Modeling the Interaction of Plastic Film Mulch and Potato Canopy Growth with Soil Heat Transport in a Semiarid Area

Plastic film mulch is an important agricultural technology to reduce water evaporation and modify the soil thermal conditions for crop production. The optical properties of plastic film mulch and the crop canopy growth are both key factors impacting soil heat transport in the soil-film-canopy-atmosphere ecosystem. In this study, a process-oriented model was developed to better understand the interaction among the plastic film mulch, potato (Solanum tuberosum L.) canopy growth, and soil thermal conditions. Canopy growth, photosynthetically active radiation transmittance, net radiation, soil heat flux, and temperature were monitored in a two-year plastic mulch field experiment in Wuwei (Gansu Province, China). Results showed that the simulation of daily soil surface temperature had a good performance with 2.8 and 1.5 degrees C of root mean square error (RMSE) for the transparent film mulch (TM) and black film mulch (BM), respectively. Moreover, the simulation of the daily net radiation and soil heat flux model indicated reasonable fluctuations with potato phenological development with the daily R-2 ranging from 0.89 to 0.98 in 2014 and 2015 for the TM and BM treatments. It was shown that the canopy temperature under BM was greater than that in TM treatment, and the maximum value difference could be up to 7 degrees C during the early potato growing period, which implied that the BM may perform better in modifying the canopy thermal condition. The model could provide heat distribution information for plastic film choosing in potato field to avoid heat stress.