Effect of Different Growing Organic Substrates on Growth and Yield Components of Pinto Bean (Phaseolus vulgaris L.) under Heavy Metals Stress

Heavy metals are the most important pollutants in the environment. One approach to reduce the accumulation of heavy metals in plants is usage of different growing substrates. In order to investigate of heavy metals effect on growth and yield components of pinto bean (cv. Sadri), a greenhouse experiment was conducted as a factorial based on completely randomized design with three replications in Yasouj university, in 2013. The first factor included of five levels of heavy metals (control without heavy metals, Cd(NO3)2, Pb(NO3)2, Ni(NO3)2 and CuSO4) and the second factor included of four levels of different growing substrates (compost, vermicompost, Populus sawdust and non-application of organic compounds). The results showed that the addition of vermicompost respectively increased plant height and root length in conditions of without heavy metals 53, 88%, nickel nitrate 61, 35%, lead nitrate 63, 17% and copper sulfate 25, 85% compared to non-application of organic compounds. Vermicompost application also increased 87% the number of pods per plant and seed per pod in cadmium nitrate stress. On the other side, use of vermicompost, compost and Populus sawdust could not limit the adverse effects of heavy metals on seed weight per plant. Vermicompost increased hundred grain weights (11%) and protein content of bean (9%) compared to non-organic material conditions. In general, the results of this study showed that application of vermicompost on soil contaminated with heavy metals, to some extent, can improve undesirable effects of heavy metals stress.