Physical-chemical Characterization and Microbial Activity of Alternative Substrates for Arugula Cultivation (Eruca sativa Mill.)

Aims: The objective of this work was to evaluate the physical, chemical and biological characteristics of the substrates formulated from carbonized rice husk, industrial sludge, vermiculite, soil and commercial substrate, as well as the development of arugula seedlings cultured in the compositions.

Study Design: Eight treatments were studied in a completely randomized design: TO = commercial substrate (SC); T1= commercial substrate + soil (1SC:1S); T2= commercial substrate + soil + carbonized rice husk (1SC:1S:1CAC); T3= commercial substrate + vermiculite (1SC:1V); T4= commercial substrate + vermiculite + carbonized rice husk (1SC:1V:1CAC); T5= sludge + vermiculite (1L:1V); T6= sludge + vermiculite + carbonized rice husk (1L:1V:1CAC); T7= commercial substrate + sludge + vermiculite + carbonized rice husk (1SC:1L:1V:1CAC), being carried in box of expanded polystyrene (PEE) with four replicates.

Place and Duration of Study: The experiment was conducted in an experimental area of Campus Pelotas, Federal Institute of Sul-rio-grandense, Pelotas, Brazil, period from October until December 2015.

Methodology: The chemical characteristics evaluated were: pH in water, organic carbon, total nitrogen, total phosphorus, total potassium and C/N ratio. The physical characteristics as total porosity, macroporosity, microporosity, water retention capacity and density. Also, organic matter, electrical conductivity and basal respiration were evaluated.

Conclusion: The SC:V and SC:V:CAC treatments present pH, C Org., N, OM and C/N characteristics close to the commercial substrate, but present P, K and EC levels below the ranges indicated in the literature as suitable for the formation of substrates. Regarding the physical characteristics, the formulation closest to the ideal was also SC:V, which results in good microporosity, total porosity, water retention capability, but low macroporosity and density.