Dairy farmers in the northeast face challenges in the application of manure in fall and on-time planting of cool-season grasses to maximize recovery of residual N and nutrients released from fall applied manure. Ammonia emission from animal manure is a serious environmental concern and can be reduced if cover crop is integrated in the farming system. On-time planting of cover crops can reduce ammonia volatilization from fall, surface-applied manure, and prevents N loss to leaching. A two-year study was conducted in 2015 and 2016 to investigate if time of planting of winter annual rye (Secale cereale L.) along with late fall application of manure when air temperature is low can influence ammonia emission and preserve nitrogen (N) to meet the N requirement of forage rape. Three planting dates (16 September, 30 September, and 14 October) of rye cover crop with two manure application treatments including late-fall application and no manure were assessed for mitigating ammonia volatilization, and also yield and recovery of N by forage rape (Brassica napus L.). The highest rates of ammonia volatilization were detected in the first 24 hours after manure spreading regardless of the treatment. The result indicated that cover crop use significantly limited volatilization compared with no cover crop. The earliest planting date produced 3823 kg ha⁻¹ dry matter of winter rye cover crop that was 16 and 35 percent higher than second and third dates of planting, respectively. The manured cover crop accumulated 132 kg N ha⁻¹ when planted early. However, biomass yield of forage rape was more when planted after all cover crop treatments with manure application. Prior to forage planting, the nitrate-N content in all three soil depths (0–20, 20–40, and 40–60 cm) in the plots with manure was higher than plots with no manure. No significant differences in forage rape yield was detected among winter rye planting dates; however, forage rape planted after winter rye was higher than after no-cover crop. The results of this study suggest that when immediate incorporation of manure into soil is not feasible, establishing cover crop early and then applying manure in the late fall, is a practical management to limit nonpoint source pollution from ammonia loss.

中文翻译：

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冬季年度黑麦播种期对深秋地表施肥氮素回收和氨挥发的影响

东北的奶农在秋季施用肥料和及时种植凉季草时面临着挑战，以最大程度地回收秋季施用的肥料中残留的氮和养分。动物粪便中的氨排放是一个严重的环境问题，如果将耕作作物整合到耕作系统中，则可以减少氨排放。适时种植有盖作物可以减少氨气从秋天挥发，表面施肥，并防止氮素流失。在2015年和2016年进行了为期两年的研究，以调查冬季一年生黑麦（Secale谷物L.）以及气温低时晚晚施肥会影响氨的排放并保留氮（N）以满足饲用油菜对氮的需求。对黑麦覆盖作物的三个播种日期（9月16日，9月30日和10月14日）进行了评估，以评估其减缓氨气挥发以及通过饲用油菜（甘蓝型油菜）的产量和氮素的回收，其中包括晚施用和不施肥两种肥料。napus L.）。无论采用何种处理方法，在撒肥后的最初24小时内，氨挥发的速率最高。结果表明，与无遮盖作物相比，遮盖作物的使用显着限制了挥发。最早的播种日期为3823 kg公顷^-1冬季黑麦覆盖作物的干物质分别比第二和第三播种日期高16％和35％。覆盖的肥料作物累积了132 kg N ha ^-1早种时。但是，在所有施用粪肥的覆盖作物处理之后进行种植时，播种油菜的生物量产量更高。在进行牧草种植之前，有肥料的地块在所有三个土壤深度（0-20、20-40和40-60厘米）中的硝态氮含量都高于没有肥料的地块。在冬季黑麦播种日期之间，未发现饲用油菜产量有显着差异。但是，冬季黑麦后播种的牧草强于无覆盖作物后的播种。这项研究的结果表明，当将肥料立即掺入土壤不可行时，应尽早建立覆盖作物，然后在秋季后期施用肥料，这是限制氨气流失面源污染的一种可行方法。