Effects Of Pig Manure Biogas Slurry On Soil Properties And Tree Growth Of Poplar Plantation

In this paper, Jiangsudongtai forest of3years old and10years old poplar plantations as anobject, to study the effects of manure biogas slurry on soil properties and tree growth of poplarplantation, changes in forest soil enzyme activity and diversity of understory vegetation were alsoinvestigated and analyzed. According to667m2biogas slurry15m3、30m3、45m3、60m3、75m3,set C1、C2、C3、C4、C5,apply averagely in March and August of2013,and set the blanktreatment CK. The main conclusions are as follows:(1) After using manure biogas slurry, soil pH and bulk density were changed. Soil pH ofyoung and mature poplar groups both had a compared downward trend;But pH had nosignificant difference.The range of young poplar soil pH was between8.42and8.75; After usingbiogas slurry,soil bulk density decreased, compared with the lower range of2.40%-5.45%, andwith the increasing of biogas slurry application rate,soil bulk density decreased more obviously.(2) Whether young or mature poplar forests from July to November, the soil organic matterand N、P、Kwere increased with the application of biogas slurry;and in November, the soilnutrient content was higher in July.(3) Biogas slurry effected on soil enzyme activities in poplar. Each treatment whetherYoung or mature forest soil catalase activity varies greatly, which only C2、C3activity increasedactivity compared to the control, and the rest declined compared with the control; biogas couldbe able to improve soil urease activity;each fertilization treatment alkaline phosphatase activitythan the control were significantly lower. Activity which in July than in March and Novemberhigher.(4) The application of manure biogas slurry had influenced on the growth of poplar.Afterusing slurry, in young growth of DBH, C2poplar DBH was most obvious, reaching3.75%.While the C5poplar DBH increment and amplitude was minimal. In tree height growth thelargest growth was in the amount of C1, C3maximum growth. Change with the same diameter,C5growth in volume and magnitude are minimal.In the mature poplar, DBH growth, compared to young poplar, forest volume growth wasn’tobvious. In the forest, tree height grew slowly, of which the greatest growth was in the amountof C2. Smaller young forest growth, and did not change significantly between the twofertilization.(5) After using manure biogas slurry,there was an effect on understory plant diversity.Woodland,Punta year,small canadensis,foxtail and barnyard showed a strong advantage in theundergrowth;Young underground plant Shannon-Wiener index H ’ largest index of0.42,Simpsonindex D maximum of0.18, compared to young forest to forest diversity smaller.In summary, the amount of biogas slurry on poplar forest land soil physicochemicalproperties and poplar growth, had a promoting effect on enzyme activity,could promotethe diversity of forest plants.