Soil nitrogen: Plant Competition Under Different Nitrogen Levels:A Garden Experiment

This garden plot experiment is located next to the E026 gardens in Field E (Old Field 44). This garden contained monocultures of major grass species from across the grassland biome of North America, and also 3 legume species (E070). The design and purpose were similar to E026, except the plots were larger. The basic experimental design consisted of growing plants in monoculture and in various competitive combinations on each of 14 different soil mixtures. In 1988 a bulldozer was used to remove 30 inches of top soil at the site. To each plot a certain amount of black dirt, ranging from 0.3 inches to 10 inches, was added. Total carbon ranged from 0.1928% to 5.63134% and total nitrogen ranged from 0.0158% to 0.4591%. The exact amounts of black soil added to each plot are described in the field operations.

Equal amounts of MgSO4, CaCO3, P2O5 \

本园田试验设置于E区（原44号地块）的E026园区旁。该园区种植了北美草原生物群区主要草本物种的单一种植群落，同时包含3种豆科植物（E070）。本试验的设计与目标与E026相似，仅地块规模更大。基础试验方案为：在14种不同的土壤混合基质上，分别以单一种植及多种竞争组合的方式栽培植物。1988年，研究团队使用推土机移除了该场地30英寸厚的表层土壤。随后向每个地块施加了厚度介于0.3英寸至10英寸的黑土。试验样地的总碳含量范围为0.1928%至5.63134%，总氮含量范围为0.0158%至0.4591%。各地块所施加黑土的具体用量详见田间作业记录。各地块均施加等量的硫酸镁（MgSO4）、碳酸钙（CaCO3）及五氧化二磷（P2O5）