Soil water repellency (SWR) is an ubiquitous soil property, that has major effects on surface and subsurface water flow, soil erosion, and therefore also affects plant growth and development. Soil water repellency has been recently observed to decrease summer maize growth, especially when the initial persistence of soil water repellency was high. However, mechanics implicated in maize biomass limitations are still unclear due to limited field observations and measurements of plant water use. This research aims to explain the possible mechanisms that impede the growth of summer maize in water repellent soils by examining soil water content, soil water evaporation and root water uptake (RWU) and comparing the measurements to simulations using HYDRUS-1D. Data from five increasing levels of SWR (CK, WR1, WR2, WR3 and WR4) from a two-year experiment were used. The soil hydraulic parameters described with the van-Genuchten model were calibrated inversely based on the observed volumetric soil water content at 26, 47 and 68 days after sowing (DAS) in 2016 and validated by water content values on 33, 62 and 91 DAS in 2017. The results showed the daily and cumulative RWU values ranked in an order of CK > WR1 > WR2 > WR3 > WR4. The RWU rates and cumulative RWU decreased with an increase of initial water droplet penetration time (persistence), which indicated weaker RWU ability of summer maize in the water repellent treatments. Thirty days after sowing, higher evaporation was observed in water repellent soils compared to CK. Weak RWU of summer maize grown in the water repellent soils and strong soil water evaporation were found. This research demonstrates the possible mechanisms that impede summer maize growth in water repellent soils could include weak RWU and high evaporation.

土壤憎水性（SWR）是一种普遍存在的土壤特性，对地表和地下水流量，土壤侵蚀具有重大影响，因此也影响植物的生长发育。最近已经观察到土壤疏水性降低了夏季玉米的生长，特别是当土壤疏水性的初始持久性很高时。然而，由于有限的实地观察和植物用水量的测量，涉及玉米生物量限制的机制仍不清楚。这项研究旨在通过检查土壤水分，土壤水分蒸发和根系水分吸收（RWU）并将测量结果与使用HYDRUS-1D进行的模拟进行比较，以解释可能在拒水土壤中阻碍夏季玉米生长的机制。来自SWR的五个递增级别的数据（CK，WR1，WR2，WR3和WR4）使用了两年的实验。用van-Genuchten模型描述的土壤水力参数是根据2016年播种后26、47和68天（DAS）的土壤体积含水量进行反标定的，并通过33、62和91 DAS中含水量的值进行了验证。 2017年。结果显示每日和累计RWU值按CK> WR1> WR2> WR3> WR4的顺序排列。随着初始水滴渗透时间（持久性）的增加，RWU率和累积RWU降低，这表明夏季玉米在拒水处理中的RWU能力较弱。播种三十天后，与CK相比，在憎水土壤中观察到更高的蒸发。在憎水土壤中生长的夏玉米RWU较弱，且土壤水分蒸发强烈。