Effects Of Different Soil And Water Loss Control Measures On Surface Runoff And Soil Nutrients In Camellia Forest In Purple Soil Region

Soil erosion is one of the global environmental problems.Soil erosion is serious in our country,which not only causes the destruction of the land resources of China,but also leads to the deterioration of the agricultural and forestry production environment,the decline of soil nutrients and the imbalance of ecological balance and so on,and also restricts the sustainable development of our country's economy and society.For a long time,due to the serious destruction of forest vegetation in the purple soil area,while the purple soil has the problems of shallow soil and low erosion resistance,the phenomenon of soil erosion is serious,and the purple soil area has also become one of the typical areas of soil and water loss in China.This study takes the soil and water loss area of purple soil in Ninghua County of Fujian Province as the research area,and takes the most important local economic forest-25 years old Camellia Forest as the research object.By setting up the standard runoff observation area for the positioning observation,the method of biological measures plus the engineering measures is adopted.Analysis of the effects of undergrowth on the nutrient indicators of soil total nitrogen,total carbon,total phosphorus,total potassium,DOC and DTN in runoff plots by T1,T2 treatment,and no treatment(CK),which can evaluate the difference of soil and water conservation capacity of different soil erosion control measures,and provide theoretical reference for soil and water loss control in purple soil area.The main conclusions are as follows:(1)Effect of different soil erosion control measures on runoff volume of Camellia forest landDuring the observation period,the surface runoff of the runoff plots with different months in different months showed the same trend with the monthly rainfall,and the rainfall of different treatments had a very significant positive correlation with the surface runoff(P<0.01).There was a significant difference in surface runoff between treatments(P<0.05)in March,April,May,July,August and November,2017.According to the annual observation data,the total surface runoff of T1 treatment and T2 treatment decreased by 36.04%and 11.29%respectively compared with CK,and the total surface runoff of T1 treatment decreased by 27.91%compared with the T2 treatment.Therefore,T1 treatment had the best effect on intercepting surface runoff and T2 treatment followed.(2)Effect of different soil erosion control measures on sediment loss in Camellia forestDuring the observation period,the amount of sediment loss in the runoff plot in the same month was the same as the monthly rainfall,and the rainfall of different treatments had a very significant positive correlation with the amount of sediment loss(P<0.01).A significant difference existed in sediment loss between treatments(P<0.05)in March,April,May,June,July and November,2017.According to the annual observation data,the sediment loss of T1 treatment and T2 treatment decreased by 51.24%and 21.78%respectively compared with that of CK,and the sediment loss of T1 treatment decreased by 37.66%compared with that of T2 treatment.Therefore,T1 treatment was the best way to intercept sediment loss,and T2 treatment followed.(3)Effects of different soil erosion control measures on total nitrogen and total carbon in soil of Camellia forestThe contents of total nitrogen and total carbon in 0-20 cm soil layer of each plot were greater than that in 20-40 cm soil layer.According to the annual observation data,the total nitrogen content of soil under the T1 treatment was 8.65%higher than that of CK.The total nitrogen content of soil under T2 treatment was 2.27%higher than that of CK,and the total nitrogen content of soil under T1 treatment was 5.32%higher than that of T2 treatment.The total carbon content of soil increased by 21.54%compared with that of CK.The total carbon content of soil under T2 treatment was 7.81%higher than that of CK,and the total carbon content of soil under T1 treatment was 12.73%higher than that of T2 treatment.The two kinds of soil erosion control measures can increase soil carbon and nitrogen content effectively,improve the soil nutrient of Camellia forest,promote the vegetation to absorb nutrients,and realize the vegetation cover faster.T1 treatment had the highest soil carbon and nitrogen content,and the best effect on soil carbon and nitrogen content.The T2 treatment effect was the second.(4)Effects of different soil erosion control measures on total phosphorus and total potassium in soil of Camellia forestThe contents of total phosphorus and total potassium in 0-20 cm soil layer of each plot were greater than that in 20-40 cm soil layer.According to the annual observation data,the contents of total phosphorus and totalpotassium in T1 treated plots and T2 treated plots were different from those in CK.The total phosphorus content in soil increased by 20%compared with CK under T2 treatment,and the total potassium content increased by 10.72%compared with CK under T2 treatment.(5)Effects of different soil erosion control measures on soil DOC and soil DTN content in Camellia forestThe soil DOC content and soil DTN content in the 0-20 cm soil layer of each plot were greater than that in 20-40 cm soil layer.According to the annual observation data,the soil DOC content increased by 96.81%compared with CK,and the DOC content of soil increased by 75.48%compared with that of CK under the T2 treatment.The soil DTN content under T1 treatment increased by 44.40%compared with CK,and the DTN content of soil under T2 increased by 19.52%compared with CK.Both of the two different soil erosion control measures can significantly improve soil DOC content and soil DTN content,improve soil fertility and speed up vegetation restoration.So it can be concluded that T1 treatment had a better effect on soil DOC and soil DTN resistance than T2 treatment.