Simulating soil surface temperature under plastic film mulching during seedling emergence of spring maize with the RZ–SHAW and DNDC models

Authors: ZHOU, LIFENG - Chinese Academy Of Sciences; ZHAO, WENZHI - Chinese Academy Of Sciences; HE, JIANQIANG - Northwest Agricultural & Forestry University; Flerchinger, Gerald; FENG, HAO - Northwest Agricultural & Forestry University

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2019
Publication Date: 12/6/2019
Citation: Zhou, L., Zhao, W., He, J., Flerchinger, G.N., Feng, H. 2019. Simulating soil surface temperature under plastic film mulching during seedling emergence of spring maize with the RZ–SHAW and DNDC models. Soil & Tillage Research. 197. https://doi.org/10.1016/j.still.2019.104517.
DOI: https://doi.org/10.1016/j.still.2019.104517

Interpretive Summary: Plastic film mulching has been widely used to increase soil temperature in areas with a cold spring, thereby stimulating plant growth. Correct simulation of mulched soil surface temperature is important to simulate growth of spring crops in order to evaluate management options with regard to optimal use and coverage of plastic film. Two crop growth models were evaluated for simulating near-surface temperature under plastic mulch during seedling emergence of spring maize. Models included the Root Zone Water Quality-Simultaneous Heat and Water (RZ-SHAW) coupled model and the Denitrification-Decomposition (DNDC) model. Full coverage and 60% coverage of plastic film mulch enhanced daily soil temperature compared with no plastic mulch. The RZ-SHAW model was robust for simulating near-surface temperature under plastic film mulch condition while the DNDC model performed poorly. Results suggested that the DNDC model could be improved by imbedding the SHAW model routines into DNDC for a sufficiently precise simulation of soil temperature.

Technical Abstract: Plastic film mulching has been widely used to increase soil temperature in areas with a cold spring. Correct simulation of mulched soil surface temperature is important for initial growth of spring crops. The hybrid Root Zone Water Quality-Simultaneous Heat and Water (RZ-SHAW) model and the Denitrification-Decomposition (DNDC) model use different approaches to quantify the effect of plastic film mulching on soil temperature. A two-year field study was conducted to compare the performance of the RZ-SHAW model and DNDC model for simulating the 5-cm soil temperature (T5) under varying plastic film mulching coverages during seedling emergence of spring maize. Three treatments were used in this study: no mulching (PM0), full plastic film mulch (PM100), and partial plastic film mulch with 60% coverage, i.e. 60 cm width of plastic every meter (PM60). Compared with no mulching, PM100 and PM60 treatments enhanced daily maximum and average T5 while not affecting the diurnal sinusoidal phase change of T5. The PM60 treatment showed a weaker effect on T5 enhancement than the PM100 treatment. The RZ-SHAW model was robust for T5 simulation under mulching condition while the DNDC model failed to predict T5 for mulched soil. Employing Tms (air temperature between plastic film and soil surface) to replace soil surface temperature may be one reason for the poor T5 simulation of DNDC in mulched plots. By contrast, the RZ-SHAW model ran a complete calculation for heat and vapour transfer within the mulched layer, which robustly simulated atmosphere–soil surface temperature gradient in the plant canopy, surface covering, and soil surface in a broader range of climatic conditions. Additionally, the longwave radiation reflected back to the soil surface by the plastic, which was not considered by DNDC model, was important and enhanced T5 simulation performance for RZ-SHAW under mulching condition. It suggested to imbed the SHAW module into DNDC for a sufficiently precise simulation of soil temperature and gas emission.