has no such effect.The content of each element in the <0.053 mm is similar to that in the 0.053-0.5mm.It can be seen that the distribution of different elements in different grain sizes is different,and Fe,Mn have a generally consistent law.Large-size(1-2 mm)and microparticles(0.053-0.25 mm and <0.053 mm)are mainly present in the form of the Fe-Mn oxides state.Medium-sized(0.5-1mm and 0.25-0.5mm)soils exist in the Organic binding state,and fertilization has less effect on each grade of Fe and Mn.Cu,Zn also have similar distribution patterns.Large-size(1-2mm)mainly exists in Organic binding state,medium-sized(0.5-1mm)exists in the form of Fe-Mn oxides state,and other forms of soil in other sizes coexist.Fertilization has a great influence on Cu,Zn.The application of organic fertilizer(except for individual treatment)increases the content of each forms of Zn,Cu in 0-20 cm and 20-40 cm soil layers.