Also known as great ragweed, horseweed, horse-cane, richweed, bitterweed, bloodweed, blood ragweed, tall ragweed, palmate ragweed. Classification and Description:Giant ragweed is an erect summer annual that is native to the U.S. and it can be commonly found throughout many parts of the country. It can reach heights from 3 to more than 16 feet. Giant ragweed is a member of the Asteraceae, or sunflower, family of plants. Seedling giant ragweed has a purple hypocotyl and cotyledons that are round to oblong and thick. The first true leaves do not have lobes but do have toothed margins and are lanceolate (long and thin) in shape. Subsequent leaves are opposite, blades simple, hairy and large (4-10 inches long and up to 8 inches wide). Leaves occur on petioles and most often have three prominent lanceolate-shaped lobes, although they can occasionally have five lobes. The lobes originate from the same point (palmate). These large, three-lobed leaves make giant ragweed a very distinctive plant. Leaf margins are serrated. Stems can be reddish and are erect, branching above, rough and sometimes hairy. Stems can be reddish. Giant ragweed has separate male and female flowers. Male flowers occur in slender racemes (columns) in the upper terminals. Female flowers occur in clusters in leaf axils below the male flowers. All flowers are small and greenish-yellow. Fruit is a large, black, woody achene that is egg-shaped, except the widest part is towards the end instead of in the middle. The widest end has one single short beak and other shorter projections, which make it resemble a crown. Seed is small and enclosed in the fruit. Reproduction is by seeds. Weed Status and Injury:Giant ragweed can readily be found along fence rows of agronomic crop fields and pastures in Tennessee. Increasingly, it is becoming established in agronomic crop fields. Herbicides commonly used on agronomic crops, like glyphosate, only provide partial control, and so giant ragweed is becoming an increasing problem in row crops. It can also be found in pastures, low woods and young Seedling giant ragweedGiant ragweed in a fence row W119Programs in agriculture and natural resources, 4-H youth development, family and consumer sciences, and resource development. University of Tennessee Institute of Agriculture, U.S. Department of Agriculture and county governments cooperating. UT Extension provides equal opportunities in programs and employment.
Purpose Sustainable crop production could contribute to feed and fuel for the ever-increasing global population. The use of heavy agricultural machinery has improved the efficiency of farming operations and increased global food production since the 1950s. But their negative impact on soil includes changing soil structure resulting in deteriorating soil productivity and environmental quality is being noticed for several decades. The purpose of this review is to summarize and help to better understand the effect of heavy machinery, tire inflation pressure, and field traffic on soil properties and crop development, yield, and economics of different farming systems published in the last 20 years. Methods Search engines such as Google Scholar, Scopus, Science Direct, Springer Link, Wiley Online, Taylor & Francis Online, Academia, and Research Gate platforms were used to collect and review the articles. This review includes indexed journals, conference and symposium proceedings, reports, academic presentations, and thesis/dissertations. Results Soil compaction increases bulk density and soil strength and reduces soil porosity and soil hydraulic properties. Stunted plant root growth due to compaction of soil affects crop growth and development, and yield. Soil compaction resulting from heavy machinery traffic caused a significant crop yield reduction of as much as 50% or even more, depending upon the magnitude and the severity of compaction of the soil. Conclusions High gross weight vehicles/machinery traffic damages soil structure and soil environment that are critical for sustainable crop production. The use of heavy machinery such as subsoiling for removing soil compaction results in more fuel use, increased use of energy, cost, and sometimes risks of re-compaction, further deteriorating soil conditions and causing additional adverse environmental consequences. The economics of different farming systems affected by soil compaction, potential soil compaction management strategies, and future research needs have also been discussed.
In greenhouse experiments, Ohio accessions of 22 weed species representing 13 dicot families were screened as alternative hosts of soybean cyst nematode (SCN, Heterodera glycines). Purple deadnettle (Lamium purpureum), henbit (Lamium amplexicaule), field pennycress (Thlaspi arvense), shepherd's-purse (Capsella bursa-pastoris), and a susceptible soybean (Glycine max) cultivar produced SCN population densities of 510, 155, 73, 1, and 366 cysts/450 cm3 soil, respectively, 5 wk after inoculation with eggs from a race 3 SCN population. Purple deadnettle was also a strong host of race 1 SCN and a weak host of race 6 SCN. Average numbers of eggs/cyst among race 3 hosts were highest in purple deadnettle (357), followed by soybean (292), field pennycress (266), henbit (122), and shepherd's-purse (none detected). To our knowledge, henbit is the only SCN host identified here that has been previously identified as a host. The weeds identified as SCN hosts in this study have a winter annual life cycle in Ohio and may serve as sites for SCN reproduction in infested fields during the early or late growing season and when soybean plants are absent.
Venkatesh -Eevera: Mass reduction and recovery of nutrients through vermicomposting of fly ash - Abstract. In view of the environmental problems generated by large-scale production of fly ash, increasing attention is now being paid to the recycling of fly ash as a good source of nutrients. Because availability of many nutrients is very low in fly ash, available ranges of such nutrients must be improved to increase the effectiveness of fly ash as a soil amendment. In our experiment, we assessed the possibility of increasing total nitrogen, total phosphorus, total potassium and micronutrients in fly ash through vermicomposting. Fly ash was mixed with cow dung at 1:3, 1:1, and 3:1 ratios and incubated with Eudrilus eugeniae for 60 days. The concentration of above said macro and micronutrient was found to increase in the earthworm-treated series of fly ash and cow dung combinations compared with the fly ash alone. This helped to transform considerable amounts of total nitrogen, total phosphorus, total potassium and micronutrients from fly ash into more soluble forms and thus resulted in increased bioavailability of the nutrients in the vermicomposted series. Among different combinations of fly ash and cow dung, nutrient availability was significantly higher in the 1:3 fly ash to cow dung treatment compared with the other treatments.
Laboratory experiments were conducted to determine the effect of three phenolic acids, acetone, and riboflavin on aqueous photolysis of chlorimuron and imazaquin. The phenolic acids investigated were caffeic acid (CA), ferulic acid (FA), andp-coumaric acid (PCA). Treatment solutions were contained in quartz vessels and irradiated with 300 to 400 nm UV light in a photoreactor. The extrapolated photolysis half-life of chlorimuron in pure solution was 107 h, compared to a half-life of 0.42 h for pure aqueous imazaquin. Chlorimuron in solutions containing 10 ppmw riboflavin, acetone, CA, FA, or PCA exhibited half-lives of 9, 57, 58, 67, and 146 h, respectively. Imazaquin in solutions containing 10 ppmw riboflavin, acetone, CA, FA, or PCA had half-lives of 0.70, 0.55, 0.55, 0.48, and 0.55 h, respectively. The presence of PCA in aqueous media delayed chlorimuron photolysis, whereas all other compounds, especially riboflavin, sensitized chlorimuron photolysis. In contrast, imazaquin photolysis was delayed in the presence of the test compounds, with riboflavin having the greatest effect and causing in a 68% increase in imazaquin half-life over that of imazaquin alone. Quantum yields for sensitized photolysis of chlorimuron by riboflavin and for riboflavin by imazaquin were 0.1134 and 0.0477, respectively. These results suggest that some soluble and naturally occurring organic compounds may enhance chlorimuron photolysis yet delay imazaquin photolysis in surface waters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.