Cover crop mixture expression

The purpose of this data set was to research what factors might influence cover crop mixture expression, as many ecosystem services from cover crops are determined by the plant growth and mixture composition. Biomass was measured of cover crop mixtures of the same seeding mix, but planted in 2 different years across 9 locations PA, and NY, USA. In particular, examing 2 factors that may impact mixture expression, soil inorganic N (soil iN) availablity and growing degree days (GDD). In addition, at a research farm in PA mixture expression was measured across a gradient of GDD and soil inorganic N (soil iN) availablity resulting from varied planting dates and N fertilizer addition. We measured fall and spring biomass of a standard five-species mixture of canola (Brassica napus L.), Austrian winter pea (Pisum sativum L), triticale (x Triticosecale Wittm.), red clover (Trifolium pratense L.) and crimson clover (Trifolium incarnatum L.) . Farmers seeded the standard mixture and a “farm-tuned” mixture of the same five species with component seeding rates adjusted to achieve farmer-desired services. Surface soil inorganic N was also measured.