Weed Composition Research Articles

Effect of chemical crop protection agents on weed infestation and potato productivity in the steppe zone of the Khakassia Republic

In the Russian Federation, large areas in farms of various forms of ownership are devoted to the potato. The wide range of uses for this crop is particularly relevant to the industry. Cultivation technology in general, particularly some elements of agronomic techniques, may have specific differences depending on the region and the soil and climate zone. An invariable negative biotic factor for any area remains weeds, which account for the agro-technological costs. The biological group and species composition of weeds significantly influence potato yields. Chemical crop protection products (herbicides) have a significant effect in reducing the negative impact of the factor. Therefore, the aim of the study is the effect of different herbicide preparations on weed infestation and potato productivity in the conditions of the steppe zone of the Republic of Khakassia. Experiments were laid from 2018 to 2020 on dark chestnut soil in the steppe zone of the Republic of Khakassia. The authors chose a medium-early potato variety of Siberian selection Tuleevsky as an object of research. The recommended potato cultivation technology for this zone was used in the study. Herbicides were selected for preemergence application (Gezagard, Lazurit, Sukhovey, Tornado), applied 20-25 days after planting, before the mass sprouting of plants. The hydrothermal coefficient changed from 1.68 to 1.85 in the years of research. Using herbicides reduced the number of monocotyledonous weeds by 18,9 - 26,7% and dicotyledonous weeds by 38,5 - 46,1% by the harvest period. Reduction of competition with weeds for life factors allowed increased biometric indicators of potatoes (height of a plant, number of leaves, weight of haulm). The increase of biometric parameters of potatoes has essentially affected the growth of economic productivity of leaves from 9,3 to 13,2 %. The yield of potatoes has increased on 3,6-6,5 t/hectare (at the maximum value at a background of Lazurite preparation) due to the increase of efficiency of work of assimilating apparatus. The use of herbicides on potatoes allows increasing the level of profitability of production by 22,3-56,4%.

Farming Intensity Affects Soil Seedbank Composition and Spontaneous Vegetation of Arable Weeds

Former studies carried out in the 2000s in the Lahn-Dill region located in the middle-east of the German state Hesse stated a depletion of arable weeds on the field scale and more diverse weed flora on the landscape scale. Current study, having started in 2018, aims to contribute to a better understanding of the interactions between arable weed species diversity, farming intensity, grown crops and landscape area. Moreover, the potential of organic farming methods for conservation and promotion the arable weed diversity is aimed to be assessed with the study. In total, 42 fields in two landscape regions were sampled—six seedbank samples were collected from each field; additionally, data on spontaneous arable weed flora were recorded each spring from 2019 to 2021; emerged aboveground weeds were identified in the fields and their coverage was documented. Four factors were considered in the field trial: Farming practice, landscape area, soil depth and the current crop. Effects of these factors on arable weed species diversity were calculated with a Generalized Linear Model (GLM), resulting in significant effects of the management system, the area and the current crop. Among the four organic farming systems that were sampled, the time period of organic growing had a significant effect on weed seed numbers in the soil with an increase in seed numbers. Average seedbank species numbers were around twice as high in organic farming systems (18 species) compared to conventional managed fields (nine species). Evidence of an ongoing species decline in the region on the landscape scale could be detected by comparison with a former study. Especially rare and endangered weed species are a concern due to seedbank and current vegetation depletion tendencies.

Contamination of crops with various methods of soil cultivation

The article presents the results of researches on the influence of various methods of soil cultivation on the contamination of soybeans in the conditions of many years of stationary experience. The following methods of soil cultivation were studied: flat-cut, layer-by-layer, moldboard plowing, direct sowing. The species composition and number of weeds and their wet weight were taken into account by counting and weighing them in the phase of a true leaf at the 3rd node (1st count) and the phase of development of fruits and seeds (2nd count). The difference in contamination between the methods of soil cultivation is best seen in the second count, because by this time the numerical growth of weeds has ceased. It was found that for the flat-cut method, after the second counting, the number of weeds decreased by 86,49% to 16,00 pcs / m2, but the wet weight increased by 1.75 to 310.26 g / m2. When cultivating the soil in layers, the number of weeds decreased by 40.08% to 60.00 pcs / m2, but the wet weight increased 2.04 times to 300.91 g / m2. For the dumping method, the number of weeds decreased by 68.05% to 40.00 pcs/m2 and the wet weight of weeds also decreased by 0.40 times to 128.53 g/m2. For the variant with direct sowing, there was a decrease in the number by 64.71% to 11.00 pcs/m2 and a decrease in wet weight by 0.89 times to 280.30 g/m2. The smallest contamination of soybean crops was revealed with direct sowing in comparison with other methods of soil cultivation.

ВЛИЯНИЕ АГРОМЕТЕОРОЛОГИЧЕСКИХ УСЛОВИЙ НА СОРНЫЙ КОМПОНЕНТ В АГРОЦЕНОЗЕ ОЗИМОЙ ПШЕНИЦЫ В ПРЕДГОРНОЙ ЗОНЕ РСО – АЛАНИЯ

Weeds are an ecological group of plants that has developed as a result of their growth together with cultivated plants in the process of continuous struggle with them. In order to successfully fight weeds, it is necessary to know their biological characteristics, classification, distribution and reproduction of weeds. The number of weeds does not always reflect the degree of their harmfulness, since it is largely determined by the power of development of the above-ground mass of weeds. Different types of weeds react differently to changes in the level of fertilizer, the method of basic tillage, the structure of crops and the rotation of crops in crop rotation. The advantage is given to those species for which all these changes are favorable and contribute to their growth, development and distribution in phytocenoses. In addition to them, weed species that have endurance and resistance to adverse environmental factors survive and maintain their population density. According to many scientists, the mass and number of weeds reflect different aspects of relationships in the community. The number shows the interaction in the surface layer of the soil, at a low altitude, as well as in the initial phases of development, and the mass of the weed component characterizes the coenotic relationships in the middle and upper tiers at later stages of development. The purpose of our research was the influence of agrometeorological conditions on the species composition, abundance, dry biomass and the ratio of biological and ecological groups of weeds in the winter wheat agrocenosis. Our research was carried out in 2017–2021. on the experimental experimental field of the SKNIIGPSh VSC RAS in the forest-steppe zone of the North Ossetia - Alania. The object of research was winter wheat variety Trio. The plot area is 100 m², repeated three times. This crop was part of a five-field soil-protective crop rotation. We have found that in the forest-steppe zone of North Ossetia - Alania, agrometeorological conditions largely affect the species composition, abundance and biomass of harmful weeds.

ПРИМЕНЕНИЕ РЕГУЛЯТОРА РОСТА НА ПОСЕВАХ ОЗИМОЙ ПШЕНИЦЫ ЛЕСОСТЕПНОЙ ЗОНЫ РЕСПУБЛИКИ СЕВЕРНАЯ ОСЕТИЯ – АЛАНИЯ

Weeds are an ecological group of plants that has developed as a result of their growth together with cultivated plants in the process of continuous struggle with them. In order to successfully fight weeds, it is necessary to know their biological characteristics, classification, distribution and reproduction of weeds. The number of weeds does not always reflect the degree of their harmfulness, since it is largely determined by the power of development of the above-ground mass of weeds. Different types of weeds react differently to changes in the level of fertilizer, the method of basic tillage, the structure of crops and the rotation of crops in crop rotation. The advantage is given to those species for which all these changes are favorable and contribute to their growth, development and distribution in phytocenoses. In addition to them, weed species that have endurance and resistance to adverse environmental factors survive and maintain their population density. According to many scientists, the mass and number of weeds reflect different aspects of relationships in the community. The number shows the interaction in the surface layer of the soil, at a low altitude, as well as in the initial phases of development, and the mass of the weed component characterizes the coenotic relationships in the middle and upper tiers at later stages of development. The purpose of our research was the influence of agrometeorological conditions on the species composition, abundance, dry biomass and the ratio of biological and ecological groups of weeds in the winter wheat agrocenosis. Our research was carried out in 2017–2021. on the experimental experimental field of the SKNIIGPSh VSC RAS in the forest-steppe zone of North Ossetia - Alania The object of research was winter wheat variety Trio. The plot area is 100 m², repeated three times. This crop was part of a five-field soil-protective crop rotation. We have found that in the forest-steppe zone of North Ossetia - Alania, agrometeorological conditions largely affect the species composition, abundance and biomass of harmful weeds.

Community composition and seasonal dynamics of upland weeds for establishing weed control systems in Okinawa, Japan

Community composition and seasonal dynamics of upland weeds for establishing weed control systems in Okinawa, Japan

СРАВНИТЕЛЬНАЯ ЭФФЕКТИВНОСТЬ СПОСОБОВ ОБРАБОТКИ ПОЧВЫ В РЕГУЛИРОВАНИИ ЗАСОРЁННОСТИ ПОСЕВОВ СЕЛЬСКОХОЗЯЙСТВЕННЫХ КУЛЬТУР

The article presents the results of evaluating the anti-weed effectiveness of the methods of basic tillage and their effect on the quantitative and species composition of weeds in the field crop rotation with the following alternation: 1-h / pair; 2-winter wheat; 3-spring wheat; 4-mustard (siderate); 5-winter wheat; 6-barley. The research was carried out on the experimental field of the Ulyanovsk Research Institute- branch of the Scientific Research Center of the Russian Academy of Sciences in 2015-2021. The usual dump and non-dump, as well as fine mulching, zero and ridge tillage were studied. Autumn plowing at 20-22cm was taken as a control in the experiments. (PLN-4-35). Analysis of the infestation of fields at the time of harvest indicates that the annual plowing by 20-22 cm was distinguished by increased anti-weed efficiency, where the total number of weeds averaged 18.1 pcs./m2 with a weight of 24.9 g/m2. Of the ploughless options, the less clogged ones were those with a 20-22cm non-fallow treatment, with shallow comb-back treatment and comb-back with soil deepening, where the number of weeds remained at the control level. 17,9-18,4-18,1 pcs / m2, but there was an increase in the mass of weeds by 5-12%. Variants of fine processing, surface peeling with a stubble-laying machine and without autumn mechanical processing contributed to an increase in the weeding of crops compared to plowing, both in terms of quantity and above-ground mass of weeds by 10-12-15%, and 12-19%. It was noted that the formation of significantly larger biomass and the number of juvenile weeds was ensured on fertilized backgrounds, the harmfulness of perennial weeds decreased with an increase in the level of fertilization.

Soybean productivity in the Northern forest-steppe of the Tyumen region, depending on agrotechnical techniques

The solution to the problem of feed protein deficiency is possible with an increase in acreage and the selection of agrotechnical methods of soybean cultivation, taking into account the conditions of the natural and climatic zone. One of the main elements of the farming system that allows to increase the yield of soybeans is rational basic tillage, its depth depending on the type of soil, providing favorable conditions for plant growth and development, which has not been studied in the northern forest-steppe in the Tyumen region. The purpose of the work was to study the influence of agrotechnical techniques on soybean productivity in the northern forest-steppe in the Tyumen region. During the research the influence of basic tillage and its depth on agrophysical (soil density, reserves of productive moisture), agrochemical soil parameters, uniformity of sowing depth, germination and preservation of soybean plants has been established. The contamination of crops, the species composition of weeds, and the degree of contamination during soybean cultivation by basic tillage with the use of herbicide during the growing season has been studied. It has been found that the highest level of profitability of 39,7 % was achieved with the differentiated method of tillage, with the mouldboard plowing (20–22 cm) it was less by 7,2 %, with the subsurface tillage (20–22 cm) it was less by 19,3 %. The decrease in the depth of processing leads to the decrease in the level of profitability by 4,0 % with the mouldboard plowing, by 2,2 % with the subsurface tillage and by 7,4 % with the diff erentiated method. With zero tillage, the profitability level was below control by 14,6 %. Thus, the most cost-effective was the differentiated method of tillage (20-22 cm) with the profitability level of 39,7 % and a profit of 9765 rubles/ha.

Diversidade de plantas daninhas em função do preparo do solo e da aplicação do herbicida glufosinato de amônio

ABSTRACT Farmers in Indonesia generally spray herbicides to control weeds and use tillage during the early stages of crop cultivation; consequently, these activities affect the weed composition and diversity. This study aimed to evaluate the dominance and diversity index of weeds and obtain abundance correlations according to the soil chemical characteristics, as well as the effect of the ammonium glufosinate herbicide, in different tillage systems. A non-factorial randomized block design was used, consisting of no-tillage (NT), 1-time tillage (T1) and 2-times tillage (T2), with three replications. The Cyperus rotundus and Ageratum conyzoides weed species were dominant in the tillages. The diversity indices were 2.261, 2.196 and 2.234 (moderate/stable condition), respectively for the NT, T1 and T2. For T2, there were increases of 2.82-folds, 41 populations and 2.43-folds, respectively for A. conyzoides, Cynodon dactylon and Euphorbia heterophylla, when compared to NT, while a decrease was observed in grasses for T1 and T2 (50.71 and 26.05 %, respectively). Moreover, there was a positive and significant correlation for E. heterophylla according to the soil cation exchange capacity (0.727). In contrast, four new weed species (Glyceria maxima, Leersia oryzoides, Scoparia dulcis and Anthoxanthum oculatum) were found due to the ammonium glufosinate application, in the different tillage systems.

Efficacy of herbicides in sunflower sowings in the conditions of the western Forest-Steppe of Ukraine

Purpose. Determinе the species composition of weeds and the most efficient system of weed control in sunflower sowings.
 Methods. Field, laboratory, mathematical and statistical.
 Results. The species composition of spring weeds in sunflower sowings was mainly represented by dicotyledonous species Amaranthus retroflexus L., Chenopodium album L., Galinsoga parviflora Cav., Matricaria inodora L., Thlaspi arvense L., Polygonum convolvulus L., Sinapis arvensis L., Xanthium strumarium L. and cereal weeds Setaria glauca L., Echinochloa cruss-galli L. The efficiency of the use of herbicides Challenge 2.5 l/ha + Harness 1.5 l/ha on the 30th day after application, against the total number of weeds, was 89.7%. Meanwhile, the use of the herbicide Challenge is the application rate of 2.0 l/ha appeared more effective with the efficiency rate of 95.6%. The herbicides, regardless of their application scheme, did not caused thinning of the sowing density; however, plant suppression did occur. This was evidenced by reduced plant height during the anthodium formation and flowering stage compared to control.
 Conclusions. The dominant weed species in sunflower crops were Amaranthus retroflexus with the share of 15%, Chenopodium album 8%, Setaria glauca L. 23% and Echinochloa cruss galli 10%. Application of herbicide Challenge 2 l/ha in the 2 to 4 leaf stage of sunflower appeared the most effective as weed control method with the efficiency rate of 92.8%. Herbicides Challenge (2.5 l/ha) + Harness (1.5 l/ha) were milder to crop plants, which ultimately contributed to the formation of sunflower yield of 3.47 t/ha in hybrid ‘NK Condy’ and 3.04 t/ha in hybrid ‘Atilla’.

Oilseed Rape Yield Performance in the Clearfield® System under Varying Management Intensities

Oilseed rape production is under pressure due to a limited availability of herbicides. Therefore, the performance in terms of management intensity (MI) and herbicide strategy (HS) and the involved yield formation was evaluated in a two-year Clearfield® oilseed rape field experiment. Furthermore, weed density and weed composition were also investigated. The variants of MI were standard sowing density (StS; seed rate: 50 seeds m−2, primary tillage: plow, row width: 12 cm), reduced sowing density (RD; seed rate: 25 seeds m−2, primary tillage: plow, row width: 50 cm), and strip-till (ST; seed rate: 25 seeds m−2, primary tillage: strip tillage, row width: 50 cm). The variants of HS were preemergence strategy (PES; application of dimethachlor, napropamide, clomazone in preemergence and application of prapaquizafop in postemergence) and Clearfield® strategy (CLS; application of imazamox, quinmerac in preemergence, no postemergence herbicide application). In the first year of the trial, there were no interactions between the factors in terms of grain yield. Grain yield in StS was 3.85 t and 5.2% significantly lower than in ST, and the value of RD was not significantly different from StS and ST. Grain yield in CLS was 3.7 t and 2.7% lower than in PES. In the second year of the trial, the grain yield in ST CLS was significantly lower, and there were no significant differences between the other variants. Higher weed emergence was observed in CLS RD (2.7 to 4 times higher weed density compared to PES RD) and CLS ST (2.8 to 4.5 times higher weed density compared to PES ST). No significant differences existed between StS PES and StS CLS in both trial years. The Clearfield® system offers significant advantages in the control of cruciferous weeds. Although these did not occur on the trial fields, the Clearfield® system in this study showed to be an alternative to the more common pre-emergence system, especially with regard to the parameter grain yield.

Weediness of oil flax (<i>Linum usitatissimum L.</i>) crops depending on the cultivation technologies and seed inoculation in the steppe Crimea

Weed control is one of the important issues that modern agriculture sets itself, especially in conditions of minimization of production. The purpose of the current study was to comparatively research the effect of direct sowing and the traditional cultivation technology of oil flax when treating seeds with a complex of microbial products on the weediness of agrophytocenosis. The study was carried out in the stationary trial of the FSBSI “Research Institute of agriculture in Crimea” in 2017-2019, in dry conditions of the steppe Crimean Peninsula, on southern low-humus blackearth (chernozem). Weediness of flax crops was estimated by a quantitative method with the determination of the varietal composition of weeds in the phase of full germination and before harvesting. In all variants, in the “herringbone” phase there was applied a tank mixture of herbicides Herbitox, VKR (MCPA 500 g/l) with a rate of 0.5 l/ha + Magnum, VDG (metsulfuron-methyl 600 g/kg) with a rate of 5 g/ha to fight against monocotyledonous and dicotyledonous weeds. There was found that for three years of study, the varietal composition of weeds differed insignificantly for both technologies, but their number under a direct sowing in the phase of full sprouting was in 1.6 times more than in the case with traditional technology. By the phase of full flax ripeness, the number of weeds decreased in 1.3 times using traditional technology and in 2.4 times under a direct sowing, and the difference between technologies was leveled. Seed inoculation had no significant effect on the weediness of the sowing. The conditions of the year had a significant effect on the weed component of the agrophytocenosis.

Hot foam and hot water for weed control: A comparison

Thermal weed control plays an important role in managing weeds in synthetic herbicide-free systems, particularly in organic agriculture and in urban areas where synthetic herbicides are prohibited. This study compares the impact on weed control of increased doses of hot water and hot foam (i.e. 0, 0.67, 1.67, 3.33, 5.00, 6.67 and 8.33 kg m–2). The doses were applied using the same machine. The temperatures, weed control effectiveness, weed regrowth after the death of the aboveground vegetative weed tissues, and weed dry biomass 30 days after the treatments were studied in two experimental fields with a different weed composition (i.e. Site I and Site II). The results showed that difficult weeds to control, such as Cynodon dactylon (L.) Pers., Digitaria sanguinalis (L.) Scop. and Taraxacum officinale Weber, like all the other species in the initial weed populations in the two experiments, died after lower doses of hot foam compared to hot water. Adding foam to hot water made it possible to lower the required dose of water by at least 2.5-fold compared to hot water used alone. By insulating the weeds, the foam led to higher peak temperatures and slower temperature decay, thus determining an effective weed control with lower doses compared to hot water. Starting from 11 days and 16 days after treatments (for Site I and Site II, respectively), there were no statistically significant differences in weed regrowth between hot foam and hot water at all the doses applied. There were no differences between the dry biomass of weeds collected 30 days after treatments when the same doses of hot foam and hot water were used.

Impact of sowing methods and weed control practices on yield and economics of wet direct seeded rice

Wet direct seeding is proved as a viable alternate to conventional transplanting method of rice. Maintenance of optimum population by adopting an appropriate sowing method followed by judicious weed control practices ensures profitability of wet direct seeded rice (W-DSR). A field experiment was carried out to find out a suitable sowing technique and weed control options for enhancing productivity and economics of W-DSR. The W-DSR was infested with twelve numbers of weed species comprising of eight families under different sowing methods. The composition of sedges, broadleaved (BLW) and grassy weeds was 83.07, 11.0 and 5.93%, respectively. Irrespective of sowing methods, weeds such as, Echinochloa glabrescens and Leptochloa chinensis among grasses, Cyperus difformis and Scirpus juncoides among sedges and Lindernia anagallis among BLW were dominant. Drum seeding recorded 6.9 and 12.7% higher gross and net return, respectively than broadcasting, but it was at par with spot seeding. Highest B: C ratio of 2.07 was recorded with drum seeding, whereas spot seeding recorded lowest B: C ratio (1.99). Crop-weed competition caused 31.7% reduction in grain yield with W-DSR. Application of early post-emergent herbicide bensulfuron-methyl + pretilachlor @ 60+600 g/ha at 10 DAS, azimsulfuron @ 35 g/ha at 20 DAS, and bispyribac sodium @ 30 g/ha at 20 DAS recorded increase in grain yield 40.3, 40.1 and 39.8%, respectively over the weedy check. Ready mix bensulfuron-methyl + pretilachlor @ 60+600 g/ha at 10 DAS registered highest B: C ratio (2.16) but it did not vary significantly with bispyribac sodium @ 30 g/ha and azimsulfuron @ 35 g/ha.

The effect of cover crops on composition and diversity of weeds in an apricot orchard

Apricot, Turkey's exports is the important role played by fruit, the weeds are the main factors that cause problems in the apricot orchards. This study was carried out in Malatya between 2014-2016 in order to determine the effects of cover crops on the control of weeds that cause problems in these areas and also on species distribution, diversity and dominance. As annual winter cover plants in the study: Vicia villosa Roth (hairy vetch), Vicia pannonica Crantz (Hungarian vetch), V. pannonica + Triticale (V.pannonica 70% + Triticale 30%) mixture and Phacelia tanacetifolia Bentham (lacy phacelia) and Fagopyrum esculentum Moench (buckwheat) was used as a summer cover plant. Weed diversity index (H) and Simpson's dominance index (Sd) values were also calculated in the study. In addition, applications were subjected to canonical discriminant analysis. The highest value of the weed diversity index (H) in the two-year period was obtained from the weed control plots. It has been determined that perennial weeds (Convolvulus arvensis and Sorghum halepense) are the dominant species in cover plants and there are also differences between practices. It has been determined that annual weeds are generally suppressed and their diversity has decreased significantly in the plots except for F. esculentum. The results obtained from the canonical discriminant analysis showed that the highest numbers of weed species in the 1st and 2nd years were found in the weedy control plots and that the cover crops suppressed the weeds.

OPTIMIZATION OF TECHNOLOGICAL METHODS OF CULTIVATION OF WINTER BARLEY IN CONDITIONS EXPERIMENTAL FIELD WNAU

The spread of areas under crops of winter barley is associated with great national economic importance, since its products include malt, feed grain, hay and are used in the food industry. The main reasons for the production of an insufficient amount of winter barley grain is a violation of cultivation technologies. Among the main ones are the untimely use of means of protection or the absence of these measures to regulate the number of harmful organisms in crops of winter barley to an economically imperceptible level. Violation of the scientific foundations of agriculture and changes in weather and climatic conditions led to an increase in the development of diseases, the number of weeds in winter barley crops. During seed dressing with modern highly effective dressing agents, conditions are created under which winter barley plants better tolerate stress, improve the development of their root system, which is important for plants in preparation for winter entry. The infestation of winter barley fields is accompanied by the appearance of both early and late crops, a certain periodicity of the appearance of weeds of different biological groups. Accordingly, in different conditions and in different fields, the weed structure can differ significantly. Therefore, the development of highly effective systems for protecting winter barley crops from weeds largely depends on the completeness of the study of phytocenoses and the species composition of weeds. The introduction of herbicides on crops of winter barley contributed to a sharp decrease in weeds. Dicotyledonous weeds were almost completely destroyed, in the agrocenoses of winter barley, mainly cereal weeds remained, but they did not pose a threat to barley plants. Control of barley and weed plant diseases in agrocenoses provides an increase in crop yields, as well as an improvement in grain quality. To obtain the planned level of grain yield of winter barley of appropriate quality, it is recommended before sowing barley seeds to treat with a disinfectant Scenik 80 FS at a rate of 1,5 l/ha, and for effective weed control in winter barley crops, spray with herbicide Caliber 75 c. g. + South Africa Trend 90 at a rate of 50 g/ha + 0,2 l/ha, which helps reduce weeds to 96,5% and will allow to obtain a grain yield of winter barley at 6,24 t/ha.

Biological and economic efficiency of herbicides on spring rape in the conditions of the south of the Non-black earth zone

The results of studies to determine the biological and economic efficiency of a complex of herbicides in crops of spring rape variety Neman in the south of the Non-Chernozem zone are presented. According to the data of the experiments, it was revealed that in the crops of rape there is a polyspecific composition of weeds. The most was the used for the control of broad-leaved weeds Etamaster, VDG, (etametsulfuron-methyl 750 g/kg), 0.025 kg/ha and for the control grass weeds Miura, EC (quizalofop-P-ethyl 125 g / l), 1 l/ha. The decrease in the number of weeds was 90%, weight – 92% compared to the control. The economic efficiency on this option was also the highest, the yield was 2.94 t/ha, the increase to the control was 1.04 t/ha, the collection of crude fat was 1.25 t/ha, the collection of crude protein was 0.82 t/ha.

Features of the specific composition of weeds on the territory of Vsevolozhsk (Leningrad region)

As a part of the ecological approach, weeds are considered as plants of secondary habitats of natural and artificial origin with disturbed natural vegetation cover. Such habitats are also available in the territory of settlements. Therefore,the study of the specific composition of weeds in the territory of settlements is an important area of scientific research. Thepurpose of this study is to identify the features of the specific composition of weeds depending on the type of habitat in thecity of Vsevolozhsk (Leningrad Region). Аs a result of the study, new data were obtained on the weeds distribution in different types of habitats within the city. For comparison, harvested clogged areas and lawns were selected, 59 and 66 species wereidentified on them, respectively. Species compositions of weeds of comparable habitat types have significant similarities in thetaxonomic structure and composition of species groups which dominate in occurrence (14 common species). The proportion of young (annual and biennial) and perennial species of weeds on the compared types of habitats varies slightly. Together,15 species from the compositions of the dominant species groups are dominant in the fields of the Leningrad Region, whichdemonstrates the relationship between the different components of the weed flora of the Leningrad Region. As a part of the ecological approach, weeds are considered as plants of secondary habitats of natural and artificial origin with disturbed natural vegetation cover. Such habitats are also available in the territory of settlements. Therefore,the study of the specific composition of weeds in the territory of settlements is an important area of scientific research. Thepurpose of this study is to identify the features of the specific composition of weeds depending on the type of habitat in thecity of Vsevolozhsk (Leningrad Region). Аs a result of the study, new data were obtained on the weeds distribution in different types of habitats within the city. For comparison, harvested clogged areas and lawns were selected, 59 and 66 species wereidentified on them, respectively. Species compositions of weeds of comparable habitat types have significant similarities in thetaxonomic structure and composition of species groups which dominate in occurrence (14 common species). The proportion of young (annual and biennial) and perennial species of weeds on the compared types of habitats varies slightly. Together,15 species from the compositions of the dominant species groups are dominant in the fields of the Leningrad Region, whichdemonstrates the relationship between the different components of the weed flora of the Leningrad Region.

PERBANDINGAN VEGETASI GULMA PADA PERKEBUNAN KELAPA SAWIT (Elaeis guineensis Jacq.) MENGHASILKAN DAN BELUM MENGHASILKAN DI LAHAN GAMBUT

Weed vegetation analysis is important to do in order to know the composition and structure of the vegetation to determine the appropriate weed control measures. This study aims to compare the composition and structure of weeds on peatland immature oil palm plantations and mature palm. This research was conducted from October to December 2020. Vegetation analysis was carried out using a survei method with purposive sampling technique. The parameters observed were density, frequency, dominance, important value index (INP), summed dominance ratio (SDR) and species diversity index (H'). The results showed that the composition of weeds on immature oil palm plantations was found 12 species with number of individual 847, while on mature palm found 9 species with number of individuals 980. The dominant weed structure on immature oil palm plantations is Lempuyangan with SDR values 29,9 % and mature palm is Bandotan with SDR value 23,4%. Weed diversity index on immature oil palm plantations and mature palm is categorized as high with a value of 1.50 for immature oil palm plantations and 1.65 for mature palm.

EFIKASI HERBISIDA ISOPROPILAMINA GLIFOSAT 240 g l-1 TERHADAP PERTUMBUHAN GULMA DI PERKEBUNAN KELAPA SAWIT (Elaeis guineensis Jacq) TANAMAN MENGHASILKAN

Oil palm (Elaeis guineensis Jacq.) Is one of the most widely cultivated plantation crops in Indonesia. The decrease in productivity of oil palm is caused by presence of weeds around the plant that can be controled. One of the most commonly used controls is the use of the isopropylamine glyphosate herbicide. This research aims to determine the dosage of the Isopropylamine glyphosate herbicide which is oil palm yields. Determining changes in weed composition after application of Isopropylamine glyphosate herbicide in oil palm yields. Determining whether phytotoxicity occurs in oil palm yields after application of the Isopropylamine glyphosate herbicide. This research was conducted in oil palm plantations owned by farmers in Jontor Kenangasari Village, Seputih Surabaya District, Central Lampung Regency and the Weed Laboratory of the Faculty of Agriculture, University of Lampung, Gedong Meneng, Bandar Lampung. The research was conducted using a randomized block design (RBD) with 6 treatments and 4 replications, namely various doses of isopropylamine glyphosate (360, 600, 480, and 720 g ha-1), manual weeding, and control. Homogeneity of variance was tested using the Bartlet test, additivity was tested by the Tukey test, and the mean difference was tested by the Least Significant Difference Test (LSD) at the 5% level. The results showed that: (1) The isopropylamine glyphosate herbicide dose of 480-720 g ha-1 is effective in controlling total weeds, grasses weeds, Brachiaria mutica weeds and Mikania micrantha weeds up to 12 MSA and the herbicide dose of 600-720 g ha-1 is effective in controlling wide leaf weeds, and Cyrtococcum acrescens weeds up to 8 MSA, (2) The isopropylamine glyphosate herbicide 360- 720 g ha-1 causes changes in weed composition at 4, 8, and 12 MSA, and (3) Application of the isopropylamine glyphosate herbicide 360 - 720 g ha-1 on plant plates did not cause poisoning to oil palm plants.