Enhancing greenhouse-grown tomatoes yield through coordinated regulation of light and temperature by a coated five-layer co-extruded film

Controlled environment agriculture (CEA) has gained popularity due to multiple pressures, including population growth and decreasing land area per capita . As a crucial element of CEA, greenhouse films have consistently faced challenges in achieving multifunctional coupling. Coated five-layer (CFL) co-extrusion technology enables functional stratification to overcome the conflict between light transmittance and thermal insulation in traditional single-function films. Through long-term monitoring of air temperature, soil temperature, light intensity, and light quality, the effects of new greenhouse film on light and temperature were investigated, while its effects on tomato yield and quality were studied via photosynthetic rate, morphological index, and yield and quality parameters. Compared with the control, the CFL film modified the light spectrum by reducing ultraviolet, blue, and green light and increasing the red/far-red ratio, while increasing light intensity by 5.04% with stable seasonal performance. It also showed higher light transmittance under low incidence angles. The film enhanced air effective accumulated temperature by 9.16% and soil effective accumulated temperature by 50.82%, improving the tolerance to adverse weather. Tomato yield increased by 4.39%, with significant improvements in sugar-to-acid ratio, vitamin C, and soluble protein content. The core breakthrough of the CFL film lies in its integrated high light transmittance, precise spectrum optimization and efficient thermal regulation, effectively resolving the conflict between light transmission and thermal insulation in conventional films. This technology exhibits substantial application value for stabilizing production, improving fruit quality and promoting the high-quality development of protected tomato cultivation.