Effects of fertilization and salinity on weed flora in common bean (Phaseolus vulgaris L.) grown following organic or conventional cultural practices

Abstract

Two field experiments were conducted to assess the effects of cultural system and irrigation water salinity on weed flora in a common bean crop (Phaseolus vulgaris L. cv. Contender). The experiments were designed as split plot designs with the cropping system as main plot (organic or inorganic fertilization), the level of water salinity as sub-plot (good quality or saline irrigation water with 0.5 or 10mM NaCl, respectively) and four replications per treatment. The lowest weed density was recorded in the saline water treatment. The results of the study showed that the order of weed sensitivity to salinity is redroot bigweed > bermudagrass > common lambsquarters > barnyardgrass >common purslane >purple nutsedge. Moreover, differences in nitrogen availability of the fertilizers had a large effect on weed density and biomass. The highest weed biomass (in 2011: 454 kg ha-1 for saline water treatment and 759 kg ha-1 for control; and in 2012: 331 kg ha-1 for saline water treatment and 578 kg ha-1 for control) was recorded in the plots treated with inorganic fertilizers. These results indicated that organic fertilization and saline water could be used for the suppression of weeds in organic common bean crops.