Preliminary studies on some waste vegetable contribution to the soil fertility

Researches on the use of waste vegetable (tomatoes, peppers) and fruits (apples, plums) in order to improve the nutritional quality of the soil have been performed. The content in nitrogen, phosphorus, potassium, humus, organic matter have been analyzed in fruits and vegetable waste and also in soil before and after mixing with each waste at a ratio of 1:2.5. Analyses were done by using current analytical methods (chemical and absorption molecular spectrometry) after previous mineralization of samples with appropriate reagents. To investigate the effect of vegetable wastes on the plants growth, wheat has been planted in the witness soil sample and in the mixed soil with wastes. The nutrients concentration in vegetable waste was higher than in fruit waste (33-75%). Available phosphorus concentration increased about two times in soil with fruit waste while in the soil with vegetable the increase was of about 3 times. Potassium concentration increased about three times in soil mixed with both types of waste. Although potassium and organic matter have higher values in the soil amended with fruit waste than in the witness soil, the height of the wheat was similar with those in the control soil due to the limiting role of phosphorus.