Study On The Effect Of Organic Manure On Soil Active Organic Carbon And Enzyme Activity In Reclaimed Land

In recent years,the government has vigorously carried out the the project of increasing and reducing the urban and rural construction land,which is an important way to balance the cultivated land resources.The construction land,especially the soil fertilizer and quality condition of the land reclamation project,becomes the key link,how to realize the sustainable utilization of the quality,quantity and ecology of reclaimed farmland is the difficulty and key point of attention.Organic manure like straw,spent mushroom substrate,pig manure are often used in the course of agricultural production and can improve soil structure,improve soil quality,reduce environmental load and improve crop quality.To explore the impact of different organic and inorganic fertilizer management practices on soil labile organic matter carbon fractions(LOC)and related enzyme activities,and the enzymatic mechanism of labile soil organic carbon fractions.In this paper,a field experiment was conducted in Chongzhou City's reclaimed rural homestead land,and eight treatments were designed including control(no fertilizer and organic material,CK),chemical fertilizer only(CF),straw with chemical fertilizer for the total amount of CF(T1),150% straw with chemical fertilizer for the 150% total amount of CF(T2),pig manure with chemical fertilizer for the total amount of CF(T3)and 150% pig manure with chemical fertilizer for the 150% total amount of CF(T4),spent mushroom substrate with chemical fertilizer for the total amount of CF(T5),150% spent mushroom substrate with chemical fertilizer for the 150% total amount of CF(T6).We main study the concentrations dynamics of soil total organic carbon(TOC),soil labile organic matter(LOC),soil carbon management index(CMI)and the activities of amylase,?-glucosidase,sucrase and polyphenol oxidase;and explore the relationships between LOFC with C-cycle enzymes under organic and inorganic fertilizers.The main research results were as follow:(1)In the wheat and corn seasons,the contents of organic manure with different gradient of straw,pig manure and bacterial residue can significantly increase the content of TOC and LOC.The content of TOC in the soil treated with six kinds of organic and inorganic fertilizer was 1.34%-23.53% higher than that of CK treatment by single fertilizer application.Among them,the most obvious promotion effect is T6 treatment.The content of H-LOC and L-LOC treated by T6 was the highest,the mean growth period of T6 treatment was 0.51-16.13% and 0.95%-35.48% higher than that of the other five kinds of organic and inorganic fertilizer treatments.T3 treatment was the optimum return to enhance the content of H-LOC,the mean growth period of T6 treatment was 2.04%-18.03% higher than that of the other five treatments.The CMI content of the six organic and inorganic fertilizer treatments was higher than that of the CK treatment,and the T6 treatment was the best,and the CK treatment was higher than the CK treatment,the8.28%-33.89% was higher than that of the CK treatment,and the mean growth period of T6 treatment was 1.52%-14.36% higher than that of the other five treatments.The results showed thatT6 treatment was a better management model for farmland tillage and fertilization,which makes the carbon pool more benign than other fertilization treatments.(2)The effect of spent mushroom substrate and pig manure on the activity of soil carbon cycle related enzymes was significant.In addition to polyphenol oxidase,organic and inorganic fertilizer treatment can improve soil carbon cycle related enzyme activity in different degrees compared with CK treatment.The amylase activity of T4 and T6 treatments was 19.83%-48.47%and 17.07%-43.26% higher than that of CK treatment,and the mean growth period of T4 and T6 treatment was 1.46%-15.25% and 2.86%-19.44% higher than that of the other four kinds of organic and inorganic fertilizer treatments.Invertase activity of T4 and T6 treatments was7.14%-54.90% and 15.19%-57.05% higher than that of CK,and the mean growth period of T4 and T6 treatment was 1.42%-22.85% and 0.72%-20.66% higher than that of the other four treatments..The enhancement effect of glucosidase was most obvious in T6 treatment,and 10.92%-30.53%was higher than that of CK treatment,the mean growth period of T6 treatment was 1.52%-14.36%higher than that of the other five treatments.The increase of soil polyphenol oxidase was reflected in the deep soil and maize season.(3)The three active organic carbon components were significantly positively correlated with amylase,invertase and beta glucosidase.The positive correlation between three kinds of active organic carbon and polyphenol oxidase is only reflected in the deep soil of wheat season and corn season.In 0-20 cm soil layer,H-LOC,M-LOC and L-LOC were negatively correlated with polyphenol oxidase.There was a significant negative correlation between polyphenol oxidase and polyphenol oxidase.There was a significant correlation between polyphenol oxidase and low activity organic carbon in the surface layer of maize,which was not related to highly active organic carbon and low active organic carbon.It indicates that there is a close relationship between soil active organic carbon pool and carbon cycle related enzymes in reclaimed homestead,indicating that soil active organic carbon pool and amylase,invertase and beta glucosidase can be used as an important index to evaluate soil fertility improvement of reclaimed homestead.(4)In the level of fertilization and the field management of this study,it is best for the homestead reclamation soil of the Chengdu plain to the 150% spent mushroom substrate with chemical fertilizer treatment and 150% pig manure with chemical fertilizer treatment.