effect of water logging (paddy-soil) and dry farming (planted with vegetables) systems on distribution status of soil heavy metals regarding the accumulative and residual effects of organic fertilizers

in order to investigate distribution status of heavy metals in cropping systems of water logging and dry farming, an experiment was conducted as split-plot arrangement based on randomized complete block design with three replications in research field of sari agricultural science and natural resources university. a paddy-soil considered for water logging system and the planted field with vegetables considered for dry farming system. main plot (fertilizer treatments added to soil) included five treatments: 20 and 40 ton.ha-1 compost, 20 and 40 ton.ha-1 sewage sludge and control. also, sub factor (application years) consisted three treatments comprised: one, two and three years fertilization. the results showed that in water logging system sewage sludge treatments had more influence on heavy metals accumulation in soil while, compost treatments had more influence than sewage sludge treatments in dry farming system. also, in paddy soil the enhancement percent of available form compared to control treatment was much more than dry farming system.