Abstract The main aim of turfgrass fertilization is to maintain high turf quality and obtain proper turf colour. Fertigation has been recognized as the best fertilization method for proper turfgrass nutrition and for minimizing nitrogen leaching. The aim of this study was to determine the optimum fertilizer rate and frequency for obtaining high-quality turfgrass and minimizing nutrient losses using a fertigation system. Lysimeter experiment was conducted on perennial ryegrass and Kentucky bluegrass mixture in 2016-2018. Three different fertigation rate treatments were applied: 60, 120, and 240 kg N ha−1 (NPK). Fertigation was applied at three intervals: 2, 4 and 8 days between fertigation (DBF). A control treatment with granular fertilizers (CTR) was also applied. The following turfgrass parameters were scored: leaf texture, overall appearance, turf cover and turfgrass colour. Additionally, colour was measured using a spectrophotometer. The colour parameters were expressed using the CIELAB colour system. Leached water samples were taken every two weeks during the vegetation period. The contents of the available forms of selected macro- and microelements (N, P, K, Mg, Ca, Na, Zn, Cu, Mn and Fe) were determined. The fertigation parameters, nutrient rate and interval between fertigation, significantly affected the contents in leachate of most nutrients and metals, except those of N-NH4, Na and Zn. Fertigation resulted in significantly lower N-NO3 losses in comparison with those under CTR. Higher rates of nutrients in fertigation solution resulted in increased N-NO3 content in leachate. The same effect was observed for P, Mg, K, Ca and Cu. The fertigation interval only affected P losses. The lowest P content in leachate was observed in the 2DBF treatment, and the P content in leachate increased as the intervals increased. The fertigation interval did not affect the leaching of any other nutrient. However, a significant difference in leachate content was observed between the CTR with granular fertilizers and fertigation. This effect was observed for N-NO3, K, Ca, Mn and Cu. A significantly higher content of all these nutrients was observed in leachate from the CTR treatment than in that from the fertigation treatments. Fertigation resulted in darker grass leaves in comparison with those under CTR. Higher fertigation rates resulted in darker leaves with higher green hue content than those at lower rates. There were no differences in colour hue in turfgrass fertigated at different time intervals. Turfgrass quality was affected by the fertigation rate and interval. This effect was significant for overall appearance, turf colour and leaf texture, but not for turf cover. The highest mean quality score was obtained at 240NPK, and the lowest was obtained at 60NPK. The optimal fertigation parameters for reduced nutrient losses and high turfgrass quality were calculated to be the 60NPK fertigation level at a fertigation interval of 4.4 days.

中文翻译：

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草坪施肥率和频率的优化

摘要 草坪施肥的主要目的是保持较高的草坪质量和获得合适的草坪颜色。施肥已被公认为适当的草坪营养和最大限度地减少氮浸出的最佳施肥方法。本研究的目的是确定最佳施肥量和施肥频率，以使用灌溉施肥系统获得优质草坪并最大程度地减少养分损失。2016-2018年对多年生黑麦草和肯塔基兰草混合物进行了蒸渗仪实验。应用了三种不同的施肥率处理：60、120 和 240 kg N ha-1 (NPK)。灌溉施肥按三个时间间隔进行：施肥间隔 (DBF) 的 2、4 和 8 天。还使用颗粒肥料 (CTR) 进行对照处理。对以下草坪草参数进行评分：叶片质地、整体外观、草皮覆盖物和草皮颜色。此外，使用分光光度计测量颜色。颜色参数使用 CIELAB 颜色系统表示。在植被期间每两周采集一次浸出水样品。确定了选定的宏观和微量元素（N、P、K、Mg、Ca、Na、Zn、Cu、Mn 和 Fe）的可用形式的含量。除N-NH4、Na和Zn外，施肥参数、养分率和施肥间隔对渗滤液中大多数养分和金属的含量有显着影响。与 CTR 相比，施肥导致 N-NO3 损失显着降低。灌溉施肥溶液中较高的养分比例导致渗滤液中 N-NO3 含量增加。对 P、Mg、K、Ca 和 Cu 观察到相同的效果。施肥间隔仅影响磷损失。2DBF 处理渗滤液中磷含量最低，渗滤液中磷含量随着间隔的增加而增加。施肥间隔不影响任何其他养分的浸出。然而，在使用颗粒肥料和施肥的 CTR 之间观察到渗滤液含量的显着差异。对于 N-NO3、K、Ca、Mn 和 Cu，观察到了这种效应。在来自 CTR 处理的渗滤液中观察到所有这些营养素的含量显着高于来自灌溉施肥处理的渗滤液。与 CTR 下的相比，施肥导致草叶颜色更深。与低施肥量相比，更高的施肥量导致叶片颜色更深，绿色色调含量更高。在不同时间间隔施肥的草坪草的色调没有差异。草坪质量受施肥率和施肥间隔的影响。这种影响对整体外观、草皮颜色和叶子质地很重要，但对草皮覆盖物没有影响。在 240NPK 处获得最高的平均质量评分，在 60NPK 处获得最低的平均质量评分。减少养分损失和提高草坪质量的最佳施肥参数计算为 60NPK 施肥水平，施肥间隔为 4.4 天。