Effects Of Organic Fertilizer Application On Soil Physical Properties And Aggregate Organic Carbon In Potato Field

Inner Mongolia is an important production base for potato cultivation and commercial production in China,however,the long-term pursuit of high yield has led to an increasing degree of land intensification and input of agricultural production materials.In addition,the special cultivation method of the potato constantly disturbs the soil from sowing to harvesting.This leads to soil degradation problems such as poor soil structure,shallow cultivation layer,low organic carbon content,serious soil erosion and frequent soil-borne diseases,which seriously hinders the sustainable development of potatoes.In this study,the effects of organic fertilizer application on soil physical properties and organic carbon aggregates were studied in the main potato producing area in the northern foothills of Yin Mountain in Inner Mongolia.By measuring soil bulk density,soil specific gravity,soil texture,soil water content,soil aggregate composition and organic carbon content of aggregates,the effects of organic fertilizer application on soil physical properties in potato fields were clarified,the distribution law of organic carbon in soil aggregates was clarified,and the effect of organic fertilizer application on potato field fertility was revealed.The experimental results provide a theoretical basis for improving soil fertility in potato fields.The main results are as follows:（1）By applying organic fertilizer in the potato field,the soil water content and porosity of the 0～20cm soil layer were effectively improved,and the soil bulk density of the 0～20cm soil layer was reduced,which had no effect on the soil texture.（2）By applying organic fertilizer,the distribution of soil aggregates was significantly changed.Compared with the treatment of purified fertilizer（T0）,the treatment with the largest proportion of organic fertilizer substitution（T3）increased the content of large aggregates（>2mm,2～0.25mm）in each soil layer,and reduced the content of microaggregates（0.25～0.053mm）and clay（<0.053mm）.（3）The content of aggregates>0.25mm(R_>0.25)in T3 treatment was significantly higher than that in T0 treatment.The mean weight diameter（MWD）and geometric mean diameter（GMD）were also significantly higher than that in T0 treatment.（4）The application of organic fertilizer can significantly increase the organic carbon（SOC）content of aggregates,with the increase of the proportion of organic fertilizer substitution,the SOC of aggregates in T3 treatment continued to increase,which was significantly higher than that of T0 treatment and the contribution rate of large aggregates to soil SOC is the largest.All treatments with the application of organic fertilizer can increase the SOC reserves of large aggregates in each soil layer and reduce the SOC reserves of microaggregates and clays.The SOC content of>2mm granular aggregates had the highest correlation with MWD value,GMD value and R_>0.25.On the whole,the application of organic fertilizer can improve soil physical properties,increase the content and stability of soil aggregates,increase the content of soil organic carbon,and increase the contribution rate and storage of soil organic carbon of aggregates,which is more conducive to the improvement of soil fertility in potato fields.