ABSTRACT
Due to long drought
periods and over utilizing of range lands in the arid lands of Jordan, the land is degraded and
lost most of its natural vegetation. To rehabilitate the natural vegetation
cover, there is a need to enhance the fertility of soil to be able to support
vegetation under limited amounts of rainfall. One of the available and viable
options that might be able to provide a solution for the soil poverty is
applying materials with high organic contents such as biosolid. Bio-solids are
nutrient-rich organic materials from the treatment of domestic sewage in a
wastewater treatment facility. Bio-solids are a beneficial resource, containing
essential plant nutrients and organic matter and are recycled as a fertilizer
and soil amendment. A pilot study is designed based on randomized block design
in which five treatments are used to represent the loading rates of bio-solids application. These loads were
10, 20, 30, 40 and 50 tons/ha with
four replicates for the control and each application load. Samples from
Bio-solid, soil and plants are tested for chemicals and microbes. Chemical
tests include: As, Cd, Cr, Co, Cu, Hg, Mo, Ni, Pb, Se, and Zn, while microbial tests
include: total fecal Coliform, Salmonella, and Helminthes eggs. Results of
total microbial count in bio-solids, soil and plant samples indicated that
there were no detectable counts found in all of the experimental plots. Results
showed increase in most of the heavy metals concentration in soil treated with
bio-solids from that of soil in control plots; some of these elements doubled after applying the
bio-solid. For the dry plant matter, analysis for heavy metals showed that most
of the heavy metals studied were below the detection limit. Only the Cr, Cu and Zn are changed but not
significantly compared with the control plot. Results obtained were showed that the highest dry biomass value was obtained with
bio-solids loading rate 40 tons/ha and more. Increasing rate
of application after 40 tons/ha did not show significant differences in the
biomass yield. Also, the total nitrogen in the plants increased by 40% for all
bio-solid application loads compared with the control lot.