Organic fertilizers and amendments to promote soil restoration and cover crop development

Cover crops are widely employed in woody cropping systems as a strategy for soil protection and restoration, aimed at preventing soil erosion and degradation. However, their successful implementation faces significant challenges across diverse edaphoclimatic conditions, such as arid and semiarid environments and highly degraded soils.

This study aims to evaluate the effects of various agricultural inputs (organic fertilizers and amendments) on cover crop characteristics (emergence, plant phenology, and aboveground biomass), as well as soil physico-chemical and biological properties (pH, electrical conductivity, infiltration, bulk density, soil moisture, macroaggregates, organic matter content, enzymatic activity and soil respiration). For this purpose, pot and field-scale trials were established using a mix of three native species commonly used as soil cover in Southern Spain—Bromus rubens, Brachypodium dystachion, and Calendula arvensis. These species were sown under six different treatments: i) unfertilized control, ii) biochar, iii) compost, iv) compost coapplied with biochar, v) pelletized organic fertilizer, and vi) pelletized organic fertilizer coapplied with biochar. For the pot trial, two replicates per treatment were set up inside a shaded structure; for the field trial, 24 microplots (1 x 1 m² each) were established following a randomized block design with four blocks. Weekly assessments have been conducted to monitor phenological stages and ground cover extent. At the end of the plant growth cycle, soil properties will be analyzed to assess treatments effects. To ensure cover crop germination, support irrigation was provided to all pots and microplots immediately after sowing.

We will present preliminary results from these trials, with plans to continue in future years. These findings will serve as a demonstration and experimental resource providing insights for practitioners and stakeholders interested in implementing cover crops in woody crop systems under challenging soil conditions. Based on these initial results, further adjustments and improvements will be introduced in the coming years.

Acknowledgements: ECOMED (PR.AVA23.INV202301.035) and TUdi (H2020 GA101000224) projects.