In Winter Wheat, No-Till Increases Mycorrhizal Colonization thus Reducing the Need for Nitrogen Fertilization

Abstract

Arbuscular mycorrhizal fungi (AMF) play a major role in the uptake of nutrients by agricultural plants. Nevertheless, some agricultural practices can interrupt fungal-plant signaling and thus impede the establishment of the mycorrhizal symbiosis. A field experiment performed over a 5-year period demonstrated that both the absence of tillage and of nitrogen (N) fertilization improved AMF colonization of wheat roots. Moreover, under no-till conditions, N uptake and aboveground biomass production did not vary significantly between N-fertilized and N-unfertilized plots. In contrast, both N uptake and above ground biomass were much lower when N fertilizer was not added during conventional tillage. This finding strongly suggests that for wheat, no-till farming is a sustainable agricultural system that allows a gradual reduction in N fertilizer use by promoting AMF functionality and at the same time increasing N uptake.

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

“…It has already been shown that both spore density and AMF colonization are representative markers of the effect of tillage on AMF biological activity. For example, in comparison to CT, NT had a positive impact on both AMF colonization of wheat roots [7] and AMF spore density [26]. The lower density of AMF spores in CT treatments could be explained by hyphal networks disturbance resulting from ploughing [26].…”

“…However, AMF are particularly sensitive to physical, chemical, and biological disturbances caused by human activities that limit their establishment in agrosystems. Although it has been shown that tillage (through aggregate disruption [4]) and N fertilization can reduce the colonization of crops by arbuscular mycorrhizal fungi [5][6][7], our knowledge of the factors that determine the successful establishment of an AMF symbiosis remains limited. Spore density of AMF together with the level of hyphal growth and branching are critical for successful root colonization [6,8].…”

Investigating the Combined Effect of Tillage, Nitrogen Fertilization and Cover Crops on Nitrogen Use Efficiency in Winter Wheat

“…Šíp et al [36] suggested that during plant vegetative growth, the environmental conditions were more favorable for N uptake, due to a better soil moisture availability when tillage was reduced. Moreover, Maltas et al [47] reported that when the soils were converted from CT to NT in the presence of cc, N mineralization increased over the conversion period, thus increasing the availability of soil N [48].…”

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

“…Such penetration resistance depends both on the type of soil and on the timing of the no-till cultivation system. If the SPR is not too high, it is not necessarily detrimental for root colonization by the AMF propagules present under no-till conditions, in comparison to those conventionally cultivated [17]. However, when there is a critical increase of soil compaction in soils managed under no-till conditions, it could limit root growth and development and thus reduce yield [54].…”

“…This is also why intensive research is currently being conducted to expand symbiotic N2 fixation to a greater diversity of crop plants [16]. An increasing number of studies have shown that conservation tillage using no-till and permanent plant cropping systems also significantly enhances the potential of plant colonization by AMF in comparison with conventional tillage [17]. The occurrence of even more efficient tripartite symbioses between legumes, Rhizobiacae and AMF has also been suggested [18].…”