Spore Density of Arbuscular Mycorrhizal Fungi is Fostered by Six Years of a No-Till System and is Correlated with Environmental Parameters in a Silty Loam Soil

Abstract

Arbuscular mycorrhizal fungi (AMF) play major roles in nutrient acquisition by crops and are key actors of agroecosystems productivity. However, agricultural practices can have deleterious effects on plant-fungi symbiosis establishment in soils, thus inhibiting its potential benefits on plant growth and development. Therefore, we have studied the impact of different soil management techniques, including conventional moldboard ploughing and no-till under an optimal nitrogen (N) fertilization regime and in the absence of N fertilization, on AMF spore density and soil chemical, physical, and biological indicators in the top 20 cm of the soil horizon. A field experiment conducted over six years revealed that AMF spore density was significantly lower under conventional tillage (CT) combined with intensive synthetic N fertilization. Under no-till (NT) conditions, the density of AMF spore was at least two-fold higher, even under intensive N fertilization conditions. We also observed that there were positive correlations between spore density, soil dehydrogenase enzyme activity, and soil penetration resistance and negative correlations with soil phosphorus and mineral N contents. Therefore, soil dehydrogenase activity and soil penetration resistance can be considered as good indicators of soil quality in agrosystems. Furthermore, the high nitrate content of ploughed soils appears to be detrimental both for the dehydrogenase enzyme activity and the production of AMF spores. It can be concluded that no-till, by preventing soil from structural and chemical disturbances, is a farming system that preserves the entire fungal life cycle and as such the production of viable spores of AMF, even under intensive N fertilization.

Evaluation of Changes in Glomalin-Related Soil Proteins (GRSP) Content, Microbial Diversity and Physical Properties Depending on the Type of Soil as the Important Biotic Determinants of Soil Quality

“…Therefore, with such a small amount taken for testing in the sequencing of the ITS variable region for fungi in the NGS method, it could happen that this material has not been amplified. Similar results in AMF spores were obtained by authors of other papers [46][47][48]. Therefore, the results obtained by us are all the more valuable because both a modern research method (NGS in paper Grz ądziel and Gał ązka [11]) and traditional methods of counting AMF spores were used in the present study.…”

The use of soil biostructures created by soil fauna ecosystem engineers fed with different organic matterials as inoculum source of arbuscular mycorrhiza fungi on cocoa seedling

“…The correlation with organic C, total-N, C/N ratio, and total-K is positively insignificant (Table 4). Several studies also reported an insignificant relationship between total AMF spore density with soil pH, organic C, total-N, C/N ratio (Sivakumar, 2013;Verzeaux et al, 2017). Wang et al (2015) reported the relationship between AMF spore density and total-P soil was insignificant, whereas in this study a positive significant correlation was found (r 2 = 0.74) at the p < 0.05 level (Table 4).…”

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

“…Residual, organic material present in the soil was also able to increase hyphal growth, independently of the host plant, which probably explains why in the absence of tillage and of N fertilization, AMF development was improved [17] as well as fungal spore density [105].…”