The Effect Of Continuous Cropping On Ⅰ-107 Poplar Plantation On Soil Organic Carton And Total Nitrogen

In order to study the effect of continuous cropping of poplar plantation on soil organic carton(SOC) and soil total nitrogen(STN), The stability characteristics of organic carbon,the effect of continuous cropping on I-107 poplar plantation on the change of distribution and soil organic canton density(SOCD) and soil total nitrogen density(STND) was studied in the Dawenhe basin. The results showed that the SOCD had a significant difference in different I-107 poplar plantation. To evaluate the effect of continuous cropping on soil carbon, nitrogen store in poplar plantation and studies on the law of C and N in plantation ecosystem under continuous cropping. Then a scientific theory for the inference of continuous cropping on soil quality in plantation ecosystem was provided and the results would provide primary data for nutrient management and productivity maintenance of poplar plantation.(1) As planting generation increased in popular plantation, tree height, DBH, and canopy were decreased, obviously. The physical and chemical characteristics of soil was affected by continous cropping of I-107 poplar. The results showed that forest harvesting resulted in increase in soil volume weight, lessening porosity, and decline in function of water holding. And soil organic nutrient snd available N, P, K were descended in large scale, while the result was increased acidity in soil.The soil went agaist growth of I-107 poplar.(2) The content of SOC and STN of the first generation plantation, the second generation plantation and the third generation plantation had significant difference after continuous cropping. The content of SOC of the first generation plantation, the second generation plantation and the third generation plantation showed an decrease trend from 0 to 60 cm soil layer, and wasteland showed increasing trend. The content of STN of the first generation plantation, the second generation plantation and the third generation plantation showed decreased firstly and increased subsequently from 0 to 60 cm soil layer, and the content of STN in surface is highest of all the forest land and wasteland.(3) The SOCD had a significant difference in different I-107 poplar plantation. The order of SOCD was the first generation plantation, the second generation plantation, the wasteland and the third generation plantation. The stock of SOC of the first generation plantation increased by 20.59%、23.37% and 48.05% compared with the second generation plantation, the wasteland and the third generation plantation. The STND had a significant difference in different poplar plantation. The order was the first generation plantation, the wasteland, the second generation plantation and the third generation plantation and the stock of STN of the first generation plantation increased by 25.27%、41.28% and 7.54% compared with the wasteland, the second generation plantation and the third generation plantation.(4) The retio of Cand N has a signifancant difference in each forestland, and by using regression analysis, we found that STN had a significant linear relationship with SOC.It shows that the abilty of nutrient supply has a great variability between the different soil leves in different forests. The regression equations all followed cubic regression model, and this to see continuous cropping played the same effects of interaction on SON and STN.(5) Contious cropping has various factors on soil LOC in different forestlands. With the increase of continuous cropping algebra, the soil carton storage activity(A) decrease gradually. The order of A in 0-60 cm soil layer was the first generation plantation(0.38) >the second generation plantation(0.31) > the third generation plantation(0.27) > the wasteland(0.25).Carton management index(CMI) has a indictation action on SOC storage and the transforming of its components. The CMI showed a increasing to linear curve in soil 0-20 cm and 20-40 cm. So we can the change and updating.speed of SOC storage is the fastest in 0-40 cm layers. CMI had a decreased tendency in 40-60 cm layers.The CMI of the first generation plantation educed 1.91 and 7.97 times from 0 to 20 and 20-40 cm soil layers; The CMI of the second generation plantation decreased by 0.81 and 2.63 times, the third generation plantation had a smaller decline of 37.7% and 39.0%, comparing with the first generation plantation and the second generation plantation, respectively.