Organic soil improvers are mainly used for their potential for preventing soil losses. This study investigates the physicochemical properties of six different organic soil improvers and their effects on the
properties and productivity of reconstituted anthropic soils during short-term application compared to
farm manure. Treatment materials were obtained from Tunisian agricultural waste composts (almond
shell (AS), sesame bark (SB), olive cake (OC), olive mill wastewater sludge (OMWS) and poultry manure
(PM)) as well as mixtures of compost–manure (CM). The characterization of soil conditioners shows that
(i) nitrogen contents are higher in olive wastes and PM-based composts; (ii) carbon/nitrogen ratio (C/N)
and the organic matter (OM) contents are in the ranges of 14.1–29.7 and 19.3–64.5%, respectively; (iii)
the electrical conductivity (EC) is higher in manure (M) and compost–manure mixture (4.8–10.4 mS/cm)
and (iv) pH values are alkaline (8.2–8.8). Treatments were applied as components of a reconstituted soil
at a rate of 14 kg/m
2
. Except for the manures, the mixtures of soil and treatment material (in a ratio of
600 L/28 kg) were placed in metallic basins to form the reconstituted anthropic soil. Plot areas of 2 m
2
were used for each treatment and 2×2m2
for the control. An assessment of the geochemical properties
of soils during the cultivation period reveals variations in soil organic matter (SOM) contents as well as
pH and EC values. Soil productivity is determined by quantitative and qualitative comparison of tomato
fruits obtained from each plot amended with manure-treated soil