Efect of sowing dates and seed rates of flax intercropped with sugar beet on productivity of both crops and competitive relationships

The aim of intercropping flax on sugar beet is to increase the cultivated area with flax due to widely cultivated area of sugar beet. So, a field experiment was carried out to study the effect of various sowing dates and seed rates of flax intercropped with sugar beet on yield, quality and economic evaluation. The main-plots were assigned to three sowing dates of flax intercropped with sugar beet and the sub-plots were allocated to four seed rates of flax. The results show that sowing date of flax after 35 days from sowing (DFS) sugar beet resulted in the highest values of sugar beet yields and quality. Maximum values of flax straw and seed yields resulted from sowing flax after 21 DFS sugar beet. Intercropping sugar beet with flax at 12.5% from recommended seed rate on top sugar beet terraces attained the most elevated values of sugar beet yield and quality. Sowing flax at 50% from recommended rate resulted in the best values of flax technical and fruiting zone length, also straw and seed yield/hectare. The maximum yield and economic return of both crops were obtained from sowing flax at 12.5% from recommended rate after (21 or 35) DFS sugar beet.

DEVELOPMENT OF RESOURCE-SAVING TECHNOLOGIES FOR OBTAINING COMPOSITE MATERIALS BASED ON THE USE OF OILSEED FLAX FIBERS

The article examines the ways to solve the problem of developing a scientific basis for obtaining composite materials of different functional purposes from oilseed flax fibers. The paper covers theoretical and experimental research in the area of processing flax raw materials. The purpose of the study is to provide scientific substantiation of developing the technologies for obtaining fillers to reinforce composite materials. In order to do it, we performed modification of oilseed flax fiber and developed technologies for processing oilseed flax straw with regulated technological and performance characteristics. The article also presents the results of the research on determining causes of low wettability of oilseed flax bast. In order to find out the causes of low bast wettability, we conducted research on examining chemical composition and anatomy of straw stems. The formulation for preparing the fiber aimed to be used as a filler for reinforcement of composite materials is offered. The study suggests evaluation of the quality of composite materials produced on the basis of using modified oilseed flax fibers.

THERMAL INSULATION MATERIALS BASED ON FLAX STRAW

The development of plant-based materials will help to solve the problems associated with the use of agricultural waste, and at the same time to get inexpensive and effective insulation materials based on environmentally friendly local raw materials. The advantages of such materials are availability, fast recovery, low cost, environmental friendliness and low thermal conductivity. In the work with the use of flax straw at a consumption of Portland cement of 150 kg per 1 m3 of concrete, thermal insulation lightweight concrete with an average density of 350 kg/m3 and a strength of 0.53 MPa was obtained. The article presents the results of research of temperature changes on the surface of external enclosing structures using the developed thermal insulation concrete based on flax straw in combination with a solar energy absorber. It is established that such a structure of an external wall provides thermal inertia of a protection within 7-7.5 hours.

Oil Flax Straw Processing and Utilization

The flax (Linum usitatissimum) is widely used as a source of linen oil and fiber. As a rule, the flax varieties serve to produce either seeds (oil), or stem fibers, as the "fiber'' varieties bring the low amount of seeds, while the "oil'' varieties have poor fibers that cannot be used in textile. The straw of the oil flax has not been applied in industry and has to be burned or degrade naturally in the field. However, it contains a low degree of polymerization cellulose, which can be used at least for varnish production. The main challenge in the industrial application of the oil flax cellulose is the necessity of separating the cellulose fibers and shive enriched in lignin. On the other hand, the low cost of the final products restricts the set of available tools. Here we describe a machine designed for oil flax straw stripping and several ways of further conversion of the obtained tow into microcrystalline or fluff-like cellulose. The supposed processes run at the temperatures below the water boiling point and at the atmospheric pressure and could be held in the plastic reactors.

Efficiency of using the biological potential of fiber flax varieties of the Tomsk school of breeding in flax straw processing

The information on the structure of the areas cultivated with fiber flax in Russia in 2016-2020 is presented. The varieties of the Tomsk school of breeding occupy almost 30% of the total area under crops. The study was carried out in the flax-growing regions of Russia in 2001-2020. The technological value of flax raw material of the studied varieties of fiber flax for processing flax of various quality at flax processing enterprises was determined. The indicators for the total fiber yield, long and short fiber yield, long fiber number and short fiber number, and the combination of these features were studied. The efficiency of using the potential capabilities of the studied varieties in relation to the data of the State Variety Testing was established. According to the results of flax straw processing and the rating assessment of these varieties in relation to the best and worst ones, it was found that the following varieties can be referred to as the ones with low-quality flax straw: Tomsk 18 - by the yield of short fiber (24.9%), Tomsk 16 - by the number of long fiber (11.08 N), Tost - by the number of short fiber (3.42 N) and the complex of features (average rating index of 9.8 positions). The group of the best varieties for the total fiber yield includes Tomsk 18 (33.2%) and Tost (32.2%), for the long fiber yield - Tost (13.1%), for the short fiber yield (23.2%) and the number of short fiber (5.20 N) - Tomsk 18 (high-quality flax). None of the varieties presented fulfil the biological potential in the processing of flax straw under production conditions in terms of the total fiber yield and the yield of long fiber, established by the State Variety Testing. Its value for the varieties of the Tomsk school of breeding is 65.2-86.3% for the total fiber yield, 17.6-31.4% for the long fiber yield (low-quality flax straw), 77.7-94.2 and 30.5-52.2%, respectively (high-quality flax straw).

Continuous Mechanical Extraction of Fibres from Linseed Flax Straw for Subsequent Geotextile Applications

Linseed flax is a multipurpose crop. It is cultivated for its seeds and particularly for its oil. The main contributors for this crop are Canada, France and Belgium. In general, straws of linseed flax are buried in the fields or burnt. However, these solutions are not good practices for the environment and from an economical point of view. In this study, straws of linseed flax (six batches in total) with different dew retting durations and harvesting techniques were studied to possibly use them for producing innovative geotextiles. Two different fibre extraction processes were investigated. A first process (A) involved horizontal breaker rollers and then a breaking card. A second one (B) consisted in using vertical breaker rollers, and an “all fibre” extraction device (fibre opener) followed by sieving. The chemical composition of fibres in parietal constituents appeared to be globally equivalent to the one of textile flax with a pectic content decreasing as a function of the dew retting duration. This contributed to an increase in the cellulose content. The fibre content was situated in a range from 29% to 33%, which corresponds to a good yield for linseed flax fibre. The level of purity can reach values of up to 90% for method A (without extra-sieving) and 96% for method B (with extra-sieving), and the length of the fibres (larger for method A than for method B) and their tensile properties make them suitable for structural geotextile yarn manufacturing.

Ensuring cleanliness and health of flax crops when treated with new pesticides

Plant protection measures in flax cultivation should provide sufficiently clean from weeds, healthy sowings, forming the crop of necessary quality level, corresponding to economic and ecological criteria of modern agrotechnologies. The work aims to find promising herbicidal and protectivestimulating agents for providing cleanness from weeds and the health of flax crops when treating them with new pesticides, contributing to increasing the yield and quality of flax products. According to the classical methodology of scientific agronomy, the main experiments were carried out in the fields of FSBSI Federal Scientific Centre for Bast Crop, Flax Research Institute in the Tver region. As a result of experiments in 2018-2020, the herbicide Shanti and its mixture with Shanstrel 300 showed relatively high biological efficacy in protecting flax against dicotyledonous weeds. Furthermore, the addition of graminicides Haloshans or Cletoshans, growth regulator Artafit or fungicide Zimoshans to anti-wort herbicides did not reduce the effectiveness of the drug mixtures on dicotyledonous weeds and eliminated cereal weeds in crops. Additionally, Artafit and Zimoshans effectively protected flax from pasmo and other diseases, naturally increasing the yield of flax products. Its maximum values in the experiment were obtained in the variant of Artafit application together with herbicides. The use of Artafit had a positive effect on the quality of flax straw, increased it by 1-2 grades (from 2.00 to 2.50).

Biocomposites of Low-Density Polyethylene Plus Wood Flour or Flax Straw: Biodegradation Kinetics across Three Environments

The purpose of this study was to assess the potential for biocomposite films to biodegrade in diverse climatic environments. Biocomposite films based on polyethylene and 30 wt.% of two lignocellulosic fillers (wood flour or flax straw) of different size fractions were prepared and studied. The developed composite films were characterized by satisfactory mechanical properties that allows the use of these materials for various applications. The biodegradability was evaluated in soil across three environments: laboratory conditions, an open field in Russia, and an open field in Costa Rica. All the samples lost weight and tensile strength during biodegradation tests, which was associated with the physicochemical degradation of both the natural filler and the polymer matrix. The spectral density of the band at 1463 cm−1 related to CH2-groups in polyethylene chains decreased in the process of soil burial, which is evidence of polymer chain breakage with formation of CH3 end groups. The degradation rate of most biocomposites after 20 months of the soil assays was greatest in Costa Rica (20.8–30.9%), followed by laboratory conditions (16.0–23.3%), and lowest in Russia (13.2–22.0%). The biocomposites with flax straw were more prone to biodegradation than those with wood flour, which can be explained by the chemical composition of fillers and the shape of filler particles. As the size fraction of filler particles increased, the biodegradation rate increased. Large particles had higher bioavailability than small spherical ones, encapsulated by a polymer. The prepared biocomposites have potential as an ecofriendly replacement for traditional polyolefins, especially in warmer climates.

Mathematical analysis of the influence of various factors on the processing of oil flax straw in the kvl-1m unit

The improvement of the primary processing of oil flax in the form of a tangled mass of broken stems in field conditions and the assessment of the operation of the KVL-1M unit when processing flax in the field are substantiated. The influence of process factors on the change in fiber quality indicators, rational parameters and operating modes of the unit to increase the efficiency of processing the stem tangled mass of oil flax have been determined.

THE EFFECT OF THE BIOCARBON TYPE ON THE TRIBOLOGICAL CHARACTERISTICS OF GREASES MANUFACTURED WITH VEGETABLE AND SYNTHETIC BASE OILS

The article presents the tribological characteristics of plastic greases in which the dispersing phase was vegetable (rapeseed) oil or synthetic ester oil (Priolube). The lithium stearate was used as a thickener in an amount sufficient to obtain a composition in the second consistency class, and the functional additives were biocarbon produced in the process of pyrolysis of the following plant waste: flax straw, wheat straw, corn leaves and stalks, and cherry stones. The compositions containing 5% m/m of biocarbon were prepared and the influence of the type of biocarbon on the tribological properties of the obtained plastic greases was assessed. The tribological characteristics of the grease compositions were determined using the T-02 tester in accordance with the requirements of the relevant standards. The influence of the applied biocarbon on the anti-wear (Goz) and anti-seize (Pt, poz) properties of plastic greases made with vegetable and synthetic basis was determined. It was found that some of the biocarbon, especially those derived from the pyrolysis of corn waste, significantly improve the tribological properties of plastic greases, both those based on plant and synthetic sources.