Intercropping planting pattern under plastic film mulching (PFM) has been widely adopted in the arid regions to reduce soil evaporation (E), improve land-use efficiency, and increase crop yield. However, water competition between intercropping components in the soil-plant-atmosphere continuum remains largely unexplored. The evaporation and radiation interception using the neighboring species model (ERIN) can effectively estimate evapotranspiration (ET) in a different intercropping ecosystem. However, the effects of soil surface resistance in the mulching area on ET are not considered in the ERIN model. Thus, the existing ET models do not accurately estimate ET in the intercropping ecosystem with PFM. In this study, we proposed a modified ERIN model (MERIN). In the MERIN model, soil surface resistance in the mulching area was taken into account, and its performance was compared to ERIN and Penman-Monteith (PM) models. These models were validated against observed ET and E using the water balance method and micro-lysimeters in a corn intercropped tomato experiment under high (HI: 30 mm for corn and 22.5 mm for tomato, a locally recommended irrigation depth), medium (MI: 22.5 mm for corn and 16.9 mm for tomato, 25% of HI), and low irrigation depth (LI: 15 mm for corn and 11.25 mm for tomato, 50% of HI) during 2018-2019, respectively. The outcomes of this study showed that the MERIN model could accurately estimate ET and E variation for a corn-tomato intercropping ecosystem under PFM during the entire crop growth season compared to the other examined models. The most intense water competition between corn and tomato was observed in stage II (the elongation and tasseling stages for corn; the flowering and fruiting stages for tomato). T of corn generally was higher than tomato, but an opposite result was also observed in stage II. Additionally, the variation of water competition under different irrigation levels was similar in the intercropping ecosystem. When irrigation depth decreased to 22.5 and 15 mm from 30 mm, average T for corn decreased by 10.7% and 16.3%, respectively, and by 12.9% and 22.4% for tomato, respectively, in both years.

地膜下套作（PFM）种植模式已在干旱地区广泛采用，以减少土壤蒸发（E），提高土地利用效率，增加作物产量。然而，土壤-植物-大气连续体中间作组分之间的水竞争在很大程度上仍未得到探索。使用邻近物种模型 (ERIN) 的蒸发和辐射拦截可以有效地估计不同间作生态系统中的蒸散量 ( ET )。然而，ERIN模型没有考虑覆盖区土壤表面阻力对ET的影响。因此，现有的ET模型不能准确估计ET在具有 PFM 的间作生态系统中。在这项研究中，我们提出了一种改进的 ERIN 模型（MERIN）。在 MERIN 模型中，考虑了覆盖区域的土壤表面阻力，并将其性能与 ERIN 和 Penman-Monteith (PM) 模型进行了比较。这些模型对观察到的验证ET和Ë使用在玉米中的水平衡的方法和微渗漏测定计间作下高番茄试验（HI：30毫米玉米和22.5毫米番茄，本地推荐灌溉深度），中（MI： 2018-2019 年，玉米为 22.5 毫米，番茄为 16.9 毫米，HI 的 25%）和低灌溉深度（LI：玉米 15 毫米，番茄 11.25 毫米，HI 的 50%）。本研究结果表明 MERIN 模型可以准确估计ET与其他研究模型相比，在整个作物生长季节期间 PFM 下玉米 - 番茄间作生态系统的E变化。在第二阶段（玉米的伸长和雄蕊阶段；番茄的开花和结果阶段）观察到玉米和番茄之间最激烈的水分竞争。玉米的T通常高于番茄，但在阶段 II 中也观察到相反的结果。此外，在间作生态系统中，不同灌溉水平下水竞争的变化相似。当灌溉深度从 30 毫米降低到 22.5 和 15 毫米时，玉米的平均T分别下降了 10.7% 和 16.3%，番茄的平均T分别下降了 12.9% 和 22.4%。