Carpathian Journal of Earth and Environmental Sciences, November 2012, Vol. 7, No. 4, p. 189 - 196 EFFECTS OF COMPOST APPLICATION ON NUTRIENT SUPPLY AND HEAVY METAL SORPTION OF SOIL Alaeddin ELFOUGHI 1 , Szilveszter BENEDEK 1* , Laila M. H. ABUSRIWIL 2 , Hosam E. A. F. BAYOUMI HAMUDA 2,3 & György FÜLEKY 1 1 Department of Soil Science and Agricultural Chemistry, Szent István University, Gödöllő, Páter Károly utca 1., 2100 Hungary, *E-mail: szil.benedek@gmail.com 2 Department of Chemistry and Biochemistry, Szent István University, Gödöllő, Hungary 3 Institute of Environmental Protection Engineering, Óbuda University, Budapest, Hungary Abstract: Analyzing the effects of compost application on chemical and microbiological soil properties, pot experiment was conducted with mixtures of a sandy-loam soil and compost originated from plant residues, including 0, 2.5, 5 and 10 v/v% compost, in four replicates. Ryegrass (Lolium perenne L.) was seeded in the pots, which were set up at 20°C in climate room by a daily irrigation to field capacity. The plants were cut at the 4 th and the 7 th week after seeding. Finally plant biomass and N, P and K content of plants was measured. Also chemical and microbiological properties of the soil-compost mixtures were determined. Same experiment was also carried out after 6 months incubation of soil-compost mixtures. During the incubation process the hot water soluble C and N content was determined monthly. The results reported an increase in growth and nutrient uptake of ryegrass plants at higher rate of compost application. Similar tendency could be detected between microbiological properties and compost application rate. These effects are more dominant when incubated soil- compost mixtures were used. Change of easily soluble C and N content during the incubation process was recognized by a decreasing tendency in case of C and an increasing in case of N. Furthermore the experiment was established to study Cu and Zn sorption capacity of the soil-compost mixtures. It was found that Cu and Zn fixation rose substantially as the quantity of compost increased. Increasing rates of compost reduced the availability of the heavy metals, however the availability of Cu was higher than that of Zn. Application of hot water extraction method showed that the soluble Cu and Zn increased by higher compost application rate. Keywords: soil, compost, organic matter, microbial activity, copper, zinc 1. INTRODUCTION Organic matter increase soil fertility in several ways and compost as an important source of organic matter has primary impacts on important soil properties. Based on the high nutrient mineralization potential and humus formation capacity, compost application can increase nutrient supply and organic matter content of soils. Organic matter plays also an important role in decreasing heavy metal availability. The aim of the present study was to examine the effects of compost application on soil fertility and productivity, to investigate the effect of compost application on nutrient availability in soil, plant biomass production and nutrient uptake of plants. To show the change of organic matter content during the incubation of soil-compost mixtures, C and N contents were determined. Furthermore also important microbial parameters were analyzed. Finally the effect of compost application on Cu and Zn sorption in soil and plant availability was examined. 2. MATERIALS AND METHODS 2.1. Pot experiment analyzing nutrient supply and microbial activity Compost was applied to the soil in 0, 2.5, 5 and 10 v/v %. Soil (classified as Luvisol) was sampled from the top layer (0-20 cm) of agricultural land in Gödöllő, Hungary and compost originated from plant residues. Analysis of pH (KCl), CaCO 3 -content, humus-content was carried out according to Buzás (1988), AL (ammonium-lactate) soluble P and K content according to Egner et al., (1960). Furthermore HWP (hot water percolation) soluble C, N, P and K 189