The effects of a water treatment residue on grain yield and nutrient content in seeds of common dry beans (Phaseolus vulgarisL. cv. Ghadra) grown in a dystrophic soil

This glasshouse study investigated the grain yield and nutrient content of seed of common dry beans (Phaseolus vulgaris L. cv. Ghadra) grown in a dystrophic sandy soil treated with 0, 50, 100, 200 and 400 g kg−1 water treatment residue (WTR) and five levels of fertiliser. Dry mass and nutrient content of the bean seed were determined. Seed mass data was compared by analysis of variance and no significant (P = 0.404) were found for the interactive effect of WTR application rate and fertiliser. However, each individual treatment was found to have a significant effect (P < 0.001). Increasing application of fertiliser significantly increased the seed mass produced for each increment of fertiliser applied. The mass of seed for the WTR treated soils were significantly greater than the control soil, with the highest yield over the average of the fertiliser treatments measured for the 100 g kg−1 WTR application rate. Macro-nutrient concentrations of the bean seed were generally within typical ranges reported for bean seed for human consumption. Concentrations of Mn and Zn tended to be over the typical ranges, though this was observed in the control treatments as well as the WTR treated soils. It was evident that increasing application rates of WTR increased the concentrations of Mn in the seed. To avoid potential risks for human consumption an application rate of WTR not exceeding 100 g kg−1 (about 260 kg ha−1) was recommended.