the effects of iron fertilization and sulfuric acid application in irrigation water on root growth and chemical composition of bean cultivars in a calcareous soil

legumes are main sources of plant proteins for human and animal nourishment. beans with 20-25% protein, 55-65% carbohydrates and 1-5% lipid play a major role in nutrition of poor nations which are not able to feed ourselves with animal proteins. thus, increasing yield and quality of beans is an effective way for reducing protein deficiency in developing countries. one of the factors that reduces yield and quality of beans in calcareous soils of iran is iron deficiency. high ph and calcium and bicarbonate contents of calcareous soils induce leaf choruses which limits plant growth and yield and reduces the quality of beans. to determine the effects of soil and foliar applied iron fertilizers and sulfuric acid on roots of four spotted bean cultivars, a factorial experiment was conducted using a completely randomized design and three replications. the experimental factors were iron fertilizers and bean cultivars. fertilizer factor included: (a) soil application of ferrous sulfate (25 and 50 mg/kg) and fe-eddha (3 and 6 mg/kg), (b) foliar application of fe-edta(1 and 2 mg/l) and ferrous sulfate (2 and 4 g/l), (3) soil application of sulfuric acid through the irrigation water (2 and 4 g/l) and (4) control (without iron fertilizer).the spotted bean cultivars used in this study were tallash, khomein, cos16 and a local cultivar. the results of this experiment showed that there were significant differences between the effects of soil and foliar applied iron fertilizers and spotted bean cultivars root with respect to root dry and weights. the bean cultivars responded differently to iron fertilization and the highest and the lowest increase in root dry and weights were measured for the local and khomain cultivars respectively . the results of  the  experiment  showed  that  application  of   sulfuric  acid by irrigation water  at  the  rate  of 4.mg/l increased  the  fresh  and  dry  weight  of  root. the application of sulfuric acid  also  increased the  root  concentrations  of  n, k, p, fe, cu, mn, and  zn significantly  . the  application  of  soil  and  foliar  applied  iron also  increased  the  root   concentration of  fe, k, n, p and decreased  the  root  concentration of cu, zn, mn.