Arbuscular mycorrhizal fungal diversity, root colonization, and soil alkaline phosphatase activity in response to maize-wheat rotation and no-tillage in North China

Abstract

Monitoring the effects of no-tillage (NT) in comparison with conventional tillage (CT) on soil microbes could improve our understanding of soil biochemical processes and thus help us to develop sound management strategies. The objective of this study was to compare the species composition and ecological function of soil arbuscular mycorrhizal (AM) fungi during the growth and rotation of crops under NT and CT. From late June 2009 to early June 2010, 32 topsoil (0-15 cm) samples from four individual plots per treatment (CT and NT) were collected at both the jointing and maturation stages of maize (Zea mays L.) and wheat (Triticum aestivum L.) from a long-term experimental field that was established in an Aquic Inceptisol in North China in June 2006. The AM fungal spores were isolated and identified and then used to calculate species diversity indices, including the Shannon- Wiener index (H'), Evenness (E), and Simpson's index (D). The root mycorrhizal colonization and soil alkaline phosphatase activity were also determined. A total of 34 species of AM fungi within nine genera were recorded. Compared with NT, CT negatively affected the soil AM fungal community at the maize sowing stage, leading to decreases in the average diversity indices (from 2.12, 0.79, and 0.82 to 1.79, 0.72, and 0.74 for H', E, and D, respectively), root mycorrhizal colonization (from 28% to 20%), soil alkaline phosphatase activity (from 0.24 to 0.19 mg/g/24 h) and available phosphorus concentration (from 17.4 to 10.5 mg/kg) at the maize jointing stage. However, reductions in diversity indices of H', E, and D were restored to 2.20, 0.81, and 0.84, respectively, at the maize maturation stage. CT should affect the community again at the wheat sowing stage; however, a similar restoration in the species diversity of AM fungi was completed before the wheat jointing stage, and the highest Jaccard index (0.800) for similarity in the species composition of soil AM fungi between CT and NT was recorded at the wheat maturation stage. Our results also demonstrated that NT resulted in the positive protection of the community structure of AM fungi and played an important role in maintaining their functionality especially for maize seedlings.

Arbuscular Mycorrhiza Stimulates Biological Nitrogen Fixation in Two Medicago spp. through Improved Phosphorus Acquisition

“…The two soils employed in this study as substrate components caused the P-sorption kinetics to differ between the two substrates ( Table 1 ). Presumably, P was more efficiently immobilized in the calcareous LT soil with pH 7.88 (Püschel et al, 2016) than in the acidic Tän Luvisol with pH 6.2 (Jansa et al, 2003b). If the Tän substrate was fertilized with 40 mg kg -1 P, the water extractable P levels exceeded 10 mg kg -1 , thereby resulting in P-sufficient conditions even for the NM plants ( Table 1 and Figure 3 ).…”

Agricultural practices to improve nitrogen use efficiency through the use of arbuscular mycorrhizae: Basic and agronomic aspects

“…Consequently, in the following spring, there was an increase in the spore density and AMF colonization rate of sunflower and maize [58]. In addition, it was observed that no-till increased the external mycorrhizal mycelium length in comparison to conventional tillage in a maize-wheat rotation [59]. It is thus advisable to improve AMF life cycles throughout crop rotation by direct seeding of mulch-based cropping systems, as mechanical soil disturbance is avoided and the plant covering period is maximized (see Fig.…”

Microbial abundance and enzyme activity in sediments of the rapid-pool-benchland systems in the natural Duliu River of China

“…Similar studies also support this point. For example, there was a poor correlation between microbial colonization rate and phosphatase activity in croplands with conventional tillage, but a significant correlation in cropland with the no-tillage management (Hu et al, 2015). Additionally, no correlations between microbial abundance and enzyme activity were found in the soils of forests because of intense human disturbances (Hu et al, 2002).…”

“…Alkaline phosphatase and soil urease catalyze dephosphorylation and hydrolysis of urea to accelerate the release of phosphate ions and ammonia from OM, as well as the cycling of phosphorus and nitrogen (Deng et al, 2009;Millar et al, 2015). These processes also result in the synthesis of small molecules, such as adenosine triphosphate, to regulate biochemical functions (Hu et al, 2015). Alkaline phosphatase and urease activities in sediment from pools were significantly higher than those in rapids and benches.…”