The Layout Measures of Micro-sprinkler Irrigation under Plastic Film Regulate Tomato Soil Bacterial Community and Root System

The change of rhizosphere soil bacterial community and root system under new water-saving device is not clear. The greenhouse tomato was used as the research object to explore the response of rhizosphere soil bacteria community, root system and yield of greenhouse tomato under micro-sprinkler irrigation under plastic film (MSPF). A completely randomized experimental design was used to explore the effects of different micropore group spacing (L1: 30 cm micropore group spacing, L2: 50 cm micropore group spacing ) and capillary arrangement density ( C1: one pipe for one row, C2: one pipe for two rows, C3: one pipe for three rows ) on tomato rhizosphere soil bacteria community, roots and tomato yield under MSPF. The Cobb-Douglas model was used to qualitatively and quantitatively describe the influence of micropore group spacing and capillary arrangement density on tomato yield. The interaction of bacterial community, root system and yield in tomato rhizosphere soil was quantitatively described based on regression analysis. Results showed that L1 was not only beneficial to the development of tomato root morphology, but also promoted the ACE index of tomato soil bacterial community structure and the abundance of nitrogen and phosphorus metabolism functional genes. The yield and crop water use efficiency (WUE) of spring tomato and autumn tomato in L1 were about 14.15% and 11.27%, 12.64% and 10.35% higher than those in L2. With the decrease of capillary arrangement density, the diversity of bacterial community structure in tomato rhizosphere soil decreased, and the abundance of nitrogen and phosphorus metabolism functional genes of soil bacteria also decreased. The small abundance of soil bacterial functional genes limited the absorption of soil nutrients by tomato roots and roots morphological development. The yield and crop water use efficiency of spring and autumn tomato in C2 were significantly higher than those in C3 about 34.76% and 15.23%, 31.94% and 13.91%, respectively. The positive interaction between soil bacterial community and root morphological development of tomato was promoted by the capillary layout measures of MSPF. The L1C2 treatment had a stable bacterial community structure and good root morphological development, which positively promoted the increase of tomato yield. The interaction between soil microorganisms and roots of tomato was regulated by optimizing the layout measures of MSPF to provide data support for water-saving and yield-increasing of tomato in Northwest China.