effects of chemical fertilization and organic fertilizer on spinach (spinacia oleracea l.) yield and nitrate accumulation.

in order to studying the effect of conventional fertilization and organic fertilizeron growth, yield and nitrate accumulation of spinach, a greenhouse experiment was carried out in factorial based on random complete design with three replications in a commercial greenhouse located at lahijan. treatments were three levels of municipal soil waste compost (0, 50 and 100 t ha-1), five chemical fertilizer levels (0, 1/3, 1/2, 2/3 and complete content of recommended chemical fertilizer (n.p2o5.k2o) for spinach) and combination of different levels of chemical fertilizer and municipal solid waste compost. result showed that by increasing chemical fertilizer and municipal solid waste compost application level quantitative characteristics (wet and dry weigh, height, leaf area, and yield) of spinach increased. also, integrated of compost with chemical fertilizer (specially 100 t∙ha-1 compost + chemical fertilizer) compare to only apiece application of fertilizers, had more affected to spinach yield. the lowest nitrate content was observed in compost application that no significant differences have with control. result show that application 50 t/ha compost can be substitute 45.83% and application 100 t/ha compost can be substitute 73.27% using current recommendation of chemical fertilizer for spinach and low content nitrate accumulation in plant.