Implications of soil management practices and application of biocontrol strains on soil disease suppressiveness for improved soil health and sustainable plant production

Project number: 031B0514A
Contact: Dr. Rita Grosch, Leibniz-Institute of Vegetable and Ornamental Crops (IGZ)
Project team: Leibniz-Institute of Vegetable and Ornamental Crops, Anhalt University of Applied Sciences, Julius Kühn–Institut, Center for Biotechnology, University Hohenheim, Helmholtz Zentrum München
Duration: 01/10/2018 - 31/01/2022


Project aim 

The project aim is the investigation of the impact of long-term farming strategies (intensive and extensive) on the soil microbiome and its function in terms of soil suppressiveness against plant pathogens. In addition, the associated rhizosphere microbiome will be analyzed considering plant characteristics (model: lettuce). 

Intensive farming strategies can result in substantial yield losses through accumulation of plant pathogens in soil and the occurrence of plant diseases. The ability of soils to suppress plant pathogens is a characteristic of soil quality and health. This ability is mediated to a large extent by the composition of the soil microbial community. A better understanding of how farming strategies affect soil properties such as the soil microbiome is key to proposing improved farming strategies for sustainable agriculture. 
Expected results 

and 2We expect to gain new insight into soil and rhizosphere microbiomes, as well as their functions involved in soil disease suppressiveness. This knowledge will allow the evaluation of farming strategies for optimizing soil functions regarding certain bacterial and fungal taxa that demonstrate positive effects on soil health, especially on the suppression of pathogens. Finding indicators for soil suppressiveness will allow the evaluation and optimization of farming strategies. Root exudate components with consistent beneficial effects on plant growth and inhibitory effects on pathogens can open new perspectives for practical application. The socio-economic part of the research enlightens consequences and interpretations of political regulations in the field and delivers recommendations for bioenergy decision-making. 


project results from phase 1  and 2

Long-term farming practice such as tillage and crop rotation affect significantly the structure of prokaryotic and fungal community in the soil and in the rhizosphere. An effect on rhizosphere microbiota was revealed also by nitrogen-fertilization intensity. A higher bacterial diversity was observed in organically compared to mineral fertilized soils. Differences in growth and plant health were found on the model plant lettuce grown under controlled conditions in soils under various farming practice. Our results confirmed the crucial role of the plant in driving rhizosphere microbiota assemblage. We revealed differences in suppressiveness against the pathogen Rhizoctonia solani comparing the soils.   

The results obtained from a long-term field experiment at Anhalt University of Applied Sciences (Campus Bernburg) show that agricultural management practices like tillage, fertilization regime and preceding crop affect soil as well as the rhizosphere microbiome and thus plant growth and health. Due to the release of organic compounds from the root system, the rhizosphere microbiome differs from the bulk soil microbiome. An increased microbial biomass and modified soil/rhizosphere microbiome due to reduced tillage (cultivator) and extensive nitrogen application improved plant health. Furthermore, the use of a consortium with beneficial microorganisms promotes plant growth under stress conditions such as drought. In addition, the analysis of plant stress indicators showed that the use of the consortium mitigates plant stress tolerance under field conditions.   


Expected results phase 3              

The effect of the microbial consortium will be tested against biotic stress (soil-borne pathogens) in combination with the cultivation of catch crops. We expect that catch crops improve the microbial diversity in the soil and result in synergistic disease suppression effects together with the application of the consortium on the main crop. Based on the integration and synthesis of all generated data we expect to obtain detailed information on the taxonomic and functional microbial rhizosphere community in relation to plant traits depending on farming practices.