Winter malt barley growth, yield, and quality following leguminous cover crops in the Northeast United States

There is growing interest in malt barley (Hordeum vulgare L.) production in the Northeast United States. This crop must meet high quality standards for malting but can command a high price if these quality thresholds are met. A two-year field experiment was conducted from 2015–2017 to evaluate the impact of two leguminous cover crops, sunn hemp (Crotalaria juncea L.) and crimson clover (Trifolium incarnatum L.), on subsequent winter malt barley production. Four cover crop treatments –sunn hemp (SH), crimson clover (CC), sunn hemp and crimson clover mixture (SH+CC), and no cover crop (NC) – were grown before planting barley at three seeding rates (300, 350, and 400 seeds m–2). SH and SH+CC produced significantly more biomass and residual nitrogen than the CC and NC treatments. Higher barley seeding rates led to higher seedling density and winter survival. However, the subsequent spring and summer barley growth metrics, yield, and malt quality were not different in any of the treatments. There is much left to investigate in determining the best malt barley production practices in the Northeast United States, but these results show that winter malt barley can be integrated into crop rotations with leguminous plants without negative impacts on barley growth, yield, and grain quality.

美国东北部地区对啤酒大麦（Hordeum vulgare L.）的种植关注度与日俱增。该作物需满足麦芽加工的严苛品质标准，若达标则可获得较高收购价格。本研究于2015至2017年开展为期两年的田间试验，以评估日光麻（Crotalaria juncea L.）与绛三叶（Trifolium incarnatum L.）两种豆科覆盖作物对后续冬播啤酒大麦种植的影响。试验设置4种覆盖作物处理：日光麻（SH）、绛三叶（CC）、日光麻与绛三叶混播（SH+CC）以及无覆盖作物（NC），并在大麦播种前以3种播种密度（300、350、400粒·m⁻²）种植覆盖作物。结果表明，日光麻单播及混播处理的生物量与残留氮含量均显著高于绛三叶单播与无覆盖作物处理；提高大麦播种密度可提升幼苗密度与越冬存活率。但各处理间后续春夏季大麦生长指标、产量及麦芽品质均无显著差异。尽管美国东北部啤酒大麦的最优种植模式仍有待进一步探究，但本试验结果显示，冬播啤酒大麦可与豆科植物纳入轮作体系，且不会对大麦生长、产量及籽粒品质产生负面影响。