Microclimate and Plant Transpiration of Tomato (Solanum lycopersicum L.) in a Sunken Solar Greenhouse in North China

Abstract

The solar greenhouse is a common protected structure for crop production when ambient temperatures are low. In the North China Plain (NCP) winter temperatures are very low and an improved solar greenhouse with a lowered soil surface (0.5–1.5 m deep), referred to as a sunken solar greenhouse (SSG), is used. A four-season experiment was conducted in a commercial SSG with tomato crops to characterize internal microclimate, sap flow (SF) and crop coefficients. Results show that temperature inside the SSG could be more than 20 °C higher than outside in winter, which favors tomato growth and resulted in acceptable yields. Daily total SF was related to solar radiation, vapor pressure deficit (VPD) and temperature, in that order, both in winter and summer. The decoupling coefficient (which is the ratio of radiative to aerodynamic influences on evapotranspiration) in daytime was 0.76 in winter and 0.84 in summer, indicating strong decoupling (i.e., predominance of radiative influences) of the internal environment where wind speed was low. Basal crop coefficients at the mid stage of crop growth averaged 1.15–1.43 in winter and 0.91–0.92 in spring and summer. Thus, in the SSG, for similar climatic conditions sap flow in winter was higher than that in summer, which should be considered in irrigation scheduling.

The potential of Monstera sp. phytoremediation in various lead-contaminated water samples

“…Lead concentration in shoots and roots, as well as total lead concentration, have a direct effect on the efficiency of lead absorption is -19.9%, 89%, and 67.8%, respectively. The indirect influence can be seen in table 19 showing that the influence varies greatly. Light intensity, temperature, relative humidity, leaf area, Concentration of lead in shoot and root, and total lead concentration indirectly affect the efficiency of absorption of lead respectively by 10.2%; -5.3%; 14.3%; -23.6%; 11.5%; 69.2%; 67.8%, but the indirect relationship between leaf area is negative, meaning that narrow leaves have a higher efficiency of absorption of lead compared to other treatments.…”

“…In general, air temperature, relative humidity and light intensity have been known as principal actuators among the various microclimate factors for plant growth and development, especially biomass production [18]. Microclimate is a critical parameter for crop production as it influences the water balance and photosynthesis process in the plants [19].…”

Greenhouse Natural Ventilation Models: How Do We Develop with Chinese Greenhouses?

“…Increasing the number of roof vents (roof vent area) resulted in a higher overall ventilation rate but weaker air movement at the crop level [85,86]. Yan [87] compared the ventilation performance in CSG with rear slope integral vents, rear slope interval vents, and top end vents (Figure 3a-c). The rear slope vents resulted in a higher daily average wind speed.…”

“…Figure 3. Chinese solar greenhouses with top end vents (a), rear slope integral vents (b), and rear slope interval vents (c)[87], and vents on the back wall (d)[89].…”

Spatial, Temporal, and Vertical Variability of Ambient Environmental Conditions in Chinese Solar Greenhouses during Winter

“…Several studies have analyzed environmental microclimate conditions to evaluate and optimize crop growth conditions and to improve the energy efficiency of greenhouses. The microclimate and transpiration of tomato plants have been investigated [22] in a sunken solar greenhouse located in North China. The findings revealed that the sunken design of the greenhouse improved the microclimate by lowering temperature fluctuations and increasing relative humidity.…”