s. a. kazemeini

 Quinoa (Chenopodium quinoa L.) is a highly nutritional seed crop from the Andean region with huge genetic variability, enabling its cultivation across a wide range of environmental conditions. The area and production under quinoa in the world in 2020 was 189000 ha with 175000 tonnes production. There is some evidence for allelopathic activity of quinoa and this potential could be probably used in terms of integrated weed management. Agronomic practices such as nitrogen fertilization influence weed emergence, growth and competition in a crop. Nevertheless, despite the numerous studies on new and promising crops globally, there is a clear lack of information on the combined effect of weed density and nitrogen fertilizer sources on quinoa crop. Therefore, the purpose of this study was to evaluate the effects of nitrogen fertilizer sources and red root pigweed densities on growth, yield and competitive ability of quinoa (Chenopodium quinoa Willd). This information could be helpful for the overall development of crop and weed management strategies in quinoa crop.
A field study was conducted during the 2021 growing season at the research farm of the School of Agriculture, Shiraz University, to assess the impact of nitrogen fertilizer sources on the growth, yield, and competitive ability of quinoa in the presence of red root pigweed at different densities. The experiment was set up in a split-plot design with nitrogen fertilizer sources (control, urea, sulfur-coated urea, and ammonium nitrate) assigned to the main plots, and red root pigweed densities (0, 5, 10, 15, 20, and 25 plants per square meter) assigned to the sub-plots. There were three replications of each treatment. For the quinoa traits and weed traits, a 2-meter square area was harvested from each plot. Quinoa traits included plant height, leaf area index, number of grains per plant, 1000 grain weight, grain yield, biological yield, and harvest index. The quinoa plants were dried in an oven at 75°C for 72 hours to determine seed yield. Weeds were also harvested from a 2 m2 area in each plot to measure plant height, shoot height, panicle length, and leaf area index. The collected data were analyzed using SAS v. 9.1 software (SAS Institute 2003). When significant differences were found among treatments, mean comparisons were performed using Duncan's multiple range tests at a significance level of P < 0.05.
 The results of the experiment indicated that the use of sulfur coated urea had a positive effect on the competitive ability of quinoa. Weed density had a detrimental impact on various growth and yield parameters of quinoa, including plant height, leaf area index, number of grains per plant, 1000 grain weight, grain yield, biological yield, and harvest index. However, the application of sulfur coated urea mitigated the negative effects of weed density. Specifically, when the highest weed density of 25 plants per square meter was present, the application of sulfur coated urea led to a 1.1-fold increase in plant height, a 2.5-fold increase in leaf area index, a 2.5-fold increase in the number of grains per plant, a 1.1-fold increase in 1000 grain weight, a 2.8-fold increase in grain yield, and a 1.8-fold increase in biological yield compared to the control. At different red root pigweed densities (0, 5, 10, 15, 20, and 25 plants per square meter), the application of sulfur coated urea resulted in significant improvements in quinoa performance. It increased the number of grains per plant by 86.5%, 118%, 139.4%, 168.8%, 149.6%, and 153.4% compared to the control at respective weed densities. Additionally, 1000 grain weight increased by 7.9% to 9.9%, and the ability of quinoa to withstand competition increased by 19.6% to 55%. The findings of this study are consistent with previous research that has demonstrated the positive effects of organic nutrients on reducing weed competition in agricultural systems. It has also been observed that weeds tend to produce more biomass in the presence of fertilizer compared to the control. Therefore, it can be concluded that the improved grain yield of quinoa resulting from the application of sulfur coated urea was primarily attributed to its ability to enhance the plant's competitive ability against weeds.
 The application of sulfur coated urea led to a higher quinoa yield compared to using control. However, weed competition was greater with urea fertilization in comparison with sulfur coated urea fertilizer. In addition, most weeds are highly responsive to soil N, so the application of all fertilizer types should be carefully considered to reduce the competitive advantage of weeds over crops.
Acknowledgements
 We would like to thank the School of Agriculture, Shiraz University for their support, cooperation, and assistance throughout this research.

 Maize (Zea mays L.) is the third most important cereal after rice and wheat, which is widely grown in the world and used as a primary staple food in many developing countries.  The area and production under maize in the world in 2020 was 202 M ha with 1162352997 tonnes production and contributed almost 5% of the world’s dietary energy supply. Recent projection indicates that by 2020 the demand of maize in all developing countries will overtake the demand of wheat and rice, with Asia accounting for nearly 60% of the global demand for maize.  Chemical control can be very important because of the low efficiency and cost effectiveness of mechanical or other methods of weed control. Hence, it is necessary to provide information about the sulfonylurea herbicides and suitable doses. Sulfonylureas such as iodosulfuron, nicosulfuron, rimsulfuron, and foramsulfuron are effective group of herbicides for annual and perennial weed control in maize. These herbicides provide a new chance for weed management in maize. Their mode of action occurs through inhibiting acetolactate synthase (ALS), thereby interfering with the production of branched-chain amino acids, leucine, isoleucine, and valine The objectives of this experiment were to evaluate the effect of different doses of MaisTer OD herbicide in comparison to the other herbicides on weeds control and growth and yield of corn.

 In order to evaluate the effect of different herbicides on weeds control and growth and yield of corn, a field study carried out during 2015 growing seasons at Seydan, Marvdasht, Fars province, Iran. The experiment was conducted in a randomized complete block design with 3 replications. Treatments included different rates of MaisTer OD (1, 1.5 and 2 l ha-1), Acetochlor (4.5, 5 and 6 l ha-1), Cruz (1.5, 2 and 2.5 l ha-1), Ultima (1, 2 and 3 l ha-1) and 2,4-D+MCPA (1.5, 2 and 2.5 l ha-1) herbicides and weed free and weedy control. The number and biomass of aboveground weeds parts were harvested within three fixed 1 × 1 m quadrats in every plot, separated by species, enumerated, oven-dried at 75 °C for 48 h, and then weighed. Then, percent weed density and biomass reductions were measured. The traits included ear length, row number per ear, grain number per ear, grain number per row, 1000 grain weight, grain yield, biological yield and yield loss percentage. Data were analyzed using SAS v. 9.1 software (SAS Institute 2003). When significant differences were observed among treatments, mean comparisons were made using Duncan's multiple range tests (P < 0.05). Correlation coefficients between different traits were also calculated.

 Results showed that the application of herbicide could reduce density and biomass of weed. The lowest biomass of redroot pigweed (Amaranthus retroflexus), lambsquarters (Chenopodium album), bindweed (Convolvulus arvensis), purple nutsedge (Cyperus rotundus) and foxtail millet (Setaria italica) was obtained, so that applying of MaisTer OD herbicide at 1.5 l ha-1 could be cause 47.10 and 27.36%, 69.38 and 56.22%, 66.79 and 70.94%, 66.85 and 74.26% and 66.85 and 80.15% reduction in density and total biomass of weeds in comparison with weedy control treatment, and grain yield increased by using MaisTer OD  herbicide at 1.5 l ha-1 in comparison to the other herbicides including Acetochlor (5 l ha-1), Cruz (2 l ha-1), Ultima (2 l ha-1) and 2,4-D+MCPA (2 l ha-1) by 53.3, 36.7, 5.7, and 56.7%, respectively. Grain yield and grain number per ear were reduced by weeds up to 60 and 50%, respectively. Highest row number per ear (16 and 15.30), grain number per row (41 and 41), grain number per ear (656 and 628.70), 1000 grain weight (286.33 and 276.33 g), grain yield (9.41 and 8.68 t ha-1) and biological yield (20.12 and 18.74 t ha-1) were obtained in weed free and MaisTer OD (1.5 l ha-1) treatments. Applying MaisTer OD herbicide showed lowest yield loss percentage (6.63%) and highest grain yield as compared to the other herbicides for weed suppression. 

 It can conclude that MaisTer OD herbicide at 1.5 l ha-1 showed the best performance for weed control, especially broadleaf weeds and were associated with the maximum corn grain yield. Therefore, due to the restricted use of herbicide in corn, the herbicide used in this experiment is not created serious injury in corn at the recommended rate while effectively controlling weeds. Hence, utilization of this herbicide could be a favorable option in contemporary weed control programs for local or regional corn growers.

 Sweet corn (Zea mays L. var. saccharata) is an important crop, grown over 2,000 hectares in Iran. The consumption demand for sweet corn in its fresh form or as a processed crop has contributed to a significant increase in its cultivation in recent years. Sweet corn is susceptible to weed competition for nutrients, moisture, and light interception. Herbicides labeled for use on sweet corn are limited. Chemical control can be very important because of the low efficiency and cost effectiveness of mechanical or other methods of weed control. Hence, it is necessary to provide information about the sulfonylurea herbicides and suitable doses. Sulfonylureas such as nicosulfuron, rimsulfuron, and foramsulfuron are effective group of herbicides for annual and perennial weed control in maize. These herbicides provide a new chance for weed management in maize. Their mode of action occurs through inhibiting acetolactate synthase (ALS), thereby interfering with the production of branched-chain amino acids, leucine, isoleucine, and valine. The objectives of this experiment were to evaluate the effect of different doses of sulfonylurea herbicides on weeds control and growth and yield of sweet corn.

 In order to evaluate the effect of different doses of sulfonylurea herbicides on weeds control and growth and yield of sweet corn (KSC403su), a field study carried out during 2015 growing seasons at the Agricultural College of Shiraz University. The experiment was conducted in a randomized complete block design with 4 replications. Treatments included different doses of nicosulfuron (1.5, 2 and 2.5 l ha-1), foramsulfuron + idosulfuron (1, 1.5 and 2 l ha-1) and acetochlor (4.5, 5 and 5.5 l ha-1) herbicides and weed free and weedy control. The number and dry weight of aboveground weeds parts were harvested within three fixed 1 × 1 m quadrats in every plot, separated by species, enumerated, oven-dried at 75 °C for 48 h, and then weighed. Then, percent weed density and dry weight reductions were measured. The traits included ear length, ear diameter, ear number per plant, row number per ear, grain number per row, grain number per ear and canned grain yield. Data were analyzed using SAS v. 9.1 software (SAS Institute 2003). When significant differences were observed among treatments, mean comparisons were made using Duncan's multiple range tests (P < 0.05). Correlation coefficients between different traits were also calculated.

 Results showed that the canned grain yield, 1000 grain weight and number of grain per ear were reduced by weeds up to 73, 33 and 60%, respectively. The highest dry weights reduction obtained were of redroot pigweed (Amaranthus retroflexus) (75.8 and 59.5%), lambsquarters (Chenopodium album) (49.84 and 38.76%), barnyard grass (Echinochloa crus-galli) (58.37 and 40.85%) and bindweed (Convolvulus arvensis) (60.56 and 55.06%), so that applying of nicosulfuron )2.5 l ha-1) and foramsulfuron + idosulfuron (2 l ha-1) herbicides caused reduction in total dry weight of weeds in comparison with weedy treatment, and canned seed yield increased by nicosulfuron )2.5 l ha-1) and foramsulfuron + idosulfuron (2 l ha-1) herbicides in comparison to the acetochlor. Acetochlor was the weakest treatment in the reduction of weed density and dry weight. The highest canned grain yield (8.00 and 7.03 t ha-1), number of row per ear (12.00 and 11.50), number of grain per row (25.00 and 24.75), number of grain per ear (299.00 and 285.50) and 1000 grain weight (325.06 and 308.44 g) were obtained in nicosulfuron )2.5 l ha-1) and foramsulfuron + idosulfuron (2 l ha-1) herbicides, respectively. Positive correlation was found between canned grain yield and 1000 grain weight (r = 0.83, p<0.05) and number of grain per ear (r = 0.96, p<0.05). Applying nicosulfuron showed a high efficiency as compared to the foramsulfuron + idosulfuron and acetochlor for weed suppression.

 It can conclude that nicosulfuron at 2.5 l ha-1 showed the best performance for weed control, especially broadleaved weeds and were associated with the maximum sweet corn canned grain yield. Therefore, due to the restricted use of herbicide in sweet corn, the herbicide used in this experiment is not created serious injury in sweet corn at the recommended rate while effectively controlling weeds. Hence, utilization of this herbicide could be a favorable option in contemporary weed control programs for local or regional sweet corn growers.

In order to investigate the effect of quinoa seed inoculation on photosynthesis rate, yield and competitive ability with weeds, an experiment was conducted as split-plot based on a randomized complete block design with three replications at experimental farm of School of Agriculture, Shiraz University, Shiraz, Iran during 2020 growing season. Treatments were three levels of weed management as main-plot (weedy, weed-free and weeding) and five levels of seeds inoculation with biofertilizers (humic acid, bioumic, seaumic, organic herbicide, and no biofertilizers) as subplots. The results showed that the highest rate of photosynthesis in all weed management levels was achieved in the presence of seeds inoculated with seaumic biofertilizer. The highest grain yield (259.63 g/m2) and grain yield components (1000-seed weight, number of seeds per panicle, and number of panicles per plant) and harvest index (48.73%) were also obtained in weed-free plots when seeds were inoculated with seaumic biofertilizer. Leaf area index and dry weight of the main weed species (wheat) was significantly reduced in inoculation of seeds with biofertilizers compared to the no biofertiliuzer condition. The highest crop’s competitive ability was achieved when the seeds were inoculated with seaumic treatment. The quinoa’s competitive ability was increased by 2.8 times and 94.11% at weedy and weed-free treatments, respectively, compared with control in seed inoculation with seaumic treatment. Thus, our finding suggests that seed inoculation with biofertilizers, especially seaumic treatment is an effective strategy that can be used to enhance germination rate, growth, yield and weed competitive ability in quinoa.

Adoption of conservative agriculture at farm level is associated with reducing the production costs and leads to crop yield stability. The aim of this study was to prioritize experimental treatments based on different criteria by applying "technique for order preference by similarity to ideal solution" (TOPSIS).A filed experiment was carried out at Zarghan research station, Fars province, Iran, during 2014-2016 growing seasons. Experimental treatments were three tillage practices including conventional tillage (CT), reduced tillage (RT) and no tillage (NT) that were assigned to main plots and four spring wheat genotypes (Chamran, Sirvan, Picaflor#1 and M-89-10)were randomized in subplots using split-plot arrangements in randomized complete block design with three replications. Selected criteria including two groups of economic- i.e. water cost, weed control cost, production cost and gross margin- and agronomic –i.e. grain yield and soil bulk density criteria used to prioritize the treatments. The weights of bulk density (0.040), grain yield (0.180), gross margin (0.280), water cost (0.0270), weed control cost (0.150), and production cost (0.080) was calculated. Results showed, considering all criteria to prioritize wheat genotypes under different tillage practices, that Sirvan and Picaflor#1 genotypes under RT practice could be the first treatments in 2014-15 and 2015-16 growing seasons, respectively. Therefore, the multiple criteriamethodshould be used for selection of the best tillage practices and wheat genotypes under tillage practices rather than a criterion such as grain yield or production cost.

In order to determine the effect of weeds interference and nitrogen on the sugar beet growth and yield, a field study was performed in the 2010 growing season as a split plot design based on RCBD with three replications in Hana region (Semirom, Esfahan). Treatments were four levels of nitrogen from urea source as the main factor (0, 70, 150 and 210 kg ha-1) and weed interference at five levels (6-leaf, 8-leaf, 10-leaf, 12-leaf, and throughout the growth stages) growth stages in sugar beet as the sub factor. The results indicated that nitrogen and weed interaction had significant effects on the quantitative and qualitative traits of sugar beet (root yield and sugar). With increasing the nitrogen levels from 150 to 210 kg ha-1, the percentages of sugar molasses, sodium, and α-amino nitrogen were increased by 7.48, 24.26 and 21.09%, respectively, while the impurity percentage of sugar, alkalinity coefficient, and extractable sugar content were reduced by 3.09, 8.18, and 4.78% , respectively. The highest  total fresh weight, root fresh weight, root dry weight, total biomass and  root yield (2.1, 2.18, 1.55, 1.73 and 1.33-times, respectively) were achieved under high levels of nitrogen (210 kg ha-1) and weed interference at the 6-leaf growth of sugar beet in comparison to the use of  no nitrogen. Reduced duration of weed competition and /or weed free till 6- leaf growth stage of sugar beet along with application of 150 kg ha-1 N led to reduction in weed interference, detrimental effect of nitrogen on quality characteristics, and increase in the root yield of sugar beet.

A field study was conducted to evaluate the effect of haloxyfop-R-methyl ester doses in different grass weeds in various growing stages in safflower during 2011-2012 growing season in Research Farm of College of Agriculture، Shiraz University. The study was carried our as split split plot based on randomized complete block design with three replicates. The main factor، sub factor and sub sub factor were supergalant (doses: 0. 6، 0. 8 and 1. 0 L ha-1)، adjuvant use (with or without adjuvant) and time of herbicide application (2 leaf، 6 leaf، tillering stages of grass weed) respectively. The treatment efficiency in weeds control was examined with generalized liner methods and introducing precise frequency after 2، 4 and 6 weeks. The results showed that the highest herbicide efficiency and the lowest weed dry weight were achieved in 1 L ha-1 supergalant with adjuvant at 2 leaf stage of grass weed. Adjuvant use could reduce weed density by 74% as compared to no adjuvant use treatments. The results also showed that adjuvant use increased weed control at all herbicide doses، and there were no significant difference between weed dry weight reduction in lower dose of herbicide with adjuvant and higher dose of herbicide without adjuvant treatments. Application of supergalant at the rate of 1 L ha-1 with adjuvant in 2 leaf stage of weed caused 87% reduction in grass weed density، which did not differ significantly with 0. 8 L ha-1 dose.

To assess the interaction effects of weeds, sowing rate, and N splitting on dryland wheat yield, field experiments were conducted in two years (2007 and 2009) at the College of Agriculture in Shiraz University. The treatments were replicated four times and analyzed as a split- split plot in a randomized complete block. The weedy and weed free were treated as the main plots, the wheat sowing rates treated as the sub plots (100, 120, 140 and 160 kg seed ha-1) and 5 levels (0-1, 1/3-2/3, 1/2-1/2, 2/3-1/3, and 1-0) of N splitting (100 kg ha-1) as the sub- sub plots. Results showed that by interaction between weeds, sowing rates and N splitting, the maximum biological yield (699 kg ha-1 and 1449.5 kg ha-1 in the first and the second year, respectively) was obtained in weed free, 120 kg seed ha-1 sowing rate and N splitting of 1/3-2/3. In the first year by interaction between weeds, sowing rates and N splitting, the highest grain yield (440.07 kg ha-1) was obtained in weed free, 120 kg seed ha-1 sowing rate and N splitting of 1/3-2/3 and the lowest grain yield (47.7 kg ha-1) was obtained in weedy plots with 100 kg seed ha-1 and N splitting of 0-1. In this study, the highest weed dry matter (367.5 kg ha-1 and 160.38 kg ha-1 in the first and the second year, respectively) was obtained in sowing rate of 100 kg seed ha-1 and the lowest weed dry matter (247.5 kg ha-1 and 52.3 kg ha-1 in the first and the second year, respectively) was obtained in sowing rate of 160 kg seed ha-1. In 2009, unusually low temperature in reproduction stage adversely affected wheat and led to no grain yield production.

In order to evaluate the interaction effects of nitrogen and organic matter on growth and yield of dryland wheat, an experiment was conducted at the research station of the College of Agriculture, Shiraz University at Bajgah in 2005 and 2006. The experimental design was split plot in which three levels of nitrogen (0, 40, and 80 kg N ha -1) were main factors and additive organic matters including liquorice root residue at 15 and 30 Mg ha -1, municipal waste compost at 10 and 20 Mg ha -1, and wheat residues at 750 and 1500 kg ha -1 (all rates equivalent to 50 and 100%) were sub factors. A check treatment (no additive materials) was also included in the experiment. Results indicated that with increasing nitrogen level from zero to 40 and 40 to 80 kg ha-1, wheat yield increased significantly. Among yield components, number of seeds per spike increased significantly with zero to 40 and 40 to 80 kg nitrogen ha-1, but number of spikes m-2 increased significantly only when nitrogen level was increased from zero to 80 kg ha-1. Compared to check (no additive materials), maximum wheat grain yield (32%) was obtained from 100% compost application. Results of nitrogen and organic matters interaction effects indicated that 100% compost application and increasing nitrogen level from 40 to 80 kg ha -1 had no significant effect on dryland wheat yield. This showed the positive impact of compost application on the reduction of nitrogen fertilizer. Thus, it appears that 50% of the required nitrogen fertilizer could be replaced by compost. Applying organic matter increased soil water in both years, however, among organic matters, compost had a more pronounced effect on increasing soil water.