Nature conservation management residues as alternative for farm yard manure: effects on nutrients, carbon and disease suppression

Residues from nature management can act as an alternative organic amendment for agricultural soils. Currently, farm yard manure application is a common practice for ornamentals cultivated in soil. Due to the higher C/P ratios of management residues compared to farm yard manure, larger carbon additions are possible at legal P application restrictions. In two field experiments with Acer campestre (maple) and Chrysanthemum ‘Merlino’, it was verified if application of chopped soft rush straw or chopped heath biomass had beneficial effects on crop, soil and disease suppression. Both field trials consisted of a soil chemistry/growth and a disease test. For both crops, three treatments (farm yard manure, chopped soft rush and chopped heath biomass) were applied in four replicates (blocks). The application rate of the three materials varied in order to apply the same dose of organic matter by each material. Measurements of CO2 fluxes at the soil surface revealed no significant differences in mineralization rate of the three organic amendments. Application of farm yard manure resulted in increased soil nutrient concentrations (mineral N, P, K, Mg, Ca) in the field maple trial only, compared to the application of management residues. No significant effects of the organic amendment on the number of Erysiphe infected maple trees was observed. Similarly, there were no significant differences in Verticillium dahliae infected chrysanthemums for the three treatments. However, chrysanthemum quality was larger for the farm yard manure treatment and in one field chrysanthemums had smaller plants for the chopped heath biomass application. Despite these small effects in plant performance, we can state that nature conservation management residues can be considered valuable substitutes for farm yard manure, especially on fields where P restrictions limit the use of other soil amendments.

Publication year:2021

Keywords:Biomass valorization, Carbon sequestration, Soil microbiome, Soil quality

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