Fertilizer N losses from agricultural systems have economic and environmental implications. Soil amendment with high C materials, such as coal char, may mitigate N losses. Char, a coal combustion residue, obtained from a sugar factory in Scottsbluff, NE, contained 29% C by weight. A 30-d laboratory study was conducted to evaluate the effects of char addition on N losses via nitrous oxide (N2 O) emission, ammonia (NH3 ) volatilization, and nitrate (NO3 -N) leaching from fertilized loam and sandy loam soils. Char was applied at five different rates (0, 6.7, 10.1, 13.4, and 26.8 Mg C ha-1 ; char measured in C equivalent) to soils fertilized with urea ammonium nitrate (UAN) at 200 kg N ha-1 . In addition, there were two negative-UAN control treatments: no char (no UAN) and char at 26.8 Mg C ha-1 (no UAN). Treatment applied at 6.7 and 10.1 Mg C ha-1 in fertilized sandy loam reduced NH3 volatilization by 26-37% and at 6.7, 10.1, and 13.4 Mg C ha-1 in fertilized loam soils by 24% compared with no char application. Nitrous oxide emissions and NO3 -N leaching losses were greater in fertilized compared with unfertilized soil, but there was no effect of char amendment on these losses. Because NO3 -N leaching loss was greater in sandy loam than in loam, soil residual N was twofold higher in loam than in sandy loam. This study suggests that adding coal char at optimal rates may reduce agricultural reactive N to the atmosphere by decreasing NH3 volatilization from fertilized soils.

中文翻译：

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地表施用煤焦的最佳用量减少土壤氨挥发损失

农业系统中的肥料氮损失具有经济和环境影响。使用高碳材料（如煤焦）进行土壤改良可以减轻氮损失。炭是一种煤燃烧残渣，从内布拉斯加州斯科茨布拉夫的一家糖厂获得，按重量计含有 29% 的碳。进行了一项为期 30 天的实验室研究，以评估炭添加对通过一氧化二氮 (N2 O) 排放、氨 (NH3) 挥发和从施肥壤土和沙壤土中浸出的硝酸盐 (NO3 -N) 造成的 N 损失的影响。以 5 种不同的比率（0、6.7、10.1、13.4 和 26.8 Mg C ha-1 ；以 C 当量测量的炭）向用尿素硝酸铵 (UAN) 施肥的土壤中施用炭，浓度为 200 kg N ha-1。此外，还有两种负 UAN 对照处理：无炭（无 UAN）和 26.8 Mg C ha-1 的炭（无 UAN）。在 6.7 和 10 处进行处理。与不施炭相比，施肥砂质壤土中的 1 Mg C ha-1 减少了 26-37% 的 NH3 挥发，施肥壤土中的 6.7、10.1 和 13.4 Mg C ha-1 减少了 24%。与未施肥的土壤相比，施肥的一氧化二氮排放和 NO3 -N 浸出损失更大，但炭改良剂对这些损失没有影响。由于砂壤土中NO3-N的淋失损失大于壤土，因此壤土中的土壤残留氮比砂壤土高两倍。这项研究表明，以最佳速率添加煤焦可以通过减少施肥土壤中的 NH3 挥发来减少大气中的农业活性氮。与未施肥的土壤相比，施肥的一氧化二氮排放和 NO3 -N 浸出损失更大，但炭改良剂对这些损失没有影响。由于砂壤土中NO3-N的淋失损失大于壤土，因此壤土中的土壤残留氮比砂壤土高两倍。这项研究表明，以最佳速率添加煤焦可以通过减少施肥土壤中的 NH3 挥发来减少大气中的农业活性氮。与未施肥的土壤相比，施肥的一氧化二氮排放和 NO3 -N 浸出损失更大，但炭改良剂对这些损失没有影响。由于砂壤土中NO3-N的淋失损失大于壤土，因此壤土中的土壤残留氮比砂壤土高两倍。这项研究表明，以最佳速率添加煤焦可以通过减少施肥土壤中的 NH3 挥发来减少大气中的农业活性氮。