Oxygenation promotes vegetable growth by enhancing P nutrient availability and facilitating a stable soil bacterial community in compacted soil

Soil compaction is a widespread phenomenon in intensive agriculture and can severely hamper root growth and crop yield. Hydrogen peroxide urea (UHP) has been employed as an effective measure for oxygenation in dryland systems. However, whether oxygenation via UHP could alleviate negative effects on vegetable growth induced by soil compaction is unknown. A pot experiment involving different soil bulk densities (1.2, 1.5, and 1.7 g cm−3) with oxygenation at different stages of development (seedling stage, mid-growth stage) was conducted in amaranth (A. mangostanus), with non-oxygenation at different soil bulk densities as a control. Increased soil compaction affected vegetative growth of both the shoot and root system of amaranth and caused yield reduction. Oxygenation in topdressing significantly improved soil O2 supply until the harvest period, imparted 17.9–20.4 % additional O2 to soils. Increased O2 supply alleviated soil compaction stress, and amaranth yield increased by 5.50–16.1 % at the same soil bulk density compared with control, respectively. Oxygenation during the mid-growth stage had a superior effect on vegetable growth compared to oxygenation at the seedling stage, coincident with the higher oxygen demand during mid-growth in amaranth. Oxygenation promoted root growth in compacted soil, and increased root length by 76.3 % at a soil bulk density of 1.5 g cm−3 and 74.7 % at a bulk density of 1.7 g cm−3 compared with control. The alleviatory effect on the root system can be linked to increased root catalase activity and decreased malondialdehyde content. Oxygenation furthermore increased phosphorus (P) bioavailability by increasing both phosphatase activity and the relative abundance of phosphate-solubilizing bacteria (Firmicutes and Proteobacteria), with an increase in DGT-P by 10.5–23.6 % compared to control. The soil bacterial co-occurrence network at a soil bulk density of 1.5 g cm−3 with oxygenation was more similar to 1.2 g cm−3 soil compaction with oxygenation, which possessed most complex and the proportion of connectors, but was dissimilar from 1.7 g cm−3 soil compaction with oxygenation, which was less stable microbial network structure. Improvement of O2 content could build a healthy and stable rhizosphere bacterial community, and increased the proportion of important nodes in the network, which was conducive to the collaborative development of microorganisms to face compaction stress. And bacterial community structure with oxygenation in compacted soil could recovery to near normal microbiology community structure. The research provides a theoretical and technical framework for the development of strategies that can maximize crop yield in compacted soil.