Short-term grassland set-asides (GLSA) have been incorporated into intensive annual crop rotations to improve soil quality. The legacy of the GLSA to subsequent annual crops, however, is not well understood. The objective of this study was to determine the impacts of 3-year-old GLSA on nitrogen (N) dynamics and the yield of the subsequent cash crop. A regional analysis was conducted over two years, utilizing eight production fields transitioning from GLSA, paired with fields in continuous annual crop rotation (ACR) with matching management. A controlled plot-scale experiment was also conducted on a single 3-year-old GLSA, comparing fertilizer types, rates, and timing of incorporation. In each experiment, soils were sampled every 10–14 days for ammonium (NH₄⁺-N) and nitrate (NO₃⁻-N), along with ion probes, installed near the rooting zone to track plant available nitrogen (PAN) throughout the season. The results from the regional analysis are confounding, in 2015 showing that GLSA supplied an additional 18 kg PAN ha⁻¹ compared to ACR but showed no PAN benefits in 2016. The controlled plot-scale experiment highlighted the importance of fertilizer type to subsequent PAN, showing synthetic treatments consistently supplied more PAN than organic. The results from this study suggest that 3-year-old GLSAs can potentially improve PAN to subsequent crops depending on how they are managed.

中文翻译：

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在不列颠哥伦比亚省的弗雷泽河三角洲并入了三年的老草原后氮的动力学

短期草原定居点（GLSA）已被纳入年度集约农作物轮作中，以改善土壤质量。但是，人们对GLSA对随后的一年生作物的遗留知之甚少。这项研究的目的是确定3年龄的GLSA对氮（N）动态和后续经济作物产量的影响。两年来进行了区域分析，利用了从GLSA过渡的八个生产领域，并与具有匹配管理的连续年度作物轮作（ACR）领域配对。还对一个3岁的GLSA进行了对照样地规模试验，比较了肥料类型，施用量和掺入时间。在每个实验中，每10-14天对土壤中的铵（NH ₄ ⁺ -N）和硝酸盐（NO ₃^- -N），离子探针一起安装在根区附近的整个赛季跟踪工厂速效氮（PAN）。区域分析的结果令人困惑，2015年显示，与ACR相比，GLSA提供了额外的18 kg PAN ha ^-1，但在2016年却没有PAN的收益。可控地块规模试验强调了肥料类型对后续PAN的重要性，表明合成处理始终提供比有机产品更多的PAN。这项研究的结果表明，使用3年的GLSA可以根据管理方式改善后代作物的PAN。