Effective Weed Control Research Articles

Efficacy of New Herbicide Mixtures on Weed Control, Yield, and Economics in Transplanted Rice

Aim: To evaluate the efficacy of new herbicide mixtures on the weed control and performance of transplanted rice.
 Study Design: Randomized Complete Block Design.
 Place and Duration of Study: AlI India Coordinated Research Project on Weed Management, PJTSAU, Hyderabad between August to December, 2021.
 Methodology: The efficacy of herbicide mixtures either ready mix or as tank mixtures were evaluated for effective and broad spectrum weed control in transplanted rice during kharif season, 2021 at AICRP on Weed Management, PJTSAU, Rajendranagar, Hyderabad. The experiment was laid out in a randomized complete block design with nine treatments and three replications. The treatments included five ready mixes (RM) one tank mix combination of new herbicides tested against one single herbicide, weedy check and hand weeding twice at 20 and 40 DAT.
 Results: The results of the study revealed that bispyribac sodium 10% SC 25 g ha-1+ penoxsulam 1.02% (20 g ha-1) (tank mix) as post-emergence (POE) fb hand weeding (HW) at 40 DAT or penoxsulam 0.97% (20 g ha-1) + butachlor (38.8%) @ 820 g ha-1 (RM) as POE fb HW at 40 DAT or penoxsulam 1.02% (20g ha-1) + cyhalofop butyl 5.1% (100 g ha-1 ) (RM) as POE fb HW at 40 DAT or bensulfuron methyl 0.6% (60 g ha-1) + pretilachlor 6% (600g ha-1) GR (RM) as pre-emergence (PE) fb HW at 40 DAT were equally effective to hand weeding twice at 20 and 40 DAT with respect to suppression of weeds at 60 DAT. The yield attributes like a number of tillers/m2, panicles no, panicle length, grains panicle-1 and test weight were found to be higher with penoxsulam 1.02% (20 g ha-1) + cyhalofop butyl 5.1% (100 g ha-1) as POE fb HW at 40 DAT which also recorded higher grain yield, straw yield, gross returns, net returns and B-C ratio but it was found to be at par with other herbicide combinations.
 Conclusion: It can be concluded that new herbicide mixtures either as ready mix or tank mix performed better than sole application or hand weeding alone.

Effect of Tillage and Herbicides on Weeds and Yield of Maize (Zea mays L.)

Based on this study, it can be concluded that for achieving effective weed control, and higher maize yield and profitability, combinations of conservation tillage (zero tillage + 6 t ha-1 residue) with tank mixture of either atrazine + tembotrione + halosulfuron at 800+90+67.5 g ha-1 or atrazine + tembotrione + bentazone at 900 + 90 + 960 g ha-1 as post-emergence can be adopted.

Effect of Chemical Weed Control on Soil Bio-Chemical Indices- A Review

Effect of Chemical Weed Control on Soil Bio-Chemical Indices- A Review

Weed control and slow-release behavior of 2-methyl-4-chlorophenoxyacetate intercalated layered double hydroxide

The efficient utilization of pesticides is an essential factor affecting crop yield. Thus, the controllable slow-release of pesticides using nanomaterials has attracted considerable attention. In this work, pesticides 2-methyl-4-chlorophenoxyacetate (MCPA) intercalated layered double hydroxides (MCPA/LDH) were successfully prepared using the coprecipitation method and characterized via FTIR, XRD, and SEM. The release behavior of MCPA/LDH was studied and analyzed under different anion, pH, and organic matter conditions. For practical applications, four types of soil from different regions were selected, and the release effect of MCPA/LDH was tested 60 days. The release behavior was fitted to the Higuchi kinetic model, in which the release mechanism was determined to be the ion exchange effect. In a pot experiment, the weed control effect of MCPA/LDH exhibited improved and long-term results than that of the control groups. Hence, this study provides an effective strategy for the efficient utilization of MCPA demonstrating its potential applications in agricultural production.

Uji Efektivitas Herbisida Pasca Tumbuh Pada Tanaman Kedelai (Glycine max. L)

The purpose of this study was to determine the effect of weed control with herbicides on soybean growth and yield. This research was conducted in the Mojosari Agricultural Experimental Garden, Mojokerto, March - July 2021. The method used was a Randomized Block Design (RAK) with 3 treatments and 4 replications. The treatments were (P0) mechanical weeding (Control); (P1) Spraying herbicide 1X; (P2) spraying. 2X herbicide. selective herbicide spraying (Agil 100 ec) with the active ingredient propaquzafop 100 ec C-12 was carried out according to the treatment. Herbicide application had a better effect on soybean yields than control (mechanical weeding). However, spraying herbicides once had the same good effect as (P2) spraying 2X. The soybean plants tested were able to produce dry pods weight of 36.85 -39.00 g/plant, and dry weight 100 seeds 18,48-20,90 g.

Target-site and metabolic mechanisms of tolerance to penoxsulam in pond lovegrass (Eragrostis japonica)

AbstractThe identification of herbicide tolerance is essential for effective chemical weed control. According to whole-plant dose–response assays, none of 29 pond lovegrass [Eragrostis japonica (Thunb.) Trin.] populations were sensitive to penoxsulam. The effective dose values of penoxsulam causing 50% inhibition of fresh weight (GR50: 105.14 to 148.78 g ai ha−1) in E. japonica populations were much higher than the label rate of penoxsulam (15 to 30 g ai ha−1) in the field. This confirmed that E. japonica was tolerant to penoxsulam. Eragrostis japonica populations showed 52.83- to 74.76-fold higher tolerance to penoxsulam than susceptible barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.]. The mechanisms of tolerance to penoxsulam in E. japonica were also identified. In vitro activity assays revealed that the penoxsulam concentration required to inhibit 50% of the acetolactate synthase (ALS) activity (IC50) was 12.27-fold higher in E. japonica than in E. crus-galli. However, differences in the ALS gene, previously found to endow target-site resistance in weeds, were not detected in the sequences obtained. Additionally, the expression level of genes encoding ALS in E. japonica was approximately 2-fold higher than in E. crus-galli after penoxsulam treatment. Furthermore, penoxsulam tolerance can be significantly reversed by three cytochrome P450 monooxygenase (CytP450) inhibitors (1-aminobenzotriazole, piperonyl butoxide, and malathion), and the activity of NADPH-dependent cytochrome P450 reductase toward penoxsulam in E. japonica increased significantly (approximately 7-fold higher) compared with that of treated E. crus-galli. Taken together, these results indicate that lower ALS sensitivity, relatively higher ALS expression levels, and stronger metabolism of CytP450s combined to bring about penoxsulam tolerance in E. japonica.

Weed control and sustainable rice production through rice intensification system and conventional practices of weed competition periods and age of transplanted seedlings

Rice is an important cereal crop of global interest based on its daily uses. It was observed that the average yield of rice is low than its potential production due to the traditional growing techniques and weed intensification. Recently, the rice intensification system (RIS) has emerged as an alternative to the conventional rice cultivation system. A two-year field study was carried out to investigate the impact of seedling age (14, 21 & 28 days) and the weed competition periods (weedy check, 20, 40, 60, 80 DAT and weed-free throughout the growing season) in rice cultivated through RIS. Weedy check and weed-free for the growing season were kept as a control treatment. The results of our study revealed that a maximum dry weight (108.7 and 111.79 gm-2) and weeds density (101.7 and 110.6 plants m-2) of weed recorded in weedy check plot where 28 days old seedlings was transplanted while minimum dry weight (11.01 and 10.3 gm-2) and weeds density (9.7 and 10.9 m-2) were achieved in plots where 21 days old seedlings were transplanted and remain weed free. It was noted that weed density and weed dry biomass were gradually increased with increasing weed competition period at all ages of the rice seedling. Purple nutsedge (C. rotundus) exhibited maximum relative proportion in total weed’s density and dry biomass and also ranked first by weed summed dominance ratio (WSDR). Agronomic yield and yield contributing traits such as number of fertile tillers per hills (58.1 and 56.0), plant height (130.5 cm and 125.6 cm), kernels per plant (186.4 and 179.4), straw yield (7.8 t ha-1 and 7.5 t ha-1) and kernel yield (5.2 and 5.0 t ha-1) were maximum in plot that remained weed-free throughout the growing season with a seedlings age of 21 days during 2010 and 2011 respectively. Percent yield losses were minimum in plots with 21 days old seedling transplantation and at 20 days of weed competition period. Hence, present study concludes that 21 days old fine rice seedlings should be transplanted and weeds should be controlled within 20 DAT under SRI for effective weed control to avoid yield losses.

Efficacy of new generation herbicidal combination for weed management in direct seeded rice (Oryza sativa L.)

Weeds are the main yield limiting factor that can potentially reduce crop yields and is one of the main constraints in the larger scale implementation of direct seeded rice. Therefore, the present experiment was conducted at Periyanarkunam during Navarai 2021 to study the efficacy of new generation herbicidal combination for weed management in direct seeded rice. The experiment was laid out in split plot design replicated thrice with main plot treatments comprised of three direct seeded rice establishment methods viz., dry seeded, drum seeded and manual wet seeded rice. The sub-treatments were nine weed management practices with combination of herbicides with hand weeding viz., Pre-emergence application of bensulfuron methyl 0.6%+pretilachlor 6% GR @ 10 kg/ha on 8 DAS (Days after sowing), early post- emergence application of triafamone 20%+ethoxysulfuron 10% WG @ 200 g/ha on 12 DAS, post-emergence application of metsulfuron methyl 10%+chlorimuron ethyl 10% @ 20 g/ha on 25 DAS, twice hand weeding on 25 and 45 DAS and un-weeded check. Among the main treatments, drum seeded rice recorded lower weed population and dry matter production, higher weed control efficiency, weed control index, crop resistance index and herbicide efficiency index and higher grain yield which was at par with manual wet seeded rice. Regarding the weed management practices evaluated pre-emergence application of bensulfuron methyl 0.6%+pretilachlor 6% GR @ 10 kg/ha on 8 DAS fb (followed by) post-emergence application of metsulfuron methyl 10%+chlorimuron ethyl 10% @ 20 g/ha on 25 DAS fb hand weeding on 45 DAS (S8) registered lower weed population, dry matter and higher yield compared to unweeded check. Hence, drum seeded rice coupled with pre-emergence application on 8 DAS fb post-emergence application on 25 DAS fb hand weeding on 45 DAS (M2S8) is an economically feasible method for effective control of weeds.

Evaluating glufosinate-ammonium and flame weeding for weed control in sweet marjoram (Origanum majorana L.) cultivation

The objective of this four-year study was to compare the effects of flame weeding and spraying with glufosinate-ammonium on weed control in sweet marjoram field cultivation. The experiment was set up in a complete randomized four-replicate design with a plot area of 8 m2. Moreover, the content of essential oil in marjoram herb obtained from the control plants, as well as the composition of this oil were also studied. Marjoram emergence began 13–17 days after sowing, and it was very uneven and in some years it was extendend up to 5 weeks. Flaming (90 kg propane ∙ ha–1) was applied in two times: immediately after noticing the first marjoram emergence or 5 days later, while glufosinate-ammonium (600 g ∙ ha–1) was applied on the same date as the first flaming. The tested methods of weeding significantly reduced the number and fresh weight of weeds growing 3–4 weeks after the start of marjoram emergence, i.e. in the period of its greatest sensitivity to weed competition. They had no soil residual activity and their effect on weeds disappeared after the first weeding. Among weeds occurring in the experiment, only barnyardgrass (Echinochloa crus-galli (L.) P. Beauv.) was partially tolerant to flaming. Flaming applied at the second time did not increase the effectiveness of weed control, but significantly decreased the number of emergence and the yield of marjoram herb. Essential oil content in marjoram grated herb varied considerably depending on the year, ranging from 1.35 to 2.34%. The oil contained from 33 to 36 identified compounds, among which trans-sabinene hydrate (28–34%) and terpinen-4-ol (17–21%) were clearly dominant.

Influence of gibberellic acid on vegetable crop and weed emergence

AbstractSmall-seeded vegetable crop production is challenged by poor emergence, stand establishment and canopy development, as well as a lack of effective weed control options. The potential use of plant growth regulators such as gibberellic acid (GA) could enhance early emergence and growth rates while potentially synchronizing weed germination with control tactics. In response, a controlled environment study was conducted to investigate the effects of GA on garden beet, cabbage, carrot, and onion. At 7 d after seeding (DAS) carrot emergence was greater when carrot seeds were treated with 2, 4, 8, 16, or 64 ppm GA compared with nontreated seeds. Total carrot emergence over the study period was 14% greater when seeds were treated with 4 ppm GA compared with nontreated seeds. Treatment of cabbage with as low as 2 to 4 ppm GA increased cabbage emergence rate and total plant emergence over the study period relative to nontreated seeds. Onion response to GA treatment was variable and unremarkable and was hypothesized to be influenced by seed dormancy because emergence was also low with the nontreated seeds. The GA rates that stimulated vegetable crop seed germination and emergence were then explored with three common weed species to determine whether a similar response was observed. If so, GA could be used to stimulate weed emergence in synchrony with management tactics. Palmer amaranth emergence was strongly affected by GA treatment, whereby the total number of emerged plants was 48% greater when 4 ppm GA was applied than in the nontreated check. Velvetleaf emergence at 3 DAS with the 4 and 8 ppm GA was 2.9 and 3.0 plants pot−1, respectively, compared to no emergence in the nontreated pots. Redroot pigweed emergence was not affected by GA treatment at any rate.

Synoptic catalogue of insect parasitoids associated with Lixinae (Coleoptera: Curculionoidea: Curculionidae)

The first host-parasitoid catalogue for Lixinae is presented. This survey is based on literature search (~300 references) and followed by two parts, firstly one of the Lixinae, and secondly one of parasitoids with distinguishing numbers of their Lixine hosts. There are at least 221 species recorded as parasitoids on 108 lixine species. Records on 12 host-parasitoid associations seem to be questable or based on misidentifications. Most common hosts are species of two genera: Lixus (112 parasitoid species) and Larinus (43). All actually known parasitoids of Lixinae are dipterans (belonging to three families) and hymenopterans (15 families). The latter listed as parasitoids of no less than 102 lixine species (94.4%) and 22 hosts (19.4%) associated with Diptera. Six lixine species associated with dipterans only. Most common parasitoids are braconids. Four parasitoid species have the most extensive list of the hosts: Exeristes roborator (at least 29 host species), Cerceris tuberculata (12), Bracon urinator (11) and Zeuxia cinerea (10). Parasitoid complex of some hosts can include more than 10 (to 44!) species. Information contained in catalogue will be helpful for programs of effective biological control of economic important pests and weeds.

Integrated Use of Herbicides and Mulching for Sustainable Control of Purple Nutsedge (Cyperus rotundus) in a Tomato Crop

Purple nutsedge (Cyperus rotundus L.) is a problematic weed in tomato (Lycopersicon esculentum L.) crops causing significant yield losses. Although several chemical options are available for this weed, the level of control is often unsatisfactory, and the consistent use of herbicides has a risk of resistance evolution. Therefore, we evaluated the efficacy of two herbicide options, halosulfuron and fomesafen + S-metolachlor, alone or integrated with natural and plastic mulches in controlling purple nutsedge in tomato crops in a three-year field study. The use of herbicides or mulches alone did not provide effective weed control (below 65%). However, the combination of natural mulch and fomesafen + S-metolachlor provided the most effective weed control by reducing the density and biomass of purple nutsedge by up to 83% and 81%, respectively, as compared with the season-long untreated control. The use of a natural mulch in combination with the herbicides halosulfuron or fomesafen + S-metolachlor also resulted in the highest tomato yield (ca. 3.3 kg per plant). This integrated treatment improved tomato yield by over 400% as compared with the season-long untreated control. The integrated use of a plastic mulch and two chemical options resulted in a 67–74% weed biomass reduction and a 332–368% yield increase over the season-long untreated control. These findings suggest that the combinations of herbicides and mulches are effective integrated weed management options for purple nutsedge in tomato crops.

Dynamics and weed control effectiveness of dicamba herbicide when applied directly on the soil and corn straw in Brazil

Dicamba is a post-emergence herbicide commonly used to control broadleaves in cereal crops. However, a portion of the herbicide might reach soil surface, and many factors could affect its dynamics and effects. The objective of this research was to evaluate the dynamics of dicamba applied to the soil, to the soil and covered with straw and over the straw, in addition, to evaluate the weed control in pre-emergence. Two field experiments at different locations were conducted with dicamba. To quantify dicamba in the soil a LC-MS/MS system was used. In both experiments, rainfall and straw played a key role in dicamba soil dynamics and weed control. Dicamba in the soil was affected by presence of straw and accumulated rainfall after the application. Higher concentrations (254–432 ng g soil−1) in the soil 0–10 cm layers and greater leaching potential were found for the application in the soil compared to over the straw. The maximum concentration of dicamba (101.6–226 ng g soil−1) was found after 10 mm of rainfall for dicamba application over the straw. Around 60–70% of weeds were controlled with concentrations greater than 20 ng/g soil−1, in the presence or absence of straw.

Pyrolysis Temperature and Application Rate of Sugarcane Straw Biochar Influence Sorption and Desorption of Metribuzin and Soil Chemical Properties

Pyrolysis temperature and application rate of biochar to soil can influence herbicide behavior and soil fertility. The objective was to investigate the effect of soil amendments with application rates of sugarcane straw biochar, produced at different pyrolysis temperatures, on the sorption–desorption of metribuzin in soil. The analysis was performed using high-performance liquid chromatography (HPLC). The treatments were three pyrolysis temperatures (BC350, BC550 and BC750 °C) and seven application rates (0, 0.1, 0.5, 1, 1.5, 5 and 10% w w−1). Amended soil with different application rates decreased H + Al and increased pH, OC, P, K, Ca, Mg, Fe, Mn, CEC and BS contents. Kf values of sorption and desorption of metribuzin were 1.42 and 0.78 mg(1−1/n) L1/n Kg−1, respectively, in the unamended soil. Application rates < 1% of biochar sorbed ~23% and desorbed ~15% of metribuzin, similar to unamended soil, for all pyrolysis temperatures. Amended soil with 10% of BC350, BC550 and BC750 sorbed 63.8, 75.5 and 89.4% and desorbed 8.3, 5.8 and 3.7% of metribuzin, respectively. High pyrolysis temperature and application rates of sugarcane straw biochar show an ability to immobilize metribuzin and improve soil fertility, which may influence the effectiveness in weed control.

Herbicide trials on Campuloclinium macrocephalum (Asteraceae) during adverse conditions reveal incompatibility with biocontrol and a narrow window of opportunity for chemical control

Herbicide trials on pompom weed Campuloclinium macrocephalum (Less.) DC. (Asteraceae) were carried out in grasslands with xeric and hydric soils, at sites in Gauteng, South Africa, from 2005 to 2008. The rust fungus Puccinia eupatorii Dietel, an established self-perpetuating biocontrol agent on C. macrocephalum, caused significant damage to shoots in late summer and autumn. Herbicide efficacy was significantly better on foliage that did not already present symptoms and that was sprayed in early summer compared with on infected plants treated in autumn, at both the xeric (F = 36.71, p < 0.001) and hydric (F = 3.59, p = 0.031) sites. This pathogen has reduced the time available for effective chemical weed control from six months to three months. However, none of the herbicide treatments achieved commercially acceptable mortality rates of ≥80%, and after three annual applications none succeeded in extirpating C. macrocephalum from the plots. Regression analyses of count data showed that metsulfuron-methyl at 45 g ha−1 (USD 20.05 ha−1), picloram at 252 g ha−1 (USD 25.47 ha−1) and 2,4-D/dicamba/MCPA at 540/360/474 g ha−1 (USD 45.41 ha−1) required five annual treatments in summer to eradicate C. macrocephalum, whereas 2,4-D amine at 1 440 g ha−1 (USD 13.65 ha−1) and MCPA at 1 200 g ha−1 (USD 14.46 ha−1) required six treatments. Hence, there is a trade-off between the use of slightly more effective herbicides against the lower costs of other selective herbicides.

Pyroligneous acids from biomass charcoal by-product as a potential non-selective bioherbicide for organic farming: its chemical components, greenhouse phytotoxicity and field efficacy.

Effective and environmentally friendly herbicides are urgently needed to meet consumer demand for organic products. To evaluate the weed control effect of four pyroligneous acid (PAs) mixtures, the byproducts of bamboo/wood/straw vinegar, two herbicide discovery tests were done: (1) the greenhouse tests by using four indicative plants: wheat (Triticum sativa), radish (Raphanus sativus), cucumber (Cucumus sativus), and Echinochloa crusgalli (L.) Beauv; (2) Field trials with four weeds: E. crusgalli, Eleusine indica (L.) Gaertn, Alternanthera philoxeroides (Mart.) Griseb, and Conyza canadensis (L.) Cronq. Greenhouse tests showed that the efficacy of PAs and acetic acid (AA) to control four test plants increased with the increasing of PAs concentration. The inhibition rates of four tested PAs (FBV (0.6-9.2% AA + (0.3-5.0% tar), HWV (0.2-1.8% AA + 0.3-4.3% tar), ASV (0.5-8.7% AA + 0.4-7.0% tar), and CWV (0.7-5.3% AA + 0.5-7.5% tar) gave inhibition rates of 56 ± 4-97 ± 2%, 21 ± 2-90 ± 6%, 29 ± 3-98 ± 5%, and 44 ± 6-86 ± 2%, respectively, and the field effects of PAs against four weeds were enhanced with the increasing of concentrations and time after spraying (1 to 14days). Their control effects against E. crusgalli, E. indica, A. philoxeroides, and C. canadensis were 4 ± 1-93 ± 4%, 7 ± 3-90 ± 3%, 32 ± 2-95 ± 3%, and 31 ± 5-96 ± 4%, respectively. The mixed effect of the four PAs was higher than the same dose of AA. These results will help to determine the potential of PAs to be developed as non-selective herbicides to control weeds in organic farming.

Model-based scenario analysis for effective site-specific weed control on grassland sites

The site-specific management of weeds in grassland is often challenging because different weed control strategies have different trade-offs regarding the required resources and treatment efficiency. So, the question arises whether a wide tractor-based system with section control or a small agricultural robot has a higher weed control performance for a given infestation scenario. For example, a small autonomous robot moving from one weed to the next might have much shorter travel distances (and thus lower energy and time costs) than a tractor-mounted system if the locations of the weeds are relatively isolated across the field. However, if the plants are highly concentrated in small areas so-called clusters, the increased width of the tractor-mounted implement could be beneficial because of shorter travel distances and greater working width.An additional challenge is the fact that there is no complete knowledge of the weed locations. Weeds may not have been detected, for example, due to their growth stage, occlusion by other objects, or misclassification. Weed control strategies must therefore also be evaluated with regard to this issue. Thus, in addition to the driving distance, other metrics are also of interest, such as the number of plants that were actually controlled or the size of the total treatment area.We performed this investigation for the treatment of the toxic Colchicum autumnale, which had been detected in drone images of extensive grassland sites. In addition to real data, we generated and analyzed simulated weed locations using mathematical models of stochastic geometry. These offer the possibility to simulate very different spatial distributions of toxic plant locations. Different treatment strategies were then virtually tested on this data using Monte Carlo simulations and their performance was statistically evaluated.

Ефективність застосування післясходових гербіцидів у посівах кукурудзи на зерно в Cхідному Лісостепу України

Goal. To determine the effect of multi-component post-emergence herbicides with a wide spectrum of action on crop weediness and corn grain yield in the conditions of the Eastern Forest Steppe of Ukraine. Methods. Field, analytical and statistical. Results. Annual cereal weeds predominated in number and raw mass of corn for grain crops, with dicotyledons annual and perennial species occupying the second and third positions, respectively. A decrease in the technical efficiency of post-emergence herbicides at high average daily air temperatures during the cultivation period was revealed. Thus, according to the results of the first accounting, the highest effectiveness in protection against cereal annual weeds was provided by the preparation rymsulfuron + dykamba + nikosulfuron (61%), dicotyledonous annuals and perennials — topramezon + dykamba (83 and 53%, respectively). According to the second record, more effective control of the number of cereal annual weeds was in the versions rymsulfuron + dykamba + nikosulfuron and nikosulfuron + rymsulfuron (respectively 61 and 61%), dicotyledons — rymsulfuron + dykamba + nikosulfuron and topramezon + dykamba (87 and 90%). Topramezon + dykamba was the best against dicotyledonous perennial weeds. The total number of weeds was most controlled by rymsulfuron + dykamba + nikosulfuron (61 and 65%, respectively). According to the records of the accumulation of raw mass by weeds, more improved control of annual cereal species was provided by rymsulfuron + dykamba + nikosulfuron (74%) and nikosulfuron + rymsulfuron (75%), dicotyledons — rymsulfuron + dykamba + nikosulfuron (99%) and topramezon + dykamba (99%), dicotyledonous perennials — topramezon + dykamba (77%). The total wet weight of weeds was better controlled by the herbicide rymsulfuron + dykamba + nikosulfuron (80%). The highest level of increase in the yield of corn grain was obtained in the option of application of the herbicide rymsulfuron + dykamba + nikosulfuron (2.72 t/ha). Conclusions. The use of the herbicide rymsulfuron + dykamba + nikosulfuron in corn crops in the phase of 4–5 leaves is promising for effective control of problematic weeds and ensuring an increase in grain yield in the conditions of the Eastern Forest-Steppe of Ukraine.

Silvicultural experiment assessment using lidar data collected from an unmanned aerial vehicle

Collecting field data in silvicultural experiments can be challenging and time-consuming. Alternatively, unmanned aerial vehicles using laser scanners (UAV-lidar) can be used for cost-effective data collection in forest stands. This work aims to assess the capability of UAV-lidar to estimate biophysical forest attributes in silvicultural experiments. The showcase experiment refers to the IMPAC II (Intensive Management Practices Assessment Center II), a long-term project of 24 plots aiming to assess the effects of fertilization and weed control on forest growth and nutrient cycling in past and ongoing silvicultural treatments in a second rotation of loblolly pine (Pinus taeda L.) plantation at age 12 years. Treatment performances were assessed based on four biometric attributes related to forest productivity: Growing stock biomass (Mg ha−1), stem volume (m3 ha−1), dominant height (m), and leaf area index (LAI, m2 m−2). We used the area-based approach (ABA) and multiple linear models to characterize these forest attributes in the different silvicultural treatments and use their predictions to run the experiment analysis. Two groups of ALS-derived metrics were tested in the modeling, traditional metrics and a novel group of metrics based on plant area density (PAD) distribution. Models using PAD-based metrics increased the correlation between observed and predicted values (R2) from 0.27–0.40 to 0.50–0.85 when compared to the same models using traditional metrics, while the relative root mean square errors (RMSE%) of the predictions were reduced from 6–18% to 4–12%. Experiment analysis using UAV-lidar data and PAD-based model predictors led to the same results as those using field observations: i) fertilization was the most effective treatment for enhancing stand attributes, especially in terms of biomass, stem volume, and LAI; ii) weed control alone provided marginal improvements in the stands; iii) actively retreating stands in both first and second rotation led to increased growth when compared to the carryover effects. UAV-lidar using PAD-based metrics was effective in characterizing enhanced silvicultural treatments and might benefit studies involving understory assessment.

Effects of different application methods of spent coffee grounds on weed growth

AbstractThe extensive and intensive use of herbicides has resulted in the spread of herbicide-resistant weeds in many crop production systems; therefore, it is imperative to devise new organic weed control methods. Recently, the application of spent coffee grounds (SCG) in agricultural fields has been found to inhibit plant growth and germination and is thus considered a potentially effective weed control measure. This study aimed to evaluate the effects of different amounts and methods of SCG application on weed growth through field experiments. The field experiments were conducted in an upland field converted from a paddy in western Japan. The results show that the plow-in application of over 10 kg m−2 of SCG and mulching application of 20 kg m−2 decreased the weed dry weight compared with the control. In addition, the growth of weed species of families other than Gramineae, such as wingleaf primrose-willow and horseweed, was not significantly affected by SCG application. Weed species of families other than Gramineae are dominant in some upland fields. Hence, the inhibitory effect of SCG on weeds may be lower in original upland fields than in the upland field converted from paddy field that was investigated in the present study. Overall, this study demonstrated that the plow-in application of 10 kg m−2 of SCG every 4 mo was effective for weed control in an upland field converted from a paddy field. Because SCG worked against grass weeds under the specific conditions in this study, it would be valuable to explore other potential applications of this novel means of weed control.