Some Weeds Community Percent in Response to Pumice Application on Soil under Water Stress Conditions

A factorial experiment (using RCBD design) with three replications was conducted in 2014 at the University of Tabriz-Iran, in order to determine the effects of pumice application (P1, P2, P3 and P4: control, 30, 60 and 90 tons per ha) on soil and water stress (I1, I2 and I3: 100%, 70% and 50% water requirement calculated from class A pan, respectively) on dominante weeds community percent. Results showed that community percent of weed species changed as a result of water stress and pumice application on soil. Distributions of Chenopodium album and Malva sylvestris were sensitive to water stress but, Amaranthus retroflexus and Solanum nigrum were neutral to water stress. In contrast, Amaranthus retroflexus, Cardaria draba, Setaria viridis, Sisymbrium irio, Xanthium strumarium, Convolvulus arvensis and Salsola rigida distribution were resistant to water stress. Community percent of Chenopodium album as sensitive species to water stress and Salsola rigida as resistance species to water stress positively affected by pumice application especially under water stress condition. Amaranthus retroflexus, Xanthium strumarium and Convolvulus arvensis were positively affected by pumice application under well and limited water supply conditions. In contrast, Cardaria draba, Sisymbrium irio and Solanum nigrum negatively affected by pumice under water stress and it had positive effect on community of these species under well watering conditions. Thus, application of pumice and water stress are two factors which change weed community precent.