A better understanding of the fate and transport of fertilizer nitrogen (N) is critical to maximize crop yields and minimize negative environmental impacts. Plastic film mulching is widely used in drylands to increase soil water use efficiency and crop yields, but the effects on fertilizer N use efficiency need to be evaluated. A field experiment with ¹⁵N-urea (260 kg N ha⁻¹) was conducted to determine the fate and transport of fertilizer N in a ridge-furrow system with plastic film mulched ridge (Plastic), compared with a flat system without mulching (Open). In the Plastic, the ¹⁵N-urea was applied to the ridge only (Plastic-Ridge), or to the furrow only (Plastic-Furrow). Maize grain yield and net economic benefit for Plastic were significantly higher (by 9.7 and 8.5%, respectively) than those for Open. Total plant ¹⁵N uptake was 72.5% greater in Plastic compared with Open, and ¹⁵N was allocated mostly to the grain. Losses of the applied urea-N were 54.5% lower in Plastic and much more residual ¹⁵N was recovered in 0–120 cm soil compared with Open (42.7 and 26.8% of applied ¹⁵N, respectively). Lateral N movements from furrow to ridge and from ridge to furrow were observed and attributed to lateral movement of soil water due to microtopography of ridges and furrows and uneven soil water and heat conditions under mulching and plant water uptake. The ridges were the main N fertilizer source for plant uptake (96.5 and 3.5% of total N uptake in Plastic from ridge and furrow, respectively) and the furrow was the main source of N losses (78.6 and 21.4% of total N losses in Plastic from furrow and ridge, respectively). Gas emissions, especially ammonia volatilization was probably the main N loss in furrow. Thus, appropriately localized N application – into the ridges, and management strategies should be designed for Plastic to maximize N use efficiency by crops, decrease N gas losses and maintain sustainable agricultural systems in drylands.

更好地了解化肥氮 (N) 的归宿和运输对于最大限度地提高作物产量和最大限度地减少负面环境影响至关重要。地膜覆盖广泛应用于旱地，以提高土壤水分利用效率和作物产量，但对肥料氮利用效率的影响需要评估。^进行了15 N-尿素（260 kg N ha ^-1 ）的田间试验，以确定采用塑料薄膜覆盖的垄沟系统（塑料）中肥料氮的归宿和运输，并与没有覆盖的平坦系统进行比较（打开）。在塑料领域，¹⁵N-尿素仅施用于田埂（塑料-山脊），或仅施用于犁沟（塑料-犁沟）。塑料种植的玉米籽粒产量和净经济效益显着高于开放种植（分别提高 9.7% 和 8.5%）。^{与开放植物相比，塑料植物对15} N 的总吸收量高出 72.5%，并且¹⁵ N 大部分分配给了谷物。与开放土壤相比，塑料中施用的尿素-N 损失降低了 54.5%，并且在 0-120 cm 土壤中回收了更多的残留^{15 N（施用的15 N分别为 42.7% 和 26.8%）。}分别为 N）。观察到从犁沟到垄和从垄到犁沟的氮素横向移动，并将其归因于由于垄和犁沟的微地形以及覆盖和植物吸水下不均匀的土壤水和热条件导致的土壤水的横向移动。垄是植物吸收氮肥的主要来源（分别占垄和沟中塑料总氮吸收量的 96.5% 和 3.5%），沟是氮损失的主要来源（分别占塑料中总氮损失的 78.6% 和 21.4%）。分别来自沟和脊）。气体排放，特别是氨挥发可能是沟内氮素损失的主要形式。因此，应适当局部施氮——进入田埂，并为塑料设计管理策略，以最大限度地提高作物的氮利用效率，