New solutions are required to maintain yields under the terms of tightened fertilizer regulations and the reduction of environmental detriments caused by industrial agriculture. Therefore, the EU has implemented microorganisms such as arbuscular mycorrhizal fungi in its fertilizer regulations. Although fundamental research has produced substantial forthcomings in the understanding of the basic functioning of plant-mycorrhiza associations and their contribution to plant nutrition and crop resource-use efficiency, field application of mycorrhiza-based products yielded in equivocal and unpredictable results that are highly site-specific. Predictability of the desired benefits that compensate for the economic investment in mycorrhiza application is, however, required, being it yield increments or staying within environmental regulations. The obvious agronomical benefits are higher yields and increased crop resource-use efficiency which mycorrhizas should confer from underground but these are emergent properties and a function of time- and area-dependent environmental conditions. Hence, the project aims to develop field application strategies that yields in successful application of mycorrhiza products and to increase the predictability of achieving the desired agronomical benefits with application of mycorrhiza.
The strategy of the project is firstly, to develop customized inoculants for maize and potato cultures comprising a consortium of mycorrhizal fungi that are compatible with plants and the field soils in pot trials. To quantify the effectiveness and the likelihood of benefit emergence upon field inoculation the project uses the novel precision-farming tool ‘Geophilus electricus’ for mapping the spatial soil texture heterogeneity in high resolution. The rationale behind the soil texture mapping is that soil texture is a trait which is variable in space and constant in time and valid over several growing seasons. It represents the basic framework that sets the physico-chemical boundaries of underground conditions for rooting plants and mycorrhizal fungi in a given climate. The weather across the growing season will induce periodical transitions between above- and below-ground limitations to plant growth. The soil properties determine the onset and duration of below-ground growth limitations which are potentially alleviated by mycorrhizas. Climatic conditions, plant growth, nutrition and mycorrhizal development will be monitored across two growing seasons within field inoculation trials that are implemented into real farming conditions under conventional farming practice and under ‘Bioland’ practice. Based on soil heterogeneity maps intelligent field designs are applied that span contrasting soil conditions.
The project combines scientific expertise from the IGZ with the knowledge of the ‘Institut für Pflanzenkultur’ in developing commercial mycorrhizal products and with two farmers (conventional farming and ‘Bioland’ farming). The project aims to strengthen implementation of mycorrhiza application into the workflow of field crop cultivation and to increase the predictability of effectiveness of mycorrhizal products. This will enable profound decision making on when and where mycorrhizal products can be applied. Area-specific inoculation will become possible that reduces the economic risks of inoculation for farmers and can maximize input-scaled yield benefits.