Soil Weed Research Articles

Differentiated In-Row Soil Management in a High-Density Olive Orchard: Effects on Weed Control, Tree Growth and Yield, and Economic and Environmental Sustainability

Two different in-row soil management techniques were compared in the Olive Orchard Innovation Long-term experiment of the Council for Agricultural Research and Economics, Research Centre for Olive, Fruit, and Citrus Crops in Rome, Italy. Rows were managed with an in-row rotary tiller and with synthetic mulching using permeable polypropylene placed after cultivar Maurino olive trees planting. The effects of the two treatments were assessed through weed soil coverage and the growth of the olive trees. Results showed better agronomic performance associated with synthetic mulching. The weed control effect along the row of a young high-density olive orchard was higher with the synthetic mulching compared to hoeing. The effect of the synthetic mulching seemed to disappear when removed from the ground (spring 2023) since no significant differences were found for tree size and yield in the two tested in-row soil management systems at the end of 2023. Finally, the growth of the young olive trees (Trunk Cross Sectional Area, Height, and Canopy expansion) measured across the three years, was higher for the synthetic mulched row than the hoed one. The use of synthetic mulching along the row positively forced the vegetative growth of the young olive trees and anticipated the onset of fruit production compared to periodical hoeing: a significantly higher fruit production was registered three years after planting. Root diameter was higher under synthetic mulching one year after planting, and no differences were observed in the following sampling dates showing similar fluctuations linked to the seasonal growth pattern. The life cycle assessment and costing highlighted that the application of mulching had a higher eco- and economic-efficiency than the periodical in-row soil hoeing.

Impact of maintenance regimes on species richness in newly established perennial wildflower meadows

Perennial wildflower meadows contribute to the enhancement of the quality of urban green spaces, of-fering benefits for both people and wildlife. Significant impact is attributed to management in fostering species-diverse plant communities. However, there are not enough studies exploring the influence of early maintenance regimes on plant diversity. A three-year experiment was conducted to investigate the impact of maintenance regimes on newly established perennial wildflower meadows and the influence of sowing mix on species richness. Three types of perennial wildflower seed mixes were sown on arable land and managed differently during the initial year. Results indicate statistical significance for each main effect, including maintenance type and sowing mix, with no significant interaction between these factors. Mowing during the early growth stage is shown to increase species richness, while no significant difference is observed between weeded and unmanaged plots. The dry meadow sowing mix demonstrates the highest diversity index (Shannon-Weaver, 1963). Maintenance regimes exhibit a significant influence on species richness independently of the sowing mix used. Furthermore, mowing during the early growth stage is found to enhance species diversity in the long term. These findings provide beneficial insights for the more efficient management and establishment of species-rich wildflower perennial meadows in both urban and suburban environments, particularly in areas with a significant soil weed seed bank.

Effect of soil nutrient management on soil weed seed bank dynamics across a soil fertility gradient in smallholder farms, Eastern Zimbabwe

Weed seed banks are latent biotic stress contributors to low crop production among smallholder farms. The objective of this study was to investigate effect of repeated soil nutrient amendments on weed seed bank dynamics in eastern Zimbabwe. Soil samples were taken from three farms with low, medium and high soil organic carbon (SOC) along the catena. Sampled treatments included varying combinations of compound D (7%N, 14%P, 7% K) fertiliser, cattle manure and lime. Weeds that emerged per plot were counted by species and data was tested for normality before running a linear mixed-effects model and Restricted Maximum Likelihood. Principal Component Analysis (PCA) was performed to establish the relationship between seasons, SOC, soil nutrient amendment, and emerged weeds. Significant (p < .05) species richness (Margalef index), and Shannon Weiner index were recorded in the medium (6.4g kg-1soil), high (8 g kg-1 soil) and low (< 3.9 g kg-1soil) SOC. Weed species emergence was significantly (p < .05) influenced by the level of SOC along the catena positions, representing results from the source. Emergency and abundance of weeds such as Richardia scabra, was associated with low SOC acidic sandy soils from the upper catena. However, application of nutrients (NPK+lime treatment) reduced weed species counts from 1.96±0.12 to 1.4±0.12. Cattle manure and NPK+CM treatments recorded significantly higher weed emergence, and weed biomass; compared to the control. Clearly, cattle manure treatments significantly increase the soil weed seed bank; thus, weeding intensity is likely to increase in cattle manure treated fields.

Weed seedbank as influenced by tillage and herbicide in direct seeded rice‐mustard cropping sequence in lateritic soil of eastern India

AbstractThe above‐ground community dynamics of weeds represent the soil weed seedbank in an agro‐ecosystem. Hence, understanding the seedbank will offer an idea for future weed management tactics. We aimed to determine the density of weed seedbank and emergence of major weeds in direct seeded rice (DSR) (Oryza sativa L.)—mustard (Brassica campestris L. var. yellow sarson) cropping sequence under varied tillage and herbicide combinations. The present study on weed seedbank was conducted using seedling emergence method after collecting the soils at the harvest of mustard at the completion of 2 years field experimentation. The experiment was conducted in split‐plot design with two tillage practices [zero tillage (ZT) and conventional tillage (CT)] in main plot and eight weed management practices in DSR [oxadiargyl followed by (fb) bispyribac‐sodium, penoxsulam + cyhalofop‐butyl, oxadiargyl fb penoxsulam + cyhalofop‐butyl, fenoxaprop‐p‐ethyl + ethoxysulfuron, oxadiargyl fb fenoxaprop‐p‐ethyl + ethoxysulfuron, pendimethalin fb bispyribac‐sodium, unweeded control, and weed free check] as subplot. The carry‐over effect of tillage and weed management practices were recorded in mustard crop. Seed emergence study revealed that ZT reduced the emergence of grassy weeds (by 13.7%) and total weed emergence (19.5%) in comparison to the CT (p < 0.05). However, emergence of broadleaf weeds was 24.5% higher in ZT than in CT. The higher infestation was recorded for Ludwigia parviflora (Jacq.) Raven under penoxsulam + cyhalofop‐butyl, fenoxaprop‐p‐ethyl + ethoxysulfuron, Cyperus iria (L.) under fenoxaprop‐p‐ethyl + ethoxysulfuron, and Eleusine indica (L.) Gaertn. under pendimethalin fb bispyribac‐sodium, oxadiargyl fb bispyribac‐sodium. Sole application of post‐emergence (POE) herbicide decreased the total weed emergence by 22.2%–28.1% than unweeded control (p < 0.05). Whereas, sequential application of PRE + POE herbicides decreased the total weed emergence by 32.8%–36.9% than unweeded control (p < 0.05). Notably, sedge weeds such as Cyperus iria (L.) and Fimbristylis miliacea (L.) Vahl were lower in ZT than in CT under herbicide treated plots (by 66.6%–84.3%) than unweeded control. Thus, ZT with oxadiargyl 90 g a.i. ha−1 fb fenoxaprop‐p‐ethyl + ethoxysulfuron (90 + 15 g a.i. ha−1) as tank‐mix can be effectively used to lower the weed seedbank density vis‐à‐vis managing complex weed flora in DSR and rice‐mustard cropping sequence.

Responses of soil seedbank and aboveground weed communities to globe artichoke–cropping systems: an on-farm analysis

AbstractGlobe artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori] is one of the most important crops across the Mediterranean basin, where weeds are an important biotic constraint limiting crop yields. However, the effects of globe artichoke–cropping systems on weeds have been rarely tested. Following the demand for eco-friendly weed management practices, a multi-location trial (13 farms) was carried out, measuring weed seedbanks and aboveground communities within four globe artichoke–cropping systems: globe artichoke monoculture (ART), past cultivation of globe artichoke (8 to 10 yr ago) (past-ART), a globe artichoke–durum wheat (Triticum durum Desf.) rotation (ART-WHEAT), and a control where globe artichoke was never grown. Both below- and aboveground weed communities were dominated by annual therophytes, but a low correspondence was found between both types of communities. Averaged over farms, ART highly reduced both the weed soil seedbank (1,600 seeds m−2 on average) and the aboveground weed biomass (only 3.4 g dry weight m−2) compared with the control, with a decrease of 72% in the soil seedbank and 99% in the aboveground flora. Moreover, on the farms where globe artichoke was previously grown, a very low aboveground weed biomass (77% less than control) was found. In addition, ART contributed to the preservation of high levels of weed diversity (except for aboveground communities) and therefore avoided the creation of a specialized weed flora. In conclusion, we suggest the inclusion of globe artichoke into crop rotation schemes in Mediterranean agroecosystems as a sustainable tool for reducing both the soil weed seedbank and aboveground weeds, thus reducing the requirement of direct weed control methods and preserving the environment.

Tillage techniques in grass crop rotations in Western Kazakhstan

The transition to new technologies is predetermined by global and domestic scientific and production experience and general trends in the development of agriculture. The basis of grass crop rotations is the general biological principle of the different effects of perennial grasses on the soil. To the problem of forage production for the conditions of the arid steppe of Western Kazakhstan with an annual rainfall of 250-300 mm, a method of using forage crops based on grass crop rotation is proposed. Periodic change of different crops in crop rotation plays a positive phytosanitary role in clearing the soil of weeds. The article discusses three types of soil cultivation techniques based on the principles of sustainable production of grain crops and stabilization of soil fertility in the conditions of Western Kazakhstan. The research was carried out on the basis of the Ural Agricultural Experimental Station LLP. The purpose of the research is to develop methods of soil cultivation in grass crop rotations for the accumulation, conservation and rational use of soil moisture in resource-saving technologies for cultivating basic field crops, ensuring the preservation of soil fertility, improving the phytosanitary condition of crops in the dry steppe zone of Western Kazakhstan. The objective of the research is to study the influence of methods for processing turf of perennial grasses in the structure of crop rotations in order to stabilize soil fertility and the phytosanitary condition of crops. Three types of processing were used in the studies: flat cutter, slotting + cultivation, cultivation. Grass crop rotation was sown over a layer of perennial grasses and included the following forage crops: sorghum, corn and millet. The best results in terms of yield were observed based on the joint interaction of technologies for factor B (slotting + cultivation).

Unanswered questions and unquestioned answers: the challenges of crop residue retention and weed control in Conservation Agriculture systems of southern Africa

Abstract Production and utilization of crop residues as mulch and effective weed management are two central elements in the successful implementation of Conservation Agriculture (CA) systems in southern Africa. Yet, the challenges of crop residue availability for mulch or the difficulties in managing weed proliferation in CA systems are bigger than a micro-level focus on weeds and crop residues themselves. The bottlenecks are symptoms of broader systemic complications that cannot be resolved without appreciating the interactions between the current scientific understanding of CA and its application in smallholder systems, private incentives, social norms, institutions, and government policy. In this paper, we elucidate a series of areas that represent some unquestioned answers about chemical weed control and unanswered questions about how to maintain groundcover demanding more research along the natural and social sciences continuum. In some communities, traditional rules that allow free-range grazing of livestock after harvesting present a barrier in surface crop residue management. On the other hand, many of the communities either burn, remove, or incorporate the residues into the soil thus hindering the near-permanent soil cover required in CA systems. The lack of soil cover also means that weed management through soil mulch is unachievable. Herbicides are often a successful stopgap solution to weed control, but they are costly, and most farmers do not use them as recommended, which reduces efficacy. Besides, the use of herbicides can cause environmental hazards and may affect human health. Here, we suggest further assessment of the manipulation of crop competition, the use of vigorously growing cover crops, exploration of allelopathy, and use of microorganisms in managing weeds and reducing seed production to deplete the soil weed seed bank. We also suggest in situ production of plant biomass, use of unpalatable species for mulch generation and change of grazing by-laws towards a holistic management of pastures to reduce the competition for crop residues. However, these depend on the socio-economic status dynamics at farmer and community level.

Above Ground Emergence and Floristic Composition of Weeds in Relation to Tillage and Weed Management Practices in Maize and Cowpea

Background: Weeds are one of the most important elements influencing crop productivity. Tillage practices have a significant effect on the weed seed bank and the appearance of weeds, both of which have a direct impact on farm productivity. Different tillage strategies based on ploughing depth, as well as weed control practices, change the dynamics of weed seeds in the soil. This research will aid in the development of integrated weed control methods by investigating the interaction between tillage and weed management practices. Methods: Field trials were carried out in two seasons, Summer and Kharif 2022, using a split-plot design with three tillage methods and four weed management practices. The treatments were replicated three times. Result: Among the different tillage treatments Mouldboard plough fb Cultivator fb Rotovator recorded the lowest weed density. With respect to weed management methods, pre- and post-emergence herbicide application and hand weeding at 20 and 40 DAS recorded the lower weed density. Interaction effects of tillage and weed management practices resulted in lower weed density in Mouldboard plough fb Cultivator fb Rotovator with herbicide application and Mouldboard plough fb Cultivator fb Rotovator with hand weeding. Highest weed density was recorded under Cultivator fb Rotovator in unweeded control. With respect to relative density, among the broad-leaved weeds (BLW) Trianthema portulacastrum and Dactyloctenium aegyptium in grasses dominated among the weed species in 30 and 60 DAS respectively. From the present study it was concluded that the Mouldboard plough fb Cultivator fb Rotovator with hand weeding twice or herbicide application reduces the weed emergence from the soil weed seed bank.

Morphological and molecular characterization, including parasitic and pathogenic studies of a new spherical cyst nematode species, Globodera vulgaris n. sp. (Nematoda: Heteroderidae), associated with potatoes in China.

In this study, a new spherical cyst nematode belonging to the genus Globodera, herein described as Globodera vulgaris n. sp., was extracted from the roots and rhizosphere soil of potato and circumjacent weeds belonging to different families in three provinces in southwest China. The new species was characterized by 8-24 ridges between the anus and fenestra and an average Granek's ratio of 2.8-3.8 in cysts, a head with 3-4 annules and dorsal knob anteriorly projected and ventral knobs round or anteriorly projected in second stage juveniles, and a head with 3-5 annules, spicule short and average length less than 30.0 μm, with a developed velum in males. Pathogenicity tests showed that G. vulgaris n. sp. infected potato but did not damage or affect the potato yield compared to control, and it parasitized tomato with a low reproduction rate (RF < 1) while did not parasitize tobacco (RF = 0). The new species was close to G. rostochiensis based on molecular diagnostic marker sequences and constructed phylogenetic analysis, that is internal transcribed spacers of ribosomal DNA (ITS), large-subunit rDNA (LSU) and small-subunit rDNA (SSU). However, the new species exhibited differences from G. rostochiensis in terms of morphological characteristics, a wide host preference, lack of damage to hosts, and egg hatching rate induced by hatching factors.

Indole-3-acetonitrile is a critical molecule with weed allopathic suppression function in broccoli (Brassica oleracea var. italica).

Cruciferous plants are frequently used for ecologically benign weed control in agricultural production. The varieties were the most effective, Most effective Broccoli varieties were screened using the entropy method-based topsis model at first. Result showed that Lvwawa and Lvbaoshi were most effective in allelopathic suppression on radishes. Column and thin-layer chromatography were used to extract the allelopathic compounds from broccoli residues, which contained various herbicidal active substances; among them, purified single-molecule indole-3-acetonitrile has a stronger inhibitory effect than pendimethalin (commercial herbicide). The weed inhibition rate increased with increasing broccoli residue dosage, with a 40 g/m2 broccoli residue dose yielding the highest suppression rate. Its effect was similar to that of indole-3-acetic acid. Too much of this substance leads to the plant's death. Moreover, broccoli residues had effective control effect on weeds in natural soils in greenhouse and field trials. The results demonstrated that broccoli residue could be used for weed management in field for abundant allopathic suppression molecules to weeds, and that Indole-3-acetonitrile is one of the most important allopathic molecule.

Uptake of 15N-urea and phosphates in Triticum aestivum with Pseudomonas putida and Rhizophagus irregularis endophytes of calcareous soil weeds

In calcareous soil, the growth and production of _Triticum aestivu_m depends on the availability of phosphates, which in turn reduces the uptake of nitrogen in the form of urea, which causes volatilization and partial leaching of both fertilizers, contributing to the greenhouse effect, and warming global. An alternative ecological solution for _T. aestivum _is to inoculate _Pseudomonas putida _and_ Rhizophagus irregularis_ with endophytes that increase phosphorus uptake such as P2O5 and urea. The objective of this research was to analyze the uptake and distribution of 15N-urea in _T. aestivum_ with _P. putida _and _R. irregularis_ fertilized with 50% urea and P2O5. In this sense, _P. putida _and_ R. irregularis_ isolated from roots of _Resenda luteola _and_ Arista purpurea_ native to the calcareous soil of northeastern Mexico. In_ T. aestivum_ with these endophytes, acid and alkaline phosphatase activity in root and stem, N (nitrogen) uptake from total urea (Nt) and yield (Y). The experimental data were analyzed by ANOVA/Tukey (P&lt;0.01). The results showed a positive response of _T. aestivum to P. putida _and _R. irregularis_ with 60 kg/ha of urea and 40 kg/ha of P2O5, equivalent to the 50% recommended for this region of Mexico. It was evidenced that in _T. aestivum, P. putida, _and _R. irregularis _endophytes of desert weeds improved the uptake of urea and P2O5 to 50% by phytohormones that optimized nitrogen with phosphatases, soil phosphate and that from the applied fertilizer. The Nt in stem and the yield of _T. aestivum _with_ P. putida and R. irregularis_ reached statistically different numerical values to those registered in _T. aestivum _with 120 kg/ha of urea and 80 kg/ha of P2O5 without _P. putida _and_ R. irregularis _at 100% (relative control), consequently the performance of _T. aestivum_ in calcareous soils. It is avoided by the generation of greenhouse gases, the contamination of surface water, by using the beneficial interaction of endophytes with weeds with _T. aestivum,_ as well as global warming.

The Impact of Root-Invasive Fungi on Dominant and Invasive Plant Species in Degraded Grassland at Nanshan Pasture

Overgrazing leads to the degradation of grazing lands, which seriously threatens the stability of grassland ecosystems. Root-invading fungi, as one of the main influencing factors, can cause plant diseases in grasslands, reduce the proportion of dominant plant species, increase the proportion of invasive poisonous weeds, and further aggravate degradation. In order to predict and improve the effects of root-invading fungi on grassland degradation, we conducted an in situ soil indoor control experiment using soils collected from non-degraded, moderately degraded, and severely degraded areas of Nanshan pasture in Hunan Province, China. We used monoculture or mixed grasslands of dominant plant species, including Lolium perenne, Trifolium repens, and the invasive weed Persicaria hydropiper, and inoculated them with local strains of pathogenic Fusarium species (Fusarium boothii and Fusarium circinatum) and beneficial fungi Arbuscular Mycorrhizal Fungi (AMF) and Trichoderma hamatum to explore how different strains of fungi affect plant growth and community dynamics. The results showed that Fusarium species (Fusarium boothii and Fusarium circinatum), as a major pathogenic fungus, inhibited the growth of the dominant grass Lolium perenne in moderately and severely degraded soils, which provided growth space and resources for invasive weeds Persicaria hydropiper and further aggravated the degree of grassland degradation. However, the collaborative effect of beneficial fungi (AMF and Trichoderma) and their inhibitory effect on Fusarium species (Fusarium boothii and Fusarium circinatum) could promote the growth of dominant plants and weeds in soils with varying degrees of degradation, which is beneficial to maintaining the stability and diversity of grassland plant communities. The collaborative effect of beneficial fungi could also increase the availability of nutrients in severely degraded soils. Therefore, using beneficial fungi (AMF and Trichoderma) for soil improvement and reducing the harm of pathogenic Fusarium species (Fusarium boothii and Fusarium circinatum) to plant growth is of great significance for promoting the protection and management of grassland ecosystems, as well as for the restoration and recovery of grasslands.

RELATIONSHIP BETWEEN SOIL WEED SEED BANK AND SOIL PROPERTIES IN ARABLE FARMLANDS IN UNIVERSITY OF PORT HARCOURT AND ENVIRONS IN RIVERS STATE-NIGERIA

This paper considered relationship between soil weed seed bank seedlings and soil physicochemical parameters in arable farmlands was sampled in rainy and dry seasons at 3 different depths of 0-5, 5-10 and 10-15cm. Arable farmlands were 22 and 3 controls. Soils were collected at four points randomly with a soil auger, prepared for laboratory analyses and 100g each placed into 225 small bowls replicated 3 times, which were perforated and having tissue papers at base for soils to prevent soil and weed seeds wash off at watering. Emerged weed seedlings were counted, identified weekly for 12 weeks. Soils were allowed to dry and turned over at 4 and 8 weeks, respectively. Unidentified weeds seedlings were transferred into bigger bowls with humus soils, labeled to grow further and then identified. The parameters considered included soil weed seed bank seedlings and soil physicochemical properties. Weed seedlings data and result from physicochemical analysis were subjected to correlation analysis. Result at 5cm depth for rainy season revealed abundance of weed species significant (p&lt;0.05) correlated with parameters K and Cu with a correlation coefficient (p-value) of 0.507 (0.016) and 0.611(0.003), respectively. But at 10cm depth it was only correlated with pH with a correlation coefficient (p-value of 0.501 (0.018). However, at 15cm weed species abundance was significant (p&lt;0.05) correlated with parameters pH, P, Mg, K and Cu with correlation coefficient (p-value) of 0.488 (0.021), 0.459 (0.032) 0.458 (0.032), 0.445(0.038) and 0.525 (0.012), respectively. The correlation result in dry season revealed that at various depths weed species abundance was not significant (p&lt;0.05). Conclusively, soil, water and cultural practices adopted by farmers might have impacted on the macro and micro nutrients availability with pH as master catalyst, while the non mobility of nutrients in dry season also affected non correlation. It can be determined from this study that the relationship between soil seed weed bank and soil properties in arable fields shows differences at the three depths.

Weed Control and Selectivity of Four Herbicides Applied in Pre-Emergence on Two Sunflower Cultivars

The sunflower (Helianthus annuus L.) is an oleaginous plant that shows high suitability for cultivation in Brazil. However, the performance of the crop is influenced by factors such as weed interference, mainly because of the few selective herbicide options. Thus, the objective of this study was to evaluate weed control and selectivity of four pre-emergent herbicides applied to two sunflower cultivars in sandy and clayey soils. Two field experiments were conducted in a randomized block design with a 2 × 6 factorial scheme, two cultivars (CF 101 and M 734) and six treatments with S-metolachlor (1920 g a.i. ha−1), sulfentrazone (150 g a.i. ha−1), flumioxazin (40 g a.i. ha−1), and trifluralin (1780 g a.i. ha−1) and two controls, one with weeding and the other without weeding and without herbicide application, in soils with contrasting textures (sandy and clayey). No injury symptoms were observed in both cultivars, regardless of soil texture. The cultivar M 734 exhibited the highest values of the agronomic parameters evaluated. The treatment with flumioxazin provided control of more than 90% of the weeds in clayey soil and more than 64% in sandy soil. The yield of both cultivars was lower in the sandy soil. Thus, all herbicide treatments were selective for both cultivars tested, since they did not interfere with sunflower grain yield.

Multifunctional living mulches for weeds control in organic apple orchards

A trial assessing the suitability of multifunctional living mulch to maintain the soil and reduce weed infestation was carried out in an organic apple orchard in the years of 2019-2020. Perennial plants (Alchemilla vulgaris, Fragaria vesca, Mentha piperita) and annual crops (Tropaeolum majus and Cucurbita maxima) were grown in the in the rows of the apple trees. The weeds number and soil weeds coverage in tree rows were assessed. Regardless of the living mulch species utilized, the soil resulted to be mostly covered by perennial weed species such as: Equisetum arvense and Taraxacum officinale and annual species such as: Lamium purpureum, Stellaria media, Galinsoga parviflora, Capsella bursa-pastoris and Poa annua, which were the most common species also for the natural cover used as control. However, all living mulch species limited weed infestation and M. piperita, F. vesca and T. majus most strongly limited weeds growth. It is concluded that living mulch species can be a feasible practice to manage the soil on the tree rows in organic orchards.

Harvest weed seed control in soybean with an impact mill

AbstractThe distribution of herbicide-resistant weeds such as waterhemp has resulted in a greater need for a more integrated approach to weed management, especially in U.S. soybean production systems. Previous research has shown harvest weed seed control (HWSC) to be an effective method of reducing the amount of weed seed returning to the soil. One form of HWSC is the use of impact mills to destroy weed seed exiting the combine during harvest. In 2019 and 2020, we investigated the efficacy and operating costs of the Seed TerminatorTM impact mill in five Missouri soybean fields that contained significant waterhemp infestations. Results indicated that 22% to 40% of the available waterhemp seed in the field at harvest drops to the soil surface because of shatter whenever the combine reel contacts waterhemp plants. Across all locations, an average of 94% of waterhemp seed exiting the Seed Terminator™ was substantially damaged and considered nonviable. Consecutive seasons of use of the Seed TerminatorTM on the same field in two of the locations resulted in a 96% to 97% reduction of waterhemp in the soil seed bank the spring following the second harvest. The estimated increased operating cost of using a Seed Terminator™ was $14.18 ha–1 compared to harvesting with a conventional combine alone. Engine load increased by 12.5%, fuel consumption was 11.3 L h–1 and 1 L ha–1 greater with the Seed Terminator™, but there was no reduction in productivity when harvesting with a combine equipped with a Seed TerminatorTM compared to a conventional combine. The use of impact mills could play a significant role in reducing soil weed seed banks in soybean production systems in at least the Midwest region of the United States in the future.

СЕМЕННАЯ ПРОДУКТИВНОСТЬ И ЖИЗНЕСПОСОБНОСТЬ СЕМЯН СОРНЫХ РАСТЕНИЙ В РАЗЛИЧНЫХ ТИПАХ ПОЧВ

The results of longterm field experiments on two types of soils (chernozem and kastano-zems) are presented. The indicators of average seed productivity of more than 50 species of weeds growing in these soils are presented. The duration of the viability of seeds planted in a 0–30 cm soil layer, the quality of seeds during their layer-by-layer placement in the soil, on its surface and during storage in a dry warehouse is indicated. It was revealed that early spring and wintering weeds in chernozem soils had the highest seed productivity (more than 50 thousand seeds per plant). It was established that these seeds remained viable in the soil from 3 to 6 years (23 species), more than 6 years (20 species), and less than 3 years (only 3 species). In kastanozems soils, the seed productivity of most weeds decreased by 11–26% compared to chernozems. The loss of seed viability occurred more intensively in kastanozems soils than in chernozem soils. It was established that the lowest viability of seeds on both types of soils was observed during their longterm stay on the soil surface: after 5 years it did not exceed 12–15%, and after 10 years – 2–3%, while in the 0–10 cm layer of chernozem soils, it reached 36 and 18%, respectively, and in kastanozems soils it decreased more strongly and did not exceed 26 and 10%. In the lower soil layers, 10–20 and 20–30 cm, higher viability of weed seeds remained in kastanozems soils.

Study of Mechanical-Chemical Synergistic Weeding on Characterization of Weed–Soil Complex and Weed Control Efficacy

Mechanical-chemical synergy has been proven efficient in weed control. However, characterizing the state of the weed–soil complex after mechanical weeding and revealing its effects on subsequent herbicide application is still challenging, which restricts the implementation of this technology. This paper first presents a method to characterize the state of the weed–soil complex from the perspectives of the fragmentation and composite characteristics. The regrowth of the weed–soil complex and the effects of complemented herbicide-reduced spraying on weed control efficacy and crop yield were then investigated. The results showed that the typical diameters of the weed–soil complexes were 10.67 cm and 2.82 cm after inter-row hoe shovel and intra-row finger weeding, respectively. There were mainly two and four weed–soil complex states after inter-row and intra-row weeding, respectively. The regrowth rate corresponding to the weed–soil complex state with the largest component proportion after inter-row and intra-row weeding was 76.91% and 18.37%, respectively. The additional chemical herbicide sprayed on the weed–soil complex significantly improved the fresh weight control efficacy of 95.12% for the preposed inter-row mechanical weeding and 138.07% for the preposed intra-row mechanical weeding in the maize silking stage. The maize yield of inter-row mechanical–75% chemical application treatment was 9.27% higher than that of chemical treatment. Mechanical weeding creates a suitable weed–soil complex state for subsequent chemical application and improves the synergistic weeding effect.

Macronutrient Applications and Irrigation Regimes Impact Weed Dynamics and Weed Seedbank Augmentation in Solanum melongena L. Fields

Weeds are a major yield-limiting factor bedeviling eggplant (Solanum melongena L.) production in Russia. This study aimed to determine the influence of macronutrient rates and drip irrigation regimes on weed flora composition and potential soil contamination by weed seedbanks in the eggplant field. Three field experiments were conducted during the 2019–2021 cropping calendar. Two-factorial field experiments were designed in four blocks whereby the composition of weed flora in eggplants was examined under the influence of different macronutrient rates (40 tons manure and N140P30, 40 tons manure and N320P120K210, and control without fertilization), and three thresholds of pre-irrigation soil moisture % least moisture capacity (LMC) (in particular, 70, 80 and 90% LMC). The results demonstrated that nutrient rates contributed to a significant increase in weed density of 27.1 to 37.6%, due to an increase in the number of annual weeds (annual winter weeds and annual early spring weeds), and an increase in soil moisture threshold from 70 to 90%. Nevertheless, low moisture availability between the rows as a result of drip irrigation utilization led to a decrease in weed populations by 10.8 to 15.9%. Potential contamination of the arable soil layer with weed seed was desirably decreased, ranging from 19.8 to 21.7% with the application of fertilizers, compared with the control. Furthermore, the soil weed seedbank was considerably reduced by an increase in the pre-irrigation threshold of soil moisture.

CONSIDERATIONS REGARDING 3D MODELLING AND FINITE ELEMENT ANALYSIS OF A CULTIVATOR TYPE EQUIPMENT

Although it has been neglected in recent years, cultivation is once again finding its place in the field of agricultural crop management. The basic activities carried out by farmers in modern agriculture include plowing, opening the top layer of the soil and mechanical removal of weeds. Tools such as harrows or cultivators are used for these activities. This work presents in the first phase the modeling of a cultivator that can be mounted on an agricultural tractor with a power of up to 20 kW. The 3D model of the cultivator was analyzed in a second phase using a specialized software, Autodesk Inventor Professional 2020. The finite element analysis aimed at highlighting the behavior of the cultivator type equipment during the work process, a very important aspect for the specialists in domain who must permanently ensure that the operation of these machines is carried out at optimal parameters. Following the analysis, the results chosen for visualization were the stresses and deformations of the cultivator's work equipment, as well as the displacements of the structure nodes.