Short-term response to vermicompost amendment of chemical and biochemical properties of soil under greenhouse farming

Intensive cultivation of greenhouse crops can damage soil quality due to higher micro-environmental temperatures than field crop production, the absence of rotations, the preference of milling to ploughing, the mineral fertilization and the removal of crop residues without the organic matter reintegration. The compost addition to agricultural soil mainly enhances the organic matter content having, in turns, effects in improving physical, chemical, biochemical and microbiological soil properties, preventing erosion, increasing water holding capacity, cation exchange capacity, nutrient absorption by plants. Further a progressive carbon sequestration in soil with the consequent mitigation of climate changes occurs whereas the non-use of organic fertilizers produces a loss in C stock in soil as carbon dioxide in the atmosphere. The degradation of soil quality is reflecting on the crop yields of the ready-to-eat food of the Plain of Sele river in Campania region in South Italy.

Objectives of this research was to assess the short-term effect of vermicompost as organic soil conditioner in place of other organic fertilizers under conventional farming. Vermicompost derived from digestate obtained in anaerobic digestion plant of the Plain of Sele using, as ingestate, livestock sewage, olive mill wastewater and whey from dairy industry. Soil solarization was carried out during the summer to control weeds and soil pathogens. The chemical and biochemical properties of soils sampled after 4 days from soil amendment were investigated to determine the correlation between the use of vermicompost as organic soil conditioner and C stock, nutrient availability, and crop yields. Solarization negatively affected soil respiration and overall enzymatic activities compared to plots without the treatment. Vermicompost as well as pellet, used as other organic soil conditioner, increased soil respiration only in not solarized plots. Conversely no significant changes in term of microbial biomass carbon among treatments occurred. Different responses in terms of crop yields of rocket were observed in plots cultivated under diverse treatment: solarized plots produced greater amount of rocket than not solarized plots and plot amended with vermicompost showed the best performance among solarized ones.

This work was part of the project “Sustainable management of soil fertility in the Sele Plain to produce ready-to-eat food as cover crops through organic amendment deriving from local livestock sector” funded by PSR Campania 2014/2020.