Dependence of soybean weed infestation on growing conditions in the Eastern Forest-Steppe of Ukraine

Goal. To establish the species composition of weeds, their dominant role and determine the type and level of weediness of soybean crops for cultivation in a fixed nine-course stationary, fallow-crop-row rotation and in monoculture in the eastern part of the Forest-Steppe of Ukraine. Methods. The research was conducted by route surveys in field experiments. Results. According to the research of 2011—2017, 30 species of weeds and contaminants were found in soybean crops after winter wheat as forecrop in the stationary crop rotation (spring early and late were 60%, winter and biennial were 17%, perennial were 23%), and 18 species (spring early and late were 72%, wintering and biennial were 6%, perennial were 22%) were found for cultivation in monoculture. They belonged to 16 families, the families Asteraceae (9 species), Poaceae (5 species) and Polygonaceae (5 species) were the most represented. The main weeds in soybean crops in crop rotation and monoculture were Echinochloa crus-galli (L.) Roem. et Schult., Chenopodium album L., Cirsium arvense (L.) Scop. and Panicum miliaceum L. In addition to these weeds for growing soybeans in crop rotation were present Setaria glauca (L.) Beauv., Amaranthus retroflexus L., Solanum nigrum L., Polygonum lapathifolium L., Sonchus arvensis L., Convolvulus arvensis L., and in monoculture were Ambrosia artemisiifolia L. and Xanthium strumarium L. Xanthium strumarium L. was the most dominant in the monoculture (43%), and Setaria glauca (L.) Beauv was subdominant in crop rotation (57%), and Echinochloa crus-galli (L.) Roem. and Schult. was subdominant in monoculture (57%). Six complex types of weeds were formed in soybean crops, cereal-dicotyledonous-dicotyledonous-root-sprouting and dicotyledonous-grass-annual-grass-root-sprouting prevailed. For cultivation in crop rotation cereal annual species predominated, and dicotyledonous annuals predominated in monoculture. At the same time, the monoculture had a higher level of weeding than crop rotation, or it was equivalent. Conclusions. The species composition of weeds in soybean crops in fallow-crop-row rotation and monoculture differs significantly, which should be taken into account by the agronomic service of farms when developing methods of their control.

Analysis of Setaria glauca (L.) P. Beauv. Population’s Vital Parameters in Grain Agrophytocenoses

The paper presents the results of research on key vital parameters of a one-year late spring segetal species Setaria glauca (L.) P. Beauv. in crops of grain and legumes in the conditions of the north-rast forest-steppe Ukraine. It has been observed that in S. glauca there is a statistically significant change in the complex population characteristics, in particular, indicators of development of the vegetative sphere and reproductive organs against the background of changes in the field conditions. It turns out that the values of the main morphometric parameters and their dynamics in weed plants statistically significantly change by gradient of different crops, which are dominant agrocenoses and significantly affect the development of segetal wild species. It is proved that each cultivated plant is an edificator of agrocenosis and has a significant phytocoenotic effect on the state of S. glauca populations. The study found that favorable conditions for the development of weed emerged in fields of peas and winter wheat, while the crops of winter rye and buckwheat significantly inhibited the development of S. glauca populations. Knowledge of the dynamics of vital parameters of S. glauca populations under various field conditions allows the effective application of the system of anti-weed crop rotation, which allows controlling the clogging of fields using environmentally safe methods without application of herbicides.

The weeds in onion and their control

The protection of onions from the weeds and their negative impact in the field production is one of the most important measures. The onion is exceptionally succeptible to the weeds, especially in the first phases of the growth, considering the weak initial growth of the crop in comparison with the weeds. The seasonal dynamics of the onion weeds is not so noticeable like with the other crops, while the weeds that appear most frequently are: Amaranthus blitoides, Ambrosia artemisiifolia, Chenopodium album, Cirsium arvense, Convolvulus arvensis, Cynodon dactylon, Datura stramonium, Portulaca oleracea, Setaria glauca and Stellaria media. The chemical control measures mean the herbicide use before or after the emergence of the crop and the weeds. Before the emergence the herbicides based on aclonifen and pendimethaline can be used, while after the emergence herbicides based on fluroxypir, clopyralid, fluazifop-P-butyl, clethodim, quizalofop-P-ethyl, quizalofop-P-tefuryl and propaquizafop are used.

EFIKASNOST KOMBINACIJE MEZOTRIONA I TERBUTILAZINA IZ RAZLIČITIH PREPARATA U USEVU KUKURUZA

The aim of study was to test the efficacy and phytotoxicity of Calaris pro (326 g kg-1 terbuthylazine+50 g kg-1 mesotrione) and Twister (125 g kg-1 terbuthylazine+50 g kg-1 mesotrione) on weeds in maize crop. The experiment was set up during 2017 at the Kruščić, by a random block system in four repetitions. High efficacy of herbicides was manifested on Abutilon theophrasti, Amaranthus retroflexus, Ambrosia artemisiifolia, Chenopodium album, Chenopodium hybridum, Cirsium arvense, Datura stramonium, Solanum nigrum, Setaria glauca, Hibiscus trionum and Xanthium strumarium, while low efficacy was on Sorghum halepense. The total efficacy for product Calaris pro was 94,16% and for Tvister 96,20%.

INFLUENCE OF FODDER CROP ROTATIONS ON CROP CONFERENCE AND PRODUCTIVITY OF AGRICULTURAL CROPS IN BAIKAL REGION

The research was carried out in Irkutsk region in 2011–2014. The purpose of this work is to study the influence of forage crop rotations on the degree of weediness of fields and the yield of forage crops. The objects of research are three forage crop rotations: one control without perennial legumes (meadow clover) and two with meadow clover in the structure of sown areas of 20 and 40%. The soil of the experimental site is gray forest heavy loamy, with the following characteristics: salt extract pH 4.7 ... 4.9, humus content 4.5 ... 4.8%, mobile phosphorus - 160 mg/kg, potassium - 130 mg/kg. The least amount of weeds in the experiment was in variants with perennial leguminous grasses (7 ... 9 pcs/m2), which ensured an increase in yield by crop rotation on average for 4 years of research by 14 ... 19%. The most contaminated was the control crop rotation. The greatest number of weeds in this crop rotation was noted in the crops of corn and pea-oat mixture - 5 ... 12 pcs/m2. Of the juvenile weeds, mainly gray mice (Setaria glauca (L.) Beauv.), wild radish (Raphanus raphanistrum), of perennial weeds, yellow sow-thistle (Sonchus arvensis L.) and field horsetail (Equisetum arvense L.) prevailed. Weediness of crops did not have a significant effect on the yield of forage crops in the links of crop rotations. Among the five-field crop rotations, the highest productivity was observed in the variant with two fields of meadow clover (2.5 thousand fodder units/ha) with the content of digestible protein in 1 fodder unit 99.1 g

The weed pollution in Miscanthus giganteus

Goal. Is to determine the species composition of weeds in Miscanthus giganteus plantings, their impact on biomass productivity and the development of an effective protection system. Methods. Field experiments, laboratory agrochemical studies, mathematical and statistical — to evaluate the reliability of the obtained data. Results. At the beginning of the first year of vegetation in the miscanthus crops, the type of weed was mixed, with a large predominance of annual monocotyledonous species 91.1—93.6%. But in the second (70.1—85.3%) and the third (51.1—79.8%) years of vegetation, dicotyledonous species prevailed, while in the fourth, the monocotyledonous species (55.6—64.8%) had a slight advantage. In the first year of vegetation the weed was quite high and amounted to 1156 p./m2, in the second year — 873 p./m2, it decreased to 380—386 p./ m2. On the variants of application of herbicides for the second and next years, a decrease in the number of weeds by 41.3—64.5% compared with the weed pollution control and depending on the year of vegetation was observed. In the conditions of co-vegetation of weed plants with the weeds, the largest mass was formed by the Chenopodium album L. (930 g/m2 in the first year and 93 g/ m2 in the fourth year), Amaranthus retroflexus L. (455 g/ m2 and 60.6 g/ m2), Artemisia annua L. (280 g/m2 and 29.1 g/m2) and annual monocotyledonous Echinochloa crus-galli (L.) Pal. Beauv. (225 g/ m2 and 17 g/ m2) and Setaria glauca (L.) Pal. Beauv (360 g/ m2 and 15.4 g/ m2). Weed pollution control on miscanthus crops helped to increase the biomass yield in the first year of vegetation to 2.6—2.7 t/ha of wet weight, to the fourth — up to 36.3—37.4 t/ ha. In the Weed pollution control, only 0.5 t/ha were obtained in the first year of vegetation, while in the fourth year it was 22.1 t/ ha. Conclusions. A mixed type of weed was found on the landing of Miscanthus giganteus, with 19 species from 12 families. Application of herbicides Task Extra and Master Power weed pollution reduction by 83.3—99.2%, which made it possible to improve the conditions of growing and development of Miscanthus giganteus plants and to obtain a dry biomass yield of 20.0 t/ha for the fourth year of vegetation.

Young peacock-shaped plants need protection

Goal. Paulownia felines — Paulownia tomentosa L., a promising bioenergy crop for our country. In the early stages of organogenesis (juvenile and immature), young plants of the peacock sprout easily suppress weeds. Therefore, young plantations of such a promising bioenergy crop need reliable and effective protection against the adverse effects of weeds. Method. Weeding processes for young peacock plantations in the small field experiments were conducted in 2018—2019. on the experimental lands of the Yaltushk SSS IBEK and the Central Bank of NAAS The area of the plots is 36 m2, the area of the plot is 25 m2. Repeat studies — 4 times. Placement of sites is regular in two tiers. Seeds and young plants (seedlings) of Clone 112 were used for growing on the plots. Results and Discussion. Contamination of plantations was mixed. The records, carried out on 01.06, recorded the presence of seedlings of Echinochloa crus-galli (L.) Pal Beauv, Setaria glauca (L.) Pal.Beauv, Chenopodium album L., Sinapis arvensis L., Thlaspy arvense L., Polygonum scabrum Moench., mustard beetle, Polygonum convolvulus L, Solanum nigrum L. The number of weeds averaged 89.5 pcs/m2. The largest number of seedlings was recorded in millet rooster 12.4pcs/m2, mouse gray — 10.3 pcs/m2, white swans — 8.7 pcs/m2, bear­ded birch — 7.3 pcs/ m2, talaban field — 7.1 pcs/m2. By the third decade of August, their number had increased to 134.0 pieces/ m2. Conclusions. Under the conditions of co-vegetation of young peacock-planted plants with weeds, the height of their plants by the second decade of September averaged 23.6.cm. The height of crop plants that vegetated without adversely affecting the presence of weed plantations (4 consecutive manual weeding) averaged 63.8 cm or 2.7 times greater. Such a negative impact requires the implementation of protection measures for young plants.

Allelopathic effect of buckwheat extract for seedlings of selected weed species

The influence of 1% aqueous extract obtained from a 14-day plants of common buckwheat (Fagopyrum esculentum Moench) on weed species was evaluated. Seedling roots of wild oat (Avena fatua L.), yellow foxtail (Setaria glauca L.), barnyardgrass (Echinochloa crus galli (L.) P. Beauv.), common windgrass (Apera spica-venti (L.) P. Beauv.), catchweed bedstraw (Galium aparine L.), scentless mayweed (Matricaria inodora L), gallant soldier (Galinsoga parviflora Cav.) and tiny vetch (Vicia hirsuta L.) were exposed to buckwheat extract and compared with control plants grown in water. The obtained results show that the buckwheat extract had lower influence on the growth of shoot than on roots of the evaluated weed species. The use of buckwheat extract in the medium caused the inhibition of root growth in all species except from tiny vetch. In the case of shoot of weeds, inhibition of growth by buckwheat extract occurred only in wild oat. Whereas in yellow foxtail, scentless mayweed and tiny vetch, the stimulation of shoot growth was demonstrated. These results may indicate that the buckwheat extracts act on directly exposed tissues. A different metabolic reaction of wild oat to buckwheat extract after 5 days of exposure than after 2 days may indicate a quick adaptation of wild oat seedlings to stressful conditions.

Study of Some Highly Eroded Wasteland Soils of Cherrapunjee, Meghalaya and Its Bio-Rejuvenation Possibilities

Cherrapunjee has ragged terrains and deep slopes. Barren rocks without any vegetation cover are dominating feature of the area. Study on soil physico-chemical properties done for re-establishment of vegetation in near future. Soils were shallow, coarse textured, less fertile in terms of available nutrient (N, P, K and Ca, Mg), and are acidic. Soil erosion is severe. Dominant plant species are Saccharum spontanum, Neyraudia reynaudiana, Setaria glauca, Axonopus compressus, and Imperata cylindrica. Some dicotyledonous species such as Trifolium repens, Robustum spp, Schima wallichii, Eugenia sp., Musanda sp. Toona ciliata, Pandanus odoratissimus, Erythrina arborescens, Myrica esculenta, Pinus kesiya, Alnus nepalensis, Exbucklandia populania etc. were observed as natural vegetation in patches. Soil conservation practices such as bench terrace, stone bunding, grassed water ways etc. can be adopted. Soil erosion could be controlled by developing grasses and pasture land. Planting nitrogen fixing herbs and shrubs at the initial stage may be done for buildup of soil nutrient and organic matter. Soil mulching along with the fertilizer treatment may prove effective for initial establishment of plantation.