Ferti-irrigational impact of sugar mill effluent on agronomical characteristics of Phaseolus vulgaris (L.) in two seasons

Ferti-irrigation response of 5, 10, 25, 50, 75, and 100 % concentrations of the sugar mill effluent (SME) on French bean (Phaseolus vulgaris L., cv. Annapurna) in the rainy and summer seasons was investigated. The fertigant concentrations produced significant (P < 0.01) changes in the soil parameters, viz., electrical conductivity (EC), pH, organic carbon (OC), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), total Kjeldahl nitrogen (TKN), phosphate (PO4 (3-)), sulfate (SO4 (2-)), ferrous (Fe2+), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), and zinc (Zn), in both seasons. The contents of Cr, Cu, Mn, and Zn except Cd were found to be below the maximum levels permitted for soils in India. The agronomic performance of P. vulgaris was gradually increased at lower concentrations, i.e., from 5 to 25 %, and decreased at higher concentrations, i.e., from 50 to 100 %, of the SME in both seasons when compared to controls. The accumulations of heavy metals were increased in the soil and P. vulgaris from 5 to 100 % concentrations of the SME in both seasons. The contents of Cu, Mn, and Zn except Cd and Cr were noted under the permissible limit of Food and Agriculture Organization (FAO)/World Health Organization (WHO) standards. Most contents of biochemical components like crude proteins, crude fiber, and total carbohydrates were found with 25 % concentration of the SME in both seasons. The contamination factor (Cf) of various metals was in the order of Cd > Cr > Zn > Mn > Cu for soil and Mn > Zn > Cu > Cr > Cd for P. vulgaris in both seasons after fertigation with SME. Therefore, the SME can be used to improve the soil fertility and yield of P. vulgaris after appropriate dilution.