Soil Enzyme Activity And Nutrient Contents In Camellia Oleifera-Arachis Hypogaea Intercropping System

In agroforestry,camellia oleifera-arachis hypogaea intercropping is commonly used model in south of China.Reasonable intercropping can improve the efficiency of land use,and can increase economic income.In this study,we chose A.hypogaea monoculture,C.oleifera monoculture,and C.oleifera-a.hypogaea intercropping as three cropping models in forest farm of forestry academy of Hunan.Meanwhile,Soil enzyme activities(urease,acid phosphatase,sucrase,protease and catalase)and soil nutrients(soil organic carbon,total nitrogen,total phosphorus,total potassium and their rapidly available form)were measured at different levels(0-10 cm、10-20 cm、20-30 cm、30-40 cm)in three cropping models.The differences of soil enzyme activity and soil nutrient under different planting patterns were analyzed.Correlation analysis and path analysis were used to study the relationship between soil enzyme activities and soil nutrients.By this meaning,we expected to provide some references for improving soil quality during C.oleifera implanting process.The results were as the following:(1)Soil enzyme activity and nutrient of all cropping models showed significant difference on spatial distribution(P<0.05),reflecting that the surface soil enzyme activity and nutrient was the highest,and decreased with the soil depth increasing.(2)Compared to C.oleifera monoculture model,C.oleifera-a.hypogaea intercropping model demonstrated a higher soil enzyme activity(P<0.05),especially towards sucrase,protease,urease and catalase.Moreover,the soil enzymatic activity was much significant difference in 0-10 cm soil layer of the two cropping models.Whereas,there was no obvious difference of soil enzymatic activity between C.oleifera-a.hypogaea intercropping model and A.hypogaea monoculture model.(3)In most moment,C.oleifera-a.hypogaea intercropping model had significantly higher amount of soil nutrient(i.e.soil organic carbon,total nitrogen,total phosphorus and total potassium)than C.oleifera monoculture model did(P<0.05).Referring to rapidly available nitrogen,phosphorus and potassium,C.oleifera-a.hypogaea intercropping model showed a significantly higher level than other cropping model did(P<0.05).(4)The relationship between soil enzyme activity and nutrient were interoperable and interactional and presented differentiation for each intercropping model.Among three intercropping models,all the soil organic carbon,total nitrogen and rapidly available potassium had positive effect on the most of soil enzyme activity(P<0.05).Whereas,soil total phosphorus and rapidly available phosphorus only improved the soil enzyme activity in C.oleifera monoculture model.Noting that all the other nutrient had little effect on soil enzyme activity.(5)Path analysis result indicated that soil organic carbon and rapidly available potassium were the key factors to effect the soil enzyme activity in C.oleifera-a.hypogaea intercropping model.Meanwhile,soil organic carbon and total nitrogen had dominant influence on most of enzyme activity in A.hypogaea monoculture model.In addition,soil total phosphorus and rapidly available phosphorus had significant positive effect on soil enzyme activity in C.oleifera only model.