Abstract: Abstract: It is well known that most plants' roots require an adequate and continuous supply of oxygen in soil to respire, grow, develop, and function normally. Industrial agriculture has developed rapidly but is accompanied by excessive irrigation and fertilization, minimal tillage and agricultural machinery driving over the soil. All these farming activities can result in soil compaction. In compacted soil, the increase in soil bulk density and the accompanying decrease in porosity can hinder the exchange of oxygen, carbon dioxide and other gases between the atmosphere and the soil, thereby causing hypoxic stress in plant roots. In addition to compaction, some natural factors, such as extraordinarily high groundwater table, long-term rainfall and tillage under clay or clay loam conditions, can often lead to soil oxygen content reduced, which limits crop yield and quality improvement. Tomato plants (Solanum lycopersicum) are one of the most vulnerable mesophytes to hypoxia in the root environment. Soil aeration has been found to be very useful in overcoming problems associated with hypoxia in the root-zone of irrigated crops including tomato, cotton, cucumber and zucchini. Over a range of soil water contents and soil types, the performance of crops can be improved under oxygen-deficient conditions. It is hypothesized that varying the aeration volume and burial depths of drip irrigation tubes (aeration position) would result in the different soil air environment in the root-zone. To date, there are no reports in the literature which specifically examined the sensitivity of tomato plants to soil aeration volume and burial depths of drip irrigation tubes in Lou soil, and the effect on the photosynthetic characteristics and dry matter accumulation. The experiments were conducted in a greenhouse at Yangling (E108°02′, N34°17′), Shaanxi, between October, 2014 and May, 2015. The tested variety of tomato was Fenyuyanggang (New Horizon Facilities Agricultural Development Co. Ltd., Northwest A&F University, China). Air was used for soil aeration, and the soil for the test was a silty clay loam (soil order was Inceptisol based on the USDA (United States Department of Agriculture) soil taxonomy). The volume of air in each plot was injected into the drip tubing via a manifold connected to the air compressor. The experiment was designed to study the responses of photosynthetic characteristics, chlorophyll content and dry matter accumulation of greenhouse-produced tomato to 4 aeration volumes in combination with 2 depths of drip-tubing placed in the soil. The drip irrigation placement depths were respectively 15 and 40 cm below the surface of the ridge. Artificial aeration treatments were 0, 24.6, 49.4 and 74.2 L/m2, respectively. Results showed that drip tubing placement and artificial aeration treatments significantly affected photosynthetic characteristics, chlorophyll content and dry matter accumulation. The changing trend of net photosynthetic rate showed an increase at first and then a decrease with the increase of aeration volume at both 15 and 40 cm depth of the tube. Chlorophyll a and dry matter accumulation of tomato also showed an increase firstly and then a decrease with the increase of aeration volume at 15 cm depth of the tube. However, chlorophyll a and dry matter accumulation increased with the increasing of the volume of aeration at 40 cm depth of the tube. Synthesizing each kind of situation, both 15 and 40 cm depth of the tube could apply to artificial soil aeration. The optimum artificial aeration volume was 49.4 L/m2 at the 15 cm deep of the tube. However, at the 40 cm deep of the tube, 74.2 L/m2 aeration volume was better than the other treatments. For the observed responses, the information on how the tomato adapts to artificial soil aeration will provide guidance for field production practices as well as indications of possible mechanisms.