Plant aboveground biomass carbon and nitrogen: Tree Competition Garden

This experiment was set up adjacent to E055 in the high disturbance, garden area. 1.75 inches of black soil was added to the CCNHA sandy soil to make four 10 feet x 54 feet plots. The soil was rototilled and aluminum flashing was installed to edge the plots and divide them into 48, 5 feet x 9 feet plots. Equal amounts of MgSO4, CaCO3, P2O5 and K2O are added to the plots each year in early May and late June. For a describtion of fertilizer added, see fertilization details. Seeds were planted with 6 replicates of each of the following treatments: 1. Agropyron repens monoculture 2. Schizachyrium scoparium monoculture 3. Pinus strobus monoculture 4. Quercus ellipsoidalis monoculture 5. Agropyron repens + Quercus ellipsoidalis on half 6. Agropyron repens + Pinus strobus on half 7. Schizachyrium scoparium + Quercus ellipsoidalis on half 8. Schizachyrium scoparium + Pinus strobus on half The competition plots were split, with half invaded by seed and half to be invaded by seedling. For treatments 5-8, the right or left sides were chosen at random, to plant the tree seeds. The plots were watered throughout the growing season to keep water from becoming a limiting resource.本实验设置于高干扰花园区域的E055地块旁。将1.75英寸厚的黑土添加至CCNHA砂质土壤中，制备得到4块10英尺×54英尺的样地。随后对土壤进行旋耕作业，并安装铝制包边以划定样地边界，将其进一步拆分为48块5英尺×9英尺的小样地。 每年5月初与6月末，向所有样地施加等量的硫酸镁（MgSO4）、碳酸钙（CaCO3）、五氧化二磷（P2O5）及氧化钾（K2O）。关于肥料添加的详细说明，请参阅施肥细则。 本实验共设置8种处理，每种处理均设置6次生物学重复，播种方案如下： 1. 匍匐冰草（Agropyron repens）单作群落 2. 小须芒草（Schizachyrium scoparium）单作群落 3. 北美乔松（Pinus strobus）单作群落 4. 椭圆叶栎（Quercus ellipsoidalis）单作群落 5. 半区种植匍匐冰草+椭圆叶栎 6. 半区种植匍匐冰草+北美乔松 7. 半区种植小须芒草+椭圆叶栎 8. 半区种植小须芒草+北美乔松 竞争样地采用分区设计：一半区域通过播种方式引入入侵种群，另一半则通过幼苗实现入侵。对于处理5至8，随机选取样地的左侧或右侧区域进行林木种子播种。整个生长季均对样地进行灌溉，以避免水分成为限制性资源。