Soil solarization: A sustainable agriculture approach to reduce microorganisms in chicken manure-treated soil

The common practice in many countries of using chicken manure in soil as a source of nutrients to plants is of paramount importance in sustainable agriculture. However, the application of non-composted manure on soil could contribute to contamination of the environment by fecal microorganisms. This creates a health hazard to humans, domestic animals, and to wildlife. The impact of soil solarization on reduction of microorganism-indicators of fecal contamination in chicken manure-treated soils has not been evaluated. In this study, 1.5 kg/m(2) of chicken manure was applied to 40 cm deeply-ploughed clayish calcareous soils of four greenhouses. The soils of four other greenhouses wereleft as control-untreated with manure. Litter incorporation in the soil was performed by a harrow with 20 cm penetration depth. Irrigation was applied to soil of the eight greenhouses to obtain an average humidity at 40 cm-soil depth equivalent to 92.9%. Soil solarization of the chicken manure-treated soils with a 50 mum thick-polyethylene film for a period of six weeks resulted in an average 20 cm-soil depth temperature at 15 hr of 40 C in comparison to 28.3degreesC obtained in soil with no polyethylene film application. Solarization resulted in reduction in different microorganism-indicators per gram of chicken manure-treated soil collected at 20 cm depth in comparison to the count in the same soil before solarization. The percent reduction in counts in increasing order was: Staphylococcus aureus (26.3), total bacteria (45.5), fungi (71.3), Clostridium perfringes (81.8), fecal coliform (92.6), and non-lactose fermenting bacteria (100.0). (C) 2002 by The Haworth Press, Inc. All rights reserved.