جستجوی مقالات مرتبط با کلیدواژه "barnyardgrass" در نشریات گروه "زراعت"

To evaluate the efficacy of bispyribac sodium SC42% herbicide (Rissin) on rice weeds control in transplanting method and comparing it with some registered herbicides, an experiment was carried out in two regions, Guilan (Rasht) and Mazandaran (Sari), Iran, in 2019. Treatments consisted as bispyribac sodium SC42% at four doses (50, 54, 58 and 62 ml.ha-1), bispyribac sodium OF10% at 250 ml.ha-1, bispyribac sodium SC40% at 65 ml.ha-1, oxadiargyl EC30% at 3.5 L.ha-1, triafamon + ethoxysulfuron WG30% at 150 g.ha-1, pertilachlor EC50% at 2  L.ha-1, together with two check treatments (weed free and unweeded treatment). The experiment was performed in randomized complete block design with three replications. The results showed that Rissin had good efficacy on weed control and did not cause rice damage even at the highest used dose. The efficacy of Rissin for weed control at three doses of 54, 58 and 62 ml.ha-1 was 85-91% for barnyardgrass (Echinochloa crus galli L.), 66-90% for nutsedges (Cyperus difformis L.) and 95-97% for crowngrass (Paspalum distichum L.) in Sari and 60-93% for barnyardgrass, 60-100% for nutsedges and 30-77% for crowngrass in Rasht. Weed biomass in the experimental field in Sari was lower than in Rasht, which explains the reason of the different control results. Rissin at the three higher doses had similar efficacy to commercial doses of the registered herbicides for weed control and in term of rice yield components (such as tiller and panicle number, biological yield and grain yield), the best result was obtained at 62 ml.ha-1 of Ressin and was similar to weed free treatment.

A two year study was carried out at Rice Research Institute of Iran in 2010 and 2012 in order to study the response of rice and paddy weeds to a new dual purpose herbicide penoxsulam in comparison with current used herbicides. First year treatments included penoxsulam doses in 24, 30, 36, 42 & 48 (gr.ai.ha-1), butachlor+bensulforunmethyl (BSM), butachlor+cinosulfuron and anilofos+Cinosulfuron and the second year treatments were penoxsulam at two levels (3 & 40 gr.ai.ha-1), oxadiargyl+BSM, thiobencarb (TB) and TB+BSM. All common herbicides were studied in recommended doses. Results showed penoxsulam phytotoxicity on rice 2 & 4 WAT was similar and more than current used herbicides respectively. Penoxsulam efficacy on barnyardgrass control in first and second year of trial was similar and less than current used herbicides. Also penoxsulam efficacy on sedges and broadleaf control was less than current used herbicides in both years. Decreased efficacy of penoxsulam in barnyardgrass control in the second year of study was probably because of water shortages and lack of permanent flooding. In first year of study average efficacy of butachlor+BSM or cinosulfuron to control “sedges and broadleaf” was 99, 89, and 85 % in 2, 4 and 10 WAT and penoxsulam in max recommended dose and similar rating times 61, 40 and 57 respectively. In second year of experiment penoxsulam max efficacy on ricefield bulrush (Schoenoplectus maritimus) and pondweed (Potamogeton nodusus) control was 31% and BSM in mixture with graminicides decreased their biomass more than 90% in 4-WAT. The highest grain yield 3650 kg/ha recorded in butachlor+cinosulfuron in first year. Butachlor + BSM yielded 291 kg/ha, statistically similar to hand weeded and recommended dose of penoxsulam. Dual purpose herbicide anilofos+ethoxysulfuron lacked enough efficacy on all weeds control and yielded similar to infested treatment statistically. Also the second year results confirmed the first year’s one, and showed mixture of graminicides (thiobencarb or oxadiargyl) with BSM had the highest grain yield (
3666 kg.ha-1) and penoxsulam in two investigated doses showed 25 and 48% less yield in comparison respectively. Based on results of this study penoxsulam in comparison with current used herbicides had more durable toxicity on rice, less consistency on barnyardgrass control and also lacked enough efficacy on two important perennial weed pondweed and ricefield bulrush.

In order to investigating the effects of herbicides and cono-weeder application on weeds population، growth indices and rice yield، an experiment was conducted in Rice Research Station at Amol، Mazandaran province، Iran، during 2010 growing season. The experiment has been set in a split-plot which arranged in a Randomized Complete Block Design (RCBD) with three replications. Main treatments were mechanical weed control at three levels including without (control)، one and two times application of cono-weeder. The second treatments were herbicides application at seven levels including application of recommended dose of bentazon، bensulfuron-methyl، oxadiazone، butachlor، thiobencarb، hand weeding and weed infested control. Based on weeds density and dry matter، the maximum control of weeds was observed in plots which treated by hand weeding control and two times of con-weeder application. The maximum of grain yield was harvested in three treatments including hand weeding control، two times of cono-weeder application without or with herbicides application. Between three mentioned treatments had no significant different for economic yield. In general، based on the results of weed control and grain yield، two times application of con-weeder was the best treatment.

Barnyardgrass has always been considered as the most important weed of rice all over the world. Meanwhile, establishment of new species of this genus which is more adaptable to paddy ecosystem will increase the importance of this genus as a new threat to rice. In order to evaluate the competition of two species of barnyardgrass with rice, an experiment was conducted at Rice Research Institute of Iran (Rasht) in 2007. The experimental design was a randomized complete block with three replications arranged in a partial additive series. The treatments included two barnyardgrass species (E. crus-galli and E. oryzoides), and species density at four levels (0, 10, 20 and 40 plant.m-2), transplanted with Hashemi land races cultivar rice in local normal density (20 bunches.m-2) and each bunch included three seedlings. Destructive samples were taken two weeks after transplanting up to harvesting, that is, 5 times by 10 days interval in 0.25 m-2. Rice total dry matter accumulation (TDM), Leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), yield and yield components were measured. Results showed that yield, yield components and growth indices were affected by both weed species significantly and no interaction between species occurred. Fitting the hyperbolic yield loss model to rice grain yield in barnyardgrass density showed that two weed species were not significantly different. Morphological similarity and ecological adaptability of new barnyardgrass species including resistance to flooding and also high similarity to crop plant that makes its hand weeding less efficient, implies E. oryzoides as a new threat for rice cultivation in northern paddy field of Iran. More investigation on biology of this species is suggested in order to present an applied integrated method for E. oryzoides management.

The aim of this research was to investigate the response of more and less competitive rice cultivars to different densities of barnyardgrass. A field experiment was conducted in 2010 in Tonekabon’s rice research station in Mazandaran province. The experiment layout was a factorial design with four randomized complete blocks. The experimental factors were six densities of barnyardgrass (0, 8, 16, 24, 32 and 40 plant per square meter) and two rice cultivars (Khazar and Line 843). Results showed that rice grain yield, fertile tiller number m-2 and grain number per panicle were decreased as barnyardgrass density increased from 0 to 40 plants m-2. However, the percentage reduction in grain yield, fertile tiller number and grain number per panicle increased more sharply in Khazar cultivar than in Line843 as barnyardgrass density increased from 0 to 40 plants m-2. On the other hand, biomass and seed production of barnyardgrass was increased more sharply in Khazar cultivar than in line 843 as barnyardgrass density increased from 8 to 40 plants m-2. In other words, line 843 compared to Khazar cultivar, could significantly reduce biomass and seed production of barnyardgrass under competitive conditions.