Herbicide Dose Research Articles

Interaction between nitrogen, soil water condition and herbicides in Urochloa plantaginea control in irrigated rice crop

ABSTRACT The present study sought to verify the existence of interactions between the soil water conditions, nitrogen and herbicides commonly used to control alexandergrass in irrigated rice crop. The experimental design was completely randomized, arranged in a 2 x 3 x 4 factorial scheme, corresponding to two soil water conditions (5 cm water depth and 100% soil water holding capacity [WHC]), three nitrogen doses (0, 80 and 160 kg of N ha-1) and four doses of herbicides (0, 0.5, 1 and 2 times the registration dose). The herbicides evaluated were cyhalofop-butyl, imazapyr + imazapic and imazethapyr. The treatments were repeated four times. Phytotoxicity and dry mass were evaluated 28 days after application. For cyhalofop-butyl and imazapyr + imazapic, the phytotoxicity at 100% WHC and 5 cm water depth conditions was higher in treatments with nitrogen fertilization. However, for imazethapyr under the 100% WHC condition of soil increased phytotoxicity in the absence of nitrogen fertilization. For the flooded condition, from the dose of 35 g of a.i. ha-1, the result in the control for the herbicide imazethapyr was optimized under the conditions of fertilization with 80 and 160 kg of N ha-1. Cyhalofop-butyl and imazapyr + imazapic undergo synergistic interaction with nitrogen fertilization and water status in the control efficiency, yet with imazethapyr, the synergistic interaction only occurs under 100% of soil WHC.

Tolerance of cowpea cultivars to pre-emergence application of sulfentrazone

Improved methods of weed control are required to support expansion of large-scale cowpea cultivation in mid-west Brazil. With the aim of testing our hypothesis that the tolerance of cowpea cultivars to sulfentrazone is dose- and genotype-dependent, we assessed the effects of increasing doses (0, 250, 500 and 1,000 g ha-1 of sulfentrazone) on the cultivars BRS Imponente, BRS Novaera, BRS Tumucumaque and BRS Itaim. The phytotoxic effects of sulfentrazone varied according to the dose of herbicide applied, although the symptoms were mild and only observable at the initial stages of development and at the highest dose tested. No statistically significant interactions were detected between cultivars and doses, and there were no significant differences between doses regarding population density, plant height, yield components and grain yield. Our results demonstrate that sulfentrazone is highly selective and can be applied to the studied cultivars without affecting growth or yield.

Effect of different single herbicide doses on sugar beet yield, quality and associated weeds

BackgroundThe objective of this work is to identify the most proper herbicidal treatment on sugar beet to compare different single weed control herbicide doses on sugar beet traits and associated weeds as well as yield and quality under sandy soil conditions. Therefore, two field experiments were conducted during the winter seasons of 2017/2018 and 2018/2019 at the Experimental Farm of the National Research Centre, El-Beheira Governorate. Tigro at 1.0 and 0.750 l fed−1, Betasana-Trio at 0.675 and at 0.9 l fed−1, Select Super at 0.5 and 0.375 l fed−1 and Betanal MaxxPro at 0.5 l fed−1 besides the unweeded and hand weeded twice were used.ResultsThe results showed that the herbicides Betasana-Trio at 0.9 l fed−1, Tigro at 1.0 l fed−1 and Betasana-Trio at 0.675 l fed−1 when sprayed twice could effectively and/or completely eliminate the broadleaved weeds associated with sugar beet plants. Moreover, the results indicated and confirmed that Tigro and Betasana-Trio herbicides are effective in controlling broadleaved weeds. Similar tendency was recorded for the narrow-leaved weeds, where Select Super or Betanal MaxxPro at 0.5 l fed−1 as well as Select Super at 0.375 l fed−1 could completely eliminate or minimize the narrow-leaved weeds associated with sugar beet plants. The greatest significant root length, root diameters and root yield plant−1 were recorded when hand weeding twice followed by Betanal MaxxPro at 0.5 l fed−1 without significant differences. Gross sugar % ranged between 12.08 and 15 .7% and extractable sugar % ranged between 8.97 and 13.8% for Betasana-Trio at 0.09 l fed−1 and Betanal MaxxPro at 0.5 l fed−1.ConclusionBetanal MaxxPro gave the highest values of root and biological yield ton fed−1. Betanal MaxxPro followed by hand weeding treatment twice resulted in the greatest sugar yield fed−1. The highest sugar yield resulted from the herbicidal treatment with Betanal MaxxPro or Tigro at 1.0 l fed−1, which gave the greatest gross and extractable sugar yield fed−1 and exceeded the hand weeding treatment by 10.4 and 7.8%.

Structural and functional responses in sun spurge (Euphorbia helioscopia L.) against post‐emergence herbicides in wheat (Triticum aestivum L.)

AbstractWe investigated changes in plant morphology, anatomy and physiology in a commonly occurring weed, Euphorbia helioscopia L. due to exposure to post‐emergence herbicides. Weed plants were sprayed with one of the following herbicides: pyrimidinyl sulphonylharnstoffe (PS), tribenuron‐methyl (TM), fluroxypyr‐methyl tribenuron‐methyl (FMTM) and bromoxynil (Br). The PS treatment significantly decreased plant height, promoted initiation of side branches and induced a prostrate habit. A specific response of root anatomy to PS and Br treatments was the high proportion of storage parenchyma. The Br‐treated plants showed thickest roots with a significantly large storage parenchyma, not only in the central portion of roots, but also in the cortical parenchyma outside the vascular tissue. A high proportion of xylem in the central portion of roots in the TM or FMTM‐treated plants provides a strong survival response in E. helioscopia. Disintegration of stem cortical parenchyma is the most prominent response of E. helioscopia when treated with a herbicide like PS or FMTM. Survival against these herbicides relates to a complete ring of vascular bundles and intact cortical parenchyma outside the vascular tissue. Increased leaf thickness was recorded in most of the cases except in the FMTM‐treated plants. The PS‐treated plants showed midrib thickness with two distinct vascular bundles. The cortical region, however, was found to be damaged by tissue collapse forming a large lysigenous aerenchyma. Euphorbia helioscopia had altered morphology, anatomy and physiology in response to herbicide application, which changed its growth in the field. To achieve control of this weed species, alternative strategies or higher doses of herbicide should be applied. Further research is required to determine the interaction of surviving weed plants with the crop.

Effect of Bentonite and Barley Straw on the Restoration of the Biological Quality of Agriculture Soil Contaminated with the Herbicide Successor T 550 SE

Environmentally safe ways are sought to prevent the accumulation and to accelerate the degradation of herbicide active substances in agricultural soil. This study aimed to determine the effectiveness of finely-ground barley straw and bentonite in mitigating the effects of agricultural soil contamination with Successor T 550 SE. This herbicide was applied in the following doses: 0, 0.73, and 14.63 mg of the active substance per kg. The bentonite and spring barley straw were used at 10 g/kg. The action of these additives was compared to soil without the addition of straw and bentonite. The application of the experimental herbicide disturbed microbial systems, such as organotrophic bacteria, oligotrophic bacteria and their spores, actinobacteria, and fungi. A positive response to the herbicide dose of 14.63 mg a.s./kg was observed only for spores of oligotrophic bacteria. Further disturbances were observed in the agricultural soil biochemical properties, i.e., in the activity of dehydrogenases, urease, catalase, acid, and alkaline phosphatase, arylsulfatase, and β-glucosidase. A significant decrease in the activity of dehydrogenases, acid phosphatase, and arylsulfatase was observed following the application of 14.63 mg a.s./kg. The yield of maize decreased following the application of the analysed plant protection agent. Based on the soil quality index (BA), the addition of straw was more effective in restoring soil homeostasis than bentonite. Both bentonite and straw can be successfully used to improve agricultural soil biological activity. However, more effective mitigation of the negative effects of the herbicide in soil was observed in objects supplemented with barley straw. This improved the microbiological and biochemical properties of the soil. Barley straw was more effective than bentonite in restoring soil biological balance.

Microemulsions of tribenuron-methyl using Pluronic F127: Physico-chemical characterization and efficiency on wheat weed

Microemulsions have received particular interest as novel vehicles for drug delivery. Herein, a new tribenuron-methyl (TM) loaded oil-in-water Pluronic F127-stabilized microemulsion is developed as a promising delivery nanocarrier for herbicides to control the growth of wheat weed (Convolvulus arvensis). The diameter for the TM-loading microemulsions was determined to be 7.5 nm. Experimental results revealed a high entrapment (83% ± 6%) and loading efficiency (0.44% ± 0.07%) of TM in F127-stabilized microemulsions. The in-vitro release profile from the microemulsions ensured a controlled and sustained release of the loaded TM, with ca. 50% release of TM was achieved from the microemulsions within the first 35 h, in comparison to a complete release of free TM within the first 5 h. After 5 weeks, TM-microemulsions were able to reduce the fresh weight (76%), dry weight (55%), acetolactate synthase activity (83%), and plant height (79%) of C. arvensis in comparison with controls. Using a herbicide concentration as low as ca. 50% [15 g of active ingredient per hectare,g a.i. ha−1)], of the recommended dose of commercial herbicides (Granstar) great inhibitions of weed growth were obtained. Therefore, the present microemulsion system opens the door to new nanocarriers for effective weed control to reduce economic costs and potential pollution issues.

ВЛИЯНИЕ РАЗЛИЧНЫХ ГЕРБИЦИДОВ НА ПРОДУКТИВНОСТЬ СОИ В УСЛОВИЯХ ЛЕСОСТЕПНОЙ ЗОНЫ РСО-АЛАНИЯ

The article considers the influence of various doses of herbicides on weed vegetation, the growth and development of crops, the quality of the products obtained, the matrix diversity of seeds and yield. The combination of Pivot 0.8; Harmony 8 g/ha had the greatest toxic effect on weeds. The contamination of crops with this combination decreased by 93.6%, and the reduction in the mass of weeds by 95.3%. The efficiency of the Trophy 2.0 variant was also very high; Harmony 8 g / ha (the reduction in the number of weeds was 92.3%, and the mass was 93.7%). The efficiency of the options Pivot 0.8; Pulsar 0.8 and Trophy 2.0; Pulsar 0.8 was significantly lower. The combination of Trophy 2.0; Pulsar 0.8 had a strong inhibitory effect on the number of nodules and their raw mass. The effectiveness of herbicides largely depended on the botanical composition of weeds and the degree of their resistance to drugs, the timing and doses of their use, precipitation and precipitation distribution after chemical treatments. In conditions of elevated air and soil temperatures, the sensitivity of weeds to all herbicides increased significantly. The introduction of Trophy 2.0; Harmony 8g / ha significantly inhibited soybean seedlings, causing a slight decrease in the density of seedlings. The combination of Trophy 2.0; Pulsar 0.8 oppressed soybeans in the first half of the growing season, causing yellowing of plants. The introduction of herbicides contributed to an increase in productivity by increasing the number of beans and grains per plant by 18.4 – 38.9%. The use of the Pivot 0.8; Harmony 8 g/ha option led to an increase in the mass of 1000 seeds by 9-11 g and did not affect the germination energy and seed germination. The drugs used did not affect the onset of soybean seedlings, but their unfriendly (uneven) and longer germination was observed. Soil herbicides reduced the density of standing plants by 0.4-1.1%, insurance herbicides-by 2.7-3.3%. Weeds take out a significant amount of nutrients from the soil. In the control variant, the total removal of nitrogen by weeds was 109.2 kg/ha, phosphorus-16.4, potassium – 81.61 kg/ha. In the best variant (Pivot 0.8; Harmony 8 g/ha), nitrogen removal was 6.69 kg/ha, phosphorus-1.11, potassium – 5.13 kg/ha. The saved amount of nitrogen would be enough to form 12.2 c of soy grain, phosphorus and potassium, respectively, 6.63 and 20.67 c.

ВЛИЯНИЕ РАЗЛИЧНЫХ ГЕРБИЦИДОВ НА ПРОДУКТИВНОСТЬ СОИ В УСЛОВИЯХ ЛЕСОСТЕПНОЙ ЗОНЫ РСО-АЛАНИЯ

The article considers the influence of various doses of herbicides on weed vegetation, the growth and development of crops, the quality of the products obtained, the matrix diversity of seeds and yield. The combination of Pivot 0.8; Harmony 8 g/ha had the greatest toxic effect on weeds. The contamination of crops with this combination decreased by 93.6%, and the reduction in the mass of weeds by 95.3%. The efficiency of the Trophy 2.0 variant was also very high; Harmony 8 g / ha (the reduction in the number of weeds was 92.3%, and the mass was 93.7%). The efficiency of the options Pivot 0.8; Pulsar 0.8 and Trophy 2.0; Pulsar 0.8 was significantly lower. The combination of Trophy 2.0; Pulsar 0.8 had a strong inhibitory effect on the number of nodules and their raw mass. The effectiveness of herbicides largely depended on the botanical composition of weeds and the degree of their resistance to drugs, the timing and doses of their use, precipitation and precipitation distribution after chemical treatments. In conditions of elevated air and soil temperatures, the sensitivity of weeds to all herbicides increased significantly. The introduction of Trophy 2.0; Harmony 8g / ha significantly inhibited soybean seedlings, causing a slight decrease in the density of seedlings. The combination of Trophy 2.0; Pulsar 0.8 oppressed soybeans in the first half of the growing season, causing yellowing of plants. The introduction of herbicides contributed to an increase in productivity by increasing the number of beans and grains per plant by 18.4 – 38.9%. The use of the Pivot 0.8; Harmony 8 g/ha option led to an increase in the mass of 1000 seeds by 9-11 g and did not affect the germination energy and seed germination. The drugs used did not affect the onset of soybean seedlings, but their unfriendly (uneven) and longer germination was observed. Soil herbicides reduced the density of standing plants by 0.4-1.1%, insurance herbicides-by 2.7-3.3%. Weeds take out a significant amount of nutrients from the soil. In the control variant, the total removal of nitrogen by weeds was 109.2 kg/ha, phosphorus-16.4, potassium – 81.61 kg/ha. In the best variant (Pivot 0.8; Harmony 8 g/ha), nitrogen removal was 6.69 kg/ha, phosphorus-1.11, potassium – 5.13 kg/ha. The saved amount of nitrogen would be enough to form 12.2 c of soy grain, phosphorus and potassium, respectively, 6.63 and 20.67 c.

The Bioefficacy of Pre- and Post-Emergence Herbicides in Winter Maize Zea Mays L.

The purpose of this research was to determine whether or not pre- and post-emergence herbicides were equally successful in suppressing weeds and fostering the development of winter maize (Zea mays L.). The study's objective was to compare the herbicides' bioeficiency in controlling weeds and their effect on crop output. The objective of the study was to evaluate the effectiveness of both pre- and post-emergence herbicides in controlling weeds in winter maize fields. Parameters of crop growth and grain output were analyzed alongside weed density and weed biomass. Herbicide dosage, timing, and weed species information was collected and evaluated. Results showed that both pre- and post-emergence herbicides were effective in suppressing weed growth and encouraging the development of winter maize. These results will help farmers and agronomists make more informed decisions when choosing herbicide treatments for winter maize fields.

Efikasnost zemljišnih herbicida u suzbijanju ambrozije u zavisnosti od količine i broja dana od primene herbicida

The effectiveness of 12 pre-em herbicides in controlling ragweed was studied: atrazine, alachlor, acetochlor, alachlor+linuron, S-metolachlor, pendimethalin, metribuzin, prometryn, napropamide, imazethapyr, oxyfluorfen and dichlobenil. The research was conducted over two years, where the herbicides were applied in May on soil that had been prepared for sowing, but not sown. The efficacy was observed 30, 45 and 60 days after the application. Herbicides were used in 4 different doses: D1 which is ½ of the recommended dose, D2 is the lowest recommended dose, D3 is the highest recommended dose and D4 is the dose where the herbicides were used with the dose higher than it is recommended (D3×1,5). Efficacy is expressed as the percentage of efficacy for the number and fresh weed biomass, compared to the control. Coefficient of multiple correlation between the percentage of efficacy (PE), as a dependent variable, and the dose (D) and the number of days from the application of herbicides (DAA), as independent variables is statistically significant and in all cases it ranges between 0,853** and 0,961****. Partial correlation coefficient of efficacy percentage dependent on the herbicide dose is positive and in almost all cases highly significant, varying from 0,739** to 0,956****. Partial correlation coefficient between the herbicide efficacy percentage for common ragweed biomass and time after herbicide application is negative and statistically significant, or highly significant and varies between -0,606* and -0,904***. The partial correlation coefficient of the herbicide efficiency percentage for the common ragweed plant number and days after herbicide application, is also negative and varies, depending on the herbicide, between -0,182NZ and -0,923****.

Effectiveness of Imazapyr Coated Hybrids and Selected Striga-tolerant Varieties on <i>S. hermonthica</i> Management and Maize Yield Performance in Western Part of Kenya

<i>Striga hermonthica</i>, an obligate root hemi-parasite, is a massive biological constraint that hinders maize (<i>Zea mays</i> L.) production in western part of Kenya particularly when susceptible varieties are used. Use of Imazapyr resistant hybrids coated with small doses of imazapyr herbicide offers potential for management of <i>Striga hermonthica</i> and increase maize production. A study was conducted to evaluate the effectiveness of Imazapyr Resistant Maize (IRM) and selected striga tolerant varieties on <i>S. hermonthica</i> management and yield of maize. Field trials were conducted during two successive cropping seasons (2018 and 2019) at Alupe Research Station (artificial inoculation), farmer’s field in Rangwe (natural infestation) and Koibatek Agricultural Training College (striga free) in Busia, Homa Bay and Baringo Counties respectively. The genotypes were evaluated in randomized complete block design with three replication. Test materials comprised of two IRM (H528IR, FRC425IR), two striga tolerant (KSTP94, GAF4), five susceptible commercial hybrids (DK8031, H513, DUMA43, DH04, Haraka 101) and two local landraces (<i>Shipindi, Nya Uyoma</i>). All striga and crop data collected were subjected to analysis of variance and means separated using Tukey’s HSD test. Results showed that IRM varieties significantly (P≤0.05) reduced number of emerged striga plants by 56 and 69% compared to the local landraces and commercial hybrids, respectively. Similarly, IRM varieties produced 50.3 and 79.5% higher grain yields compared to striga tolerant (KSTP94 and GAF 4) and susceptible hybrids, respectively under striga infestation. However, the grain yields recorded at Koibatek ATC (striga free) were 67 and 70% higher than at the Rangwe and Alupe sites, respectively. These findings show that use of Imazapyr resistant technology in maize production contributes to improved striga management and enhances maize grain yields. This technology can be integrated with other measures to contain striga in infested areas.

Reakcija paradajza, paprike, suncokreta i soje na niske količine nikosulfurona

Drift is the movement of plant protection product droplets through the air and can affect any non-target organism or the environment. In fact, there are three possible scenarios that can be considered as an off-target movement: particle drift, volatility, and contamination of the spray tank. Significant damages that can occur as a consequence of drift are damages to neighbouring crops, environmental pollution, lower level of efficiency of the applied herbicide. Meanwhile, in the case of tank contamination, injuries can occur only in the treated field. In order to examine the negative consequences of nicosulfuron drift, four crops were grown in a greenhouse and treated with low doses of herbicide, after which they were returned to cultivation. After 21 days, the effects of applied treatments were assessed through visual assessment of injury, dry weight, leaf height, and leaf area. Based on the obtained results, it can be concluded that low doses of nicosulfuron expressed different effects on the tested plants and that it is necessary to take precautionary measures to prevent herbicides from spreading to neighbouring plants.

Impact of tank mixing plant hormones with bentazon and mesotrione on sweetpotato injury and weed control

AbstractDue to excessive crop damage, currently, there are no selective postemergent (POST) herbicides registered for sweetpotato [Ipomoea batatas (L.) Lam] to control broadleaves and nutsedge species. Expansion of bentazon and mesotrione herbicide labels to include sweetpotato would be beneficial for growers. Two experiments were conducted. The first evaluated the dose response of sweetpotato cultivars Beauregard and Covington to bentazon (514, 1,028, and 1,542, g a.i. ha–1) and mesotrione (105, 210, and 315 g a.i. ha–1) when melatonin, 24‐epibrassinolide, or ascorbic acid (AsA) were included in the tank mix. The second experiment evaluated the efficiency of bentazon and mesotrione for control of yellow nutsedge (Cyperus esculentus L.) and Palmer amaranth (Amaranthus palmeri S. Wats.), when different doses of melatonin, 24‐epibrassinolide, or AsA were added to each herbicide. In the first experiment, when treated with herbicide alone, Beauregard exhibited injury levels lower than Covington for both herbicides. No injury was observed when plants were treated with plant hormones or AsA alone. At the lowest dose of bentazon and mesotrione, the addition of AsA or plant hormones in the tank mix significantly reduced percentage injury and increased plant tolerance, requiring higher doses of herbicide to cause 10, 20, and 30% injury. In the second experiment, the addition of plant hormones and AsA in the tank mix had no antagonistic effect on herbicide effectiveness, exhibiting similar levels of injuries as herbicides application alone. These results suggest that the use of plant hormones and AsA could improve sweetpotato tolerance to POST applications of bentazon and mesotrione without reducing herbicide effectiveness.

Influence of fertilizer application timing and reduced herbicide dosage on weed infestation and maize grain yield

A field trial was conducted in the southern Guinea savanna of Nigeria during 2018 and 2019 to determine the better time of fertilizer application and identify effective weed management options to manage weed infestation and increase maize grain yield. The treatments consisted of two fertilizer application timings and six weed control treatments. The experiment was a 2 x 6 factorial in a randomized complete block design and replicated three times. The fertilizer application at 0 and 6 weeks after seeding (WAS) was found better than application at 2 and 6 WAS in minimising weeds, however both the application timings had no significant influence on maize grain yield. The formulated ready-mixtures (RM) of metolachlor (373 g) + atrazine (375 g) at 1.5 kg/ha followed by (fb) one hoeing at 6 WAS, metolachlor (375 g) + atrazine (373 g) at 1.5 kg/ha fb nicosulfuron 0.03 kg/ha at 6 WAS, metolachlor + atrazine (RM) 1.5 kg/ha fb paraquat 0.7 kg/ha at 6 WAS and metolachlor + atrazine (RM) at 1.5 kg/ha fb 2,4-D (900 g) at 1.5 kg/ha significantly (p=0.05) reduced weed infestation by 89.3, 63.8, 48.2 and 39.8%, respectively. The use of metolachlor + atrazine (RM) 1.5 kg/ha fb one hoeing at 6 WAS, metolachlor + atrazine (RM) 1.5 kg fb nicosulfuron 0.03 kg/ha increased maize grain yield by 82.5 and 69.7%, respectively. These treatment combinations integrated with fertilizer timing application at 0 and 6 WAS may be used for efficient, economical and more eco-friendly management of weeds for increasing maize grain yield.

IN VITRO СКРИНИНГ ЗА ХЕРБИЦИДНА СЕЛЕКТИВНОСТ НА НОВИ МУТАНТНИ ГЕНОТИПОВЕ ПИПЕР С РАЗЛИЧЕН ПРОИЗХОД И ОЦВЕТЯВАНЕ НА ПЛОДА

The study presents an in vitro test development as a model for herbicide phytotoxicity. It provides reliable data on how the herbicide affects the seed germination and early growth stages, in dynamic, during the cultivation. The sensitivity of five mutant pepper genotypes with different origin and fruit colour to the herbicide napromamide (Devrinol 4F) was investigated. All studied herbicide doses, corresponding to 3, 4, and 5 L/ha, caused phytotoxicity expressed by decreased germination and growth inhibition. A strong genotype dependence was established – two breeding lines (18 and 85), originating from local populations, demonstrated a low sensitivity to the herbicide, additionally confirmed by higher plant survival and adaptability after transplanting to soil ex vitro.

Correlation and path analysis of interaction between green pea yield and its components with crop management

Determinations of interaction between yield its components and foliar mixed application of Lactofol® with insecticides and herbicides. The path-coefficient analysis is very important statistical technique that can be used to quantify the interrelationship of different yield components. It was applied to study the interaction of applied agronomic activities on productivity of mid-early Bulgarian garden peas Pisum sativum cv. Promethei seeking to minimize pesticide use and to maintain sustainable quality and quantity of yield, and to prevent underground water pollution caused by using Dual 930EK/930g/l-s (metachloras) minimized herbicide doses from vegetative herbicide Basagran-200g/l (Bentazon) and Fusillade-200g/l (Fluasifop-P-Butil). Data was collected from long years trials on plants treated with different combinations of foliar suspension fertilizer Lactofol® with insecticides and herbicides. Results showed that grain yield (0.997), dry matter of the grain (0.996), Chlorophyll "a" (0.993), Zn (0.992), N (0.991), grain/whole pod ratio (0.984), total nitrogen (0.982), K (0.975), weight of 50 grains (0.973) fresh weight of 50 beans (0.962), fertile pollen (0.961), plant density/ m2 (0,873), the length of beans (0.871), sterile pollen (0.837) had positive impact on yield. Dry matter, grain yield, dry matter of grains, chla, N, weight of 50 pods, fertile pollen, and plant density/ m2 showed positive direct and indirect effects on yield. Other factors such as sugars (0.797), chlorophyll “b” (0.739), and starch (0.620) had an indirect effect on total yield. Grain yield should be given prior attention in field pea improvement programmers due to its major influence on yield. This research gave valuable information about which steps of agro techniques needs more attention to enhance best quality and quantity of sustainable yield.

Результати експериментального оцінювання умов роботи машини для контактного знищення бур’янів

Abstract. The article presents the results of research carried out during the creation of a machine for contact weed control and clarification of the parameters of its operation. The purpose of the research, the results of which are set out in the article, is to prove experimentally the hypothesis put forward in the course of creating a machine for contact weed control about the effect of acceleration of the cut of the stem on which the working solution is on the value of unproductive losses of the working solution. Methods. To achieve the goal of the work, experimental studies have been carried out. The experimental results were processed according to the method of a mathematical full-factor experiment on the MathCAD v.14 software product. Results. In the course of experimental studies, it was found that the operation of the machine at a height of less than 0.2 m is inappropriate, because the accelerations during the oscillatory process of the stem reach significant values and lead to the dropping of the working solution from the stem of the plant. Based on the results of experimental studies, a regression equation was obtained, which reveals the dependence of the efficiency of weed control on the installation height of the machine, the diameter of the weed stems, and the cut angle. Conclusions. In the process of experimental studies, it was found that the acceleration of the edge (cut) of the stem, on which the applied working solution is located, significantly affects the amount of unproductive losses of the working solution. A sharp increase in the acceleration of the tops of the stems when they move from the deflected position to the initial position leads to the discharge of the applied drop of herbicide from the cut of the stem. This is unacceptable for two reasons. First, the herbicide enters the soil and, as a result, leads to its pollution. Secondly, the effectiveness of weed control is significantly reduced due to losses and leads to the need to increase the doses of herbicides. This leads to increased financial costs for weeding. It has been experimentally established that it is advisable to cut plants at a height of at least 0.2 m. The introduction of the established requirement for the height of the machine location allows avoiding the indicated undesirable consequences.

FOLIAR AND STEM CHEMICAL CONTROL OF THE INVASIVE SPECIES AILANTHUS ALTISSIMA FROM PASTURES

The present paper presents the results of the chemical foliar control research of the species Ailanthus altissima. In the shrubs sprayed on the foliar apparatus, the effect was 100%, only where the solution reached the leaves, and in the tops of the trees where the solution did not spread, the leaves were not affected, having a normal vegetation. It should be noted that this method applied by spraying the foliar apparatus did not affect other shrubs in the vicinity, only the treated herbicide had an effect on those treated. In conclusion, the herbicide had its effect only where it came in contact with the leaves, the rest of the leaves not being affected. In those injected with a herbicide dose of 4 ml / cm in the diameter of the tree (15 cm in diameter corresponds to a dose of 60 ml pure herbicide) at a distance of 30 cm above the ground, the herbicide made its effect 100%, these shrubs drying completely. They were also affected, in addition to those injected a no. of 10 and 12 trees, respectively, on a perimeter of 10 m2 , but not entirely, the foliar apparatus being affected 70-80% of the foliage and at the same time new shoots of approx. 30-40 cm long, and the tendency of herbicidal trees to regenerate after approx. 35 days.

CONTROLE QUÍMICO DE CAPIM-RABO-DE-BURRO EM DIFERENTES ESTÁDIOS DE DESENVOLVIMENTO

O capim-rabo-de-burro é uma Poaceae, considerada planta daninha recente nas lavouras desoja por seus crescentes níveis de infestação e dificuldades de controle. Diante disso,objetivou-se com este trabalho avaliar a eficiência de diferentes doses de herbicidasaplicados isolados ou em associação, no controle de capim-rabo-de-burro em diferentesestádios de aplicação. Foram realizados três experimentos, um em casa de vegetação complantas em estádio inicial de desenvolvimento e dois a campo com touceiras. Os herbicidastestados foram glyphosate; fluazifop; sethoxydim; fenoxaprop; clethodim; quizalofop;haloxyfop; pinoxaden, nicosulfuron; glufosinate e as misturas de glyphosate com clethodim,quizalofop, haloxyfop ou sethoxydim. Os tratamentos com glyphosate, isolado ou emmistura, apresentaram maiores níveis de controle em todos experimentos. Além deglyphosate, glufosinate, clethodim, haloxyfop e sethoxydim foram eficientes no controle decapim-rabo-de-burro nos estádios iniciais de desenvolvimento. Para manejo de touceiras, osherbicidas glyphosate e haloxyfop isolados demonstraram eficiência superior a 90%independente da dose e clethodim e sethoxydim na dose mais alta. Os herbicidas pinoxadene nicosulfuron não são alternativas para controle de capim-rabo-de-burro.

Effect of nicosulfuron on chlorophyll content of marandu-grass cultivated in crop-forest-livestock integration systems

The aim of this work was to study the effect of sub-doses of herbicide nicosulfuron on the levels of chlorophyll and growth of marandu-grass in an forest-livestock integration system. The treatments consisted of eucalyptus consortium with sorghum (BRS 655 hybrid) and forage Urochloa brizantha cv. Marandu (marandu-grass) at 12×2 and 12×3 m spacings in agroforestry systems, in addition to sorghum + marandu-grass and marandu-grass in monoculture. The doses of nicosulfuron applied at the marandu-grass were 0, 15 and 30 g ha-1. At 30 and 120 days after the application of nicosulfuron, chlorophyll a and chlorophyll b were measured usinf a portable chlorophyll meter, with six measurements per plant. Afterwards, the total chlorophyll content and chlorophyll a/b were calculated. We also measured the mass of the total dry matter of marandu-grass and growth rate of the culture. Marandu-grass plants cultivated in monoculture showed higher quantities of chlorophyll and the highest growth rates. The levels of chlorophyll a, b and chlorophyll a/b and the growth rate of marandu grass were similar between systems integrated with eucalyptus (12x2 and 12x3 m). The increase of herbicide dose negatively influenced on chlorophyll content in marandu-grass in all treatments evaluated. The use of nicosulfuron in doses of 25 and 50 g L-1 reduced the growth rate of marandu grass only when grown in monoculture