Root carbon/nitrogen data: 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园区内E055号样地旁侧。向CCNHA砂质土壤中添加1.75英寸厚的黑土，搭建4块10英尺×54英尺的大样地。随后对土壤进行旋耕处理，并安装铝制挡边以划分样地边界，最终将4块大样地拆分为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）。关于所施肥料的详细说明，请参阅施肥细则。本实验设置以下8种处理方式，每种处理均设置6次重复： 1. 匍匐冰草（Agropyron repens）单作群落 2. 须芒草（Schizachyrium scoparium）单作群落 3. 北美白松（Pinus strobus）单作群落 4. 椭圆叶栎（Quercus ellipsoidalis）单作群落 5. 半侧种植匍匐冰草+椭圆叶栎 6. 半侧种植匍匐冰草+北美白松 7. 半侧种植须芒草+椭圆叶栎 8. 半侧种植须芒草+北美白松 竞争类样地均进行对半划分：一半通过种子入侵构建群落，另一半将通过幼苗定植实现入侵。对于处理5至8，随机选取样地的左侧或右侧区域种植乔木种子。整个生长季对样地进行补水，以避免水分成为限制因子。