Effects of municipal waste compost and nitrogen fertilizer on growth and mineral composition of tomato

Purpose Since simultaneous use of organic and mineralfertilizers on the basis of their chemical compositions canlead to better plant growth and soil fertility, the roles ofmunicipal waste compost (MWC) and nitrogen (N) fertilizeron growth and mineral composition of tomato andsome soil properties were evaluated under greenhousecondition.Methods Treatments involved four MWC rates (0, 1, 2,and 4% on the basis of soil dry weight) and four N levels(0, 50, 100, and 200 mg kg-1 soil). Red cloud variety oftomato was sown in treated soils and 9 weeks later driedplant shoots and soil sub-samples were subjected toanalysis.Results Combined use of MWC and N led to better growthof tomato than sole application of either MWC or N fertilizer.Plant concentration and/or uptake of nitrogen,phosphorus, zinc, copper, iron, and manganese wereincreased by both MWC and N. The beneficial effect ofMWC on nutrients uptake was more pronounced with Naddition. Plant and soil concentrations of cadmium andlead were under the detection limit of atomic absorptionspectrophotometer. Soluble salts, organic matter, sodium,chloride and DTPA-extractable zinc, copper, iron, andmanganese in the soil were effectively increased withaddition of MWC.Conclusions Due to high soil pH and calcium carbonateequivalent (CCE) values of the calcareous soil, MWCheavy metals had no hazardous effect on tomato and evenplayed a nutritional role. The most important problemraised from MWC application was the accumulation ofsoluble salts in the soil which must be monitored whenmaking repeated application of MWC over an extendedperiod of time.