ABSTRACT

Nitrification inhibitors can reduce nitrous oxide (N₂O) emissions and nitrate leaching losses from agricultural soils. Technologies have been developed to detect and target urine patches for inhibitor application, thereby reducing the total amount of inhibitor used. However, in practice there will be a time delay between the urine deposition and inhibitor application, potentially leading to physical separation of the inhibitor and urine that could reduce the effectiveness of the inhibitor compared to when the inhibitor and urine are well mixed. In this study, 2L of cattle urine was applied on two soil types in New Zealand. Twenty-four hours later the inhibitor dicyandiamide (DCD) was applied. The soil was sampled within 18 h and again after a rainfall event. DCD concentrations were measured in the 0–20 mm, 20–50 mm, and 50–100 mm depth ranges. The movement of the urine in the soil was simulated using the HYDRUS model. Before the rain most of the DCD was within the top 20 mm and intercepted 21–29% of the urine. After the rainfall event the DCD concentration decreased in the 0–20 mm layer and increased in the 20–50 mm layer. 18–55% or 63-79% of the urine was intercepted by DCD at a concentration of >4 ppm using the measured and modelled DCD concentrations, respectively. However, only 0–27% or 0-53% of the urine was intercepted at a DCD concentration >10 ppm.

摘要

硝化抑制剂可以减少一氧化二氮（N ₂O) 农业土壤的排放和硝酸盐淋失损失。已经开发了用于检测和靶向用于抑制剂应用的尿片的技术，从而减少使用的抑制剂的总量。然而，在实践中，尿液沉积和抑制剂应用之间会有时间延迟，可能导致抑制剂和尿液的物理分离，与抑制剂和尿液充分混合时相比，这可能会降低抑制剂的有效性。在这项研究中，将 2L 牛尿施用于新西兰的两种土壤类型。24 小时后，使用抑制剂双氰胺 (DCD)。土壤在 18 小时内取样，并在降雨事件后再次取样。在 0-20 mm、20-50 mm 和 50-100 mm 深度范围内测量 DCD 浓度。使用 HYDRUS 模型模拟尿液在土壤中的运动。在下雨之前，大部分 DCD 都在顶部 20 毫米内，截获了 21-29% 的尿液。降雨事件后，DCD 浓度在 0-20 mm 层降低，在 20-50 mm 层增加。分别使用测量和模拟的 DCD 浓度，18-55% 或 63-79% 的尿液被浓度 >4 ppm 的 DCD 拦截。然而，只有 0-27% 或 0-53% 的尿液在 DCD 浓度 >10 ppm 时被截留。分别使用测量和模拟的 DCD 浓度为 4 ppm。然而，只有 0-27% 或 0-53% 的尿液在 DCD 浓度 >10 ppm 时被截留。分别使用测量和模拟的 DCD 浓度为 4 ppm。然而，只有 0-27% 或 0-53% 的尿液在 DCD 浓度 >10 ppm 时被截留。