Fertilizer applications on lawns have raised environmental concerns in many Canadian municipalities. In this greenhouse study, NO₃–N leaching losses from Kentucky bluegrass (Poa pratensis L.) lawns were evaluated on two soils (a schist loam and a clay loam) and on a sand/peat moss rootzone mix (80% sand, 20% peat moss). Eight different fertilizer N sources (urea, Polyon 8 and 12-wk release, Duration 45 and 90-d release, XCU, corn gluten meal, and UFLEXX) were assessed at five application rates (25–200 kg N ha^–1 yr^–1) and two application frequencies over two 8-wk trials. Average NO₃–N concentration in leachate were measured at levels of 3.5, 7.4, and 1.4 mg L^–1 from turf grown in loam, clay, and sand respectively, but losses from loam and clay were mostly affected by N mineralization from organic matter. Turf fertilized with rates ≥100 kg N ha^–1 generally resulted in acceptable visual quality on both soils, but coated-urea fertilizers were more efficient to reduce leaching. In sand, UFLEXX and urea (150 and 200 kg N ha^–1) as well as XCU (200 kg N ha^–1) resulted in higher NO₃–N losses, varying from 8.5 to 23.7 mg L^–1, and losses from other N sources were consistently below 3 mg L^–1. Our results show that it is possible to maintain good quality turfgrass while keeping low NO₃–N leaching losses (i.e., <4 mg L^–1) in loam, clay, and sand by selecting the ideal combination of N source, N rate, and application frequency.

中文翻译：

---

减少住宅草坪草坪施肥的硝酸盐浸出损失

在草坪上施肥引起了加拿大许多城市的环境问题。在这项温室研究中，肯塔基早熟禾 ( Poa pratensis L.) 草坪的NO ₃ -N 浸出损失在两种土壤（片壤土和粘壤土）和沙子/泥炭藓根区混合物（80% 沙子，20 ％ 泥炭藓）。以五种施用率（25-200 kg N ha ^–1  yr ^{– 1} ) 和两个 8 周试验中的两个应用频率。渗滤液中平均 NO ₃ –N 浓度分别为 3.5、7.4 和 1.4 mg L ^–1分别来自壤土、粘土和沙子中生长的草皮，但壤土和粘土的损失主要受有机质中 N 矿化的影响。以≥100 kg N ha ^{–1 的}比例施肥的草坪通常会在两种土壤上产生可接受的视觉质量，但包膜尿素肥料更有效地减少浸出。在沙子中，UFLEXX 和尿素（150 和 200 kg N ha ^–1）以及 XCU（200 kg N ha ^–1）导致更高的 NO ₃ –N 损失，从 8.5 到 23.7 mg L ^–1不等，从其他氮源始终低于 3 mg L ^–1。我们的结果表明，在保持低 NO ₃ –N 浸出损失（即 <4 mg L^–1 ) 在壤土、粘土和沙子中，通过选择氮源、施氮量和施用频率的理想组合。