Phenological characteristics of the invasive weed Cucumis melo

Phenology is the study of periodic biological events. The time of weed appearance, growth and reproduction are very important for decisions on invasive weed management. Cucumis melo is an annual invasive weed of soybean fields in the north of Iran that reproduces and spreads predominately through seed production. In order to study the phenology of wild melon was conducted an experiment in CRD at Research Farm of Gorgan University of Agricultural Sciences and Natural Resources, Iran, during 2012. Seeds first germinated after 10 days of planting, as soon as optimal soil temperatures were achieved. The weed exhibited monoecious tendencies, with production of male flowers rapidly followed by production of both male and female flowers on the same vine. Cucumis melo exhibited prolific fruit production, until senescence occurred at 75 and 92 days after establishment. First fruit formation was observed between 40 and 49 days after emergence, depending on temperature. To complete growth cycle, of Cucumis melo required about 448 and 733 degree days, respectively for late of May and 8 of June. The weed produced a maximum of 100 fruits/plant, but an average plant typically produced 48 fruits/plant. The seed number and seed weight was on average about 190 seeds/fruit and 0.55 g per 100 seeds, respectively. The results indicated that wild melon could produce a lot of fruits and seeds within a growth period of about 75 and 92 days.Keywords: Growth, monoecious plants, reproduction, wild melonPhänologische Eigenschaften der invasiven Unkrautart Cucumis meloZusammenfassungDie Phänologie befasst sich mit wiederkehrenden biologischen Abläufen. Auflauf, Wachstum und Samenproduktion invasiver Arten sind wichtig für Bekämpfungsentscheidungen. Cucumis melo ist eine einjährige, invasive Unkrautart, die im Norden Irans im Sojabohnenanbau vorkommt und sich vorwiegend durch Samenproduktion vermehrt und ausbreitet. Untersuchungen zur Phänologie dieser Unkrautart wurden 2012 auf der Versuchsstation der Gorgan Universität im Iran durchgeführt. Das Auflaufen erfolgte von Anfang bis Mitte Mai nach Erreichen optimaler Bodentemperaturen. Die Unkrautart zeigte monözische Tendenzen indem sowohl männliche als auch weibliche Blüten an einer Pflanze ausgebildet wurden. Cucumis melo zeigt eine starke Fruchtentwicklung bis zum Beginn der Seneszens nach etwa 75 Tagen nach der Keimung. In Abhängigkeit von der Temperatur wurde die erste Fruchtbildung 40 bis 49 Tage nach der Keimung beobachtet. Wachstumszyklus für Ende Mai und 8. Juni abzuschließen, Cucumis melo der erforderlichen etwa 448 und 733 Grad-Tagen. Die Unkrautart produzierte maximal 100 Früchte pro Pflanze und im Mittel produzierte eine Pflanze 48 Früchte. Die Samenanzahl und das Samengewicht lagen bei 190 Samen pro Frucht und 0,55 g pro 100 Samen. Die Ergebnisse zeigen, dass wilde Melonenarten innerhalb von 75 Tagen eine hohe Anzahl von Früchten und Samen produzieren können.Stichwörter: Monoecious Pflanzen, Reproduktion, Wachstum, wilde Melon

Surfactant and rainfall influenced clodinafop-propargyl efficacy to control wild oat (Avena ludoviciana Durieu.)

Abstract A nonionic (Citogate) and cationic (Frigate) surfactant were evaluated for their efficacy to enhance clodinafop-propargyl performance and minimize rainfall effect in controlling wild oat (Avena ludoviciana Durieu.). Moreover, by using the capillary rise technique the surface tension of these surfactants or surfactants plus clodinafop-propargyl aqueous solution was determined. Lower and higher surface tension values were recorded with aqueous solution of Citogate and Frigate alone and along with clodinafoppropargyl, respectively. The critical micelle concentration of Citogate (0.15% v/v) was higher than of Frigate (0.1% v/v). Both the tested surfactants minimized the rainfall effect and improved the performance of clodinafop-propargyl on wild oat. When Citogate was added to clodinafop-propargyl, herbicidal activity was higher than when Frigate was added, indicating that the surfactants potency to reduce surface tension of spray solution is a momentous factor in order to enhance clodinafop-propargyl performance. The data from rainfall treatment have confirmed this hypothesis, as it seems when Citogate was added to clodinafop-propargyl; rainfall adverse effect was lower which is presumably due to quick absorption of clodinafop-propargyl by wild oat leaves. In other words, clodinafop-propargyl infiltrated in short-term before it was washed off the wild oat leaf surface as a hypothesis

The Effect of Sugar Beet Broadleaf Herbicides on Fluorescence Induction Curves in Amaranthus retroflexus L. and Portulaca oleracea L.

Chlorophyll fluorescence analysis is a simple and rapid method for detecting herbicide effects after a short time following their application in photosynthetic apparatus in plants. Chlorophyll fluorescence measurements were carried out against two broad of weeds to describe how the Kautsky curve and its parameters were affected by herbicides. Desmedipham + phenmedipham + ethofumesate changed the chlorophyll fluorescence induction curve at all time intervals except four hours after spring (HAS) in Amaranthus retroflexus L. and at all doses of Portulaca oleracea L. 4 HAS. In contrast, chlorophyll fluorescence inhibition was evident by chloridazon at doses of 650 and 325 g a.i. ha-1 in P. oleracea and A. retroflexus respectively, for all time intervals. Furthermore, chlorophyll fluorescence decays only occurred by clopyralid in A. retroflexus at the highest dose. A biomass effective dose (ED50 and/or ED90) based on log-logistic dose-response curves for A. retroflexus were considerably higher than that of P. oleracea. The maximum quantum efficiency (FV/Fm) was stable, whereas the relative changes at the J step (Fvj) and area (the area between the Kautsky curve and the maximum fluorescence (Fm)) was more sensitive to all three herbicides. There was a relatively good correlation between fluorescence parameters taken 24 hours after the spraying and the dry matter taken three weeks later, for both species under study

CHEMICAL CONTROL, PHYSIOLOGY, ANATOMY, AND GLYPHOSATE ABSORPTION-TRANSLOCATION IN FIELD BINDWEED UNDER WATER STRESS

Control of field bindweed (Convolvulus arvensis L.) with glyphosate {N-(phosphonomethyl)glycine} alone and glyphosate in combination with growth regulators was studied under field conditions and the effect of soil moisture on physiological, morphological-anatomical, and (\u2714)C-glyphosate absorption translocation characteristics of field bindweed were studied under greenhouse and laboratory conditions. Discing at least 4 weeks before herbicide application resulted in better control of field bindweed (79%) than in non-disced plots (55%) when other weeds were present. Field bindweed control was generally over 81% and up to 100% at glyphosate rates as low as 0.8 kg/ha following a discing when soil moisture was good. Low soil moisture without tillage gave under 66% control at rates up to 3.4 kg/ha. Of two ecotypes, the most common to Nebraska was more tolerant to glyphosate than a narrow-leaved type. Field bindweed control was best (88 to 100%) with 2 years application of glyphosate. Combining glyphosate with growth regulators, dicamba (3,6-dichloro-o-anisic acid), 2,4-D {(2,4-dichloro-phenoxy)acetic acid}, chlorflurenol {a combination of IT3456 (methyl-1-2-chloro-9-hydroxyfluorene-9-carboxylate), IT3294 (methyl-9-hydroxyfluorene-9-carboxylate), and IT5733 (methyl-2,7-dichloro-9-hydroxyfluorene-9-carboxylate)}, and ethephon (2-chloroethyl phosphonic acid) showed little improvement in control unless glyphosate was used at rates less than 0.8 kg/ha. The most effective treatment time for a single treatment was in September during rapid vegetative growth compared to October, or fruiting stage. Field bindweed control went from 21% with glyphosate alone at 0.6 kg/ha to over 88% when 2,4-D (0.6 or 0.1 kg/ha), dicamba (0.1 or 0.6 kg/ha), or ethephon (0.6 kg/ha) were added to glyphosate. Laboratory plants were grown from root segments for 65 days (young plants) and 100 days (mature plants). Water potential and leaf conductance were measured on young and mature plants which were kept under high (field capacity), medium (1/2 field capacity), and low (1/3 field capacity) soil moisture for 15 and 35 days, respectively. An overall reduction of the vegetative organs occurred in plants under moisture stress in the greenhouse. Water potential measurements showed that mature plants adapted to low soil moisture. Plants under medium soil moisture conditions and younger plants which were stressed only for 15 days maintained lower leaf water potentials (down to -19 bars). Leaf conductance per unit area was highest in plants under low soil moisture after adaptation and lowest in plants under medium soil moisture conditions. Low soil moisture caused an increase in cuticle and leaf thickness, more compact mesophyll cells and increased epicuticular wax deposition. Correlation coefficients were determined between physiological characteristics and morphological-anatomical characteristics and were more predictable in plants not adapted to stress (young plants) compared to those that adapted more to stress (mature plants). (\u2714)C-glyphosate was applied to exporting leaves of the young and mature plants and harvested 72 h later. About 20 (+OR-) 5% of recovered herbicide was taken up by the plants and from this amount, 45 (+OR-) 10% was translocated out of the treated leaf and accumulated in growing leaves and roots. Slightly more (6 (+OR-) 3%) herbicide was absorbed in plants under no stress than in plants under medium or low moisture stress. In young plants four to eight times more radioactivity accumulated in roots than in foliage (excluding treated leaf). Similar quantities of radioactivity accumulated in foliage and roots of mature plants. Such translocation may be a major factor in susceptability of young plants to glyphosate. Absorption and translocation were not affected enough by water stress to be a major factor in reduced glyphosate control of field bindweed under stress

Study of Seed Dormancy in Seven Medicinal Species from Apiaceae

Seeds of seven species of medicinal plants collected from the natural habitat in Lorestan province in summer 2011. Germination test carried out in a completely randomized design with four replications of 25 seeds in H2O. Species of Smyrnium cordifrolium, Kelussia odoratissima, Dorema aucheri and Ferulago angulata had no germination while Heracleum persicum, Bunium luristanicum and Falcaria vulgaris showed germination of 30, 96 and 97% respectively. Different treatments of breaking dormancy applied to the species with germination below 30% [moist-chilling for periods of 2, 4, 6, 8, 10 and 12 weeks, with two concentrations of 250 and 500 ppm of gibberellic acid, a combination treatment (gibberellic 250 ppm + 4 weeks moist-chilling and gibberellic acid 500 ppm + moist-chilling for 4 weeks) and potassium nitrate 2 g/l]. The results showed that moist-chilling was the most effective treatments to break seed dormancy of Heracleum persicum (6 weeks), Dorema aucheri (12 weeks), Kelussia odoratissima (12 weeks) and Ferulago angulata (12 weeks). Therefore, based on their reactions to the treatments, dormancy of Kelussia odoratissima and Ferulago angulata could be classified as deep physiological dormancy and species of Dorema aucheri and Heracleum persicum intermediate physiological dormancy type

Joint action of some usable important broadleaf herbicides in sugar beet

Introduction: The assessment of the effect of mixtures could be based on various concepts whether we work within toxicology, pharmacology or weed control. Combinations of certain herbicides can give better weed control than use of the individual herbicide alone and/or loss of weed control when use of certain other herbicides in combination. Predicting the joint action of mixtures is extremely difficult, unless the compounds are known to interact at the same site of action. These most common methods to analyze the joint action of herbicide mixtures are the Additive Dose Model (ADM) or the Multiplicative Survival Model (MSM). The ADM assumes the two compounds have similar modes of action (do not interact) in the receiver plant, i.e. effective doses of each component will not change by mixing. ADM has been widely accepted as a valid method to estimate joint action of mixtures sharing the same or similar action mechanisms in the receiver plant. MSM has been reported to yield more accurate results for mixture toxicity than ADM do when the components exhibited different or dissimilar modes of action in the receiver plant. ADM or Concentration Addition (CA) is used here to test for deviation of additivity of doses using the ADM isoboles as reference; any deviation from the ADM is characterized by antagonism when the efficacy of a mixture is lower than predicted by the reference model and synergistic when the efficacy is higher than predicted. Materials and Methods: In order to determine joint action of some usable important broadleaf herbicides in sugar beet, six experiments were conducted at the research glasshouse in Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. The plants were sprayed with seven doses of commercial formulation of desmedipham + phenmedipham + ethofumesate (Betanal Progress- OF®, 427 g a.i. L-1, Tragusa, Spain), chloridazon (Pyramin®, 1361 g a.i. L-1, BASF, Germany), clopyralid (Lontrel®, 149 g a.i. L-1, Golsam, Gorgan, Iran) either alone or in binary fixed-ratio mixtures of the three herbicides. The ratio of the herbicides of the binary mixtures were chosen with the aim of obtaining a contribution to the overall effect of the two herbicides of 100:0, 75:25, 50:50, 25:75, and 0:100 for seven-mixture-ratio experiments. Spraying was performed by overhead trolley sprayer (Matabi 121030 Super Agro 20 litre sprayer), 8002 flat-fan nozzle at 300 kPa and a spray volume of 200 Lha-1. The plants were treated at 21 days (at the four- to six-true leaf stage) after planting. Dose-response curves were estimated by fitting a three log-logistic dose–response model against dose for ED50 and ED90 response levels. ADM was used as reference model of joint action with their equations. As the results with the herbicide mixtures originate from up to twelve separate experiments it was necessary to standardize the x- and y-axes so that the ED50, ED80 and ED90 doses of the herbicides applied separately were always fixed to 1. Results Discussion: The results showed that mixtures of chloridazon and clopyralid were less phytotoxic than predicted by ADM particularly in Amaranthus retroflexus at ED50 and ED80 response levels. These binary mixtures of herbicides were either followed ADM or less than predicted by ADM in Solanum nigrum. In contrast, mixture of desmedipham + phenmedipham + ethofumesate and clopyralid was synergistic in both species. Whereas desmedipham + phenmedipham + ethofumesate and chloridazon binary mixture was synergistic in Solanum nigrum to followed according to ADM in Amaranthus retroflexus. Conclusion: The present study has revealed that mixtures of photosystem II, lipid biosynthesis and auxin inhibitor herbicides either followed ADM, or performed better than predicted by ADM, i.e. applying mixtures of these herbicides will not result in an excessive use of herbicide compared to applying the herbicides separately. In contrast, mixtures of chloridazon and clopyralid were trend antagonistic and the two herbicides should not be applied in mixture

Isobolographic Analysis for Mixture Effects of Mesosulfuron-Methyl+Iodosulfuron with Pinoxaden in Wheat (Triticum aestivum)

Introduction: Farmers usually combine various herbicides with the aim of reducing the number of machinery passes across the field, preventing weed resistance to herbicides, and saving time and money. Combination of herbicides is not only recommended for the management of herbicide resistance, but for increasing efficacy compare with a single herbicide application and expanding spectrum weed control. Materials and Methods: In order to assess the mixing herbicides that used in wheat, several experiments were conducted in the Research greenhouse and Farm of Agricultural Faculty of Ferdowsi University of Mashhad, Iran in 2013. The greenhouse experiments were arranged in a completely randomize design with a factorial arrangement of treatments with four replications. Greenhouse studies were included two combination experiments. Experiments included of 7 doses (0, 2.25, 4.5, 9, 13.5, and 18 g ai ha-1) of mesosulfuron-methyl+iodosulfuron and (0, 5.6, 11.25, 22.5, 33.75, and 45 g ai ha-1) of pinoxaden (Axial 10% EC, EC; Syngenta, Switzerland) alone on wild oat (Avena ludoviciana Durieu) and littleseed canarygrass (Phalaris minor Rtez.). Wild oat seeds were sown in pots directly. Littleseed canarygrass seeds were placed in petri dishes with 9 cm diameter which contains a layer of filter paper then 6 ml of KNO3 solution (2 g L-1) was added to each petri dish. Petri dishes were kept for 10 days at 4 to 5 °C in the refrigerator in darkness condition and then transferred to a germinator with 20/10 °C temperature in 45/65% relative humidity for a 16/8 h day/night. Then, they were planted in 1L plastic pots filled with a mixture of clay, loam soil, and sand (1:1:1 v/v/v). The pots were irrigated every two days. The seedlings were thinned to 4 plants in per pot. The spray treatment was done at the three to four-leaf stage by using an overhead trolley sprayer (Matabi 121030 Super Agro 20 L sprayer; Agratech Services-Crop Spraying Equipment, Rossendale, UK), equipped with an 8002 flat fan nozzle tip delivering 200 L ha-1 at 2 bar spray pressure. Four weeks after spraying, the plants of the experimental units were harvested and oven-dried at 75°C for 48 h, then weighed. The greenhouse temperature varied from 18–25 °C during the day and 14–21°C at night. Field trial was conducted in completely randomized block design with three replications at Research Farm of Agricultural Faculty of Ferdowsi University of Mashhad, Iran in 2014. Because the appropriate ED50 obtained in the greenhouse therefor he recommended doses were used for field trial. Minitab 16.0 software was used for variance analysis and Mean comparison also for regression analysis, R software was applied. Results and Discussion: Greenhouse experiment results showed that pure application of mesosulfuron-methyl+iodosulfuron and pinoxaden herbicide was effective on wild oat and littleseed canarygrass. The results of mixing experiments on wild oat and littleseed canarygrass showed that mixture of mesosulfuron-methyl+iodosulfuron with pinoxaden had additive effect of both species. ED50 of different ratios of the two herbicides showed that maximum efficacy (maximum intensity effect) in decreasing dry weight of wild oat was related to ratio 100: 0 mesosulfuron-methyl+iodosulfuron and pinoxaden with ED50= 2.16 and minimum efficacy (minimum intensity effect) was related to ratio 75:25 mesosulfuron-methyl+iodosulfuron and pinoxaden with ED50= 4.22. The results of the field almost were consistent with the results of the greenhouse so that the different ratios no significant difference was observed in both species of wild oat and littleseed canarygrass. All herbicide treatments resulted in at least 85.4% and 86.86% reduction biomass and population of wild oat. Except control treatments, all tank mixing ratios of mesosulfuron-methyl+iodosulfuron and pinoxaden weren’t significantly different. On the other hand, jointed effects of the two herbicides on wild oat in field experiment had the same effect as when each herbicide applied separately. Also, comparisons between greenhouse and field results showed that twice condition have same response. The results of yield and yield components showed that parameters of grain yield and biological yield was significant at the 5% level. Conclusion: None of herbicides had effect on others and the results of greenhouse were consistent with field experiment. It may be possible without diminished performance, these herbicides were used to postpone weed resistance in weed management

The Influence of Ammonium Sulphate added to the Spray Solution of Calcium Carbonate-Containing Glyphosate and Nicosulfuron on Barnyardgrass and Velvetleaf Control

Introduction: There are many reasons for no effectiveness of herbicides on weeds, including the incorrect herbicide, the insufficient use of herbicide, the unprincipled sprayer, spraying at the wrong time especially adverse weather conditions, and a factor that often overlooked is the "water quality in herbicide spray tank". Most of the herbicides are mixed with water and applied as a spray. Obviously water quality is an extremely important issue. Water quality factors in this regard that effect on uptake and translocation of herbicides included as water hardness, pH, bicarbonate ion concentration, turbidity, organic matter and other substances. Hardness is determined by the amount of calcium and magnesium present and is expressed as calcium carbonate (CaCO3) equivalent in parts per million. Petroff (27) classified water based on hardness: water with a hardness 0-75 ppm is considered “soft” water, 75-150 ppm is “medium hard”, 150-300 ppm is considered “hard”, and more than 300 ppm is “very hard”. Hard water is a problem in over 85% of the United States according to the US Geological Survey. The contrast between the herbicides and dissolved ions depend on amount and type of minerals in the spray tank. So that different herbicide may show different responses to the same action. If soft water is not available, surfactant and chemicals additives such as ammonium sulfate (AMS), ammonium nitrate (AMN) and urea- ammonium nitrate can be added to the spray tank to increase herbicide efficacy (7). These compounds prevent from the adverse effects of the ions in water. Glyphosate and nicosulfuron belong to two different chemical families of herbicides and are soluble in water. Therefore, water quality such as the presence of calcium carbonate may have a significant effect on these herbicide performances, while removing the inhibitory effect of water hardness by adding nitrogen compounds such as ammonium sulfate need to experiment. According to the above, basic experiments carried out as the influence of adding ammonium sulphate to spray solution of calcium carbonate-containing glyphosate and nicosulfuron on barnyardgrass and velvetleaf control. Materials and Methods: Four experiments were performed as factorial arrangement of treatments 6×2 based on completely randomized design with six replications (+six control pots for each weed species) at Research Greenhouse of the Ferdowsi University of Mashhad in 2010. Factors were included different concentrations of calcium carbonate (CaCO3; Merck, Germany) of water in spray tank at six levels 0, 100, 200, 300, 400 and 500 ppm in deionized water (w/v) in combination with 0 (-AMS) or 3 kg/ha (+AMS) ammonium sulphate (Merck, Germany) as adjuster the hardness. Glyphosate (Roundup®) and nicosulfuron (Cruse®) herbicides were applied post emergent at 385 and 550 mL ha-1 as commercial products (158 and 22 g ai ha-1; based on ED50 outcome preliminary test (12), recpectively) at the 3-4 leaf stage of the weeds (barnyardgrass and velvetleaf) in a spray volume of 250 L ha-1. Four weeks after treatment, survival, plant height, leaf area, and shoot dry weight of weeds (% control) were calculated. The data of experiment were subjected to ANOVA using MSTATC software. Means of the treatments were separated using Duncan’s Multiple Range Test at α = 0.05. Also, based on the distribution of data, regression analysis was used as linear, two, and third-degree polynomial by EXCEL 2007. Results and Discussion: The results showed a significant reduction (p≤0.01) for survival, plant height, leaf area, and shoot dry weight of weeds (% control) with addition of calcium carbonate in spray tank of glyphosate and nicosulfuron herbicides, but this effect was not similar. So that, 500 ppm Ca2+ to the nicosulfuron spray solution compared with its absence increased barnyardgrass and velvetleaf biomass (% control) 16 and 50%, respectively. The corresponding values for glyphosate were 78 and 51%. Accordingly, Nalewaja et al. (24) reviewed the effect of different calcium compounds such as calcium carbonate (0.02 mol) in water as a solvent nicosulfuron herbicide (15 g ai ha-1; 160 L ha-1) interaction to seven surfactants on finger grass (Digitaria sanguinalis L.) at greenhouse conditions found that CaCO3 across seven surfactants reduced about 8% nicosulfuron performance. In research conducted by Buhler and Burnside (5) concluded that an increase in calcium ion (prepared from CaCl2) to 2 mmol in spray tank was not affected on glyphosate (400 g ai ha-1; 190 L ha-1) performance. With the increasing of Ca++ to 8 mmol, was reduced significantly (P≤0.05) toxicity herbicide on oat (Avena sativa L.) from 80 to less than 20%, 14 days after spray at the greenhouse experiment. Adding ammonium sulphate (+AMS) decreased the antagonistic effects of water hardness, and increased herbicides efficacy on barnyardgrass and velvetleaf. However, the synergistic effect of +AMS on velvetleaf control by glyphosate was higher. Green and Cahill (10) concluded adding 2% AMS to spray tank increased the pH of nicosulfuron solution from 4.6 to 4.7 and finger grass was well controlled by this herbicide because of increasing nicosulfuron solubility from 12 to 16%. In research conducted by Mueller et al. (22), the presence of calcium (Ca++) and magnesium (Mg++) ions concentration of 250 ppm reduced the effectiveness of three types of glyphosate salt, but adding 2% by weight of ammonium sulfate (AMS) to the spray tank overcame to the ions antagonistic effect. Conclusion: Results of current experiment emphasized the role of water hardness (CaCO3) in spray tank of glyphosate and nicosulfuron on barnyardgrass and velvetleaf control

Effects of weed management strategies on weed density and biomass and saffron (Crocus sativus) yield

In order to study and compare chemical and non-chemical methods of weed management in saffron (Crocus sativus) fields, two field experiments were carried out in a randomized completely block design with three replications at Research Field Station of Gonabad during 2009 to 2011. Treatments included cover crops of barely, Mushroom bed mulch, herbicides of haloxyfop R methyl ester (EC10%), iodosulfuron methyl sodium+mesosulfuron. methyl + mefenpyr. diethy (WG6%) l, hand weeding (DF75%) and control. For determining the ability of treatments for weed control, dry matter of weed, leaf dry weight of saffron, stigma and saffron flower yields were determined. Results showed that dominant weed species were mouse barely (Hordeum murinum), wild barley (Hordeum spontaneum) Hoary cress (Cardaria draba), and yarrow (Achillea millefolium). Herbicides of iodosulfuron methyl sodium + mesosulfuron methyl + mefen pyr. Diethy (WG6%) destroyed grasses and broadleaf, but it destroyed saffron plant too. Haloxyfop. R methyl ester damaged grasses but decreased stigma yield and leaf of saffron. Applied mulch was not be able to control the weeds, however, it increased saffron stigma yield. Cover crops of barley significantly decreased weed dry matter weights. Barley caused least weeds dry matter weight similar to hand weeding. In conclusion, the treatments of cover crops showed the best performances in weed control and saffron yield comparing to other studied weed management methods

Photocontrol of Weed and Application Reduced Dosage of Imazethapyr and Trifuralin on Weed Management of Chickpea

Introduction: Weed cause enormous loss of chickpea yield and its quality. Photocontrol of weeds (soil cultivation in darkness) is a preventive weed control method, the basic aim of which is to reduce the germination of light sensitive weed seeds by excluding light during soil disturbance, in order to reduce the emergence of weeds in the crop. Considerable research has examined the potential use of lower-than-labeled herbicide doses. There are reasons for the potential successful use of reduced herbicide doses: (i) registered doses are set to ensure adequate control over a wide spectrum of weed species, weed densities, growth stages, and environmental conditions; (ii) maximum weed control is not always necessary for optimal crop yields; and (iii) combining reduced doses of herbicides with other management practices, such as tillage or competitive crops, can markedly increase the odds of successful weed control. This study was conducted to evaluate the photocontrol of weeds and application of reduced dosage of Imazethapyr and trifluralin herbicides on weed control and yield of chickpea. Materials and Methods: The experiment was designed as a strip plot based on a complete randomized block with three replications. The experiment had 3 factors: main plot consisted of tillage method at 3 levels (night tillage, day tillage, light-proof cover tillage), subplot consisted of Trifuralin (480, 960 and 1440 grams of active ingredient per hectare) Imazethapyr (50, 100 and 150 grams of active ingredient per hectare), weed infestation and weed free were considered as control. During the growing season, six sampling steps (28 days after planting (410 Growth Degree Day (GDD)), (45 days after planting (715 GDD)), (57 days after planting (975 GDD)), (70 days after planting (1280 GDD), (75 days after planting (1620 GDD)), (90 days after planting (2025 GGD)) were carried out. For statistical analysis the data normality of the distribution were analyzed with Sigma plot software, and if necessary, the data transforming and then ANOVA was performed using MSTATC. The means were compared using Duncan's multiple range test and graphs were drawn using Excel and Sigma plot software. Result and Discussion: In the growing season, the application of herbicide had significant effect (P≤ 0.05) on weed density. In all stages of sampling, weed density was higher in light-proof cover tillage treatments than day and night tillage operations. According to the results based on the type of tillage, night tillage and light-proof cover tillage treatments did not reduce weed density compared to day tillage. In the reduced Imazethapyr application, there was significant difference at 1620 GDD with others, but this amount of application did not effectively control weeds. In treatment of 1280 GDD, the amount of reduced application of Trifuralin was significantly different with other amounts but could not control weeds. However, there was no significant difference between the amounts of Trifuralin from this stage until the end of the growth season. By examining the biomass of chickpea during the growing season in the applied amounts of herbicides, it was determined that the growth of all treatments was the same order of 1200 GDD. From this stage, the difference between treatments increased until the end of the growing season, in the end of the growing season, control of weed control was the highest and control without chickpea was the least biomass. The effect of herbicide application dosage on the density of the weeds was significant (P≤ 0.05). Chickpea grain yield in light -proof cover tillage was 45 percentage lower than night-time tillage and day time tillage treatment and there were no significant differences between night-time tillage and day-time tillage treatment. The lowest and the highest yield was respectively in weed infestation (1151 Kg/ha) and weed control (1977 Kg/ha) and yield in the dosage of herbicides. Did not differ significantly. The results of this experiment show that reduced dosage of herbicides can control weed without negative effects on chickpea yield. Conclusion: The results showed that weed density and weed biomass was more than in light-proof cover tillage treatment compared to night and day tillage and there were no significant differences (P≤ 0.05) between night and day tillage. Weed biomass showed no significant differences between herbicide treatments. The reduced dosage of herbicide in Imazethapyr treatment did not have enough control but there were no significant differences between herbicide treatments. Chickpea yield had no significant difference (P≤ 0.05) between reduced, recommended and increased dosage herbicide