Effects Of Organic Materials On Enzyme Activities And Organic Carbon Components In Degraded Black Soil And Growth Of Soybean Seedlings

Black soil is the main farming soil in northeast my country.It is rich in organic matter and has high fertility.However,in recent years,due to serious soil erosion,unreasonable farming,predatory development,and climate factors,the black soil has been seriously degraded,resulting in a sharp decrease in the organic matter content of the black soil.The layer becomes thinner,the physical and chemical properties deteriorate,and crop yields are severely reduced.Therefore,in order to ensure the food security of our country,how to restore the fertility of degraded black soil is a problem that we urgently need to solve.In this experiment,two organic materials:organic fertilizer and biochar were added to study their effects on the basic physical and chemical properties of degraded black soil,soil respiration,soil enzyme activity,organic carbon and its components,and soybean seedling growth,in order to restore the fertility of degraded black soil Provide theoretical basis.In this experiment,through the soil cultivation experiment and the soybean pot experiment,the effects of adding biochar and organic fertilizer on the basic physical and chemical properties of degraded black soil,soil respiration,soil enzyme activity,organic carbon and its components,and the effects of adding biochar and organic fertilizer on soybean seedlings the impact of growth.Among them,the experimental design of soil culture experiment and pot experiment is a completely random experiment design with 2 factors and 3 levels,respectively,with 9 treatments,including 3 levels of organic fertilizer(M0:0 g·kg^-1;M1:13.64 g·kg^-1;M2:27.27 g·kg^-1),3 levels of biochar(C0:0 g·kg^-1;C1:1.36 g·kg^-1;C2:2.73 g·kg^-1),each treatment 4 repeats,numbered M0C0,M1C0,M2C0,M0C1,M1C1,M2C1,M0C2,M1C2,M2C2.The research results are as follows:1.After 120 days of cultivation,organic fertilizer and biochar and their interactions have extremely significant effects on the maximum soil water holding capacity and p H value,but have no significant effect on the water loss rate.Organic fertilizer and biochar have extremely significant effects on soil organic matter.Compared with the control,the maximum water holding capacity and organic matter content of the black soil treated with M2C2 were the highest,the maximum water holding capacity was 10.41%higher than that of M0C0 treatment,and the organic matter was 196.04%higher than that of M0C0 treatment.The water loss rate of the M1C1treatment was the slowest,and the soil p H value of the M2C0,M0C1,and M0C2 treatments was closest to 7.2.Organic fertilizer or biochar and the interaction of the two have a very significant effect on the rate of CO₂and the amount of CO₂accumulation.After adding organic fertilizer and biochar,the CO₂rate reached a peak on the 15th day of culture and then rapidly dropped to 120 days.The soil respiration rate of each treatment was close to that of the control treatment.On the 15th day of culture,the highest respiration rate of the M1C2 treatment was 359.41 mg·kg^-1,which is 10.90times higher than that of MOC0 treatment.With the increase of the cultivation time,the accumulation of CO₂respiration gradually increased but the growth rate gradually decreased and finally stabilized.On the 120th day of culture,the accumulation of CO₂respiration between treatments was 5106.22 mg·kg^-1for M1C2 treatment,which was significantly higher than 234.85%for M0C0 treatment.The interaction of organic fertilizer and biochar,and the interaction of the two have significant or extremely significant effects on the activities of invertase,catalase,and polyphenol oxidase.As the cultivation time increases,invertase,catalase,and more the activity of phenol oxidase gradually increased,and the enzyme activity reached the highest on the 80th day of culture.The highest activity of invertase in M2C1 treatment was 0.3039 mg·g^-1on the 80th day of culture,which was significantly higher than that of M0C0 treatment of 8.07%and M0C2 the highest catalase activity of the treatment was 0.4322 umol·g^-1,which was 10.14%higher than that of the M0C0 treatment.The highest polyphenol oxidase activity of M1C0 treatment was 2.9548 mmol·g^-1,which was 9.74%higher than that of M0C0 treatment.3.During the 120-day cultivation period,organic fertilizer,biochar and their interactions all affect soil organic carbon,active organic carbon,microbial biomass carbon,humic acid,free humic acid,water-soluble organic carbon,reducing sugar,the content of phenolic compounds has a significant or extremely significant effect.With the increase of incubation time,the content of soil organic carbon,humic acid,water-soluble organic carbon,and reducing sugar reached their peaks at the 60th day of culture.Among them,the highest soil organic carbon content of M2C0treatment was 29.76 g·kg^-1,which was significant 86.35%higher than M0C0 treatment.The highest humic acid content in M2C1 treatment was 3.7093 mg·g^-1,which was significantly higher than M0C0 treatment by 125.59%.The highest water-soluble organic carbon in M1C1 treatment was 2.0499 mg·g^-1,which was 18.82%higher than that in M0C0 treatment.The highest reducing sugar content in M2C2 treatment was 170.8826 ug·g^-1,which was 92.03%higher than that in M0C0 treatment.The content of soil active organic carbon reached its peak on the 30th day,and the highest content of soil active organic carbon in M2C0 treatment was 1.9833 mg·g^-1,which was significantly higher than that of M0C0 treatment by 116.94%.The content of soil microbial biomass carbon and phenolic compounds reached the peak at the 80th day of culture.The highest soil microbial biomass carbon content of M2C1 treatment was 90.5273 mg·kg^-1,which was significantly higher than that of M0C0 treatment by 17.84%and M2C2 treatment of phenols.The highest compound content was 21.1123 ug·g^-1,which was 37.81%higher than that of M0C0treatment.The highest free humic acid in soil was 2.6425 mg·g^-1in M2C2 treatment on the 10th day of culture,which was 109.53%higher than M0C0 treatment.4.Organic fertilizer or biochar and the interaction of both have significant or extremely significant effects on plant dry weight,nitrogen,phosphorus and potassium accumulation,root dry weight,root length,root tip number,root surface area,root average diameter,and root volume.Among them,the interaction of organic fertilizer and biochar and the interaction of the two has no significant effect on SPAD,and the interaction of the two has no significant effect on the average root diameter.The plant dry weight,NPK accumulation,SPAD,root dry weight,root length,root tip number,root surface area,and root volume were the highest in M2C1 treatment,which were33.95%,63.21%,48.14%,50.66%,and 50.66%higher than those of M0C0 treatment,respectively.11.80%,106.51%,35.54%,49.05%,19.87%,61.34%.The average root diameter of M1C2treatment was the highest,which was 3.97%higher than that of M0C0 treatment.In summary,the main component analysis of all measurement items and its changes is known that the M2C1 treatment is best,and is optimal.Therefore,administration of organic fertilizers can improve the soil physicochemical properties of degraded dark soil,promote soil breathing,improve soil enzyme activity,increase soil organic carbon,active organic carbon,microbial carbon,humic acid,water soluble organic carbon,etc.It can promote the growth of soybean seedlings.