Abstract
Increased nutrient and/or water uptake by arbuscular mycorrhizal (AM) symbiosis can affect soil biochemical properties and emission of the greenhouse gas carbon dioxide (CO2). Therefore, an experiment was designed to investigate the effect of AM fungi (AMF) on CO2 emissions from turfgrass. Three different AMF species (Funneliformis mosseae, Claroideoglomus etunicatum, and Rhizophagus irregularis) were used in this experiment. Turfgrass plants were cultivated in pots containing both mycorrhizal and non-mycorrhizal soils over a 10-week period. To mimic real-world conditions, the plants underwent irrigation cycles at intervals of 1, 2, and 3 days, replicating common irrigation practices in turfgrass fields. The research aimed to comprehensively understand the effects of AMF and varying irrigation intervals on CO2 emissions, soil characteristics, plant growth, and AMF parameters. It was observed that the changing irrigation intervals affected the AM symbiosis and this effect increased as the irrigation interval increased. It was determined that this AM symbiosis created with the plant significantly reduced CO2 emissions. In addition, it was determined that it regulates the soil structure and increases plant growth. In conclusion, it can be said that AMF species reduce CO2 emissions by reducing the need for water in the turfgrass.
HIGHLIGHTS
Host plants inoculated with arbuscular mycorrhiza (AM) symbiosis are believed to tolerate stressful situations.
Increased CO2 emissions in soil may pose a threat to a sustainable ecosystem.
CO2 emissions and soil temperature have been reduced with mycorrhiza treatments.
It has been determined that AM fungi increases plant growth under different irrigation intervals.
INTRODUCTION
Turfgrass production, an essential part of the green ecosystem, directly depends on irrigation. However, while the amount of water used may pose a problem for the water needs of the increasing world population, increasing CO2 emissions in the soil can pose a danger to a sustainable ecosystem (Allaire et al. 2012; Hatfield-Dodds et al. 2017; Song et al. 2018). To avoid this, the availability of arbuscular mycorrhizal fungi (AMF), which have the potential to increase the water cycle and thus improve environmental quality in various ecosystems, has been reported (Gianinazzi et al. 2010; Jackson et al. 2012).
It creates arbuscular mycorrhizal (AM) symbiosis by interacting with plant roots of AMF (Smith & Read 2010; Smith & Smith 2011; Boyno & Demir 2022). This symbiosis has been demonstrated by research in which photoassimilate carbon compounds exchange in the uptake of soil nutrients, especially phosphorus (P) (Kiers et al. 2011; Fellbaum et al. 2014; Boyno et al. 2022). It has also been suggested that these fungi may affect CO2 emissions in the soil through their direct respiration or indirect effects on heterotrophic microorganisms (Johnson & Bridge 2002; Langley & Hungate 2003; Cavagnaro et al. 2008).
AM symbiosis can also affect CO2 emissions in the soil through changes in soil physical properties (Augé 2004; Cavagnaro et al. 2012). The amount of water in the soil significantly impacts the microbial communities and changes the processes of mineralization, gaseous diffusion, oxygen availability, nitrification, and denitrification (Blagodatsky & Smith 2012). A large body of research suggests that, in addition to the direct effects of soil on water retention, AM symbiosis modifies plant–water interactions and makes mycorrhizal plants more resilient to water stress than non-mycorrhizal plants (Augé et al. 2001; Burger et al. 2005). Mycorrhizal plants often have their stomatal conductivity unchanged for longer than non-mycorrhizal plants when soil moisture is lowered by lengthening the watering interval (Duan et al. 1996). Similarly, mycorrhizal plants frequently display better photosynthetic rates in low soil moisture situations, demonstrating a more substantial tolerance to drought and internal water use efficiency (Augé et al. 2001; Ruiz-Lozano et al. 2012). Mycorrhizal plants typically have more significant plant sizes, allowing hyphae to explore the soil's water and nutrients more deeply, increasing the rate of photosynthetic activity (Augé et al. 2001; Birhane et al. 2012). However, among plants of comparable size and nutritional content, mycorrhizal and non-mycorrhizal plants vary in their water interactions (Kothari et al. 1990). Compared to non-mycorrhizal plants, mycorrhizal plants may absorb more water, which might lead to reduced plant water demand and soil moisture, affecting biogeochemical soil cycles and CO2 emissions (Augé et al. 2001; Augé 2004).
AM symbiosis of plant roots may boost water and nutrient usage effectiveness, enhancing the quality of the environment in many environments (Gianinazzi et al. 2010; Jackson et al. 2012). The development of sustainable ecological practices depends on understanding how these symbiotic interactions affect plant nutrition and biogeochemical cycles. This study examined how AM symbiosis affects CO2 emissions from the soil under varying irrigation intervals of turf plants. We hypothesized that mycorrhizal plants would reduce CO2 emissions by reducing their water requirement. To test this hypothesis, a controlled in vivo experiment was designed.
MATERIALS AND METHODS
Plant/fungal materials and study area
Daily temperatures [] and humidity [
] inside the climate room throughout the experimental period.
Daily temperatures [] and humidity [
] inside the climate room throughout the experimental period.
Study design
In the research, 16 × 18 cm plastic pots that can hold 1 l of mixture were used. In the experiment, cultivation soil containing 1:2 sand, which was disinfected by keeping it in an autoclave at 121°C for 1 h, was used. Based on this soil volume, 10% AMF inoculum (F. mosseae, C. etunicatum, and R. irregularis) was added to the cultivation soil and mixed; 10% sterile sand was added to the pots without AMF application. Turfgrass mixture consisting of 40% L. perenne, 35% F. rubra rubra, 15% F. rubra commutata, and 10% P. pratensis was planted in this cultivation soil at 50 g m−2 seeds per pot (Celebi et al. 2009). The sowing rate, amount, and selection of turfgrass varieties were determined considering the purity and the germination rate of the seeds before the study. The seeds were covered with peat, burnt-sieved barn manure, and the soil at a ratio of 1:1:1 and pressurized by weight. Peat was preferred to protect the soil and seeds from excessive light and other external factors, while barn manure was preferred to increase moisture retention despite the soil's light texture. After the sowing process was completed, 4 g m−2 of 26% ammonium nitrate fertilization was applied (Celebi et al. 2009). The turfgrass lawn mowing was initially made to be cut from 8 to 6 cm in order not to prevent the development of roots and crops and then to be cut from 5–6 to 3–4 cm approximately every 8–10 days (Morris & Shearman 1998).
The field capacity (pot capacity) and irrigation water amount were determined on a weight basis. The non-mycorrhiza treatment was placed in the water pan and kept in the pan until complete wetting of the soil surface through capillarity. Then it was drained with gravity to remove excess water above the field capacity, and the field capacity was determined as 0.322 m3 m−3. The irrigation water amount applied in each irrigation was determined with I = Wfc – Wi where I is the irrigation water amount (mL), Wfc and Wi are weights of the pot (kg) at field capacity and measurement day, respectively.
Soil analysis
In the experimental soil, particle size distribution (Gee & Bauder 1986), bulk density, specific gravity (Blake & Hartge 1986), aggregate stability (Kemper & Rosenau 1986), CaCO3 (Nelson 1982), organic matter (Nelson & Sommers 1982), total nitrogen (Bremner & Mulvaney 1982), available phosphorus (Olsen et al. 1982), and available potassium (Knudsen et al. 1982) were determined by analysis. Soil reaction (pH) (McLean 1982) and electrical conductivity (EC) (Corwin & Rhoades 1984) were determined using a pH meter and conductometer in the saturation extract, respectively, while the porosity (Danielson & Sutherland 1986) and organic carbon (Avramidis et al. 2015) were also calculated. According to the USDA classification, the soil was sandy loam, and the study of soil properties is given in Table 1.
The properties of experimental soil
Property . | . | Property . | . |
---|---|---|---|
Soil texture | Sandy loam | EC (dS m−1) | 0.615 |
Sand (%) | 66.3 | pH | 7.17 |
Silt (%) | 15.6 | CaCO3 (%) | 2.2 |
Clay (%) | 18.1 | Organic matter (%) | 0.81 |
Bulk density (g cm−3) | 1.37 | Organic carbon (%) | 0.47 |
Specific gravity | 2.69 | Total N (%) | 0.040 |
Porosity (%) | 49.1 | P2O5 (kg ha−1) | 59.0 |
Aggregate stability (%) | 48.1 | K2O (kg ha−1) | 662 |
Property . | . | Property . | . |
---|---|---|---|
Soil texture | Sandy loam | EC (dS m−1) | 0.615 |
Sand (%) | 66.3 | pH | 7.17 |
Silt (%) | 15.6 | CaCO3 (%) | 2.2 |
Clay (%) | 18.1 | Organic matter (%) | 0.81 |
Bulk density (g cm−3) | 1.37 | Organic carbon (%) | 0.47 |
Specific gravity | 2.69 | Total N (%) | 0.040 |
Porosity (%) | 49.1 | P2O5 (kg ha−1) | 59.0 |
Aggregate stability (%) | 48.1 | K2O (kg ha−1) | 662 |
Irrigation water analysis
In the middle of the study, the tap water was used as irrigation water, cations (Ca, Mg, Na, and K) were determined by inductively coupled plasma - optical emission spectrometry (ICP-OES) (Anonymous 2007), CO3 and HCO3 were determined by titration with sulfuric acid, CI was determined by titration with silver nitrate using a potassium chromate indicator (Tuzuner 1990), SO4 was determined by a spectrophotometer (HACH 2010), pH and EC were determined by the pH meter and the conductivimeter by direct reading. The sodium absorption rate (SAR) and percent sodium (%Na) were determined by calculation (Kanber & Unlu 2010). The values regarding irrigation water quality are given in Table 2.
The properties of irrigation water used in the study
Property . | . | Property . | . |
---|---|---|---|
Ca (me L−1) | 1.96 | CO3 (me L−1) | - |
Mg (me L−1) | 3.65 | HCO3 (me L−1) | 2.91 |
Na (me L−1) | 0.42 | Cl (me L−1) | 1.22 |
K (me L−1) | 0.22 | SO4 (me L−1) | 1.97 |
EC (dS m−1) | 0.644 | SAR | 0.25 |
pH | 7.91 | %Na | 6.72 |
Property . | . | Property . | . |
---|---|---|---|
Ca (me L−1) | 1.96 | CO3 (me L−1) | - |
Mg (me L−1) | 3.65 | HCO3 (me L−1) | 2.91 |
Na (me L−1) | 0.42 | Cl (me L−1) | 1.22 |
K (me L−1) | 0.22 | SO4 (me L−1) | 1.97 |
EC (dS m−1) | 0.644 | SAR | 0.25 |
pH | 7.91 | %Na | 6.72 |
The plant growth parameters
At the end of the study, turfgrass color values were determined by three researchers according to a 1–9 scale (1: yellow, 3: light yellow-green, 5: green, 7: dark green, and 9: highly dark green) and turfgrass quality values were also determined according to the uniformity, density, color, and homogeneous appearance, again with the same method, according to the 1–9 scale (Morris & Shearman 1998). Plant fresh weights were determined by weighing. The plant materials were dried at 70 °C for 48 h and measured to estimate the dry weights. The root length (cm) was determined using a digital caliper (Insize-1112–150, Germany).
AMF root colonization, spore density, and mycorrhizal dependency assays
Carbon dioxide (CO2) measurements
Carbon dioxide emission from soil was measured with a gas analyzer instrument (EGM-5, PP Systems, Stotfold, UK), which is a portable dynamic closed chamber infrared gas analyzer system, by taking three measurements from each treatment at the same time every day and continued until the end of the study. The non-steady state through the flow chamber (SRC-1, PP Systems, Stotfold, UK; volume 1,334 cm3 and area 78.5 cm2) had only one opening to the soil. In addition, these values were recorded at the time of carbon dioxide measurement to determine the relationship of carbon dioxide with soil temperature and soil moisture. Soil temperature was measured at a depth of 5 cm with an STP-1 soil temperature probe connected to the EGM-5 (Buragiene et al. 2019; Yerli & Sahin 2021), while the soil moisture was determined according to weight.
Statistical analysis
Statistical analyses were performed by using the SPSS software (V23.0). ANOVA was applied to the data, and Duncan's multiple range test was used to compare significant means. In addition, linear regression analysis was used to evaluate the relationship of CO2 emission with soil temperature and soil moisture.
RESULTS
Soil properties
The effects of AMF species (F. mosseae, C. etunicatum, and R. irregularis) on soil properties at different irrigation intervals are presented in Table 3. It was determined that mycorrhizal treatments had no effect on EC and pH values in the soil compared to non-mycorrhizal treatment at varying irrigation intervals. However, it was determined that mycorrhizal treatments increased other parameters (organic matter, organic carbon, total nitrogen (N), P2O5, and K2O). In particular, the highest values for organic matter, organic carbon, and total N ratios were determined in C. etunicatum and R. irregularis treatments, while the highest values in P2O5 and K2O ratios were determined in C. etunicatum treatment. When the mean day (1, 2, and 3 days) intermittent irrigation treatments were examined, statistical differences were not observed in all parameters (Table 3).
Chemical soil properties in different mycorrhiza species and irrigation intervals
Mycorrhiza . | Irrigation intervals . | EC (ds m−1) . | pH . | Organic matter (%) . | Organic carbon (%) . | Total N (%) . | P2O5 (kg ha−1) . | K2O (kg ha−1) . |
---|---|---|---|---|---|---|---|---|
Non-mycorrhiza | 1 day | 0.652 ± 0.002ns | 7.49 ± 0.17 ns | 0.88 ± 0.02 ns | 0.51 ± 0.01 ns | 0.042 ± 0.001 ns | 60.3 ± 0.2 ns | 666 ± 9 ns |
2 days | 0.644 ± 0.013 | 7.34 ± 0.10 | 0.87 ± 0.01 | 0.50 ± 0.01 | 0.045 ± 0.002 | 60.4 ± 0.5 | 667 ± 5 | |
3 days | 0.640 ± 0.011 | 7.39 ± 0.07 | 0.89 ± 0.02 | 0.51 ± 0.01 | 0.042 ± 0.001 | 61.4 ± 0.2 | 668 ± 8 | |
Mean | 0.642 ± 0.005ns | 7.41 ± 0.07ns | 0.88 ± 0.01 C** | 0.51 ± 0.01C** | 0.043 ± 0.001 B** | 60.7 ± 0.2 C** | 667 ± 4 C** | |
F. mosseae | 1 day | 0.624 ± 0.008 ns | 7.47 ± 0.10 ns | 0.93 ± 0.02 ns | 0.54 ± 0.01 ns | 0.047 ± 0.003 ns | 68.4 ± 1.4 ns | 678 ± 4 ns |
2 days | 0.638 ± 0.013 | 7.39 ± 0.02 | 0.94 ± 0.03 | 0.55 ± 0.02 | 0.050 ± 0.003 | 67.5 ± 2.3 | 675 ± 5 | |
3 days | 0.620 ± 0.004 | 7.32 ± 0.17 | 0.97 ± 0.03 | 0.56 ± 0.02 | 0.045 ± 0.003 | 67.4 ± 2.4 | 672 ± 8 | |
Mean | 0.627 ± 0.005 | 7.39 ± 0.06 | 0.95 ± 0.01 B | 0.55 ± 0.01 B | 0.047 ± 0.002 B | 67.8 ± 1.0 B | 675 ± 3 BC | |
C. etunicatum | 1 day | 0.646 ± 0.012 ns | 7.39 ± 0.05 ns | 0.99 ± 0.02 ns | 0.57 ± 0.01 ns | 0.055 ± 0.006 ns | 70.7 ± 0.5 ns | 684 ± 8 ns |
2 days | 0.618 ± 0.010 | 7.44 ± 0.14 | 1.08 ± 0.05 | 0.63 ± 0.03 | 0.051 ± 0.004 | 70.9 ± 0.4 | 691 ± 6 | |
3 days | 0.634 ± 0.003 | 7.52 ± 0.07 | 1.00 ± 0.01 | 0.58 ± 0.01 | 0.059 ± 0.009 | 70.9 ± 0.5 | 691 ± 9 | |
Mean | 0.633 ± 0.006 | 7.45 ± 0.05 | 1.02 ± 0.02 A | 0.59 ± 0.01 A | 0.055 ± 0.003 A | 70.8 ± 0.2 A | 689 ± 4 A | |
R. irregularis | 1 day | 0.635 ± 0.014 ns | 7.29 ± 0.06 ns | 1.00 ± 0.07 ns | 0.58 ± 0.04 ns | 0.053 ± 0.003 ns | 69.1 ± 1.1 ns | 687 ± 2 ns |
2 days | 0.617 ± 0.003 | 7.48 ± 0.06 | 0.98 ± 0.01 | 0.57 ± 0.01 | 0.054 ± 0.001 | 69.5 ± 0.4 | 680 ± 3 | |
3 days | 0.625 ± 0.010 | 7.59 ± 0.05 | 0.99 ± 0.05 | 0.63 ± 0.03 | 0.061 ± 0.001 | 69.6 ± 0.5 | 372 ± 4 | |
Mean | 0.626 ± 0.006 | 7.45 ± 0.05 | 0.99 ± 0.03 A | 0.59 ± 0.02 A | 0.056 ± 0.002 A | 69.4 ± 0.4 AB | 680 ± 2 AB | |
Mean | 1 day | 0.635 ± 0.005 ns | 7.41 ± 0.05 ns | 0,95 ± 0.02 ns | 0.55 ± 0.01 ns | 0.049 ± 0.002 ns | 67.1 ± 1.3 ns | 678 ± 4 ns |
2 days | 0.629 ± 0.006 | 7.41 ± 0.04 | 0,97 ± 0.03 | 0.56 ± 0.02 | 0.050 ± 0.002 | 67.1 ± 1.3 | 678 ± 3 | |
3 days | 0.630 ± 0.004 | 7.45 ± 0.05 | 0.96 ± 0.02 | 0.57 ± 0.01 | 0.052 ± 0.003 | 67.3 ± 1.2 | 676 ± 4 |
Mycorrhiza . | Irrigation intervals . | EC (ds m−1) . | pH . | Organic matter (%) . | Organic carbon (%) . | Total N (%) . | P2O5 (kg ha−1) . | K2O (kg ha−1) . |
---|---|---|---|---|---|---|---|---|
Non-mycorrhiza | 1 day | 0.652 ± 0.002ns | 7.49 ± 0.17 ns | 0.88 ± 0.02 ns | 0.51 ± 0.01 ns | 0.042 ± 0.001 ns | 60.3 ± 0.2 ns | 666 ± 9 ns |
2 days | 0.644 ± 0.013 | 7.34 ± 0.10 | 0.87 ± 0.01 | 0.50 ± 0.01 | 0.045 ± 0.002 | 60.4 ± 0.5 | 667 ± 5 | |
3 days | 0.640 ± 0.011 | 7.39 ± 0.07 | 0.89 ± 0.02 | 0.51 ± 0.01 | 0.042 ± 0.001 | 61.4 ± 0.2 | 668 ± 8 | |
Mean | 0.642 ± 0.005ns | 7.41 ± 0.07ns | 0.88 ± 0.01 C** | 0.51 ± 0.01C** | 0.043 ± 0.001 B** | 60.7 ± 0.2 C** | 667 ± 4 C** | |
F. mosseae | 1 day | 0.624 ± 0.008 ns | 7.47 ± 0.10 ns | 0.93 ± 0.02 ns | 0.54 ± 0.01 ns | 0.047 ± 0.003 ns | 68.4 ± 1.4 ns | 678 ± 4 ns |
2 days | 0.638 ± 0.013 | 7.39 ± 0.02 | 0.94 ± 0.03 | 0.55 ± 0.02 | 0.050 ± 0.003 | 67.5 ± 2.3 | 675 ± 5 | |
3 days | 0.620 ± 0.004 | 7.32 ± 0.17 | 0.97 ± 0.03 | 0.56 ± 0.02 | 0.045 ± 0.003 | 67.4 ± 2.4 | 672 ± 8 | |
Mean | 0.627 ± 0.005 | 7.39 ± 0.06 | 0.95 ± 0.01 B | 0.55 ± 0.01 B | 0.047 ± 0.002 B | 67.8 ± 1.0 B | 675 ± 3 BC | |
C. etunicatum | 1 day | 0.646 ± 0.012 ns | 7.39 ± 0.05 ns | 0.99 ± 0.02 ns | 0.57 ± 0.01 ns | 0.055 ± 0.006 ns | 70.7 ± 0.5 ns | 684 ± 8 ns |
2 days | 0.618 ± 0.010 | 7.44 ± 0.14 | 1.08 ± 0.05 | 0.63 ± 0.03 | 0.051 ± 0.004 | 70.9 ± 0.4 | 691 ± 6 | |
3 days | 0.634 ± 0.003 | 7.52 ± 0.07 | 1.00 ± 0.01 | 0.58 ± 0.01 | 0.059 ± 0.009 | 70.9 ± 0.5 | 691 ± 9 | |
Mean | 0.633 ± 0.006 | 7.45 ± 0.05 | 1.02 ± 0.02 A | 0.59 ± 0.01 A | 0.055 ± 0.003 A | 70.8 ± 0.2 A | 689 ± 4 A | |
R. irregularis | 1 day | 0.635 ± 0.014 ns | 7.29 ± 0.06 ns | 1.00 ± 0.07 ns | 0.58 ± 0.04 ns | 0.053 ± 0.003 ns | 69.1 ± 1.1 ns | 687 ± 2 ns |
2 days | 0.617 ± 0.003 | 7.48 ± 0.06 | 0.98 ± 0.01 | 0.57 ± 0.01 | 0.054 ± 0.001 | 69.5 ± 0.4 | 680 ± 3 | |
3 days | 0.625 ± 0.010 | 7.59 ± 0.05 | 0.99 ± 0.05 | 0.63 ± 0.03 | 0.061 ± 0.001 | 69.6 ± 0.5 | 372 ± 4 | |
Mean | 0.626 ± 0.006 | 7.45 ± 0.05 | 0.99 ± 0.03 A | 0.59 ± 0.02 A | 0.056 ± 0.002 A | 69.4 ± 0.4 AB | 680 ± 2 AB | |
Mean | 1 day | 0.635 ± 0.005 ns | 7.41 ± 0.05 ns | 0,95 ± 0.02 ns | 0.55 ± 0.01 ns | 0.049 ± 0.002 ns | 67.1 ± 1.3 ns | 678 ± 4 ns |
2 days | 0.629 ± 0.006 | 7.41 ± 0.04 | 0,97 ± 0.03 | 0.56 ± 0.02 | 0.050 ± 0.002 | 67.1 ± 1.3 | 678 ± 3 | |
3 days | 0.630 ± 0.004 | 7.45 ± 0.05 | 0.96 ± 0.02 | 0.57 ± 0.01 | 0.052 ± 0.003 | 67.3 ± 1.2 | 676 ± 4 |
Values with the lowercase letters (a,b,c) in each treatment are not significantly different when followed by Duncan's multiple range test at *P < 0.05 and **P < 0.01, ns, non-significant.
Values with the capital letters (A,B,C) in each treatment's mean are not significantly different when followed by Duncan's multiple range test at *P < 0.05 and **P < 0.01, ns, non-significant.
Data in the table are indicated as mean ± SE.
The plant growth parameters and AMF analyzes
The effects of AMF species on the growth parameters of plants at different irrigation intervals are presented in Table 4. While these parameters were at the highest values in 1-day interval irrigation conditions, gradual decreases were determined in 2- and 3-day interval irrigations. However, it was determined that the plants forming AM symbiosis had the highest mean growth parameters in general compared to the plants non-mycorrhiza. In the leaf color and turfgrass quality mean values, it was determined that the growth parameters of plants forming symbiosis with C. etunicatum and R. irregularis were higher, while the highest value in other parameters occurred in plants forming symbiosis with C. etunicatum (Table 4).
Turfgrass growth and mycorrhiza analyzes in different mycorrhiza species and irrigation intervals
Mycorrhiza . | Irrigation intervals . | Leaf color (1–9) . | Turfgrass quality (1–9) . | Fresh weight (g m−2) . | Dry weight (g m−2) . | Root length (cm) . | AMF colonization (%) . | AMF spore density (spore g soil−1) . | Mycorrhizal dependency . |
---|---|---|---|---|---|---|---|---|---|
Non-mycorrhiza | 1 day | 5.6 ± 0.6 ns | 5.4 ± 0.1 a** | 283 ± 24a* | 68 ± 7 a** | 2.5 ± 0.3 b** | – | – | – |
2 days | 4.8 ± 0.1 | 5.1 ± 0.5 a | 222 ± 26a | 50 ± 1 b | 3.8 ± 0.2 a | – | – | – | |
3 days | 5.1 ± 0.1 | 3.6 ± 0.1 b | 155 ± 27b | 17 ± 2 c | 2.6 ± 0.3 b | – | – | – | |
Mean | 5.2 ± 0.2 C** | 4.7 ± 0.3 C** | 220 ± 23 C** | 45 ± 8 D** | 3.0 ± 0.3 B** | – | – | – | |
F. mosseae | 1 day | 7.0 ± 0.4 ns | 6.9 ± 0.3 a* | 349 ± 25a** | 82 ± 18a** | 3.6 ± 0.3 a** | 66.5 ± 3.7 a** | 153 ± 3 a* | +17.1 |
2 days | 7.0 ± 0.2 | 6.6 ± 0.4 ab | 284 ± 14b | 63 ± 4b | 3.7 ± 0.3 a | 58.2 ± 1.8 b | 130 ± 6 b | +26.0 | |
3 days | 6.7 ± 0.2 | 5.6 ± 0.1 b | 165 ± 12c | 32 ± 3c | 2.1 ± 0.3 b | 32.3 ± 6.5 c | 137 ± 3 b | +46.9 | |
Mean | 6.9 ± 0.1 A | 6.3 ± 0.2 A | 266 ± 28 BC | 59 ± 9 C | 3.1 ± 0.4 B | 52.3 ± 5.6 B** | 140 ± 4 B** | +30.0 | |
C. etunicatum | 1 day | 7.8 ± 0.6 ns | 7.6 ± 0.4 a* | 403 ± 29a** | 128 ± 12a** | 4.8 ± 0.3 a* | 64.5 ± 2.9 ab* | 153 ± 9 a* | +46.9 |
2 days | 6.8 ± 0.1 | 6.8 ± 0.4 ab | 379 ± 64b | 110 ± 7a | 3.6 ± 0.3 b | 68.8 ± 2.7 a | 147 ± 3 ab | +54.5 | |
3 days | 7.1 ± 0.1 | 5.6 ± 0.1 b | 270 ± 80c | 67 ± 4b | 3.9 ± 0.3 b | 56.4 ± 4.0 b | 133 ± 7 b | +74.6 | |
Mean | 7.2 ± 0.2 A | 6.6 ± 0.3 A | 351 ± 29 A | 102 ± 10 A | 4.1 ± 0.4 A | 63.2 ± 2.4 A | 144 ± 4 B | +58.7 | |
R. irregularis | 1 day | 6.6 ± 0.6 ns | 6.4 ± 0.4 a* | 350 ± 12a** | 119 ± 3a** | 4.5 ± 0.4 a* | 49.7 ± 2.9 b* | 143 ± 3 b* | +42.9 |
2 days | 5.8 ± 0.1 | 5.8 ± 0.5 a | 289 ± 45b | 78 ± 8b | 3.5 ± 0.3 b | 54.5 ± 4.5 a | 167 ± 9 a | +35.9 | |
3 days | 6.1 ± 0.1 | 4.6 ± 0.1 b | 228 ± 13c | 47 ± 7c | 3.8 ± 0.3 b | 48.1 ± 3.2 b | 160 ± 6 ab | +63.8 | |
Mean | 6.2 ± 0.2 B | 5.6 ± 0.3 B | 289 ± 23 B | 81 ± 11 B | 3.9 ± 0.2 A | 50.8 ± 2.1 B | 157 ± 5 A | +47.5 | |
Mean | 1 days | 6.7 ± 0.4 A** | 6.6 ± 0.2 A** | 346 ± 16 A** | 99 ± 9 A** | 3.9 ± 0.3 A** | 45.2 ± 8.2 A** | 112 ± 20 ns | +26.7 |
2 days | 6.1 ± 0.2 B | 6.1 ± 0.3 B | 293 ± 25 B | 75 ± 7 B | 3.7 ± 0.1 A | 45.4 ± 8.1 A | 111 ± 20 | +29.1 | |
3 day | 6.3 ± 0.2 AB | 4.8 ± 0.3 C | 204 ± 16 C | 41 ± 6 C | 3.0 ± 0.3 B | 34.2 ± 6.7 B | 108 ± 19 | +46.3 |
Mycorrhiza . | Irrigation intervals . | Leaf color (1–9) . | Turfgrass quality (1–9) . | Fresh weight (g m−2) . | Dry weight (g m−2) . | Root length (cm) . | AMF colonization (%) . | AMF spore density (spore g soil−1) . | Mycorrhizal dependency . |
---|---|---|---|---|---|---|---|---|---|
Non-mycorrhiza | 1 day | 5.6 ± 0.6 ns | 5.4 ± 0.1 a** | 283 ± 24a* | 68 ± 7 a** | 2.5 ± 0.3 b** | – | – | – |
2 days | 4.8 ± 0.1 | 5.1 ± 0.5 a | 222 ± 26a | 50 ± 1 b | 3.8 ± 0.2 a | – | – | – | |
3 days | 5.1 ± 0.1 | 3.6 ± 0.1 b | 155 ± 27b | 17 ± 2 c | 2.6 ± 0.3 b | – | – | – | |
Mean | 5.2 ± 0.2 C** | 4.7 ± 0.3 C** | 220 ± 23 C** | 45 ± 8 D** | 3.0 ± 0.3 B** | – | – | – | |
F. mosseae | 1 day | 7.0 ± 0.4 ns | 6.9 ± 0.3 a* | 349 ± 25a** | 82 ± 18a** | 3.6 ± 0.3 a** | 66.5 ± 3.7 a** | 153 ± 3 a* | +17.1 |
2 days | 7.0 ± 0.2 | 6.6 ± 0.4 ab | 284 ± 14b | 63 ± 4b | 3.7 ± 0.3 a | 58.2 ± 1.8 b | 130 ± 6 b | +26.0 | |
3 days | 6.7 ± 0.2 | 5.6 ± 0.1 b | 165 ± 12c | 32 ± 3c | 2.1 ± 0.3 b | 32.3 ± 6.5 c | 137 ± 3 b | +46.9 | |
Mean | 6.9 ± 0.1 A | 6.3 ± 0.2 A | 266 ± 28 BC | 59 ± 9 C | 3.1 ± 0.4 B | 52.3 ± 5.6 B** | 140 ± 4 B** | +30.0 | |
C. etunicatum | 1 day | 7.8 ± 0.6 ns | 7.6 ± 0.4 a* | 403 ± 29a** | 128 ± 12a** | 4.8 ± 0.3 a* | 64.5 ± 2.9 ab* | 153 ± 9 a* | +46.9 |
2 days | 6.8 ± 0.1 | 6.8 ± 0.4 ab | 379 ± 64b | 110 ± 7a | 3.6 ± 0.3 b | 68.8 ± 2.7 a | 147 ± 3 ab | +54.5 | |
3 days | 7.1 ± 0.1 | 5.6 ± 0.1 b | 270 ± 80c | 67 ± 4b | 3.9 ± 0.3 b | 56.4 ± 4.0 b | 133 ± 7 b | +74.6 | |
Mean | 7.2 ± 0.2 A | 6.6 ± 0.3 A | 351 ± 29 A | 102 ± 10 A | 4.1 ± 0.4 A | 63.2 ± 2.4 A | 144 ± 4 B | +58.7 | |
R. irregularis | 1 day | 6.6 ± 0.6 ns | 6.4 ± 0.4 a* | 350 ± 12a** | 119 ± 3a** | 4.5 ± 0.4 a* | 49.7 ± 2.9 b* | 143 ± 3 b* | +42.9 |
2 days | 5.8 ± 0.1 | 5.8 ± 0.5 a | 289 ± 45b | 78 ± 8b | 3.5 ± 0.3 b | 54.5 ± 4.5 a | 167 ± 9 a | +35.9 | |
3 days | 6.1 ± 0.1 | 4.6 ± 0.1 b | 228 ± 13c | 47 ± 7c | 3.8 ± 0.3 b | 48.1 ± 3.2 b | 160 ± 6 ab | +63.8 | |
Mean | 6.2 ± 0.2 B | 5.6 ± 0.3 B | 289 ± 23 B | 81 ± 11 B | 3.9 ± 0.2 A | 50.8 ± 2.1 B | 157 ± 5 A | +47.5 | |
Mean | 1 days | 6.7 ± 0.4 A** | 6.6 ± 0.2 A** | 346 ± 16 A** | 99 ± 9 A** | 3.9 ± 0.3 A** | 45.2 ± 8.2 A** | 112 ± 20 ns | +26.7 |
2 days | 6.1 ± 0.2 B | 6.1 ± 0.3 B | 293 ± 25 B | 75 ± 7 B | 3.7 ± 0.1 A | 45.4 ± 8.1 A | 111 ± 20 | +29.1 | |
3 day | 6.3 ± 0.2 AB | 4.8 ± 0.3 C | 204 ± 16 C | 41 ± 6 C | 3.0 ± 0.3 B | 34.2 ± 6.7 B | 108 ± 19 | +46.3 |
Values with the lowercase letters (a,b,c) in each treatment are not significantly different when followed by Duncan's multiple range test at *P < 0.05 and **P < 0.01, ns, non-significant.
Values with the capital letters (A,B,C) in each treatment's mean are not significantly different when followed by Duncan's multiple range test at *P < 0.05 and **P < 0.01, ns, non-significant.
Data in the table are indicated as mean ± SE.
Considering the AMF parameters, it is seen that C. etunicatum treatment has the highest percentage of AMF root colonization with an mean of 63.2%, while R. irregularis treatment has the highest soil spore density with an mean of 157 spores g soil−1 (Table 4). One-day interval irrigations in plants forming symbiosis with F. mosseae; 1 and 2 days interval irrigations in plants forming symbiosis with C. etunicatum; 2-day interval irrigations in plants forming symbiosis with R. irregularis, the highest AMF colonization rate, and soil spore density occurred. While it was determined that mycorrhizal dependence occurred in all treatments, a parallel increase was observed according to the irrigation intervals in general. Especially C. etunicatum has the highest values in mycorrhizal dependence (Table 4).
Carbon dioxide (CO2) emission
Mean carbon dioxide emission in different mycorrhiza types and irrigation intervals.
Mean carbon dioxide emission in different mycorrhiza types and irrigation intervals.
Mean soil moisture in different mycorrhiza types and irrigation intervals.
Mean soil temperature in different mycorrhiza types and irrigation intervals.
The linear relationship of carbon dioxide with soil moisture and soil temperature.
The linear relationship of carbon dioxide with soil moisture and soil temperature.
DISCUSSION
This research investigated the effects of AM symbiosis on rhizosphere soil, turfgrass growth, and CO2 emissions from soil under different irrigation intervals (intervals of 1, 2, and 3 days). While there was no change in EC and pH in mycorrhizal rhizosphere soils at all irrigation intervals, an increase was determined in other parameters (organic matter, organic carbon (C), total N, P2O5, and K2O) (Table 3). It is known that plant C allocation to mycorrhizal fungi in the rhizosphere plays a dominant role in the formation and stabilization of organic matter through the production of mycorrhizal biomass, exudates, and necromass (Schmidt et al. 2011; Cotrufo et al. 2013; Frey 2019). In addition to being an important nutrient store for plants, this organic matter creates more than twice as much carbon (Schlesinger & Andrews 2000) and more than 80% of soil nitrogen (N) than the atmosphere and terrestrial vegetation combined (Simpson et al. 2007). Yang et al. (2011) also revealed that AMF treatments at different irrigation intervals can be a critical factor in the fixation of organic carbon and total N in the soil. In particular, the organic carbon attached to the soil increases the mineralization of organic phosphorus (P) (Zhang et al. 2016, 2018). As a result, AMF can increase plant growth by regulating the soil structure and helping the plant to take up water and nutrients that it cannot reach (Wu et al. 2008; Celebi et al. 2010; Erman et al. 2011; Lazcano et al. 2014). In addition, some researchers have shown that the effect of AMF on plant growth is highest even in soils with limited irrigation (Birhane et al. 2012; Ruzicka et al. 2012; Veresoglou et al. 2012). In our study, the increase in the growth parameters of trufgrass plants forming AM symbiosis supports this result (Table 4). This effect is especially prominent in C. etunicatum and R. irregularis species. As a matter of fact, when AMF parameters are examined, it is seen that C. etunicatum treatments have the highest AMF colonization percentage, while R. irregularis treatments have the highest soil spore density (Table 4). It has been observed that plants form a more effective symbiosis with mycorrhizal fungi under water stress (Manoharan et al. 2010; Demir et al. 2022). In particular, the fact that C. etunicatum has the highest values in both root colonization and mycorrhizal dependence shows that it forms a high degree of symbiosis with grass (Table 4). Suharno et al. (2017) reported that C. etunicatum forms an effective symbiosis with plants belonging to the Poaceae family.
The mean carbon dioxide (CO2) emission from soil was 3.5, 5.6 and 5.2% lower in F. mosseae, C. etunicatum and R. irregularis treated soils, respectively (Figure 3). This case was evaluated as mycorrhiza provides organic carbon retention in the soil. As a result of the study, the high organic carbon content in mycorrhizal soils also supports this case (Table 3). Mean CO2 emissions were 4.3 and 9.6% higher in 1-day intermittent irrigation compared to 2- and 3-day intermittent irrigations (Figure 3). Cheng et al. (2012) and Averill et al. (2014) reported that mycorrhiza treatments reduce carbon emissions from the soil. Paterson et al. (2016) also stated that mycorrhiza reduces organic matter mineralization in soil. As a matter of fact, nitrogen in the soil can be oxidized and cause CO2 emissions (Yu et al. 2014). The ratio of organic C to total N in the soil can affect CO2 emissions by changing the oxidation process and the amount of organic matter (Yerli & Şahin 2021). This case can be evaluated in relation to the fact that irrigation frequently changes the organic matter dynamics in the soil and increases oxidation due to increased microorganism activity. Jabro et al. (2008) reported that increased microbial activity with increasing soil moisture causes decomposition of organic matter and thus increases CO2 emissions. Similarly, Sinaie et al. (2019) stated that with the decrease in soil moisture, microorganism activities slowed down and CO2 emissions decreased accordingly. In our study, higher mean soil moisture (Figure 4) and lower mean soil temperature occurred in soils with frequent irrigation (Figure 5). This case can be evaluated in relation to the cooling effect of water ingress into the soil. Similarly, it is stated that the continuous application of water to the soil increases soil moisture and decreases soil temperature (Yerli & Şahin 2021). Mancinelli et al. (2015) reported that water ingress into the soil can create a cooling effect by increasing soil moisture. This suggests that it activates the soil biology and increases the release of CO2 from the soil as a result of mineralization. Soil moisture balance and processes can increase emissions by affecting the oxidation scale of organic C and N (Morugan-Coronado et al. 2011). Senyigit & Akbolat (2010) stated that by reducing soil moisture, CO2 emissions decreased. Yerli et al. (2019) noted that scarce irrigation practices reduce emissions. Du et al. (2019) and Zhao et al. (2020) revealed that soil temperature, which affects mineralization, is positively related to CO2 emissions. Jabro et al. (2008) reported that soil temperature increased CO2 emissions by 59%. In fact, the CO2 emission reduces when the water need of the plants forming the AM symbiosis lowers (Cheng et al. 2012; Averill et al. 2014), and the results of our research are consistent with this.
CONCLUSION
The study findings showed that AM symbiosis increases with increasing irrigation interval. In particular, CO2 emissions in soil decreased in colonized plants of AMF. It can be said that the reason for this decrease is that AMF reduces the water requirement in the plant. However, this symbiosis has also shown that turf plants improve growth and regulate soil structure under varying irrigation intervals. Soil management that enhances the colonization of plant roots by arbuscular mycorrhizae can contribute to more efficient use of water in changing environmental conditions, as well as reduce CO2 emissions and, therefore, the environmental impact of agricultural practices.
RESEARCH INVOLVING HUMAN PARTICIPANTS AND/OR ANIMALS
The research involved no human participants or animals.
INFORMED CONSENT
The research involved no human participants and animals, so a statement on the welfare of animals is not required.
DATA AVAILABILITY STATEMENT
All relevant data are included in the paper or its Supplementary Information.
CONFLICT OF INTEREST
The authors declare there is no conflict.