The potential effects of drip irrigation on soil environment, root distribution and yield of greenhouse tomato

Abstract

The change of soil temperature and moisture will directly affect the spatial distribution of roots and crop yield formation, and water regulation is one of the main factors that affect the soil moisture and heat environment. In this study, taking greenhouse tomato with drip irrigation under film in North China as the research object, three water treatments were set as Tl (0.9 Ep), T2 (0.7 Ep), T3 (0.5 Ep) respectively, according to the cumulative evaporation (Ep) of a 20 cm standard evaporating pan, to investigate the variation of soil temperature and moisture, spatial distribution characteristics of tomato root, and the effect of different water treatments on tomato yield. The results indicate that: (1) T1 was conducive to increase the soil moisture at about 20 cm depth, T2 was conducive to decrease the soil moisture at about 40 cm depth in later growth stage, and the soil moisture under T3 treatment was relatively low at 20 cm depth. (2) Roots were mainly concentrated in the soil shallow layer, and root length density between plants was significantly higher than that between rows in the shallow layer (10-30 cm). Tl treatment could promote the root growth better in deeper soil, while T2 treatment could promote the shallow roots growth better. (3) There was good quadratic regression function relationship between root length density and soil depth under three water treatments (R2 >0.74), and the tomato root length density distribution model based on the coupling of soil temperature and moisture had high fitting degree (R2 > 0.76). (4) The single harvest yield of tomato under three water treatments showed a trend of T2>T1>T3, and T2 presented the highest total yield (147.151 t hm2) and largest root length density (1,687.370 mm иг3) among the three treatments. The results are of great significance to the realization of precision irrigation of drip irrigation crop in greenhouse, the formulation of reasonable irrigation program, and the improvement of greenhouse tomato yield.