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.

本实验选址于E055邻近的高干扰花园区域。将1.75英寸厚的黑土覆于CCNHA沙质土壤之上，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翻土，并安装铝制围边以划定样地边界，将其分割为48块5英尺×9英尺的小样地。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）与氧化钾（K2O）。有关肥料添加的详细说明，请参阅施肥细则。
针对下述各处理组，每组设置6次重复后进行播种：
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. 半幅区域种植匍匐冰草+椭圆叶栎
6. 半幅区域种植匍匐冰草+北美乔松
7. 半幅区域种植小须芒草+椭圆叶栎
8. 半幅区域种植小须芒草+北美乔松

竞争样地分为两半，一半以种子方式定植，另一半则将以幼苗方式定植。对于处理5至8，随机选取样地的左侧或右侧区域种植树木种子。整个生长季均对样地进行灌溉，以避免水分成为限制因子。