mahnaz mirzaei

Based on the chemical properties of herbicide and carrier water, water hardness might have different impacts on herbicide performance. A study was conducted in the greenhouse to determine the effect of chloride and bicarbonate forms of Mg+2 and Na+ on the performance of clodinafop-propargyl and sulfosulfuron for littleseed canarygrass control. The concentrations of bicarbonate and chloride forms of Mg+2 and Na+ had no significant effect on the ED50 of clodinafop-propargyl. The relative potency of clodinafop-propargyl, in the presence of all mineral salts, was 1.0 or had no significant difference from 1.0. On the contrary, increasing the mineral salts reduced the ED50 of sulfosulfuron significantly, especially in the presence of bicarbonate forms of Mg+2 and Na+. In this regard, the relative potency of sulfosulfuron as affected by 100 to 800 ppm Mg(HCO3)2 was about 0.5 to 0.7 times higher than control. This value was increased from 0.5 to 2.2 at 100 to 800 ppm sodium bicarbonate. Hence, the ranking of the mineral salts on improving sulfosulfuron performance was NaHCO3 > Mg(HCO3)2 > MgCl2 > NaCl. It is suggested that because of the lipophilic nature of clodinafop-propargyl, the presence of mineral salts did not affect the performance of this herbicide. It is concluded that, in determining the effect of water hardness on herbicide performance, in addition to chemical properties of herbicide, type of mineral salt, and its concentration, it is also essential to know the changes in the pH of the carrier water due to the mineral salts.

The present study was conducted to investigate the effect of different water hardness levels on the efficacy of clodinafop-propargyl and mesosulfuron+iodosulfuron+mefenpyr-diethyl with and without adjuvants in control of winter wild oat (Avena ludoviciana). The experiment was conducted as a randomized complete block design in factorial arrangement with three replications at the research greenhouse of Iranian Research Institute of Plant Protection during 2017-2019. The experiment factors included herbicides doses at four levels of 25, 50, 75% and 100% of the recommended field rate of each herbicide (the recommended dose for Topik and Atlantis were 64 and 18 g a.i ha-1 , respectively), concentrations of hardness at five levels (0, 250, 500, 750 and 1000 ppm of Calcium bicarbonate) and different levels of ammonium sulfate and urea ammonium nitrate adjuvants at three levels (0, 1 and 2% v/v). The results indicated that the water hardness higher than 500 ppm led to a reduction in the efficacy of clodinafop-propargyl in control of winter wild oat. However, the efficacy of mesosulfuron+iodosulfuron+mefenpyr-diethyl was not influenced by any level of water hardness. According to the results of this experiment, the use of ammonium sulfate 2% or ammonium urea nitrate 1 to 2% reduced the negative effects of hard water containing calcium carbonate with a concentration of more than 500 ppm on the effectiveness of the herbicide clodinafop-propargyl, and reduced the recommended dose of this herbicide by 25 to 50%. Furthermore, the use of ammonium sulfate 2% or urea ammonium nitrate 1% increased the efficacy of mesosulfuron+iodosulfuron+mefenpyr-diethyl.

Weeds movement and their dispersal power are amongst the major factors affecting the agricultural plants success. Diversity reflects the complexity of a system and can maintain its sustainability. Higher diversity results in higher inherent complexity of agro-ecosystems and strengthens their processes. It is necessary to realize the spatial distribution and temporal properties of the biodiversity components in agro-ecosystems, for the conservation and optimal utilization. Since weeds as a complementary component of agro-ecosystems are inseparable, studying species and their functional and structural diversity plays an important role in weed management and balance of ecological systems. Pistachio is one of the most economically important and strategic agricultural products in Iran. Weeds are one of the serious problems in pistachio orchards creating problems through competition, and costs imposed on farmers. Studying distribution and density of weed species can play an effective role in weed management. Therefore, this study was to assess the weeds flora and their distribution in pistachio orchards at Kerman city.
In order to investigate the flora and weeds distribution in pistachio (Pistacia vera) orchards of Kerman city, 19 orchards in 4 regions were selected. Weeds population sampling was conducted in a W pattern using 0.5×0.5 m² quadrates in 2014. The weeds at each quadrate were identified based on genus and species and the number of weed species was counted. Indices including frequency, uniformity of distribution, mean density, and abundance index as well as relative frequency, relative uniformity of distribution, relative mean density, and relative abundance were also calculated. Finally, weed species were classified based on cluster analysis using the Ward method and Euclidean distance square.
The weeds of pistachio orchards were belonged to 18 families and 57 species that dicotyledons with 45 species (78.95 percentage) had higher diversity than monocotyledons with 11 species (19.30 percentage). Family of Asteraceae with 12 weed species was the most abundant weed at Kerman’s pistachio orchards followed by Poaceae with 10 weed species, Chenopodiaceae with eight weed species and Fabaceae with seven weed species. According to the photosynthetic pathway, diversity of C3 weed species with 38 species (66.67 percentage) was more than twice of C4 weed species with 16 species (28.7 percentage). Based on life-cycle, diversity of annuals with 32 species (56.14 percentage) was more than perennials with 32 species (42.10 percentage). Five species of mouse barley (Hordeum murinum L.), field bindweed (Convolvulus arvensis L.), knapweed (Acroptilon repense L.), bermuda grass (Cynodon dactylon L.), and saltbush (Atriplex sp. L.) had the greatest frequency. The most important species of weeds with maximum abundance index were mouse barley, knapweed, saltbush, field bindweed, and bermuda grass. Based on cluster analysis, species were divided into four groups and based on importance were performed from the bottom to the top of the dendrogram.
Although the number of halophytic weeds in the pistachio orchards of Kerman was remarkable, the frequency and relative density of these weeds were not considerable. Identifying weed species, as well as their structural and functional diversity in pistachio orchards seems to improve the horticultural production management.