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的E055号区域旁。将1.75英寸厚的黑土添加至CCNHA沙质土壤中，搭建4块规格为10英尺×54英尺的样地。随后对土壤进行旋耕，并安装铝制挡边（aluminum flashing）以勾勒样地边界，将其划分为48块5英尺×9英尺的次级样地。每年5月初与6月末，向各块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，请参见施肥细则（fertilization details）。
本实验共设置8种处理，每种处理均设置6次生物学重复，具体播种方案如下：
1. 匍匐冰草（Agropyron repens）单优群落
2. 小须芒草（Schizachyrium scoparium）单优群落
3. 北美乔松（Pinus strobus）单优群落
4. 椭圆叶栎（Quercus ellipsoidalis）单优群落
5. 半区混播匍匐冰草与椭圆叶栎
6. 半区混播匍匐冰草与北美乔松
7. 半区混播小须芒草与椭圆叶栎
8. 半区混播小须芒草与北美乔松
竞争样地被拆分，一半通过种子定植，另一半将通过幼苗定植。对于处理5至8，随机选取样地的左侧或右侧区域播种乔木种子。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。