Hemp Growing

In asking about cannabis use, an expanded instrument was used to capture a wide variety of use beyond common forms  that are the focus of traditional instruments but may miss the wide variety of products that have become readily available in states where cannabis is legal. For example, asking specifically about hash reveals some cannabis use that would be missed by asking about marijuana alone. We also measured cannabis dependence with the Cannabis Use DisorderI dentification Test.Research assistants abstracted information from the electronic health records, including documented crash characteristics, disposition,and bio-samples obtained for clinical use, using a standardized data form. Given that scene fatalities would not be transported to the hospital,this study has inherent selection bias towards less severe MVCs. The Portland site was the only one to recruit 24/7 , so the overnight shift, which may see more trauma and substance use, may be relatively under sampled. Recruitment of drivers in collisions may have created a bias in reporting of cannabis use due to fear of legal or medical consequences, as discussed above. Acute use within an 8-hour period does not necessarily translate to impairment. There may have been other factors,including unmeasured con-founders, contributing to crash occurrence.Choosing thresholds of time for the window in which we decided to inquire about drug and alcohol use was subjective and required trade-offs.

For example, for alcohol use, if we chose a short window, we might exclude those with heavy alcohol use but would be more likely to capture drinking that impacted driving; if we chose a longer window, mobile grow system we would capture those with heavy use but might also capture those whose alcohol use was low to moderate and no longer an influence on their driving. In this study of drivers in MVCs presenting to the EDs of three cities where cannabis is legal for recreational use, several observations are notable. First, self-reported use in the period prior to the MVC was relatively low, while bio-samples suggested a much higher rate of acute use. Second, usual past-year use and cannabis dependence was high compared to prior ED studies and compared to national samples. Many high-risk crash features were common in MVCs associated with cannabis, as they werefor alcohol use and co-use of cannabis and alcohol; however, while patients requiring admission were less likely to report cannabis use, they were more likely to report alcohol use, suggesting there may have been cannabis-related driving behaviors that contributed to MVCs but mitigated against more serious harms.The prevalence of past-year use in this study population was higher than reported in national samples  and previous ED reports but concordant with more recent observations of increasing national rates of cannabis use, particularly in states with legal medical and recreational marijuana use .

EDs continue to be an important place to capture epidemiologic trends in drug and alcohol use and individuals at high risk for health consequences from substance use.In our previous work , we have used self-report as the standard for drug and alcohol use, as it has demonstrated concordance with objective measures in a variety of settings . Therefore, we chose self-report a priori as the primary criteria for substance use. However, mobile vertical rack in the current study, we found a large difference between rates of use as divulged by self-report and acute use suggested by bio-samples. The bio-sample might have detected cannabis use that fell outside of the 8-hour window during which we felt use was most likely to influence driving. Further,there is likely variability in the accuracy of the cannabis levels depending on the route of use and variable absorption times . However, when asked about past-year use,which would not carry as much social or legal implication, particularly in a cannabis legal state, respondents reported high levels of use, suggesting a potential bias in our capture of acute use.An additional explanation for the difference between self-reported and bio-samples might be the specific circumstances of the study: we asked about drug use in relation to an MVC, in which drivers might be concerned about the legal implications of divulging information related to their culpability in the event, despite the increasing normalization of drug use, and drug use reporting,over time . Among racial and ethnic groups in particular, individuals may reasonably fear harsher assessments of culpability and sentencing , Lack of earned trust of the medical establishment among racial minority populations likely also played a role.Study participants may have been reluctant to report drug use due to social desirability bias and concerns of how such information may impact their clinical care.

Moreover, to the best of the Authors’ knowledge, no literature data are available on the complex relationship between anxious-depressive symptoms, rumination, CPBS, CRSE and cannabis use outcomes. Specifically, existing studies did not test double-mediation models on the relationship between anxious-depressive symptoms and cannabis use outcomes via rumination and constructs of cannabis use regulation, such as CPBS and CRSE. Testing indirect effects in such, more comprehensive mediation models might contribute to gain a better understanding of joint pathways of rumination and reduced self-control over cannabis use on the relationships between anxious-depressive symptoms and outcomes of cannabis use . Namely, based on previous literature findings, it might be possible that anxious-depressive symptoms and maladaptive responses to these symptoms  can contribute to depletion of self-regulation capacities over cannabis use  which in turn can increase the levels of cannabis use frequency and harmful cannabis use . The present study aimed to test a double-mediation model with the mediating effects of brooding, grow lights for cannabis reflection, NU, CPBS and CRSE on the relationships between anxious-depressive symptoms and frequency of cannabis use and harmful cannabis use .

It was assumed that higher levels of anxious-depressive symptoms would be associated with higher rates of brooding and NU which in turn contribute to lower rates of CRSE and CPBS which subsequently lead to more frequent and harmful cannabis use. Alternatively, it was also hypothesized that anxious-depressive symptoms would show a positive relationship with reflection which in turn lead to higher levels of CRSE and CPBS which in turn contribute to less frequent and harmful cannabis use. To the Authors’ best knowledge, this is the first time that a comprehensive mediation model was tested which simultaneously covers anxious-depressive symptoms, rumination, NU, multiple constructs of cannabis use regulation  and outcomes of cannabis use . However, it is important to emphasize that this proposed mediation model was built only on theoretical considerations and the suggested mediated links can be deceptive as the cross-sectional design of this study did not allow to specifically examine the temporal directions between the variables. Existing empirical findings showed that cannabis use disorder  is positively associated with major depressive disorder  and generalized anxiety disorder. Causal pathways were suggested to account for these co-occurrences, such as the self-medication  or the cannabis-induced models. Other exploratory models, such as the allostatic hypothesis, highlight the dominant function of anxious-depressive symptoms in the psychopathology of more severe forms of substance use disorders via negative reinforcement motivational processes .

Emotion regulation  strategies – which can be defined as “processes by which individuals influence which emotions they have, grow cannabis when they have them, and how they experience and express these emotions”as transdiagnostic constructs can explain the associations between anxious-depressive symptoms and problematic substance use .The present sample was based on a study using cross-sectional design, non-representative, convenience sampling and online questionnaires. Participants were recruited on the social media site of Facebook. The online recruitment was performed in thematic, illicit drug use-related Facebook pages and groups. These thematic pages and groups had content on the psychological, medical, social and political aspects of illicit drug use  as well as on personal experiences of using cannabis and/or other illicit drugs . That is, it was assumed that the self-selection of those individuals was presented in the study who show interest in illicit drug use-related topics and who have high motivation for using cannabis and other illicit drugs.

Moreover, it might be possible that some individuals were followers of multiple thematic groups and pages. Thus, individuals who used more frequently.The invitation to participate in the study was shared with the followers in a post in each thematic group and page. The invitation posts provided the names of the principal investigators, brief descriptions about the study aims  and about the conditions of the participation  and the link of the online questionnaire. The research protocol was approved by the Research Ethics Committee at the Faculty of Education and Psychology of ELTE E¨otv¨os Lor´and University, Budapest, Hungary . Participation was anonymous and voluntary, and informed consent regarding the study aims and terms of participation was also required from the participants. In total 1359 individuals were included in the sample.

Beggartick was affected by soybean in all living ratios  in substitutive experiments. The larger inhibitions of this weed were observed when 75% of beggar tick plants competed with 25% of soybean , at which point the observed productivity was farthest from the expected. In soybean, beggar tick in low densities causes significant losses, but if it provided the fastest development to crop, this weed is properly suppressed by soybean complementarily to chemical control. The Genus Bidens infests several crops, being highlighted Bidens pilosa with worldwide occurrence, being also very aggressive and efficient in the extraction of water from soil . Soybean, regardless of its proportion, accumulated dry mass volumes close to the expected ; this illustrates its potential to suppress beggar tick under field conditions, although with some harm to its own development. With proportion of 75%:25% soybean/beggar tick, as example, dry mass of crop was 61% of the total obtained in the community, compared to the expected ratio of 75% . In the same situation, the dry weight of the weed, which should represent 25% of the system, represented something around 5%. The ecological system  was hampered by competition, and the total productivity of the system cannabis vertical farming, which should be 100%, has always been lower than expected, with 55% reduction at proportion 75:25 beggar tick/soybean .

In summary, there were losses in the system when soybean competed with beggar tick, being the crop superior in competitive ability although it suffered due to the need for energy to be applied in competition against the weed instead of growth. In fact, the relative competitiveness  and aggressiveness  coefficients indicated that soybean is more competitive than beggar tick, which was also reflected by the clustering coefficient However, when considering the density of the crop and the weed under field conditions, one should see the need for associating weed control methods to optimize soybean suppression on this weed. It should be noted that the competition between plants is more drastic when the involved individuals have similar life cycle, germinate and are included in the same botanical family or have similar morpho-physiological characteristics between themselves. Under these conditions, the great determinant of which species will be most affected is the potential for competition with the species with which it competes. If the emergence of one of the competitors is delayed, usually the individual that germinates first takes advantage in the competition. Thus, one should always install crops in a weed-free area, and ensure its rapid establishment. Of course, if there are differences in the density between crop and weeds, or if crop stand is uneven, weeds may have competitive advantage. Table 7 presents a summary of results we obtained in the experiments for both methods, where we tried to create a link between them and find the main differences.

Although distinct in the interpretation of the data, both competition study methods provided information with practical nature and applicable to the field, though obviously limited because they were basic and exploratory studies. Competition results from controlled environment, regardless of the method of study, must be complemented by field trials. The substitutive method, when compared to the additive method  has two disadvantages: first, it requires the installation of a pre-test to determine the minimum population for each species, from which occurs stabilization in the dry mass. This pre-test,cannabis drying racks although desirable when choosing the additive method, is not compulsory and density of plants in this study method can be determined per se, at the discretion of an experienced researcher on the subject—since data is interpreted only in the studied range.

The second drawback relates to difficulty in data processing and obtaining the graphics and coefficients inherent to the substitutive method. For the additive method, virtually any statistical software and spreadsheet with basic skills in graphics generation make it possible to analyze experimental data; for the substitutive method, although part of the easiness in installing and conducting the experiment and data collection are similar to the additive method, data analysis software based on programming languages  is demanded. While data processing can be accomplished in spreadsheets also for substitutive experiments, this way is neither easy nor indicated.Research has reported that due to substitutive experiments to be installed in fixed densities, they cannot be used for inferences about mixtures where density is not kept constant . Substitutive experiments are widely used, but the results cannot be easily interpreted because they are so restrictive that valid generalizations should not be made beyond that particular situation inherent in the experiment. The findings of most studies using this method require some review .

Ferguson et al.  showed that a 3.7 cm layer of wood chip mulches from southern redcedar  E. Murray and southern magnolia  provided control of redroot pigweed  and large crabgrass  Scop.Mulch products would likely be applied at or near the time of potting, and presumably would be applied to containers free of weed seed. Any weed seed introduced into the container thereafter would have to germinate and establish on the surface of the mulch product. Alternatively, mulches could be applied sometime throughout the production cycle of a crop. Containers might be hand-weeded to remove existing weeds, and then mulched. In this scenario, a large weed seed bank could be present on the substrate surface. Seed present at the time of mulch application could germinate from beneath the mulch product. A third scenario would be the carryover of weed seeds from liners into larger containers at the time of transplant. In this situation too,indoor cannabis grow system a seed bank present on or near the surface of the newly potted liner would have to germinate and establish through the mulch. Establishment of weed seed above and below mulch products has been studied previously. Cochran et al.  showed that placement of eclipta or prostrate spurge seed above or below 1.3 to 2.5 cm pine bark mulch had no effect on weed number or fresh weight accumulation.

Likewise, Richardson et al.  showed that bitter cress and oxalis establishment in containers mulched with 3.8 to 7.6 cm pine bark was not affected by seed placement above or below the mulch. Parboiled rice hulls  are dry rice husks removed from rice grains with steam or hot water. Hereafter they will be referred to as rice hulls. Rice hulls are commercially available for horticultural use, and are currently used as a component in greenhouse and nursery substrates. Rice hulls can also be used as a container mulch. One manufacturer  recommends a rice hull mulch depth of 3.8 to 5.0 cm for effective weed control in container crops. Previous research has shown that rice hull mulch at a depth of 2.5 cm provides excellent flexuous bitter cress  and liverwort  control when seed or propagules are disseminated onto the mulch surface . The objective of this research was to determine if application of seed above or below the mulch surface affects flexuous bitter cress or creeping wood sorrel establishment. Repeated measures analyses showed that flexuous bitter cress numbers and shoot fresh weight when seeded above the mulch layer were affected by the interaction of time and rice hull depth Containers with 0.6 cm rice hulls had fewer established flexuous bitter cress than non-mulched controls with the exception of 4 WAP. Despite reduced numbers, shoot fresh weights of bitter cress with 0.6 cm rice hulls were similar to non-mulched controls with the exception of 8 WAP.

Containers with 1.3 or 2.5 cm rice hulls had similar flexuous bitter cress numbers and shoot fresh weight,cannabis grow set up and both were significantly lower than non-mulched controls or those with 0.6 cm rice hulls. No flexuous bitter cress established throughout the experiment when seeded above 2.5 cm rice hulls, similar to results observed by Altland and Krause . Weed numbers among containers with flexuous bitter cress placed beneath the mulch changed over time . Flexuous bitter cress numbers declined sharply from 4 to 8 WAP, as many of the applied 40 seed had germinated by the first harvest date.There were no differences in bitter cress number or shoot fresh weight with respect to rice hull depth from 8 to 16 WAP. Lack of differences among mulch treatments was due to there being relatively few bitter cress germinating after the first harvest. There was an interaction between seed placement and rice hull depth on percent establishment . Non-mulched controls in both groups had similar percent establishment . Establishment decreased linearly and quadratically when seed were placed above the mulch, with lower establishment in 0.6 cm rice hulls compared to non-mulched controls. In contrast, establishment decreased linearly when seed were placed beneath the mulch layer with only the greatest rice hull depth reducing establishment below the non-mulched controls. At each rice hull depth , establishment was lower when seed were placed above the mulch layer than when placed below the mulch layer. At 4 WAP, creeping wood sorrel number and shoot fresh weight were affected by an interaction between seed placement and rice hull depth .

At this time point, the green biotype appeared slightly more damaged by the fungus than the red biotype. This effect was supported by fresh weight analysis from plants at the 48-h time point . Severe loss of fresh weight occurred in both biotypes compared to that of untreated their respective control plant shoots. The green biotype was slightly more damaged with respect to fresh weight biomass. Three-week-old green biotypes were generally more susceptible to infection by MV than were red biotype plants at this age . Severe infection of 3-week-old biotypes  occurred after 48 h, and increased to 4.5 after 96 – 120 h. In comparison, a disease rating of only 2.6 occurred on 3-week-old red biotype plants after 96 h, but this increased to a disease rating of 3.5 after 120 h . In the biotypes, MV disease progression and severity were generally greater on 3-week-old plants as compared to 6-week-old plants . The green biotype might be compromised under natural environmental conditions and stress since betalains have been shown to be involved in plant photoprotection mechanisms. For example, photosynthetic capacity damage was reduced in red-pigmented versus green leaves after exposure to excess light Betalain synthesis in a related plant, cannabis grow system Amaranthus tricolor, has been shown to be under photo control .

Other reports show that betalain production in plants is upregulated after exposure to light or UV radiation There was a definite trend that the green biotype was somewhat more susceptible to MV when treated under greenhouse conditions. This may suggest that lack of the red betacyanin pigment renders the green biotype less resistant to pathogen attack. As outlined and presented earlier, betacyanin has been implicated in disease resistance. Further testing of the effects of MV on these two biotypes under field conditions and expanded characterization of the pigment contents and traits of these two biotypes  will help to clarify the interaction of the bioherbicide, Myrothecium verrucaria on these two glyphosate-resistant Palmer amaranth biotypes. In 1990, the Federal government enacted a non-indigenous aquatic nuisance prevention and control act to compact the effect of invasive species in the United States of America. Many organizations and agencies were created to specifically tackle problems that result from the nuisance invaders. In 2005, Governor Mike Foster of Louisiana formed a 29-member non-indigenous aquatic species advisory task force from public and government entities. This task force designed a management master plan for the state and several agencies were later empowered to carry out control, management and eradication of aquatic invasive species when possible.

Tulane and Xavier University Center for Bioenvironmental Research, Louisiana State University AgCenter, Louisiana Sea Grant, United States Army Corp of Engineers, and Louisiana Department of Wildlife and Fisheries are among the organizations that have been assessing and controlling the impacts of aquatic invasive plants in the state. There is a need to review what has been done by these agencies and assess the current trend of aquatic invasive plants in Louisiana State. The southeastern part of the country has the highest diversity of habitat, marijuana grow system with 47 percent of the nation’s wetlands, 78 percent of its coastal marshes, and over 70 major river basins. The warm climate and ample rainfall help support many of the world’s plants and animals. The abundant waterways open the region to non-native species more than any other regions of the country. Invasive species are non-native aquatic plants and other organisms whose introduction can cause adverse impacts on environment, economy and human health.

These invaders have been introduced into the Louisiana coastal waterway through shipping vessels, animal and human immigrations. Ecologically, they make the waterways to have unsightly aesthetics, serve as vector habitat, alter food web relationships, and disrupt recreation, flood control, and hydroelectricity. Toxicity of the surface waters can result in fishkills, and health hazards for humans.This includes plants that are rooted in the sediment with part or all of the plant underwater, as well as plants that float freely without contacting the sediment Aquatic plants may invade both marine and freshwater environments, including habitats such as wetlands, lakes, rivers, estuaries, coastal zones, irrigation systems, hydroelectric systems, and aquaculture facilities . These aquatic invasive plants have several traits such as short reproductive cycle, high genetic variability, ability to thrive in a wide range of environments and ability to aggressively compete to displace other plants from the coastal waterway .

The distribution of dry matter between the above- and below-ground parts of a plant does not account for these differences at the seedling stage, however, which is also the case for annual and perennial plants . Based on initial seedling growth, all fescues , with the exception of Kentucky bluegrass, showed a greater accumulation of dry matter, biological productivity and growth rate within the first 5 weeks when compared to the nimblewill, showing that nimblewill has a slower developmental stage and can be suppressed by pastures in field conditions. In general, the first plant to take root has a better chance in competing for environmental resources. However, bluegrass showed an accumulation of dry matter that was less than that of the weed, indicating that the bluegrass and pasture may suffer from competition with the nimblewill. In another experiment,  found that bluegrass grows much slower than other species. Those species that grow faster would be able to preempt the uptake of growth resources and, thus, would be expected to be more competitive . Control of spreading nimblewill is usually attempted with a nonselective systemic herbicide, when the weedy plants are young.

The mother plants are easily killed but, oftentimes, the weed will return, growing from the stolons; thus, an additional application of the herbicide is recommended.One must weigh the advantages and disadvantages before deciding whether to attempt control measures. Knowledge of the best stage during weed development to apply a control measure may increase the effectiveness of management strategies. Information on nimble will growth rates can be used to estimate the optimum period for post-emergence weed control with herbicides and the optimum timing of herbicide application or cultural control in conventional planting. Although riparian areas comprise less than 2% of the land area in the arid and semiarid western United States, they contribute disproportionately to physical and biological processes. They serve as pathways for the flow of energy, matter,cannabis grow equipment and organisms through the landscape, acting as ecotones between the terrestrial and aquatic zones and corridors across regions . Riparian vegetation plays important roles in trapping soil eroded from uplands and removing nutrients from surface and soil water , stream morphological dynamics , and aquatic, avian, and large game habitat requirements . Since the late 1800s, dry land small grain production has been practiced on nearly all the arable land of the inland Pacific Norwest .

Before widespread motorized mechanization of farming practices in the 1940s, the bottomland of second and higher order streams in this region were used extensively for grazing livestock, particularly draft horses, mules, and oxen. Beginning in the 1940s, much of this bottomland was converted to small grain production, resulting in the elimination of natural stream channels and riparian areas and the disruption of flood plains. Infrastructure  maintenance requirements, the need for farm operation efficiency, and government incentives led to the channelization of many of the streams in this region. Channelization creates steep banks unprotected by vegetation cover or consolidating root structure. Deep, channelized storm flow saturates unprotected stream banks, creating positive pore pressures that cause bank failure when the storm flow recedes , and concentrates energy to transport soils eroded from uplands, stream banks and bottoms to deposition areas.

Whereas the goal of stream channelization is to drain soil water more efficiently, the effect is to disconnect the hydrologic flux between stream channel and adjoining land. In forest or rangeland situations, this change in hydrology facilitates the establishment of opportunistic weed species. In croplands, the rapid draining of soil water short-circuits chemical and biochemical processes that would occur if the water were resident longer. For example; if water is stored in a floodplain from 2 to 10 days, nitrate concentrations would be reduced through denitrification . Functioning riparian areas are necessary to create multifunctional production systems as described by Jordan et al. . Until the late 1990s, efforts to restore or rehabilitate riparian areas occurred primarily in forests and rangelands on public lands through the efforts of USDA Forest Service, USDI-Bureau of Land Management, and USDI-National Park Service, with smaller scale private land projects sponsored by nongovernmental organizations such as The Nature Conservancy.

Under HDPE film mulching cropping system, the objective of this study is to select the optimal thickness of HDPE film for rice production. Herein, we investigated the effect of various thickness of HDPE film on physiological index of rice, soil parameter and weed control, etc. It is hoped that our study could improve current management strategies in rice production. Ontario is one of the leading provinces in Canada in production of dry bean , producing 118,000 MT of dry bean on 49,000 hectares with a farm-gate value of approximately $108 million in 2012 . Major market classes of dry bean grown in Ontario include black, cranberry, kidney, and white  bean. Dry beans are very sensitive to weed interference resulting in substantial yield losses. In research conducted in Ontario the average yield loss due to weed interference in winter wheat was 2%, in spring cereals 12%, in soybean 40%, in corn 52% and in dry beans 58% . More research is needed to identify new weed management herbicide options that have an adequate margin of crop safety, provide consistent broad spectrum weed control, have low environmental impact and maximize dry bean yield and net returns.

Halosulfuron is a sulfonylurea herbicide that controls nutsedge species , redroot pigweed , common lambsquarters , wild mustard , ladysthumb , velvetleaf  and cocklebur , including triazine resistant biotypes . Halosufuron is readily absorbed by roots and foliage and is translocated throughout the plant causing rapid growth inhibition in susceptible plants. Halosulfuron can be applied preplant incorporated , preemergence  or postemergence . Injury symptoms in susceptible plants include chlorosis, death of the growing point and complete death within 14 – 21 days Halosulfuron has low environmental impact as it is active at low doses, has low mammalian toxicity,cannabis grow trays and is relatively immobile in soils . Halosulfuron will be available for the first time in the Ontario market during the 2014 field season. Halosulfuron will provide Ontario dry bean growers with a new, low-use-rate herbicide that provides full-season control of a number of annual broadleaf weeds. There is little information on the crop safety and efficacy of halosulfuron applied PPI, PRE and POST to control broadleaf weeds in dry bean under environmental conditions in Ontario. Mangroves are habitat specific and inhabit swampy and saline environment  Mangrove weed are plants that are found in disturbed mangrove forest such as reclaimed land, sand filled and dredged sites .

Weeds are unwanted plants that grow in any place that is favorable for their growth and survival such as water, soil, tree trunk, wall of building and coastal soil.For instance these weeds can change the ecology of the area by supplying or utilizing soil nutrients, which may be detrimental to the native species Weed can affect fish spawning capability by obstructing breeding grounds ; they can also increase the heavy metal concentration through the actions of their root, which break up the parent soil to expose more metals. Humans also introduce seeds of weed into the mangrove forests, which embed in the soil and grow. Growth of weed in disturbed mangrove forests converts indigenous mangrove soil to sandy soil. The weed species are able to grow at the fringes and perimeters of the mangrove forest that had been cut down for the purpose of creating access way for pipelines .

This is because the pipeline route is usually covered with sandy soils brought elsewhere, which further introduce and accelerate weed growth . Furthermore, the sand filling of mangrove forest also changes the soil chemistry when muddy soils are converted to sandy soil. Change in soil chemistry can lead to increased heavy metal load, which has ripple effect on the aquatic environment . For instance, fishes and other aquatic organisms bioaccumulate the excess heavy metals, which they pass on to humans who feed on them Over the years several questions had been asked as to the role played by the mangrove weeds, which are often found in degraded mangrove forests. Do these foreign plants growing in mangrove forest play positive and/or negative roles? These questions are yet to be addressed. However, it is revealed by previous studies that in agricultural farms weeds can act as habitat for insect pollinators e.g. butterfly, grasshoppers, praying mantis beetles etc., which is a positive role for nearby plants. Nevertheless, weeds can play negative role by acting as nesting sites for pathogenic organisms such as mosquitoes, black fly etc. .

The vote of each tree is tallied; then the unknown sample is assigned the class in which it received the most votes. For each tree, a subset of the variables is used to develop the split. Also, a variable importance ranking is derived with the algorithm. Analysts can evaluate the ranking and identify variables that are relevant to the model for prediction or classification problems, leading to reduction in the number of variables used for the analysis. Random forest ranks very well among other classifiers . Recently, it was ranked in the top ten of 100 classifiers tested for classification purposes . It is capable of processing large datasets, can analyze numerous variables without deletion, is robust for analysis of datasets with missing variables, and has the ability to process unbalanced datasets. Models derived for classification can be used on other datasets. Light reflectance data recorded from sensors on-board satellite, airborne, and ground-based platforms have shown promise as input data for random forest to use for classification   and regression   problems. Currently, no information is available on using vegetation indices derived from multispectral data as input into random forest for soybean weed discrimination. The objective of this study was to evaluate normalized difference vegetation indices as input into random forest to differentiate soybeans and three broad leaf weeds: Palmer amaranth, redroot pigweed, and velvetleaf.

The study focused on leaf multispectral reflectance data of simulated World View 3 satellite sensor bands. Two experiments were completed in 2014 in which 30 replicates of soybean variety 4928LL , Palmer amaranth, redroot pigweed, and velvetleaf were grown in a greenhouse located at USDA-ARS, Stoneville, MS. Planting dates were June 13, 2014, and August 28, 2014, for experiments one and two, respectively. Seeds of the different plants  were sown into plugs. After emergence, the plant species were transferred to two liter pots. All plant species were exposed to a fourteen-hour photoperiod, and light was supplemented at the beginning and ending of the day with sodium vapor lamps. Day/night temperatures of the greenhouse was maintained at 28˚C/24˚C ± 3˚C, cannabis grow tray respectively. The soybean variety used in the study had an indeterminate growth habit and gray pubescence and was assigned to maturity group 4.9. The weed seeds were obtained from a seed bank maintained at the laboratory. Leaf reflectance measurements were obtained with a plant contact probe attached to a spectroradiometer  sensitive to a spectral range of 350 to 2500 nm. The contact probe has its own light source allowing the user to collect data anytime during the day or night. Reflectance measurements were collected from the most recently matured leaf of each plant; each reading was an average of fifteen readings. The spectroadiometer was calibrated in fifteen minute intervals with a white spectralon panel. Leaf reflectance measurements were collected prior to the plants reaching 1 foot tall. The goal of weed management strategies is to detect and kill the weeds in the vegetative growth stages and prior to the seeds reaching full maturity levels. Broadband and narrowband data have been used to develop vegetation indices.

Therefore, the simulated band center wavelength closest to center wavelengths used in other studies were employed in developing each vegetation index. Periodically, two vegetation indices were developed for a designated index because the band centers were equidistance from the band centers used by other investigators. These include the advanced normalized difference vegetation index , shortwave infrared water stress index , and structure insensitive pigment index . The hsdar package of R  and base R packages  were used to develop the sixteen spectral bands and the twelve vegetation indices, respectively. The conditional inference version of random forest was used for the classifications.Cforest is more stable in deriving variable importance values in the presence of highly correlated variables, thus providing better accuracy in calculating variable importance . Differences of cforest compared with the original version of random forest are as follows. Cforest employs conditional inference trees as base learners; random forest uses classification and regression trees as base learners Cforest develops unbiased decision trees based on subsampling without replacement instead of using bootstrap samples. The algorithm uses the conditional permutation scheme described by Strobl et al.   to determine variable importance ranking.

According to their report, the distribution of P. hysterophorus was limited to roadsides, rural villages, and urban areas with less abundance while all other IAPS had already interred to agricultural fields. However, the current investigation confirmed that the coverage of P. hysterophorus was more abundant in the cities. It is alert that the weed has already established itself and ready to move to agricultural fields such as the arable and grazing lands. Furthermore, the weed has started spreading from the area surrounding the Zeghibridge to the adjacent cropland and pasture on both sides of the river. In this particular study, there was no way to know when and how the plant was first introduced to the place; however, we speculated that the weed might have introduced with sand and stones used for the construction/maintenance of the bridge. Moreover, the presence of P. hysterophorus at the nursery site most likely speeds up its spread across the area. It should be noted that raising seedlings at the place infested with P. hysterophorus is like providing transportation to agricultural fields. This way, the weed will not only infest crop fields but also be able to travel long distances and cover large areas relatively within a short period. In general, P. hysterophorus is on the fast move to agricultural fields in the MZ.

The crop and livestock production in the area has been already constrained by many factors like lack of agricultural technologies, disease and pests’ pressure, and low production awareness of farmers. Thus, the invasion of Parthenium in agricultural fields, coupled with the existing problems, can be devastating and causes food insecurity. Therefore, the public administrators and policymakers of the regional government, in collaboration with all stakeholders, should take a decisive and timely decision to mitigate the weed when it is still sparse and small. The critical weed-free period has provided Ontario growers with the knowledge of when to control the weeds that cause detrimental yield loss in maize  and soybean  for quite some time. Researchers have also recognized that the critical weed-free period can vary from year to year and location to location undermining the potential utility and implementation of this integrated weed management strategy . Yet, research continues to be conducted as a better understanding of some of the underlying physiological mechanisms that underpin the critical weed-free period have recently been published In general,indoor cannabis grow system crops need to be maintained under weed-free conditions from the start of the critical weed-free period until at least the 10-leaf stage in maize   and the R1  stage in soybean Ontario maize and soybean growers have numerous herbicide options  for managing weeds during the critical weed-free period. Unfortunately, growers can sometimes miss registered herbicide application windows due to adverse weather conditions or mechanical breakdowns which leave large, highly competitive weeds present in the crop at a point beyond the critical weed-free period when rapid yield loss occurs.

At this time, growers would like to apply a high dose of postemergence  herbicide to ensure effective control of these large weeds, but growers also are concerned that crop injury could negatively impact yield. Regrettably, the tolerance of maize and soybean to a high herbicide dose at a late POST application timing is largely unknown. The exception to this is maize, which can tolerate over two-fold of the maximum labeled dose of glyphosate applied at the 10-leaf stage with minimal injury and little to no yield loss . Furthermore, to the best of our knowledge, few studies have been conducted in the absence of confounding weed competition effects that examine both a range of herbicides comparing relative crop tolerance  and the tolerance of crops to a late POST herbicide application . Therefore, the objective of this research was to determine the tolerance of maize and soybean to a late application of select POST herbicides in the absence of weed interference. Maize exhibited excellent tolerance to the POST herbicides applied at the 9- to 10-leaf growth stage. At 3 DAT, only the sequential application of 2,4-D/atrazine caused significant visible injury of 9%.At 7 DAT, the sequential application treatments of dicamba/diflufenzopyr, foramsulfuron, and 2,4-D/atrazine caused 6, 8, and 9% injury, respectively.For example, 3% injury was observed for a single foramsulfuron application whereas the sequential application treatment caused 7% injury 14 DAT.Furthermore, a single application of dicamba/diflufenzopyr caused no injury, but the sequential application caused 6% injury 14 DAT.

Weeds control by chemical method, aiming balance shifting of the agro-ecosystem in favor of cultivated crop, which proved to be relatively more efficient and economical. The efficacy of herbicides, however, depends more upon their formulation in addition to time, methods and rates of application . It was concluded from an experiment that hand weeding and mixture of herbicides Puma super 75 EW and Buctril-M 40 EC showed better results for controlling winter weeds .  while evaluating 5 post-emergence herbicides alone at recommended doses and in combination with DMA-6 for weed control in wheat concluded that herbicide application suppressed weed population effectively. Dosanex + DMA-6 and Arelon provided the best weed control. However, Dicuran M.A. 60 WP + DMA-6 produced the maximum grain yield. DMA-6 alone and in combination with Dicuran M.A. 60 WP was more economical than all other herbicidal treatments.  investigated the effect of different graminicides used at varying levels and concluded that lesser dose of Topik15WP is required for the control of wild oat as compared to Puma Super 75 EW. The maximum weed efficiency was noted for Isoproturon 50 WP while minimum value  was observed for Aim 40 DF . These results are in line with who reported that herbicides application effectively controlled weeds.

These findings are also in conformity with those of , who reported that herbicides significantly reduced weed density. Similarly,stated that Puma Super 75 EW @ 1.25 L·ha–1 gave maximum control of narrow-leaved weeds in wheat out of varying herbicides applied at different doses. The best performance of Isoproturon 50 WP and other herbicidal applications could be attributed to the best control of weeds due to minimal weed competition which caused an increased flow of nutrients towards the grain and ultimately yield was increased. These results are supported by . They reported that herbicidal treatments significantly increased the grain yield in wheat. The maximum number of tillers m–2 was noted for Isoproturon 50 WP whereas minimum number  was reported in weedy check. These results showed that maximum weed control enhanced the production of fertile tillers m–2 which subsequently contributed towards the increase in wheat yield. These results are in agreement with the work of  who obtained an increase in tillering with the application of different herbicides. The low yield  in weedy check plots indicated that weeds utilize maximum resources of the main crop which ultimately reduced the crop yield. These results are in conformation with those of , who applied Puma Super 75 EW and Topik 15 WP at different doses to control Avena fatua in wheat crop and reported that lesser dose of Topik 15 WP and higher dose of Puma Super 75 EW was required to control this weed. Wheat is the most important cereal crop in the USA, where it was planted on 23 million ha in 2012 .

Most of the wheat grown in the USA is winter wheat . Kansas state ranks first in winter wheat cultivation  in the USA . Winter wheat is not a good competitor with some broadleaf weeds even when wheat emerges before weeds . Common weeds found in winter wheat in the US are blue mustard , cannabis grow tray henbit , flixweed , bushy wallflower , field pennycress , wild buckwheat , shepherd’s purse , and pinnate tansymustard.Their interference can cause significant yield reduction in winter wheat. Season-long competition of 11, 33, and 98 blue mustard plants·m−2 reduced wheat grain yields by 28%, 42%, and 51%, respectively . Conley and Bradley reported yield reductions of 13 and 38% because of henbit interference at 82 and 155 plants·m−2 , respectively. Northam et al. also reported wheat grain yield loss of 48% with 221 henbit plants·m−2 . Bushy wallflower at 272 plants·m−2 reduced wheat yields by 25% . Hence, winter annual broadleaf weed control is very important for successful wheat production. For more than two decades acetolactate synthase -inhibiting herbicides have been primary herbicides used in winter wheat, however continuous usage of those herbicides led to selection of ALS-inhibitor resistant weeds. Currently 126 ALS-inhibitor resistant weed species have been reported worldwide; 45 in the USA . Bushy wallflower and flixweed, two common broadleaf weeds in winter wheat, were reported ALS-inhibitor resistant in 2005 and 2006, respectively in Kansas . Rotating herbicides with different modes of action can avoid selection for weeds biotypes that are resistant to certain herbicides. Hence, there is a need for herbicides with alternative modes of action to ALS-inhibitor herbicides in wheat.Pyrasulfotole inhibits 4-hydoxyphenylpyruvate dioxygenase  and blocks the pathway of prenylquinone biosynthesis in plants .