Agriculture Reference
In-Depth Information
10.3.2.3
Effect of MSWC Heavy Metals on Agricultural Soil
Heavy metals do not degrade throughout the composting process, and frequently
become more concentrated due to microbial degradation and loss of carbon and
water from the compost (Richard 1992 ). A significant decrease of soil microbial
biomass was noted after three years of MSW compost application (Bouzaiane et al.
2007b ). The decrease of microbial biomass was due to heavy metals content eleva-
tion in compost at 80 t ha −1 treated soil. Thus according to the authors the highest
rate of MSW compost induced the lowest ratio of biomass C to soil organic carbon
and the lowest ratio of biomass N to soil organic nitrogen.
Carbonell et al. 2011 conducted to assess the inputs of metals to agricultural
land from soil amendments. Maize seeds were exposed to a municipal solid waste
(MSW) compost (50 Mg ha −1 ) and NPK fertilizer (33 g plant −1 ) amendments con-
sidering N plant requirement until the harvesting stage with the following objec-
tives: (1) determine the accumulation of total and available metals in soil and (2)
know the uptake and ability of translocation of metals from roots to different plant
parts, and their effect on biomass production. According to the authors the results
showed that MSW compost increased Cu, Pb and Zn in soil, while NPK fertilizer
increased Cd and Ni, but decreased Hg concentration in soil. The root system acted
as a barrier for Cr, Ni, Pb and Hg, so metal uptake and translocation were lower in
aerial plant parts. Biomass production was significantly enhanced in both MSW and
NPK fertilizer-amended soils (17 %), but also provoked slight increases of metals
and their bioavailability in soil. The highest metal concentrations were observed in
roots, but there were no significant differences between plants growing in amended
soil and the control soil. Important differences were found for aerial plant parts as
regards metal accumulation, whereas metal levels in grains were negligible in all
the treatments.
10.4
Conclusion
The MSW compost application to an agricultural soil can improve and maintain
soil quality by decreasing the need of chemical fertilizers and pesticides, improving
soil tillage, increasing soil microbial biomass and enzyme activities, increasing the
organic matter of degraded soils and increasing the plants productivities. However
the MSW compost could be contaminated by heavy metals, toxics compounds and
pathogens that limits the use of the compost. The utilization of MSW compost in
low rate should be used for sustainable agricultural soil to mitigate the cumulative
effects of environmental pollution and gain public acceptance.
Acknowledgment Special thanks to all who helped in the water treatment and recycling labora-
tory of CERTE (Centre de Recherche et des Technologies des Eaux).This mini review expressed
the views of the authors and do not necessarily reflect the opinion of CERTE.
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