Changes of Soil Water and Heat Transport and Yield of Tomato (Solanum lycopersicum) in Greenhouses with Micro-Sprinkler Irrigation under Plastic Film

Abstract

This study aimed to expound the changes in soil water flow, heat transport, and tomato production under micro-sprinkler irrigation and plastic film (MSPF) conditions. The effects of different irrigation amounts (I1:0.7 Epan; I2:1.0 Epan; and I3:1.2 Epan (Epan is the cumulative evaporation from a 20 cm diameter standard pan, mm)) on soil water, soil temperature, and tomato yield were studied. A completely randomized trial design was used; meanwhile, the drip irrigation under plastic film (CK1) and micro-sprinkler irrigation without mulch film (CK2) were used as controls. The results showed that the shape of soil moisture was banded under MSPF; the soil wetting range was larger than that of CK1 and CK2 in the profile of MSPF. The change range of 5 cm soil temperature of MSPF 1–5 days after irrigation was 4.05 °C. The change range of 5 cm soil temperature of MSPF was lower than that of CK1 from 1 to 5 days after irrigation. During the growth period of spring and autumn tomato, the average soil moisture content of 0–40 cm with CK1 was 1.97% and 3.83% (spring and autumn, respectively) higher than that of MSPF, and the average soil temperature of 5–25 cm was 2.36% and 1.66% (spring and autumn, respectively) lower than that of MSPF. Compared with CK2, the average soil moisture content of 0–40 cm under MSPF increased by 8.30% and 3.83% (spring and autumn, respectively), and the average soil temperature of 5–25 cm under MSPF increased by 5.85% and 1.68% (spring and autumn, respectively). The spring and autumn tomato yield of MSPF was significantly higher than that of CK1 by 19.39% and 4.54%, respectively. The spring and autumn tomato yield of MSPF were higher than that of CK2 by about 20.46% and 49.22%, respectively. With an increase in the irrigation amount of MSPF, the soil moisture and yield of spring and autumn tomato increase; the soil temperature and water use efficiency of spring and autumn tomato decrease. Considered comprehensively, the MSPF can be used as one of the methods of greenhouse tomato micro-irrigation, and 1.0 Epan is recommended for irrigation parameters in northwest China facility agriculture.