In the vicinity of copper foundry “Głogów” agricultural farms exist for 35 years. The aim of the work was to determine if biotypes of common lambsquarters (Chenopodium album L.) growing for many years in heavy metals polluted environment showed any differences in the efficacy of herbicides’ control. Seeds of C. album were collected near Głogów, from four cultivated fields with different content of heavy metals in soil (mainly copper). From these seeds experimental plants were grown in greenhouse conditions. In greenhouse experiments the efficacy of control of C. album by different pyridate (6-chloro-3-phenylpyridazin-4-yl S-octyl thiocarbonate) doses also in combinations with 0.2% CuSO4 was compared. Also the efficacy of pyridate in control of C. album seedlings which were grown in pots with soils collected from the vicinity of smelter was tested. Additionally, in growth chamber, the effect of increasing copper concentration on shoot and root growth was analyzed. Pyridate showed similar efficacy on tested populations of C. album without respect of soil contamination level, seeds’ origin and presence of copper ions in spray solution in which herbicide was used in full dose. Statistical differences were observed when herbicide was applied at ⅓ pyridate full dose, especially in the presence of Cu2+ ions in spray solution.
The herbicide atrazine was incorporated in the granules manufactured in the process of tumbling agglomeration to obtain controlled release (CR) formulations. The formulations contained bentonite as a CRmatrix forming agent (960–974 g/kg of dry granules), atrazine (10 g/kg), citric acid (3.2 g/kg), and sodium alginate as a matrix binder and a release modifier (12.8–26.8 g/kg). The release characteristics of atrazine were studied by immersion of the granules in static water. The effects of formulations on atrazine transport through soil were studied using model soil columns irrigated with water. The release of atrazine from CR granules into water was affected by increasing the alginate concentration in a particular formulation because the time necessary for the release of 50% of the active ingredient was longer for the granules containing a higher amount of alginate. The CR formulations significantly reduced the amount of atrazine leached to the soil surface horizon in comparison with the commercial water suspension of the herbicide.
The “second generation” of glyphosate-tolerant soybean (GT2 soybean) was developed through a different technique of insertion of the glyphosate-insensitive EPSPs gene, in comparison with “first generation” of glyphosate-tolerant soybean. However, there is not enough information available about glyphosate selectivity in GT2 soybean and the effects on the quality of seeds produced. The aim of this study was to evaluate tolerance to glyphosate and seed quality of soybean cultivar NS 6700 IPRO (GT2) with cp4-EPSPs and cry1Ac genes, after application at post-emergence (V4). The experiment was conducted in a randomized block design with four replicates and seven treatments, or rates of glyphosate (0; 720; 1,440; 2,160; 2,880; 3,600; 4,320 g of acid equivalent − a.e. · ha−1). Assessments were performed for crop injury, SPAD index and variables related to agronomic performance and seed quality. A complementary trial with the same cultivar and treatments in a greenhouse was conducted in a completely randomized design with four replications. Data analysis indicated no significant effect of glyphosate on V4 on agronomic performance and physiological quality of seeds, for two growing seasons. The soybean cultivar NS 6700 IPRO (GT2), with cp4-EPSPs and cry1Ac genes, was tolerant to glyphosate up to the maximum rate applied (4,320 g a.e. · ha−1) at post-emergence (V4). The quality of soybean seeds was not affected by glyphosate up to the maximum rate applied (4,320 g a.e. · ha−1) at post-emergence (V4).
Weeds are one of the most important limiting factors in the production of chickpea (Cicer arietinum) in Iran, especially in autumn sown chickpea. Weed density and biomass in autumn chickpea are seven and two and a half times higher than the spring chickpea, respectively. The weed damage to chickpea in Tabriz, Kermanshah and West Azerbaijan was estimated at 48.3, 57 and 36%, respectively. Sixty-four weed species were identified in chickpea fields. Convolvulus arvensis L. and Galium tricornutum Dandy have the highest presence in chickpea fields. Pyridate and linuron are the only herbicides registered for use in chickpea fields in Iran. However, research results show that fomesafen and isoxaflutole are the most appropriate herbicides for chickpea fields. Oxyfluorfen, imazethapyr, metribuzin, trifluralin, simazine, terbutryn and pendimethalin are the major herbicides studied in weed control research. The combination of herbicides and mechanical control is one of the effective methods to reduce weeds. Hand weeding and cultivation between rows are the most effective mechanical methods of weed control. High nitrogen enhances weed dry weight. Safflower and barley residues reduce weed populations and biomass. Barley-chickpea and wheat-chickpea intercropping systems increase chickpea yield together with proper weed control. In future research, more attention should be paid to surfactants to reduce the use of herbicides, rotation crops and integrated weed management in chickpea.
There are few reports in literature about the selectivity of postemergence application of herbicides for the control of eudicotyledon weeds (broadleaf) in chickpea. For this reason, the aim of this study was to investigate the selectivity of diphenyl-ether herbicides in chickpea influenced by the herbicides and application rates. A field experiment was conducted from February to June 2017 in Urutaí, state of Goiás, Brazil. Cultivar BRS Aleppo was used in the experiment. The experiment was set up in a randomized block design with 2 × 3 + 1 factorial arrangement and three replications. The first factor was herbicides (fomesafen and lactofen) with the second factor being herbicide rate (50, 75, and 100% of referenced rate) plus an untreated check as a comparison. The applied rates of herbicides were 250 and 180 g ⋅ ha–1 of fomesafen and lactofen, respectively. The selectivity of herbicides was evaluated according to agronomic characteristics (plant population, height, dry matter, number of pods per plant and 100-grain weight) and yields. Both herbicides, regardless of dosage, were selective in chickpea cultivation, even exhibiting leaf necrosis symptoms with visible injuries below 20% with no effect on yield.
This weed management investigation was carried out at the Zonal Agricultural Research Station (ZARS), Bangalore, during the summers of 2017 and 2018 to standardize agrotechniques for weed management of rice grown under aerobic conditions. The experiment was laid out in a randomized complete block design with eleven treatments replicated thrice. It consisted of two pre-emergence herbicides and one early post-emergence herbicide, the stale seedbed technique, mulching, hand weeding and intercultivation which was compared to the weedy check. The results showed that pyrazosulfuron ethyl 10% wettable powder (WP) at 35 active ingredient (a.i.) g ⋅ ha–1 as PE fb bispyribac sodium 10% SC at 30 ml ⋅ ha–1 a.i. as an early post-emergence herbicide performed better in terms of rice grain and straw yield (5,800 and 9,786 kg ⋅ ha–1, respectively), plant height (58.42 cm), rice total dry matter production (149.84 g ⋅ plant–1), productive tillers ⋅ hill–1 (40.32), panicle length (24.53 cm), 1000 grain weight (25.35 g), net returns (Rs. 62424), higher B : C ratio (2.59) and lower total weed density, weed dry weight at different stages of rice and weed index (3.80%) as well as higher weed control efficiency (90.52%). This practice could be recommended to farmers growing aerobic rice under these climatic conditions.
Two field experiments were established at the Agricultural Experimental Station of the National Research Centre at Nubaria, Beheira Governorate, Egypt to study the herbicidal potential of the leaf extract of Eucalyptus citriodora at 5, 10, 15, 20 and 25% compared to two hand hoeing, unweeded treatments and the chemical herbicides Bentazon + Clethodium, Bentazon + Fluazifop-P-butyl and Butralin on pea plants and associated weeds. The results indicated that two hand hoeing achieved the maximum weed depression as expressed by the dry matter of total weeds. The dry matter of total weeds decreased by 95.08 to 94.77% as compared with unweeded treatment 50 and 70 days after sowing (DAS) followed by Butraline (93.93–94.65%), Bentazon + Clethodium (93.26–94.07%), Bentazon + Fluazifop--P-butyl (91.82–92.77%) and leaf extract of Eucalyptus at 25% (91.61–91.95%). Furthermore, the reduction in weed development was accompanied by enhanced pea growth and yield. The results revealed that two hand hoeing was the best treatment to increase plant height, shoot dry weight and SPAD value at 50 and 70 DAS. Also, two hand hoeing produced the maximum values of pod length and number of seeds/pod. The results also indicated that Bentazon + Clethodium treatment gave observable values [recorded 72.96% in pod yield (ton ⋅ fed.–1) over that of unweeded control] of number of pod/plant, weight of pod/plant, seed yield/fed and protein percentage. Also, the results revealed great increases in the growth of pea as well as yield due to treatment with E. citriodora dry leaf extract at 25%. [recorded 64.8% in in pod yield (ton ⋅ fed.–1) over that of unweeded control]. So, the results indicated using Bentazon + Clethodium as well as E. citriodora dry leaf extract at 25% to control weeds associated with pea plants. The authors suggested application of E. citriodora dry leaf extract at 25% in controlling weeds associated with pea plants as a safe method that avoids environmental contamination.
Redroot pigweed (Amaranthus retroflexus L). is a broadleaf weed in autumn crop fields in Russia. Four field experiments were performed in Stalskiy region, southern Russia in two growing seasons, 2016 and 2017, to investigate the effects of postemergence applications of applied alone or in tank mixtures in winter wheat cultivars Tanya and Bagrat. Redroot pigweed control was greatest with tribenuron and all herbicide treatments containing tribenuron. The lowest redroot pigweed control was with aminopyralid/florasulam (study 1) and triasulfuron (study 2), respectively, whereas redroot pigweed had intermediate responses to the other examined herbicides. Tribenuron plus fluroxypyr sprayed on wheat cultivar ‘Tanya’, and tribenuron plus triasulfuron on wheat cultivar ‘Bagrat’ resulted in increased wheat grain yields. Overall, tribenuron and herbicides containing tribenuron provided the most efficient redroot pigweed control compared with the other herbicides and consistently maintained optimal winter wheat yields. Tribenuron could ameliorate redroot resistance to herbicides in wheat fields in southern Russia.