Effects of Artificial Soil Aeration Volume and Frequency on Soil Enzyme Activity and Microbial Abundance when Cultivating Greenhouse Tomato

Abstract

Artificial soil aeration can enhance soil enzyme activity, improve soil nutrient cycling, and increase crop growth and yield. We studied the response of soil microorganisms and soil enzyme activity to two levels of burial depths of subsurface tubing in combination with four levels of aeration volume and three frequency levels of supplemental soil aeration. The aeration volumes (V) were 0, 0.5, 1, and 1.5 times (CK, V 1 , V 2 , and V 3 , respectively) the estimated porosity of the plot rhizosphere. Burial depths (D) of subsurface tubing were 15 and 40 cm (D 15 and D 40 ). Aeration frequencies (F) levels were none and at 2-and 4-d intervals (CK, F 2 , and F 4 ). The results demonstrated that aeration frequency and volume positively affected soil urease, phosphatase, and catalase activity and soil microbial abundance. The impact of aeration treatment on rhizosphere soil enzyme activity was greater than its impact on non-rhizosphere activity. When the drip irrigation tube depth was 15 cm, V 2 volume with 2-d aeration intervals led to an increase in the mean yield of first picking fruit of 75.1% compared with the unaerated control. When V 3 volume with 2-d aeration intervals was performed with a 40-cm irrigation tube, the mean yields of the first picking fruit increased by 135.5% compared with the unaerated control. These results suggest that artificial soil aeration can improve the plant root zone environment, increase microbial abundance and soil enzyme activity, and promote nutrient uptake, thus promoting plant growth and fruit output. S oil microorganisms and soil enzymes are important components of agricultural ecosystems. Bacteria, fungi, and actinomycetes play important roles, including decomposing organic matter, degrading cellulose, and forming antibiotic substances. Nitrogen-fixing bacteria provide nitrogen sources for plants, whereas nitrobacteria prevent the accumulation of nitrite in the soil (Clarholm, 1985). Fungi are involved in the soil carbon cycle by decomposing cellulose, lignin, and pectin to release nutrients, and the development of the mycelium improves the physical structure of the soil (Tedersoo et al., 2014 Core Ideas• Rhizosphere soil enzymes activity showed an initial increase followed by a decrease.• soil aeration can enhance the activities of three rhizosphere soil enzymes.• Aeration frequency and volume can significantly affect rhizosphere enzyme activities.• Aeration can enhance the activities of non-rhizosphere soil enzymes.• soil aeration can increase tomato yield.

Irrigation Combined with Aeration Promoted Soil Respiration through Increasing Soil Microbes, Enzymes, and Crop Growth in Tomato Fields

“…As seen in Figure 2, cfub made up the majority of soil microbes, followed by cfua and cfuf, which was generally supported by the results of Li et al [16] and Zhu et al [25]. Nevertheless, the microorganism abundance in the study of Zhu et al [25] were greater than the values of the current research ( Figure 2), which was influenced by higher soil temperature in their study (their study vs. our study = 18-32 • C vs. 9-29 • C).…”

“…Heterotrophic respiration, as a primary contributor to the soil respiration, is impacted by soil carbon-use efficiency which varies based on soil microbial abundance and richness [22]. A previous study demonstrated that the abundance of bacteria (cfub), fungi (cfuf), and actinomycetes (cfua) are involved in the soil carbon cycle by decomposing organic matter, degrading cellulose, and forming antibiotic substances [16]. Soil microbial biomass carbon (MBC), which affects the transformation of all organic matter entering the soil, is the key and driving force of the nutrient and energy cycle in the whole ecosystem and is also an important source and reservoir of soil nutrient transformation.…”

“…With respect to the control, greater Rs under aeration (averaging 6.2% increase) was mainly driven by soil water-filled pore space, soil bacteria, and soil fungi. The results of this study are helpful for understanding the mechanisms of soil CO 2 release under aerated subsurface drip irrigation.Catalysts 2019, 9, 945 2 of 17 oxidize soil organic matter [15] and intrinsically affect heterotrophic respiration, while the effect of AI on soil microbes and enzymes has been less tested [16]. Additionally, the properties of root morphology (total length, surface area, and volume) not only determine the ability of water and nutrient absorption but also determine the intensity of autotrophic respiration.…”

“…Catalysts 2019, 9, 945 2 of 17 oxidize soil organic matter [15] and intrinsically affect heterotrophic respiration, while the effect of AI on soil microbes and enzymes has been less tested [16]. Additionally, the properties of root morphology (total length, surface area, and volume) not only determine the ability of water and nutrient absorption but also determine the intensity of autotrophic respiration.…”

Aeration Irrigation Can Improve Growth of Table Grape cv. Red Globe (Vitis vinifera L.) in Greenhouse

“…Electric energy was supplied by solar panels, and air compressors were used for gas injection processing; the pressure was 0.04 MPa, 60 L · min -1 (Zhao et al, 2018). The injection volume was selected according to the formula V = 0.001 SH (1 -r b /r s ) n (Li et al, 2016a), where V is the amount of each aerated liter (L); S is PVC box surface area in square centimeters; H is PVC box height of 60 cm; r b refers to soil bulk density (1.40 g · cm -3 ); r s refers to the soil density, 2.65 g · cm -3 ; and n is the number of gas injection boxes, 15. According to this formula, the single minimum injection rate was 520.3 L. Considering the dispersion effect and the pretest results of SDI with tanks, aeration treatment was set up to once daily for 20 min from 09:00 to 09:20 AM (Beijing time).…”