EFFECTS OF ORGANIC AMENDMENTS APPLICATION ON GRAIN YIELD,LEAF CHLOROPHYLL CONTENT AND SOME MORPHOLOGICAL CHARACTERISTICS IN SOYBEAN CULTIVARS

A field experiment was conducted to evaluate the effect of organic amendments on grain yield, leaf chlorophyll content, and some morphological characteristics of three soybean cultivars in Mazandaran province located at north of Iran in 2006. Chemical fertilizer (75 kg ha^?1 potassium sulfate and triple superphosphate), two levels of municipal solid waste, vermicompost and sewage sludge biosolid (20 and 40 Mg ha^?1) enriched with%50 chemical fertilizers needed by soil were applied to soybean cultivars (‘032’ and ‘033’ promising lines and ‘JK’ cultivar). The experiment was carried out in split plot based on randomized complete block design with three replications. Some important plant characters such as grain yield, leaf chlorophyll content, number of branches, number of nodes on the main stem, length of internodes, stem diameter, first pod height and plant height were determined. Results showed that application of 40 Mg ha^?1 sewage sludge enriched with chemical fertilizers increased plant grain yield and stem diameter and application of 40 Mg ha^?1 vermicompost enriched with half chemical fertilizer increased the number of nodes on the main stem, significantly. The maximum length of internodes, first pod height and plant height were obtained when the 40 Mg ha^?1 sewage sludge and vermicompost enriched with half chemical fertilizer in ‘032’ line was used. Biomass, number of branches, stem diameter, number of nodes on the main stem of soybean cultivars had a positive and significant correlation with grain yield.