Effect Of Soil Layer Replacement And Soil Fertilizing On Soil Fertility Of Calcic Chernozem

Soil layer replacement is a soil improvement measure,which can eliminate some soil obstacles and improve soil physical properties.In this paper,based on soil replacement and conventional fertilization,the effects of three soil fertility measures,returning straw to field,applying organic fertilizer and increasing phosphate fertilizer,on the soil fertility of calcic chernozem were studied.There are eight treatments in the experiment,which are:T1 soil replacement conventional fertilization,T2 soil replacement straw application,T3 soil replacement with a small amount of organic fertilizer,T4 soil replacement with a medium amount of organic fertilizer,T5 soil replacement with a large amount of organic fertilizer,T6 soil replacement with 20%phosphate fertilizer,T7 soil replacement with 40%phosphate fertilizer and T8 soil replacement with 60%phosphate fertilizer.The research results are as follows:（1）After continuous soil fertilization for 3 years,compared with the conventional application of chemical fertilizer in soil layer replacement,the treatments of returning straw to field,adding organic fertilizer and increasing phosphate fertilizer,0-20 cm soil layer,the contents of soil alkali-hydrolyzed nitrogen,soil available phosphorus and soil available potassium were all increased,the contents of soil organic matter were increased by returning straw to field and applying organic fertilizer,and the contents of soil organic matter and Soil alkali-hydrolyzed nitrogen were increased in 20-40 cm soil layer,the effect of soil available potassium was not obvious,and the application of organic fertilizer could increase soil available phosphorus.（2）In 0-20 cm soil layer,the soil p H is between 8.17 and 8.76.Compared with the conventional application of chemical fertilizer in soil layer replacement,the effect of straw returning treatment on soil p H is not obvious,and the soil p H decreases with increasing application of organic fertilizer.With the increase of phosphate fertilizer application,the soil p H increased.In 20-40 cm soil layer,the soil p H was between 8.24 and 9.85.Compared with the conventional application of chemical fertilizer in soil layer replacement,the soil p H of all other treatments was decreased except the addition of 60%phosphate fertilizer.The soil p H decreased with the increase of the amount of organic fertilizer applied.With the increase of phosphate fertilizer application,the soil p H increased.（3）After continuous fertilization for 3 years,the content of water-soluble calcium was increased and the content of water-soluble Sodium Ion,chloride ion and sulfate ion was decreased in 0-20 cm soil layer,compared with that of conventional replacement with chemical fertilizer Water-soluble potassium ion,calcium ion,magnesium ion,chloride ion and sulfate ion were increased and water-soluble sodium ion was decreased by adding organic fertilizer The content of water-soluble Potassium Ion,calcium ion,magnesium ion and sulfate ion increased,but the content of water-soluble sodium ion and chloride ion decreased.The contents of water soluble potassium ion,calcium ion,magnesium ion and sulfate ion were increased and the contents of water soluble sodium ion and sulfate ion were decreased in 20-40 cm soil layer with straw returning treatment,and sulfate ion was increased in the treatment with increasing organic fertilizer,potassium Ion,sodium ion,magnesium ion and hydrogencarbonate ion decreased,sulfate ion content increased,water soluble potassium ion,sodium ion and hydrogencarbonate ion content decreased.（4）After continuous fertilization for 3 years,the content of exchangeable Ca²⁺and Mg²⁺increased and the content of exchangeable Na⁺decreased significantly in 0-20 cm soil layer The content of exchangeable calcium ion increased and the content of exchangeable sodium ion and magnesium ion decreased,while the content of exchangeable calcium ion increased and the content of exchangeable sodium ion decreased significantly.In 20-40 cm soil layer,the content of exchangeable calcium ion was increased,the content of exchangeable magnesium ion and sodium ion was decreased,and the content of exchangeable sodium ion was significantly decreased with the increase of phosphate fertilizer application rate,increased exchangeable magnesium ion content.（5）After continuous fertilization for 3 years,the soil urease activity,Catalase activity,phosphatase activity and sucrase activity increased in 0-20 cm soil layer with straw returning The activities of urease and sucrase in soil treated with more organic manure increased,the activities of Catalase in soil treated with less organic manure and more organic manure increased,and the activities of Catalase treated with more organic manure and more organic manure increased The soil urease activity,Alkaline phosphatase activity and sucrase activity increased with the increase of 20%phosphate fertilizer,and the soil Catalase activity and Alkaline phosphatase activity increased with the increase of 40%phosphate fertilizer,the urease activity and the Catalase activity were increased by applying 60%phosphate fertilizer.In 20-40 cm soil layer,soil urease activity decreased in straw returning treatment,and increased in all other treatments except a little organic fertilizer The soil sucrase activity increased in the treatments of straw returning to field,organic manure application and phosphate application,except for 60%phosphate application.（6）In 2019,the accumulation of total nitrogen（TN）and total phosphorus（TP）in the aboveground part of maize plant increased after 3 years of continuous soil fertilization,compared with the conventional application of chemical fertilizer in soil layer replacement,straw returning to field,increasing organic fertilizer application and increasing phosphorus fertilizer application The accumulation of total potassium in the above-ground part of maize plants was increased by straw returning to the field,increasing the medium amount,increasing the amount of organic fertilizer and increasing the amount of phosphorus fertilizer by 40%and 60%The accumulation of total nitrogen in the roots of maize plants was increased by applying medium and large amounts of organic fertilizer and increasing phosphorus fertilizer,while the accumulation of total potassium in the roots of maize plants was decreased by returning straw to field,applying organic fertilizer and increasing phosphorus fertilizer,accumulation of total phosphorus increased.The accumulation of total nitrogen and total phosphorus in maize roots increased with the increase of organic fertilizer application,and the accumulation of total nitrogen in maize roots increased with the increase of phosphorus fertilizer application.According to the soil fertility index,three kinds of soil fertilizing measures have good effects on the fertility of calcic chernozem after soil layer replacement,in which the organic fertilizer is applied,the phosphorus fertilizer is increased and the whole stalk is returned to the field.