Short‐Term Soil Responses to Late‐Seeded Cover Crops in a Semi‐Arid Environment

Abstract

Cover crops can expand ecosystem services, though sound management recommendations for their use within semiarid cropping systems is currently constrained by a lack of information. This study was conducted to determine agroecosystem responses to late‐summer seeded cover crops under no‐till management, with particular emphasis on soil attributes. Short‐term effects of late‐summer seeded cover crops on soil water, available N, near‐surface soil quality, and residue cover were investigated during three consecutive years on the Area IV Soil Conservation Districts Research Farm near Mandan, ND. Mean aboveground cover crop biomass was highly variable across years (1430, 96, and 937 kg ha−1in 2008, 2009, and 2010, respectively), and was strongly affected by precipitation received within 14 d following cover crop seeding. During years with appreciable biomass production (2008 and 2010), cover crops significantly reduced available N in the 0.9‐m depth the following spring (P= 0.0291 and 0.0464, respectively). Cover crop effects on soil water were subtle, and no differences in soil water were found between cover crop treatments and a no cover crop control before seeding cash crops the following spring. Late‐summer seeded cover crops did not affect near‐surface soil properties or soil coverage by residue. Soil responses to late‐summer seeded cover crops did not differ between cover crop mixtures and monocultures. Late‐summer seeded cover crops may enhance ecosystem services provided by semiarid cropping systems through biomass production and N conservation, though achieving these benefits in a consistent manner appears dependent on timely precipitation following cover crop seeding.