NUTRIENT CONCENTRATIONS, GROWTH, AND YIELD OF TOMATO AND SQUASH IN MUNICIPAL SOLID-WASTE-AMENDED SOIL

The effects of municipal solid waste (MSW) materials on growth, yield, and mineral element concentrations in tomato (Lycopersicon esculentum Mill.) (1991 and 1992) and squash (Cucarbita maxima Duch. Ex Lam.) (1 992 and 1993) were evaluated. Agrisoil compost (composted trash), Ewes on compost (co-composted trash and sewage sludge), or Daorganite sludg e (chemically and heat-treated sewage sludge) were incorporated into c alcareous limestone soil of southern Florida. The control had no MSW m aterial added to the soil. The effect of MSW an crop growth, yield, an d mineral element concentrations varied considerably between years for tomato and squash. In 1991, tomato plants grown in soil amended with Eweson or Daorganite had a greater canopy volume than plants in the co ntrol treatment. Tomato plants grown in Daorganite had greater total f ruit weight (1991) than plants in Agrisoil and more marketable fruit ( 1992) than control plants. In both years, tomato plants in Agrisoil ha d higher root Zn concentrations than plants in the other treatments. I n 1995 tomato plants in Eweson had lower root Mn concentrations than p lants in the other treatments, whereas Mg concentrations in the roots were higher in the Daorganite treatment than in Eweson. Tomato plants in Agrisoil had higher ph concentrations in the roots than plants in a ll other treatments. In 1991, leaves of tomato plants in Agrisoil had lower Ca concentrations than leaves of plants in the control treatment . In 1992, leaf Zn concentrations were greater for tomato and squash i n Agrisoil than in the control or Daorganite. In 1992, canopy volume a nd yield of squash were greater for plants in Daorganite than for plan ts in the control and other MSW treatments. Although canopy volume and total squash fruit weight did not differ among treatments in 1993, pl ant height was greater for squash plants in the MSW treatments than fo r those in the control. In 1993, leaf Mg concentrations were greater f or squash grown in Daorganite than for plants in the control or Agriso il. In 1993, fruit Cd concentration was higher for plants with Eweson than for plants in the control or Agrisoil. However, the fruit Cd conc entration in squash grown in Eweson compost (1.0 mg/kg dry weight) was far below a hazardous level for human consumption. Our results indica te that amending calcareous soils with MSW materials can increase grow th and yield of tomato and squash with negligible increases in heavy m etal concentrations in fruit.