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In order to evaluate the effect of different weed management treatments on weeds, pest and natural enemies populations in sesame (Sesamum indicum L.), a 2-year study was conducted in East Azarbaijan, Iran in 2020–2021. The study was conducted based on randomized complete block design with four replications. The weed management treatments consisted of trifluralin use (960 g ai ha−1), wheat straw mulch (WSM), living mulches of fenugreek (Trigonella foenum-graecum L.) (FLM), bitter vetch (Vicia ervilia L.) (VLM), calendula (Calendula officinalis L.) (CLM) and one-time hand weeding (OHW). The effect of weed management treatment was significant on densities of insect pests, natural enemies and weed and also weed biomass and sesame seed yield. The lowest densities of insect pests including Myzus persicae, Brevicoryne brassicae, Helicoverpa armigera and Spodoptera exigua were observed in CLM treatment. Also, the highest densities of natural enemies Coccinella septompunctata, Coccinella undecimpunctata and Orius niger were observed in CLM treatment. The highest reductions in grass (51.0%), broadleaf (72.0%), and total (62.6%) weed biomasses and highest seed yield (1456 kg ha−1) were obtained in OHW. The seed yields in CLM and WSM treatments were not significantly different with trifluralin treatment and could be recommended in sustainable production of sesame. [ABSTRACT FROM AUTHOR]

Plant growth-promoting bacteria (PGPBs) play a crucial role in mitigating the oxidative damage caused by water stress in different plant species. The aim of this study was to determine the effects of PGPBs and mycorrhiza-like fungi (Piriformospora indica) on improving drought tolerance in moldavian balm (Dracocephalum moldavica L.), a medicinal and aromatic plant. For this purpose, a greenhouse study was conducted in a factorial experiment based on a randomized complete design with three replications. Results indicate that water stress reduces the membrane stability index (MSI), total chlorophyll content (Chlt), carotenoids, and maximum photochemical efficiency of photosystem II (Fv′/Fm′) in moldavian balm plants, while increasing superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and hydrogen peroxide (H2O2) content compared to the control (no water stress). Inoculation with PGPBs and Piriformospora indica helped alleviate the negative effects of water stress. The highest MSI (48%) and Fv′/Fm′ value (0.82) were observed when inoculated with Enterobacter and Piriformospora, respectively, under non-water-stressed conditions. Inoculation with Agrobacterium, Piriformospora, and Enterobacter improved the Chlt and leaf proline contents, as well as the SOD activity under high water stress, compared to the non-inoculated control values. Furthermore, inoculation with Pseudomonas under high water deficit stress levels increased the MDA content (0.51 mmol g−1 FW) and H2O2 levels (0.40 mmol g−1 FW). The highest yield of flowering branches (2.414 g pot−1) in moldavian balm was obtained with Enterobacter. Based on the enhanced physiological and biochemical responses, as well as increased antioxidant enzyme activity that improve water tolerance in this plant, it is recommended to use PGPBs and Piriformospora indica fertilization. [ABSTRACT FROM AUTHOR]

Plant growth-promoting bacteria (PGPBs) play a crucial role in mitigating the oxidative damage caused by water stress in different plant species. The aim of this study was to determine the effects of PGPBs and mycorrhiza-like fungi (Piriformospora indica) on improving drought tolerance in moldavian balm (Dracocephalum moldavica L.), a medicinal and aromatic plant. For this purpose, a greenhouse study was conducted in a factorial experiment based on a randomized complete design with three replications. Results indicate that water stress reduces the membrane stability index (MSI), total chlorophyll content (Chlt), carotenoids, and maximum photochemical efficiency of photosystem II (Fv′/Fm′) in moldavian balm plants, while increasing superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and hydrogen peroxide (H2O2) content compared to the control (no water stress). Inoculation with PGPBs and Piriformospora indica helped alleviate the negative effects of water stress. The highest MSI (48%) and Fv′/Fm′ value (0.82) were observed when inoculated with Enterobacter and Piriformospora, respectively, under non-water-stressed conditions. Inoculation with Agrobacterium, Piriformospora, and Enterobacter improved the Chlt and leaf proline contents, as well as the SOD activity under high water stress, compared to the non-inoculated control values. Furthermore, inoculation with Pseudomonas under high water deficit stress levels increased the MDA content (0.51 mmol g−1 FW) and H2O2 levels (0.40 mmol g−1 FW). The highest yield of flowering branches (2.414 g pot−1) in moldavian balm was obtained with Enterobacter. Based on the enhanced physiological and biochemical responses, as well as increased antioxidant enzyme activity that improve water tolerance in this plant, it is recommended to use PGPBs and Piriformospora indica fertilization. [ABSTRACT FROM AUTHOR]

Intercropping is one of the most important components of sustainable agriculture. The effects of chemical fertilizer (CF), arbuscular mycorrhizal fungi (AMF) (Glomus sp.) and AMF + nitrogen-fixing bacteria (NFB) including Azospirillum and Azotobacter (AMF + NFB) was studied on essential oil yield and compositions of Moldavian balm (Mb) (Dracocephalum moldavica L.) in sole cropping and intercropping with fenugreek (F) (Trigonella foenum-graecum L.). The experiment was conducted during 2020 and 2021 growing seasons in East Azarbayhan, Iran. The highest dry herbage yield (6132 kg ha−1) was obtained in Mb:F(4:2) and CF treatment. After sole Moldavian balm, the highest essential oil yield (15.28 kg ha−1) was obtained in Mb:F (4:2) and AMF + NFB treatment. Geranial, geranyl acetate, geraniol, neral, and nerol were the main chemical constituents of essential oil. In AMF + NFB treatments the geranial contents in intercropping patterns of Mb:F (1:1), (2:2) and (100:50), increased by 25.1, 15.5 and 34.6% compared with sole Moldavian balm. The highest LERT values were observed in Mb:F (100:50) cropping pattern in 2021 (1.70 and 1.63 for CF and AMF + NFB treatments). Generally, it can be concluded that Mb:F (100:50) intercropping and use of AMF + NFB bio-fertilizer could be recommended to medicinal plant growers in sustainable production systems. [ABSTRACT FROM AUTHOR]

Astrodaucus orientalis is a weed species in cropping systems and rangelands in Iran. The effects of temperature, light, NaCl concentration, water potential, seed burial depth and crop residue cover were assessed on seed germination and seedling emergence of two populations of A. orientalis from Ardabil (Meshginshahr population) and East Azarbayjan (Tabriz population) provinces of Iran. The A. orientalis populations indicated different responses to environmental factors and burial depth. In the Tabriz population the greatest germination (88.5%) was observed in 20/12°C day/night temperature but in the Meshginshahr population (83.2%) it was obtained in 24/16°C day/night temperature. Over a broad range of light period (10–24 hr light) germination was 74–83%, but it decreased (less than 37%) under 24 hr dark in both A. orientalis populations. With respect to water potential, the C50 parameters were −0.62 and − 0.49 MPa for Tabriz and Meshginshahr populations, respectively. The D50 parameters (the burial depth that caused 50% decrease in emergence) for Tabriz and Meshginshahr populations were 2.42 and 3.13 cm, respectively. Generally, the results showed that emergence of both populations of A. orientalis was delayed as depth of burial increased up to 4 cm and in cropping systems a shallow tillage that locates the seeds to >4 cm of depth in soil could be used in order to suppress seedling emergence. Our findings also could be useful in integrated management of A. orientalis in winter annual crops and rangelands. [ABSTRACT FROM AUTHOR]

The Moldavian balm essential oil contains numerous medicinal values in addition to its other wide application. The present study was carried out to evaluate the effect of plant growth-promoting bacteria and mycorrhiza-like fungi inoculation on Moldavian balm (Dracocephalum moldavica L.) essential oil yield and composition under drought stress condition. The experiment was arranged as factorial based on a randomized complete block design with three replications. The first factor was drought stress at four levels including no drought stress, low, medium and high drought stress. The second factor was inoculation treatments comprising of non-inoculated control, inoculation with Enterobacter sp., Pseudomonas sp., Agrobacterium sp. and Piriformospora indica. The results indicated that the interaction effect of drought stress × inoculation was significant on dry weight, essential oil content and yield of D. moldavica. Under all drought stress levels, inoculation with Enterobacter, Agrobacterium and Piriformospora increased the dry weight and essential oil yield of D. moldavica, compared with those in non-inoculated control. While the result of dry weight and essential oil yield from inoculation with Pseudomonas was almost equal to that of the non-inoculated control. The main components of essential oil were geranial followed by geraniol, geranyl acetate, neral, neryl acetate and geranyl formate. The chemical composition of essential oil was affected by drought stress and inoculation levels. Under all drought stress levels, the geranyl acetate content was found to increase in inoculation treatments with Enterobacter sp., Pseudomonas sp., Agrobacterium sp. and Piriformospora indica respectively. In general, inoculations with Piriformospora indica, Agrobacterium and Enterobacter increased the dry weight and essential oil yield under all drought stress levels and could be recommended to growers to reduce the application of chemical fertilizers in D. moldavica production. [ABSTRACT FROM AUTHOR]

Common cocklebur (Xanthium strumarium L.) is a summer annual weed of the corn fields in the north-western parts of Iran. Field experiments were conducted in 2013 and 2014 to examine the seedling emergence and growth of common at different achene (seed) burial depths (3, 6, 9, 12, 15 and 18 cm) and wheat straw mulch amounts (0, 1.5, 3.0 and 4.5 ton ha-1). Results indicated that increasing achene burial depth and mulch amount reduced X. strumarium seedling emergence. In both years, no seedling emergence was observed from 18-cm achene burial depth. X. strumarium biomass and achene number per plant were affected by achene burial depth and mulch amount, and were greater in 2014 than in 2013. The corn leaf area index (LAI) and grain yield were higher in the treatments which deeper achene burial depth and mulch amount were high. Therefore, X. strumarium emergence in the corn can be suppressed by a tillage that buries the achenes to ≥18 cm of soil depth. Maintaining a thick residue cover will provide competitive advantage of corn over X. strumarium due to an inhibitory effect on X. strumarium emergence and growth and may lead to a reduction in the future weed infestation. [ABSTRACT FROM AUTHOR]

Lepidium vesicarium is a weed species with a wide distribution in the rangelands and dry-land farming in East Azarbaijan, Iran. The experiments were undertaken to assay the effects of light, temperature, pH, osmotic potential, NaCl concentration and burial depth on seed germination and emergence of L. vesicarium. Germination was maintained at high levels (> 80%) over a wide day/night temperature range (10/5 to 30/20°C), but a severe reduction in the germination rate of L. vesicarium was found below 20/10°C. Germination of L. vesicarium was influenced by different light/dark regimes, as the germination rate was highest at 16 h light for the all treatments (0, 8, 12, 16 and 24 h light). Germination was 92-95% over a wide range of pH (2-10). Germination was >50% at a water potential of −0.7 MPa and salinity of 21 dS/m, indicating that drought and salt conditions have a minimal impact on seed germination. With increasing burial depth from 0 to 2 cm, the number of days required for 50% emergence increased and no germination was observed at burial depths deeper than 3 cm. This suggests that L. vesicarium would become troublesome in the rangelands and for growers in reduced-tillage cropping systems. The ability to emerge from shallow depths, coupled with tolerance of a wide pH range, drought and salinity at germination, should be taken into account when managing this weed species. [ABSTRACT FROM AUTHOR]

Field experiments were conducted in 2006 and 2007 to evaluate the competitive ability of bush type red kidneybean (RKB) ( Phaseolus vulgaris L.) cultivars against redroot pigweed ( Amaranthus retroflexus L.). Three cultivars of RKB (Akhtar, Sayyad and D81083) and five A. retroflexus densities (0, 4, 8, 16 and 32 plants m −2 ) were established in a factorial arrangement. A. retroflexus had a greater plant height and growth rate (GR) but a lower leaf area index (LAI) than RKB cultivars in almost all treatments. Higher densities of A. retroflexus increased LAI and GR but decreased yield of RKB cultivars. The cv. Sayyad and D81083 had the greatest and lowest LAI and GR, respectively, in competition with A. retroflexus . The maximum intercepted photosynthetically active radiation (PAR) at noon by A. retroflexus was 90.4 and 66.0% in competition with cv. D81083 and Sayyad, respectively. The seed yield and pod number per plant of RKB cultivars decreased severely with increasing A. retroflexus density. A. retroflexus seed number m −2 was the highest and lowest in competition with cv. D81083 and Sayyad, respectively. The competitive ability of RKB cultivars was compared using parameters estimated through two-parameter yield loss-relative leaf area model. The relative ranking of the RKB cultivars examined for their competitiveness, supported by modeling results, was Sayyad > Akhtar > D81083. [ABSTRACT FROM AUTHOR]

• Integration of herbicides with straw mulch increased the weed control efficacy and EO yield in Moldavian balm. • Generally the weed control efficacy of trifluralin was higher than that of pendimethalin. • The highest weed biomass reduction (83.8 %) and EO yield (22.51 kg ha−1) were observed in trifluralin R + mulch. • Straw mulch application increased the geraniol content and decreased the geranyl acetate content in EO of Moldavian balm. • Trifluralin 50 %R + mulch could be recommended as a more sustainable weed management method in Moldavian balm production. In sustainable production of medicinal and aromatic plants, reduction in herbicide application rate and using straw mulch could be used as strategies for integrated weed management. The field study was carried out to evaluate the effects of herbicides reduced rate integrated with straw mulch on sustainable weed management, essential oil (EO) content and composition of Moldavian balm (Dracocephalum moldavica L.). The experiment was done in Agricultural Research Station of University of Tabriz, Iran, from April 2016 to July 2017. The treatments were consisted of two herbicide rates including recommended rate (R) and reduced rate (50 % R) of trifluralin and pendimethalin, integration of all herbicide treatments with mulch application (5 t ha−1) and mulch application alone. The effect of weed management treatment was significant on weed density and biomass and Moldavian balm dry weight and EO yield. Among the weed management treatments, the lowest weed biomass (17.1 g m-2) and the highest EO yield (22.51 kg ha−1) were observed in trifluralin R + mulch (TR + M) treatment. Integration of all herbicide treatments with straw mulch reduced the weed density and biomass and increased the Moldavian balm dry weight and EO yield, significantly. Generally the weed control efficacy of trifluralin was higher than that of pendimethalin. Gas chromatography - mass spectrometry analysis showed that the main constitutes of EO were geraniol, geranial, geranyl acetate, neral, nerol and neryl acetate. The contents of main components were influenced by weed management treatments, differently. The highest content of geraniol (41.4 %) and geranial (24.7 %) were obtained in TR + M and pendimethalin R + mulch (PR + M) treatments, respectively. Integration of all herbicide treatments with straw mulch increased the geraniol content and reduced the geranyl acetate content in EO. The weed density and biomass and Moldavian balm EO yield in trifluralin 50 % R + mulch (T50R + M) treatment were not significantly different with those in trifluralin R (TR). Therefore TR treatment could be replaced with T50R + M and recommended to medicinal plants growers as a more sustainable weed management method in Moldavian balm production. [ABSTRACT FROM AUTHOR]

Organic fertilizers and intercropping with legumes can be used as alternatives for chemical fertilizers in sustainable production. In order to evaluate the effects of chemical fertilizer (CF), bio-fertilizer (BF) and vermicompost (VC) on essential oil content, yield and chemical compositions of Moldavian balm (MB) in sole crop and intercropping with faba bean (FB) a field study was carried out in Iran in two growth seasons. Results indicated that the interaction effect of cropping pattern × fertilizer was significant on dry herbage yield of Moldavian balm (P ≤ 0.05) and among the intercropping patterns the highest values were obtained in FB:MB 2:2 intercropping. Essential oil content affected by fertilizer treatment and the highest value (0.57%) was observed in CF treatment. The effects of year, cropping pattern and fertilizer were significant (P ≤ 0.01) on essential oil yield and among the intercropping patterns the F:M 2:2 had the greatest value (19.26 kg ha−1). The major chemical components of Moldavian balm essential oil were geraniol, geranyl acetate, geranial and neral. The contents of major components were affected differently by cropping pattern and fertilizer. In intercropping patterns the contents of geraniol increased in BF and VC treatments but the content of geranyl acetate increased in CF treatment compared with sole crop. In both years and all treatments the land equivalent ratios (LER) were greater than one and the greatest LER (1.38) was obtained in FB:MB 2:2 under BF treatment. Generally we can conclude that intercropping and application of bio-fertilizer and vermicompost increased the yield of Moldavian balm and faba bean and also enhanced the contents of major components of essential oil. Therefore these strategies could be considered as alternatives for chemical fertilizer in order to recommend in sustainable production of Moldavian balm. • The highest essential oil yield of Moldavian balm was obtained in FB:MB 2:2 intercropping pattern. • The chemical fertilizer had the highest Moldavian balm essential oil content and yield. • Geraniol, geranyl acetate and geranial were the major components of Moldavian balm essential oil. • The highest geraniol content (42.13%) was obtained in FB:MB 1:1 intercropping and vermicompost treatment. • At all intercropping and fertilizer treatments the land equivalent ratios (LER) were greater than one. [ABSTRACT FROM AUTHOR]

Cropping systems of safflower (Carthamus tinctorius L.) with faba bean (Vicia faba L.) under different fertility were compared with sole cropping of each crop during 2015 and 2016 at the Research Farm of Tabriz University in Iran. The treatments were cropping systems (safflower and faba bean sole croppings, intercropping systems of safflower and faba bean with ratios of 1:1 and 2:1), and nutrient levels (100% chemical fertilizers, 60%, 30% chemical + biofertilizers and no fertilizer). A factorial set of treatments based on a randomized complete block design replicated three times was used. Cropping system and fertility effects were significant for yield and yield components of each crop. Yield and yield components were increased with the integrated use of 60% chemical plus biofertilizers for both years, while seed yield was reduced by intercropping. Maximum land equivalent ratio (LER), relative value total (RVT), system productivity index (SPI) and monetary advantage index (MAI) were achieved in nutritive level of 60% chemical plus biofertilizers as intercropped plants in ratio of 1:1 for both years. The total actual yield loss (AYL) values were positive and greater than zero in all mixtures, indicating an advantage from intercropping over sole crops. Intercropped safflower had a higher relative crowding coefficient (RCC) than intercropped faba bean, indicating that safflower was more competitive than faba bean in intercropping systems. From this study, it is inferred that intercropping (safflower and faba bean) with integrated use of the reduced chemical and biofertilizers may give better overall yield and income than sole cropping of each crop species. [ABSTRACT FROM AUTHOR]

Multispecies competition effects of Xanthium strumarium L. and Datura stramonium L. have not been characterized in maize (Zea mays L.). Such information would be useful in developing an integrated approach to managing these two problematic weeds. Field experiments were conducted during 2 yr to evaluate multiple weed species interference of X. strumarium and D. stramonium at the total densities of 0, 4, 8, 12, and 16 plants m-2 (alone, and all possible combinations of the two weeds) with maize. Crop yield was associated with the density of D. stramonium and X. strumarium and decreased severely with increasing weed density. The maximum maize yield loss (63%) occurred when 12 X. strumarium and 4 D. Stramonium plants m-2 were allowed to compete with the crop. The total weed density (expressed in X. strumarium equivalent density) required to cause a 5% maize yield loss was about 0.50 and 0.56 plants m-2 in 2006 and 2007, respectively. Total canopy leaf area index and crop yield were reduced more strongly by competition with X. strumarium than with D. stramonium. Averaged over multispecies populations, X. strumarium contributed 84 and 67% of the total weed biomass in the first and second years, respectively. Owing to the high competitive ability and biomass production of X. strumarium in mixed crop and weed communities, it should be given a greater priority for control than D. stramonium in maize. [ABSTRACT FROM AUTHOR]