Fungal Indicators of Sensitivity and Resistance to Long-Term Maize Monoculture: A Culture-Independent Approach

Abstract

Although fungi are regarded as very important components of soils, the knowledge of their community in agricultural (monocultural) soils is still limited. This indicates that soil fungal communities are investigated less intensively than bacteria. Therefore, the main goal of this paper was to evaluate the fungal mycobiome structure in monoculture soils in a culture-independent approach. Firstly, the study was conducted to identify the core mycobiome composition and its variability at different stages of the maize growing season (spring, summer, and autumn). Secondly, we identified and recommended fungal indicators of both sensitivity and resistance to long-term maize monoculture. Two neighboring fields from the Potulicka Foundation area were selected for the study: K20 sown with a Gorzow mixture (intercropping mixture) to improve soil quality after a maize monoculture in 2020 and K21, where long-term (over 30 years) monoculture cultivation was continued. The basic chemical features [acidity, redox potential, total organic carbon (TOC), and moisture] of soils were determined, fungal genetic diversity was assessed by ITS next generation sequencing (NGS) analyses, and biodiversity indices were calculated. The results of the NGS technique facilitated recognition and classification of the fungal mycobiome to the taxonomic genus level and changes in the fungal structure in the three periods (spring, summer, and autumn) were assessed. It was evidenced that the mycobiome composition was dependent on both the seasons and the agricultural practices. It was also found that even a 1-year break in the monoculture in favor of an intercropping mixture improved soil properties thus contributing to higher biodiversity. Mortierella was recommended as a potential indicator of sensitivity to long-term maize cultivation, whereas Solicoccozyma and Exophiala were proposed as indicators of resistance to long-term maize cultivation. We proved that the precision farming principles applied on the Potulicka Foundation farm had a very positive effect on fungal biodiversity, which was high even in the long-term maize monoculture field. Therefore, the monoculture cultivation carried out in this way does not induce biological degradation of monoculture soils but preserves their good biological quality.

Reduced Chemical Fertilizer Combined With Bio-Organic Fertilizer Affects the Soil Microbial Community and Yield and Quality of Lettuce

“…Soil microorganisms play a crucial role in energy flow and nutrient cycling in soil, and participate in the decomposition of organic matter, degradation of xenobiotics, soil carbon sequestration, and prevention of crop diseases ( Morris and Blackwood, 2015 ; Tao et al, 2015 ). Bacteria and fungi are indicator species of the soil environment ( Hermans et al, 2017 ; Wolińska et al, 2021 ), and are conducive to the improvement of the soil structure and plant growth. Fungi can grow symbiotically with crops to form mycorrhizae, which are of major significance for promoting plant growth and maintaining agroecosystem stability ( Brito et al, 2012 ).…”

Synthetic Microbial Community Promotes Bacterial Communities Leading to Soil Multifunctionality in Desertified Land

“…The CF treatment increased the relative abundance of Mortierellomycota as a dominant phylum. Mortierellomycota often survive in nutrient-rich soils as saprophytes and have been strongly correlated with soil pH, nitrogen, and phosphorus nutrients in previous studies [ 34 ]. Combined fertilizer applications can avoid the problems of nutrient imbalance and poor structure associated with single applications [ 35 ].…”

Effect of Reduced Nitrogen Fertilization Recommended by the EC "From Field to Table" Strategy on the Chemical and Biological Traits of Soils under Maize Crops

“…The large-scale area of agricultural soils (20 ha) managed by the Potulicka Foundation and dedicated to the current experiment is a guarantee of the representativity of the obtained results (taking into account the heterogeneity of the soil environment). Moreover, the Potulicka Foundation agricultural acreage is predominantly (>95%) mapped using GPS, and the precision farming system is successfully applied in the whole area [24]; hence, precise doses of fertilizers were applied and samples for analysis were collected from the same places. Within each of the 10 ha fields (Figure 1), 2.5-ha "micro-plots" were exposed to the following N treatments: (1) control sites with no fertilization (0.0 kg ha -1 ) from which 5 composite samples were taken and variable N rates: (2) amount suggested by the fertilizer manufacturer (115.0 kg ha -1 ) represented by 5 composite samples, (3) standard fertilizer rate reduced by 20% (in agreement with the EC directive) represented by 5 composite samples, and (4) standard fertilizer rate reduced by 40% (also 5 composite samples).…”