Planta Daninha 2019; v37:e019182818 MIRZAEI, M. et al. The response of different weed species to glyphosate using ammonium sulfate and hard water ABSTRACT -Water hardness antagonism and the effect of ammonium sulphate (AMS) on efficacy of glyphosate have been well documented. However conflicting results between weed species were noted by the authors. Greenhouse experiments were conducted twice at the Ferdowsi University of Mashhad in a randomized complete block design with a factorial arrangement and three replications during 2014-2015. Four experiments were arranged separately on cypress (Kochia scoparia), redroot pigweed (Amaranthus retroflexus), little seed canary grass (Phalaris minor) and winter wild oat (Avena ludoviciana) using ammonium sulphate and deionizad water and in the presence of different salts, (i.e. NaHCO 3 , CaCO 3 , MgCl 2 and CaCl 2 at 500 ppm) against three doses of glyphosate (256.25, 512.5 and 1,025 g a.i. ha -1 ), with and without ammonium sulphate (AMS) as adjuvant (2% w/v). The results showed the application of AMS overcomes the inhibitory effects of salts in the spray solution in tested species. The degree of effectiveness in A. retroflexus was more than A. ludoviciana and P. minor. Glyphosate with AMS caused reduction in dry matter in grasses from 0.34 to 0.28 g, while glyphosate toxicity in A. retroflexus with AMS was 100 percent and all of the plants were destroyed (0.82 to 0 g). The application of AMS in overcoming the inhibitory effects of water hardness had no effect on K. scoparia control. However, Increasing AMS could overcome the inhibitory effects of hard water in the spray solution on glyphosate efficacy in A. retroflexus and K. scoparia, but it had no effect on tested grassy weeds. We may conclude that glyphosate work differently on weed species using AMS and hard water.

This study investigates the effect of nitrogen and moisture superabsorbent on yield, yield components, seed nitrogen and biological traits in the field of pumpkin during two cropping years (2018-2019) in Kermanshah, Iran. The experiment was carried out as a split-plot based on Randomized Complete Block Design (RBCD) with three replications. The main plot factor was the application of moisture superabsorbent at various levels of 0 (control), 40, 80, 120 kg ha-1, respectively, and nitrogen fertilization at the levels of 0, 50, 100 and 150 kg ha-1 were considered as sub-factor. Results show that treatments significantly affected fruit fresh weight, fruit dry weight, leaf dry weight, stem dry weight, fruit number per plant, grain weight, grain number per fruit, grain nitrogen percentage, except for fruit number per plant. In the most traits, there was an increasing trend when nitrogen levels increased, although N2 levels of 100 and 150 kg ha-1 were not significantly different. In addition, increasing the moisture superabsorbent enhanced the mentioned traits. As a result, the combination of nitrogen 100 and superabsorbent 120 is the best and most economical combination.

In order to investigate the effect of deficit irrigation and chemical fertilizers on yield and some physiological traits of quinoa an experiment was conducted in 2019 as split plot based on a randomized complete block design in two locations (Mashhad and Neishabour). Irrigation included, I0: full irrigation, I1: no irrigation at emergence stage, I2: no irrigation at stem elongation stage, I3: no irrigation at flowering stage, I4: no irrigation at seed setting stage. Fertilizer treatments included control (no fertilizer application); chemical fertilizer application according to local practices; manure application of 10 tons; and manure application of 20 tons per hectare. In general, seed yield, percentage of protein and seed oil in Mashhad was higher than in Neishabour. I2 treatment had the least negative effect on relative leaf water content. Application of chemical fertilizers, 10 tons and 20 tons of animal manure increased the percent of seed protein by 1.43, 1.66 and 2.37 compared to the control, respectively. The highest percentage of seed oil (5.91%) was obtained for treatment I2 in Mashhad and the lowest percentage of seed oil (4.18%) was obtained for treatment I4 in Neishabour. The lowest seed yield due to I1 treatment was observed in Neishabour and the highest seed yield was related to I0 treatment with 20 tons of manure and was observed in Mashhad. The results showed that the yield and water stress tolerance potential of quinoa can be modified by irrigation, fertilizer source and location.