Conventional row crop farming in the United States is associated with multiple environmental challenges including soil and water degradation and decreased biodiversity. Sustainable agriculture advocates have encouraged agroforestry, or the integration of woody perennial crops like trees and shrubs into agricultural systems, to ameliorate environmental challenges and provide on-farm benefits. Despite promised environmental bene...

Quantifying nutrient limitation of primary productivity is a fundamental task of terrestrial ecosystem ecology, but in a high carbon dioxide environment it is even more critical that we understand potential nutrient constraints on plant growth. Ecologists often manipulate nutrients with fertilizer to assess nutrient limitation, yet for a variety of reasons, nutrient fertilization experiments are either impractical or incapable...