Results of the study of the weed-field flora of Primorsky Territory in 2016-2020

The results of the study of the weed component of soybean, early grain crops and maize agrocenoses in Primorsky Territory are presented. In total, 111 species of weeds belonging to 35 families were found during the period from 2016 to 2020. Compared with the results of crop surveys conducted in 2006-2015, the total number of species detected has increased by 23. The largest number of species belongs to the families Asteraceae (24), Poaceae (15), Polygonaceae (11), Fabaceae (9), Brassicaceae (8), Caryophyllaceae (7) and Lamiaceae (5). The remaining 26 families were represented by 1-3 species each. For the first time weeds-representatives of the families Scrophulariaceae, Violaceae, Lythraceae, Onagraceae, Asclepiadaceae and Boraginaceae have been discovered. The floristic composition of soybean agrocenoses was the highest with 108 weed species from 31 families. In cereal and maize crops, weed diversity was less significant, with 75 species in 22 families and 72 species in 25 families, respectively. Weed vegetation in all the above crops is represented by 62 species of 19 families. The main weed species that grew on 97-99% of the surveyed territory with a sufficiently high average density of standing (21-61pcs/m2) were Asian copperleaf, cockspur grass and common ragweed. Also, more than half of the surveyed crops of soybeans, cereals and corn were hairy cupgrass, perennial sow thistle, common couch-grass, common lamb’s quarters, wormwood species, field horsetail, yellow thistle, dayflower and yellow foxtail. Practical measures to protect against weeds on the Primorsky Territory should be primarily aimed at controlling these species.

Sympoietic Art Practice in Co-expressive Re-worlding with Hegel’s “Vegetal Subject”

“Sympoietic art practice”, construed as co-creative making-together-with plants, contributes to posthumanist discourse by forming cross-species partnerships which re-configure exploitative relations with plants. The posthumanist commitment of sympoietic practice to live equitably with the more-than-human world is inherently opposed to the tradition of anthropocentrism widely associated with Hegel’s idealization of reason and culture. But when Hegelian philosophy comingles with the radically different assumptions of sympoietic art practice in this exploratory paper, a co-expressive “worlding with plants” emerges. A transformative re-reading of Hegel’s Philosophy of Nature reveals that the English translators have smoothed away the vibrant concept of a “vegetal subject” explicitly used by Hegel in the original German. The resulting interpretive fissure makes space for a creative scrutiny of human exceptionalism, humanist and posthumanist conceptions of plant subjectivity and human-plant relations. Our transdisciplinary article concludes with a performative knitting together and composting of shreds of Hegelian text with vibrantly participative strands of living couch grass.

Differences in biological efficiency of one- and two-component graminicide on sugar beet crops in Tula region

One of the most urgent tasks in sugar beet production for Russia today is irregularities in cultivation technology and a low-efficiency crop protection. It leads to a high level of weed infestation of agricultural fields. Developing and identifying the most efficient, selective and accessible herbicides, which have low phytotoxicity, do not have a negative effect on soil chemical characteristics and can be used in sugar beet cultivation is relevant today. The aim of this study was to examine and compare biological efficiency of various doses and concentrations of one- and two-component graminicides on sugar beet crops against the following weeds: Cockspur grass Echinochloa crusgalli (L.) Beauv., Wild millet Setaria glauca (L.) Beauv. and Couch Grass Elytrigia repens (L.) Nevski. The experiment was conducted on the territory of the Tula region in 2020. The total field experiment area was 480 m2. Application of clethodim + quizalofop-P-ethyl (0.5 l/ha) resulted in reducing the number and weight of annual weeds by 6471 %, reducing the number and weight of perennial weeds by 5458 %, which had the same efficiency as clethodim (0.6 l/ha). The efficiency of clethodim + quizalofop-P-ethyl (1.0 l/ha) was higher than Clethodim (0.6 l/ha) and amounted to 7387 % of reduction in the number of weeds compared to the control, but was lower than Clethodim (1.8 l/ha), which resulted in 8995 % reduction in the number of weeds compared to the control. The highest sugar beet yields were obtained in the variants with clethodim (1.8 l/ha) and two-component herbicide (1 l/ha), which amounted to 28 and 25 % yield increase, in comparison with the control.

Coastal Observations: Rapid development and colonization of a UK sand dune system

Between the years 1200 and 1600, vast quantities of sand were brought inshore from offshore bars as a result of centuries of ferocious storms, to form a series of dune systems along the South Wales coastline. Today, as a result of many housing, leisure, and industrial developments only a few remnants exist. On one such remnant at Porthcawl, Wales, UK, became a caravan site in the 1930s, which was abandoned in 1993 for political reasons. Within 27 years a minimum of 120,000 m3 of sand was transported from the adjacent beach and formed dunes >4 m in height along a 400- m frontal edge that extended some 130 m inland, approximately a third of the site. Typical vegetation found along the frontal part of the system are Ammophila arenaria (marram), Agropyron junceiforme (sand couch grass) and Euphorbia maritimum (spurge). To the rear of the system, vegetation included Agrostis tenuis and stolonifera, (bent and creeping bent grass), Cirsium avense (creeping thistle), and Caluna vulgaris (heather). A 4-m-high and c. 3000m2 area of a vigorous stand of Hippophae rhamnoides (sea buckthorn) has also formed. The rapidity of dune formation and vegetation colonization is staggering.

EVOLUTION OF WEED FLORA IN SUGAR BEET CROPS UNDER DIFFERENT DEGREESOF ANTHROPOGENIC LOAD IN THE 20TH CENTURY AND EARLY 21STCENTURY

The south of the Non-Chernozem Region is the north-ern boundary of sugar beet production in the Russian Fed-eration. An important factor restraining the growth of crop productivity is the high weed infestation of crops. To devel-op an effective system of crop protection against weeds, it is necessary to study their species composition in order to determine the most occurring and noxious weed species. The available data of geobotanical surveys since the 1930s showed that at different levels of anthropogenic impact the core of the most noxious weed species was formed. Under extensive agriculture conditions, the following species were the most widespread ones: Elytrigia repens(L.) Nevski, Equiseeum arvenseL., Sonchus arvensis L., Convolvulus arvensisL., Cirsium setosum(Willd.) Besser., Artemisia absinthiumL., Chenopodium albumL., Polygonum avicula-reL., Apera spica-ventiL., etc. The introduction of mechan-ical plowing decreased the population density of A. spica-ventiL., Dracocephalum thymiflorumL., and P. aviculareL. Further intensification of agriculture contributed to the narrowing of the weed species composition. Avena fatuaL., not previously found, appeared in abundance in crops and surpassed all other species in terms of number and frequency of occurrence, as well as species resistant to herbicides from the 2.4-D dimethylamine group -Poaceae, Galium aparineL., Tripleurospermum inodorum(L.) Sch. Bip. Couch grass(Elytrigia repens(L.) Nevski) was com-pletely substituted. Currently, the agrophytocenoses con-tain the most harmful rhizome and root-sucker weeds and spring species. Thefollowing early spring weeds are par-ticularly harmful and highly spread in crops: common wild oat (Avena fatuaL.), hemp-nettle species (Galeopsis), and Chenopodium albumL.; overwintering weeds resistant to 2.4-D dimethylamine which seeds accumulate in the soil during the cultivation of other crops in crop rotations where weed control is not so intense.

A Concept of a Compact and Inexpensive Device for Controlling Weeds with Laser Beams

A prototype of a relatively cheap laser-based weeding device was developed and tested on couch grass (Elytrigia repens (L.) Desv. ex Nevski) mixed with tomatoes. Three types of laser were used (0.3 W, 1 W, and 5 W). A neural network was trained to identify the weed plants, and a laser guidance system estimated the coordinates of the weed. An algorithm was developed to estimate the energy necessary to harm the weed plants. We also developed a decision model for the weed control device. The energy required to damage a plant depended on the diameter of the plant which was related to plant length. The 1 W laser was not sufficient to eliminate all weed plants and required too long exposure time. The 5 W laser was more efficient but also harmed the crop if the laser beam became split into two during the weeding process. There were several challenges with the device, which needs to be improved upon. In particular, the time of exposure needs to be reduced significantly. Still, the research showed that it is possible to develop a concept for laser weeding using relatively cheap equipment, which can work in complicated situations where weeds and crop are mixed.

A Review of Non-Chemical Management of Couch Grass (Elymus repens)

Couch grass (Elymus repens) is a morphologically diverse, rhizomatous, perennial grass that is a problematic weed in a wide range of crops. It is generally controlled by glyphosate or intensive tillage in the intercrop period, or selective herbicides in non-susceptible crops. The aim of this review is to determine the efficacy of non-chemical strategies for E. repens control. The review shows that indirect control measures like crop choice, subsidiary crops, and fertilizer regimes influence E. repens abundance, but usually cannot control E. repens. Defoliation (e.g., mowing) can control E. repens growth, but efficacy varies between clones, seasons, and defoliation frequencies. Tillage in the intercrop period is still the main direct non-chemical control method for E. repens and its efficacy can be increased, and negative side-effects minimized by an appropriate tillage strategy. Some new tillage implements are on the market (Kvik-up type machines) or under development (root/rhizome cutters). Alternative methods that can kill E. repens rhizomes (e.g., steaming, soil solarization, biofumigation, hot water, flooding) often have high costs or time requirements. More studies on the effect of cropping system approaches on E. repens and other perennial weeds are needed.

Special aspects of the development of black currant bushes depending on weediness level in the Ukrainian polissia

We studied the weeds species composition in the black currantplantations of Ukrainian Polissia. The species composition of weeds has been analyzedand is was typical for thisarea. Twelve weed species were found during the study; they included annual (89.8%) and perennial ones (10.2%). A number of species were prevalent among the perennial weeds, namely common dandelion (Taraxacum officinaleWigg.) –2.5 pcs/m2, field milk thistle (Sonchus arvensisL.) –2.8 pcs/m2, couch grass (Elytrigia repensL.) –8.8 pcs/m2, and field sorrel (Rumex acetostellaL.) –3.2 pcs/m2. The most common annual species of weeds were lamb’s quarters (Chenopodium albumL.) –44.2 pcs/m2, shepherd’s purse (Capsella bursa-pastorisL.) –36.3 pcs/m2, smooth meadow grass (Poa annuaL.) –25.1 pcs/m2, and Amaranthus retroflexus(Amaranthus retroflexusL.) –19.6 pcs/m2. Throughout the study period, the least common weeds in black currant plantations were chickweed (Stellaria mediaL.) –14.8 pcs/m2, annual nettle (Urtica urensL.) –1.6 pcs/m2, quickweed (Galinsoga parvifloraCav.) –9.1 pcs/m2, and field pansy (Viola arvensisMurr.)–2.6 pcs/m2. We registered that with theweediness of 8-9 points the area of black currant leaves from a bush decreases by 1.9 m2, while the chlorophyll content in the leaves reduced by 20.8mg/100g. On the contrary, the dry matter content inleaves increasedfrom 29 to 61%. Significant negative effect of weeds on the activity of black currant and leads to a decrease in plant tolerance againstthe sucking pests and diseases. Thus, under high and very high weediness (8-9 points),the development of anthracnose (Gioesporium ribisMont.) was 32–48%, powdery mildew (Sphaerotheca mors Uvae.) and septoria blight (Mycosphaerella ribisLind.) were 16 and 15% respectively. We proved that a high weediness level reduces the yield of berriesby 56%in black currant plantations.

Reliable protection of lentils against weeds

Goal. To identify the features of the infestation of crops of lentils and improve on this basis, the elements of chemical protection from adverse impact of weeds. Methods. Field experiments were laid out in 2016—2019 according to the scheme: 1. Clogged control. 2. “Clean” control. 3. Gesagard 500 WF + Panther 4%, K. E. (3 l/ ha + 1 l/ ha). 4. Zenkor 70 WG + Targa Super, k.e. (0.6 l/ ha + 1.0 l/ ha). 5. Stomp 330, k.e. + FUSILADE Forte 150 EC, k.e. (3.0 l/ ha + 0.7 l/ ha). Results. The contamination of crops of lentils in the years of research had mixed. As a result of pre-release areas from the presence of perennial plants (couch grass, convolvulus arvensis) weeds, mostly introduced annual grasses and dicotyledonous species. The most widespread in crops were plants of foxtail glaucous — 19.5 pieces/ m2 (22.5% in the structure of impurity), Echinochloa ordinary and 17.3 (19.9%), amaranth thrown back to 10.7 (12.3%), nightshade black — 6,8 pieces/ m2 (7.8%). In General, the time of counts (end of III decade of may) the number of weeds was 86.7 pieces/ m2. Use for protection of lentil combinations of herbicides of soil action of Gezagard 500 FW, k.s. (3.0 l/ ha) and graminicide Panther, 4% k.e. (1.0 l/ ha) reduced the ability of those present in the crops of weeds to form their mass. In average per years of research, the mass of weeds in crops of version 3 testing amounted to a total of 388 g/ m2 or 13.6% of the weedy control. Herbicides provided the reduction of the mass of weeds in 86.4%. Conclusions. In terms of the use of herbicides of Gezagard 500 FW, k.s. (3.0 l/ ha) + Panther, 4% k.e. (1.0 l/ ha) received an average of 1.49 t/ ha of seeds, or 83.7% of the maximum in the testing of the level of harvest. Much more effective was the use Zenkor 70 WG, v.g. (0.6 l/ ha) Targa Super 5% k.e. (1.0 l/ ha) and stomp 330, k.e. (3.0 l/ ha) + FUSILADE Forte 15% k.e. (0.7 l/ ha), which provided the formation of 1.61 and 1.56 t/ ha of seeds, 90.4 and 87.6% of the “clean” control, respectively.