Adequate fertility combined with effective weed management is important in maximizing corn (Zea mays L.) grain yield. Corn uptake of nitrogen (N) is dependent upon many factors including weed species and density and the rate and formulation of applied N fertilizer. Understanding interactions among corn, applied N, and weeds is important in developing management strategies. Field studies were conducted in North Carolina to compare corn and weed responses to urea ammonium nitrate (UAN), sulfur-coated urea (SCU), and composted poultry litter (CPL) when a mixture of Palmer amaranth (Amaranthus palmeri S. Wats.) and large crabgrass (Digitaria sanguinalis L.) was removed with herbicides at heights of 8 or 16 cm. These respective removal timings corresponded with 22 and 28 days after corn planting or V2 and V3 stages of growth, respectively. Differences in N content in above-ground biomass of corn were noted early in the season due to weed interference but did not translate into differences in corn grain yield. Interactions of N source and N rate were noted for corn grain yield but these factors did not interact with timing of weed control. These results underscore that timely implementation of control tactics regardless of N fertility management is important to protect corn grain yield.
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机译：充分的肥力和有效的杂草处理对最大限度地提高玉米（Zea mays L.）谷物的产量至关重要。玉米对氮（N）的吸收取决于许多因素，包括杂草的种类和密度以及施用的氮肥的比例和配方。了解玉米，施用的氮和杂草之间的相互作用对于制定管理策略很重要。在北卡罗来纳州进行了田间研究，比较了玉米和杂草对混合使用Palm菜a菜（Amaranthus palmeri S. Wats）的尿素硝酸铵（UAN），硫包膜尿素（SCU）和堆肥家禽垫料（CPL）的反应。然后用高度为8或16厘米的除草剂去除大的马尾草（Digitaria sanguinalis L.）。这些分别的清除时间分别对应于玉米播种后第22天和28天，或分别处于生长的V2和V3阶段。由于杂草的干扰，在季节的早期发现了玉米地上生物量中氮含量的差异，但并未转化为玉米籽粒产量的差异。玉米籽粒产量中氮源和氮素含量之间存在交互作用，但这些因素与杂草防治时机不相关。这些结果强调，无论氮肥管理如何，及时实施控制策略对保护玉米籽粒产量都很重要。
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