An experiment was conducted based on RCBD with four replication and eight teammates during Fall of 1995 to compare the efficacy of trifluralin , ethalfluralin Cyanazine , alachlore and propizamid herbicides us well as hand weeding inxcontrolling of oil seed rape weeds in Eraghi-Mahalleh agricultural research station.xResults indicated a significant difference on wild mustard density between herbicide treatments and control as well as two or four times hand weeding. Wild out significantly controlled by herbicides. However, cyanazine and alachlore herbicides were less effective on it. Treatments didn't affect on oil seed rape density. Crop yield in herbicide treatments significantly increased compare to control.  

In order to have a healthy environment, high productivity and reduced costs, it is essential to use lower rates of herbicides in chemical weed control. To investigate the effects of reduced rates of herbicides on weed control and soybean yield, an experiment was carried out in a randomized complete design with 11 treatments and four replications at experimental station of Agriculture College of Sari, Iran, during the growing season of 2000. Three herbicides were used at three rates each, namely, the recommended rate, 50 and 75% of the recommended rate of trit10uralin (pre - plant incorporation), bentazon, and sethoxydim (post emergence). Eleven treatments were triflouralin (pre - plant incorporation) at 0.84 kgailha (recommended rate), 0.63 and 0.42 kgai/ha, sethoxydim (post emergence) at 0.224 kgai/ha (recommended rate), 0.168, 0.112 kgai/ha and bentazon (post emergence) at 0.84 kgai/ha (recommended rate), 0.63, and 0.42 kgai/ha and two control treatments of weed - free check and weedy - check. Considering soybean seed yield of weed free check, reduction of herbicide application is possible to 50 percent of recommended rate. All treatments could control velvetleaf (Abutilon teophrasti) and pigweed (Amaranthus retroflexus) more than ninety percent (90%). The best grass control was seen in 50% of the recommended rates of trit10uralin and sethoxydim. The herbicides had no adverse effect on soybean. With reduced herbicide rates, both weed control percentage and soybean yield did not show any significant difference in comparison to recommended rate.

A Field experiment was conducted in order to investigate effects of weeding,Trifluralin (pre-sowing herbicide), Haloxyfop ethoxyethyl, Bentazon, Sethmoxdim (post-emergenc herbicides) and a combination of these treatments on weed control in common bean. The experiment was carried out in 2000-2001 using RCBD with 10 treatments and 4 replications at the Azad University of Shahr-e-Rey experimental field station. Results showed that highest yield (581.1 g/m2) was achived from Trifluralin + twice weeding treatment followed by. twice weeding (527.6 g/m2). Maximum yield (466.4 g/m2) from post emergence herbicides group was obtained from Trifluralin + Haloxyfop ethoxyethyl treatment. Treatments in which weeding was included were the best.This finding signifies the importance of weeding in common bean crop production. Results of this experiment indicate that sole application of pre-sowing herbicide (Trifluralin) for weed control in common bean is noteffective. However, in order to control weeds in common bean we suggest application of Trifluralin together with twice hand weeding. Hand weeding in small fields with cheap workers is economically acceptable. Otherwise, a combination of Trifluralin (pre-sowing herbicide) and Haloxyfop ethoxyethyl (post-emergence herbicide) should be applied.

In order to determine the best weed control method in dry-farming of rapeseed and reach to optimal yield and also the best use of soil-water sources in drylands, this experiment was conducted in three years as RCBD desing in three replications at Maragheh, Dry Land Agricultural Research Station on Oilseed rape Cv. PF7045,91. The factors of trial were A1: No weed control (check), A2: One hand weeding before stem elongation, A3: Two hand weedings (one in mid of rosette and other before stem elongation), A4: Mechanical control with sweep before stem elongation, A5: Chemical control with Treflan 1.5 litha-1 before planting and A6: Chemical control with Treflon 2.5 litha-1 before planting. Combined analysis of the data showed that year effect was significant at 1%propability level on weeds per unit area, pods per plant, seeds per pod, grain yield, oil percentage and percentage of moisture lost. Only seed per pod and 1000 seed weight were affected by yearx control methods interaction. Two hand weeding streatment with 487.5 kgha-1 grain yield was arranged in class A, and chemical control by Treflan 2.5 litha-1 with 285 kgha-1 grain yield in class B. Chemical control by 2.5 litha-1 Treflan with 107 kgha-1 oil yield, arranged after two hand weeding, treatment. Over-all chemical weed control treatment by 2.5 litha-1 Treflan before planting is recommended for Maragheh region and other regions with similar climatic conditions.

In order to determine the best weed control method in spring safflower under dryland conditions and to optimize grain yield and to materialize the best use of soil and water resourses under drylands, this experiment was conducted in two cropping seasons (2000, 2001) using randomized conplet block design with 3 replications at Maragheh, Dryland Agriculture Research Station. The treatments were: A1= No weed control, A2= Two hand weedings (in mid-rosette, and before stem elongation), A3= Mechanical control with sweep cheisd before stem elongation, A4= Chemical control by Trifluralin (Ec=44.5%) with 1.5 L/ha as before planting herbicide and A5= Chemical control by Trifluralin with 2.5 Lit/ha as pre planting herbicide. Combined analysisg of variance results showed that the year effect was significant at 5% probability level on height of primary secondary branches as well as the number of capitols/plant. Control methods effect was significant at 1% probability level on weeds number per unit area, plant height and grain yield. Only grain yield was affected by year ´ control method interactions. Twice hand weeding with 1251 kg/ha grain yield produced the highest and was followed by chemical control with 2.5 L/ha Trifluralin with 1002 kg/ha grain yield. In conclusion chemical weed control with 2.5 L/ha Trifluralin as before planting herbicide could be recommended for Maragheh region and other regions with similar climatic conditions.

Present investigation carried out to study different weed control methods in spring safflower under rain fed condition.The experiment was conducted in Sararood Research Station located in west of Iran in 2002. the experiment caried out in Mixed Factorial based on RCBD witht four replications. Factor A was included 4 different herbicides Trifluralin at 960 g a.i./ha, Pendimethalin at 660ga.i./ha, Ethalfluralin at 1172.5 g a.i./ha ,Imazametabenz at 625 g a.i./ha. and Factor B was 4 different method including without mechanical control, hand weeding at the 6 leaves stage, cultivator at 6 leaves stage, hand weeding at the 12 leaves stage + cultivator at 6 leaves stage along with two checks namely without weed, and without anyweed control. The results showed that according to analysis of variance weeds chemical control did not significant effect on seed yield but mechanical control had significant at %1 level on grain yield and dry matter and have not significant interaction of chemical and mechanical control have on yield and related traits of safflower so have not significant difference seed oil percent. Among mechanical methods that used, a hand weeding at 6 leaves stage had highest yield. According to standard method EWRS, effect soil application herbicides on weeds that exite on the area experiment have placed in poor degree and Imazametabenz herbicide in fair degree. With due attention to high plan, number of heads per plant and number of grain per plant safflower had the highest tolerance to Trifluralin and Imazamethabenz herbicides.

In order to control cotton weeds chemically and introducing new herbicides with different modes of action, an experiment was carried out in three locations (Varamin, Golestan, Khorasan) in 2004. The experiment was conducted in randomized complete block design with 11 treatments and 4 replications. trifluralin at 1200 g(ai) /ha (ppi), ethalfluralin at 1160 g(ai) /ha, diuron at 2400 g(ai) /ha (pre emergence), trifloxysulfuron sodium at 11.25 and 15 g(ai) /ha with cytogate 2/1000 (post emergence at the 5- 8 leaf stages of cotton), fluometuron+prometryn at 1232, 1936, 2464 g(ai) /ha (pre sowing) and fluometuron+prometryn at 1499, 2024, 2552 g(ai) /ha (pre emergence) were used. Results showed that fluometuron+prometryn at 2024 and 2552 g(ai) /ha (pre emergence) and trifloxysulfuron sodium at 11.25 and 15 g(ai) /ha and Diuron at 2400 g(ai) /ha increased yield and yield components of cotton. Fluometuron+prometryn at other treatments effectively increased yield components compared with trifluralin and ethalfluralin. Fluometuron+prometryn at 2024 and 2552 g(ai) /ha (pre emergence) and trifloxysulfuron sodium at 11.25 and 15 g(ai) /ha were most effective in decreasing dry weight and density of weeds. Depending on weed species, trifloxysulfuron sodium and fluometuron+ prometryn showed some difference in control of weeds.