Optimized Tomato Production in Chinese Solar Greenhouses: The Impact of an East–West Orientation and Wide Row Spacing

Abstract

Experimental studies were conducted on the cultivation of tomatoes (Solanum lycopersicum L.) at Shandong Agricultural University, China, from 2022 to 2023. Three cultivation patterns were designed as follows: a north–south orientation with a row spacing of 1.40 m (NS-1.4m), a north–south orientation with a row spacing of 1.80 m (NS-1.8m) and an east–west orientation with a row spacing of 1.80 m (EW-1.8m). A functional–structural plant model using the open source interactive modeling platform of GroIMP was constructed for the cultivation of tomatoes. The growth of plants as well as the light distribution and light interception capacity of the crop canopy were simulated and analyzed. The impacts of these cultivation patterns on the growth, photosynthetic characteristics, fruit ripening time, quality and yield of tomato plants were analyzed. The studies revealed that compared with the NS-1.4m treatment, the canopy light interception of tomato plants under the NS-1.8m and EW-1.8m treatments increased by 6.08% and 9.80% in a winter–spring crop and 6.80% and 19.76% in an autumn–winter crop, respectively. Their plant height, leaf area, aboveground dry matter accumulation, leaf net photosynthesis rate as well as the lycopene, vitamin C and sugar–acid ratio of the fruit all exhibited increasing trends, while fruit ripening was accelerated. The yield of the NS-1.8m and EW-1.8m treatments increased by 3.92% and 6.18% in a winter–spring crop and 4.17% and 9.78% in an autumn–winter crop, respectively. Structural equation modeling was used to further analyze the data, confirming that the cultivation of an east–west orientation with wide row spacing is beneficial for tomato cultivation in Chinese solar greenhouses. This cultivation pattern maximizes the canopy’s light interception, thus leading to improved fruit quality and yield. Overall, this study provides valuable insights for optimizing the cultivation pattern of solar greenhouse crops.