Ridge intertillage alters rhizosphere bacterial communities and plant physiology to reduce yield loss of waterlogged cotton.

Waterlogging stress is an increasing threat to cotton production worldwide. The use of cultivation measures to combat waterlogging stress is a promising approach. As a traditional cultural practice, ridge intertillage is usually conducted before flowering to form a ridge along a row and a furrow between two rows in order to reduce lodging and control weeds in cotton fields. However, it is unclear whether ridge intertillage can alleviate waterlogging stress in field-grown cotton. Flat and ridge intertillage were conducted at 10 days after squaring of cotton to establish flat and ridge–furrow configurations, respectively, with or without 10-d waterlogging. To determine effects of intertillage pattern on mitigating waterlogging stress, changes in rhizosphere bacterial communities and plant physiological parameters were examined in waterlogged cotton. Compared with flat tillage, ridge intertillage significantly decreased hydrogen peroxide production, malonaldehyde content, and alcohol dehydrogenase and pyruvate decarboxylase activities in both roots and leaves of waterlogged cotton but significantly increased nitrogen, phosphorus, and potassium concentrations, leaf area, and plant biomass. Compared with flat intertillage under waterlogging (FIW), ridge intertillage under waterlogging (RIW) changed the abundance and composition of rhizosphere bacterial communities. In addition, several taxa of bacteria with beneficial functions were enriched in the rhizosphere under ridge intertillage. Pearson correlations indicated that changes in rhizosphere bacteria and plant physiological parameters in waterlogged cotton were significantly correlated (P < 0.05), suggesting that adjustments in rhizosphere bacterial communities were involved in the physiological response to waterlogging stress. Moreover, compared with FIW, RIW increased canopy photosynthesis and lint yield of waterlogged cotton by 51.5% and 18.3%, respectively, and decreased lint yield loss by 61.3%. Compared with flat intertillage, ridge intertillage induced adjustments in rhizosphere bacterial communities, reduced oxidative membrane damage, improved nutrient uptake and canopy photosynthesis, and ultimately reduced the stress damage and yield loss of waterlogged cotton. Ridge intertillage before flowering is a promising agronomic measure to combat waterlogging stress in cotton and possibly other major field crops. • Ridge intertillage produced ridge-furrow configuration by piling up the topsoil to cotton plants base before flowering. • Effects of flat and ridge intertillage on waterlogged cotton were compared. • Ridge intertillage adjusted rhizosphere microbe and nutrient uptake of waterlogged cotton. • The adjustments induced a set of physiological changes and reduced the yield loss of waterlogged cotton. [ABSTRACT FROM AUTHOR]