WEED leaf area damage coefficient (l) denotes the increase in WEED competitiveness per unit increase in its leaf area.Although the variability of this parameter has been confirmed, it was assumed to be constant in many researches. The objective of this study was to determine the interactions between herbicide dose andλ. Field experiments were conducted to determine the relationship between competitive indices of maize, Xanthium strumarium and Amaranthus retroflexusduring 2007 and 2008. Five doses of the herbicide nicosulfuron as main factor, and 16 density combinations comprised of 4 densities of A. retroflexus × 4 densities of X. strumarium as sub plots were arranged in a one-replicate split factorial. ForA. retroflexus, the l value was constant. For X. strumarium, the l value was constant with no herbicide and 0.25 rate of the full dose. With increasing the dose up to half the recommended dose, the l value increased and again with increasing dose to 0.75 rate, it returned to the level with no herbicide. This relationship was properly described by Gaussian model. Herbicide at half rate probably removed the apical dominance and increased the number of lateral shoots. Herbicide as an external factor was the most important determinant in the change of X. strumoriumcanopy shape. Deep understanding of the system behavior, relations and interactions with herbicide applications is of great help in improving the predictive power of WEED management models

The presence of WEED in soybean is a serious threat to crop yield. Little research has addressed MULTIPLE WEED species interference in soybean. Field experiments were conducted at the Research Farm of University of Tehran, Karaj, Iran, during the growing season of 2007 and 2008 to determine the influence of density of single and multispecies populations of common cocklebur and redroot pigWEED on soybean yield and competitive abilities of WEEDs. Common cocklebur and redroot pigWEED seeds were sown concurrently with soybean and established at selected density within 15 cm on either side of soybean row. The experimental design was factorial based on randomized complete block design with three replications. Results showed that soybean grain yield was significantly affected by WEED COMPETITION. Soybean yield loss due to COMPETITION was 86% and 70% in first and second experiment, respectively. Soybean yield was affected more by common cocklebur than by redroot pigWEED. Common cocklebur at a density of 2.3 (in 2007) and 6.25 (in 2008) plants per m-1 of row reduced soybean yield by 50%. In contrast, same reduction in soybean yield from redroot pigWEED was obtained at density of 5.9 and 12.1 in 2007 and 2008, respectively. Competitive effect of common cocklebur was equivalent with 2.37 and 1.91 plant of redroot pigWEED density in 2007 and 2008, respectively.

To determine chickpea genotypes COMPETITION ability against WEEDs, 49 chickpea genotypes were evaluated under WEEDs-free and WEEDy conditions using 7 × 7 simple lattice design with two replications in 2006 in Kheirabad Agricultural Research Station of Zanjan, Iran. Each plot was equally divided into two sub-plots in which the first sub-plot was WEED-free and the second was left with WEEDs to grow naturally. Results of correlation between seed yield and its components with WEEDs density (in two growth stages) and dry weight (in one grown stage) showed that WEEDs density in early days of plant growing had the highest reduction of seed yield. Factor and correlation analyses and biplot method of grain yield in both conditions showed that MP, GMP, STI indices were more suitable for identification of genotypes with higher yield stability. Cluster analysis based on tolerance indices and yield under WEEDs-free and WEEDy conditions grouped chickpea genotypes in four clusters and genotypes of higher tolerance were located in the first and second clusters. The more sensitive genotypes with the largest margin were located in the fourth cluster.

To study the critical period of WEEDs COMPETITION with sugar beet and determine the duration that the crop can tolerate the WEEDs, a field experiment was carried out at Esfahan Agicultural Research Center, in Kabotarabad-Esfahan during 1999-2000. The experiment conducted in RCB Design with 14 treatments and four replications. The treatments included control throughout the growth season (as a check), till and after 4, 6, 8, 10, 12 and 14 weeks from crop emergence together with no WEED control during the whole growing season. The result showed that the WEEDing until four weeks after planting had a positive effect on root yield and sugar yield. The results also indicated that there was a critical period for WEED control between 4-21 weeks after planting ( WAP).There was a significant interaction between the plant density and establishment with the period of WEED control. There was no critical period for sugar content, Na, K and NO3. This study showed that the best period for WEED control in Baran(Esfahan) would be 4-21 WAP.

Choosing varieties with high WEED competitiveness is important in integrated WEED management (IWM). This experiment was carried out in order to study WEED tolerance and COMPETITION indices of 18 wheat genotypes under natural WEED interference or without interference at the research field of agricultural faculty, University of Mohaghegh Ardabili, during 2010-2011 growing season. Significant differences were found in the indexes of wheat genotypes. Stress tolerance index of genotypes was between 110. 3 to 915. 0 kg ha-1. More tolerance indices such as Mean Productivity, Harmonic index and WEED Interference Tolerance Index were higher for N-80-19 and Alvand genotypes and lower for Dabira and Toos than others. Among the tolerance indices, WEED interference tolerance index (WITI) and ability of WEED COMPETITION (AWC) were more efficient to classify wheat genotypes to WEED tolerance. Alvand and C-85-9 genotypes had the highest competitive index (CI). This finding can be used for non-chemical WEED management programs.

WEEDs are one of the main obstacles to production in agricultural systems. The type of nutrient source and fertilizer can affect the density and flora of WEEDs, in addition to affecting the growth of agricultural plants. In order to investigate the effect of fertilizer sources on the zinia flower, a split-plot experiment was conducted in the form of a randomized complete block design with three replications on a private farm in Razavi Khorasan province (Khalilabad) in 2023. The investigated factors include two levels of WEED presence and absence as the main factor in two levels (presence and absence (hand WEEDing)) and fertilizer treatment as a secondary factor in four levels (control (no use of fertilizer), fertilizer NPK chemical (according to soil test), vermicompost (5 tons per hectare), and animal manure (cattle manure) (10 tons per hectare). The results showed that all investigated traits of the Ahar flower showed a significant decrease in the presence of WEEDs. In the presence of WEEDs, the number of flowers in the cattle manure treatment was the highest (11.71). The consumption of all three sources of fertilizer caused a significant increase in density and dry weight of WEEDs, but the highest density and dry weight were observed (23.30 plants/m2 and 10.99 g/m2, respectively) in the treatment with chemical fertilizer. The chemical fertilizer treatment had the lowest COMPETITION index (0.79), which can be attributed to the higher WEED biomass in this treatment. The highest COMPETITION index (1.37) belonged to cattle manure, which had a significant difference from other treatments. Therefore, it is recommended to use cattle manure in the field of WEED infestation.

COMPETITION law is a newcomer to the legal system recently. A sound understanding of COMPETITION policy can provide us with sufficient bases to apply a fundamental and normative view of the issues of COMPETITION law. The difference in supervision and regulation determines how the market functions and in order to understand this difference one must understand COMPETITION policy. COMPETITION policy may be based on governmental support for national production and industry or on a non-interventional and regulatory posture. Moreover, supervision, based on the principle of non-intervention in the market mechanism, is rooted in liberal ideas; however, regulation, whether as a rule or an exception, is based on the assertion that the market has been ineffective in attaining its goals. Therefore, the government will resort to interventions to regulate inefficiencies.  This paper aims to analyze Supervisory Authority in Implementing Competitive Policy by employing the description method. In this article the author tries to first delineate COMPETITION policy, its related requirements and imposed deviations to the market. Then, by defining the supervisory entity and clarifying its distinction from the regulatory institutions, the author considers the characteristics of an appropriate supervisory entity conducting a comparative study of this issue in Iran and the U.S.A. This form of COMPETITION policy because of its applicable experiences which have been well described by recent scholarship is considered suitable for the native system.

Purpose: The present study aims to identify and explain the futures of Iranian provinces in the COMPETITION for the development of NBIC technological convergence (synergy between nanotechnology, biotechnology, information technology and cognitive sciences) with a focus on Yazd province. Method: This research, which has been conducted with a qualitative and descriptive approach, is classified as an exploratory futures-study. In this way, the relevant research records were first reviewed to compile a list of drivers in the development of convergent technologies. The list was then refined and prioritized to identify two key drivers, with the Delphi process attended by fourteen experts. By intersecting the uncertainties of these two drivers, four scenarios of the province's future in technological convergence COMPETITION emerged. Findings: The two key drivers affecting the success of the province in the COMPETITION for convergent technologies are: the rate of development of the innovation ecosystem and the amount of financial resources allocated to this process. Based on this, four scenarios of the future situation of the province in this field were identified, which have been named as "Vanguard", "Buyer", "Remnant" and "Hired". Conclusion: In order for the provinces to be able to succeed in the forthcoming COMPETITIONs in the production and operation of convergent technologies, it is necessary to plan for strengthening the ecosystem infrastructure from now; at the same time, it is necessary to make efficient efforts to provide sufficient financial resources for the research and commercialization of these technologies.