Estimating Carbon Capture Potential of Fallow Weeds in Rice Cropping Systems

Weeds occurred during the fallow season can well perform the function of carbon(C)capture due to receiving little human disturbance.This study aimed to evaluate the C capture potential of fallow weeds in rice(Oryza sativa L.)cropping systems.A six-region,two-year on-farm investigation and a three-year tillage experiment were conducted to estimate C capture in fallow weeds in rice cropping systems.The on-farm investigation showed that the average mean C capture by fallow weeds across six regions and two years reached 112 g m^(-2).The tillage experiment indicated that no-tillage practices increased C capture by fallow weeds by 80%on average as compared with conventional tillage.The results of this study not only contribute to an understanding of C capture potential of fallow weeds in rice cropping systems,but also provide a reference for including fallow weeds in the estimation of vegetative C sink.

Fungal Flora on Weeds in the Cashew (Anacardium occidentale L.) Orchard in Côte d’Ivoire

Since 2015, Côte d’Ivoire has been the world’s largest cashew producer. However, cashew orchards in Côte d’Ivoire are infected by fungal diseases that weaken production. And the contribution of weeds to the spread of these diseases is not yet understood. This study was initiated with the aim of establishing the role of weeds in the proliferation of pathogenic fungi in orchards. It consisted of a survey of weeds showing disease symptoms in cashew orchards in Côte d’Ivoire from February 2021 to July 2022. The itinerant method was used for the weed inventory. Symptomatic leaves were collected and sent to the laboratory for diagnosis on PDA (Potatoes Dextrose Agar) medium. In total, 50 species in 46 genera and 23 families were recorded. Laboratory diagnosis of the samples showed that 80% of the weeds identified harboured pathogenic fungi. The highest infection rates were obtained on Danielia oliveri R. (99.33% to 100%), Vitellaria paradoxa G. (100%), Pterocarpus erinaceus P. (83.91% to 99.33%), Micuna pruriens L. (98.33% to 100%) and Isoberlinia doka C. et S. (56.33% to 100%). The diagnosis revealed the presence of Lasiodiplodia sp, Colletotrichum sp, Pestalotia sp, Alternaria sp and Curvularia sp on weeds in the cashew orchard in Côte d’Ivoire.

Investigation of Types and Hazard of Weeds in Coffea arabica Orchads in Nujiang River Basin

[Objective] Through the investigation of weeds in Coffea arabica orchads in NuJiang River basin, this study aimed to provide scientific guidance for the weed control and improving the ecological and economic benefits of the plantation of Cof- fea arabica. [Method] The types of weeds and the characteristics of weed occur- rence in Coffea arabica orchads in Nujiang River basin were investigated from July to August in 2012. [Result] The results showed that there were 69 types of weeds belonging to 21 families in Coffea arabica orchads. The predominant harmful types were shown as follows： Commelina nudiflora L. ＋ Leptochloa chinensis, Cyperus ro- tundus L. ＋ Bidens pilosa L. ＋ Eleusine indica, Imperata cylindrical ＋ Ageratum conyzoides L. ＋ Eupatorium odoratum L., Ageratum conyzoides L. ＋ Digitaria san- guinalis （L.） Scop. The preponderant weeds consisted mainly of 10 species, namely, Cyperus rotundus L., Commelina nudiflora L., Leptochloa chinensis, Digitaria san- guinalis （L.） Scop, Imperata cylindrical, Bidens pilosa L., Ageratum conyzoides L, E- upatorium odoratum L., Eleusine indica and Chenopodium serotinum L. [Conclusion] The result from this study is of great significance for the plantation of Coffea arabica in Nujiang River basin, as well as the control of weeds.

Effects of Rice-duck Mutualism on Diseases Insect Pests and Weeds and Economic Benefits

[Objective] Study on the effects of rice-duck mutualism on weeds and insects pests and economic benefits of paddy field. [Method] Comparison of the incidence of weeds, sheath blight and insects pest under rice-duck mutualism, conventional cultivation and control treatment, the yield and economic benefits were analyzed under the 3 treatments. [Result] Average occurrence of weeds in rice-duck mutualism group decreased by 2.33 and 52.0g ind/m^2 compared with that in conventional cultivation and control treatment ; the control rate of mutualism was up to 75% against rice hopper, but just between 25% -60% against rice leaf roller and Chilo suppressalis. The rates of diseased plant and diseased bell against rice sheath blight were higher and disease indices were lower compared with control group. The yield of mutualism group was identical with conventional cultivation, Which was greatly higher than that of control group. The results suggested an higher economic benefits and lower cost benefit ratio for rice-duck mutualism treatment. [Conclusion] Rice-duck mutualism gives birth to a positive effect to control the diseases, insect pests and weeds, as well as to economic benefits, providing basis on extension of rice-duck mutualism system.

Damage and Control of Poisonous Weeds in Western Grassland of China

Western grassland is the main source of living and means of production of western inhabitants. For many years, desertification and poisonous-weeds growth in grassland were resulted from over-grazing, over-reclaiming, over-spading and population growth. Western natural ecological environment is destroyed severly. Meanwhile, it has restricted the sustainable development of animal husbandry. The fast spreading poisonous-weeds, which caused grassland ecology unbalance, is one of the considerable bioecology problems and an important index of grassland degeneration. Based on analysis and induction of previous data, this article introduced the situation of poisonous-weeds disaster of western grassland in recent decades, category and distribution of poisonous-weeds, integrated control and reasonable utilization.

Control Efficiency and Crop Safety of 20% Cyhalofop-butyl WP on Grass Weeds in Direct Seeded Rice Fields

The purpose was to define the control efficiency and safety of 20% cy- halofop-butyl WP on grass weeds in direct seeded rice fields, in order to provide the basis for chemical weeding. This study measured Leptochloa chinensis（L.） Nees, Echinoch/oa crusgalli （L.） Beauv and other gramineous weed control efficiency with four concentrations of 20% cyhalofop-dutyl WP and 100 g/L cyhalofop-dutyl EC in direct seeded rice fields, and analyzed the yield-increasing effect and safety of rice. The results showed that 20% cyhalofop-butyl WP had a good control efficiency on grass weeds such as Leptochloa chinensis（L.） Nees, Echinoch/oa crusgalli（L.） Beauv and other grasses. The effective dosage of 90-150 g/hm2 was over 90.7% on Lep- foch/oa chinensis（L.） Nees and the comprehensive control effect of the grass weeds was above 86.7%, which was basically consistent with 100 g/L cyhalofop-dutyl EC. Furthermore, 20% cyhalofop-dutyl WP was high security for direct seeded rice fields. The yield of rice was increased by 10.18%-11.22% after spraying herbicide. There- fore, 20% of cyhalofop-dutyl WP can be used as a special herbicide for controlling Leptochloa chinensis（L.） Beauv in direct seeded rice fields, and has a good applica- tion prospect.

Chemical Control of Herbicide Monosulfuron Plus Propazine 44% WP against Weeds in Millet Fields and Study on Factors Influencing Yield of Millet

[Objective] The paper was to resolve the poor efficacy or phytotoxicity problems in promotion of herbicide monosulfuron plus propazine 44% WP. [Method] Using orthogonal test and Duncan＇s new multiple range statistical analysis with four factors four levels and three factors two levels, the effects of factors such as herbi- cide dose, irrigation water volume, quality of soil preparation and soil moisture content on chemical control of monosulfuron plus propazine 44% WP against weeds and millet yield were compared in the test. [Result] Seven factors all had great impact on control effect of monosulfuron plus propazine 44% WP against weeds, of which her- bicide dose, irrigation water volume, quality of soil preparation and soil moisture content were the most important factors affecting millet yield. According to millet yield and economic benefit, the optimal scheme to ensure safe, efficient and economic control of monosulfuron plus propazine 44% WP against weeds was as follows： the dose of monosulfuron plus propazine 44% WP was 1 800 g/hm2, the soil was treat- ed after sowing and before seedling emergence; the soil should be smooth and sol- id; the soil moisture should reach 15%; the fields should not be irrigated after herbi- cide application, and the damage of weeds in millet fields could be effectively con- trolled within 45 d during high efficacy duration, especially the damage of dicotyledonous weeds. [Conclusion] The study provided useful information for comprehensive technology of weeds control and ensuring high yield and good harvest of millet.

Effects of Paddy Field Rotation on Diseases,Pests and Weeds of Rice

[ Objective] The paper was to explore ecological effect of paddy field rotation on reducing disease, pests and weeds of rice. [ Method] With long-term continuous cropping rice as control, according to field location experiments for consecutive 14 years, the effects of paddy field rotation on diseases, pests and weeds of rice were studied in details. [ Result] Paddy field rotation in some extent could reduce diseases, pests and weeds of rice. The diseased plant rate and disease in- dex of rice sheath blight in early rice under paddy field rotation treatment were averagely 10% and 0.4% lower than those in continuous cropping treatment, respec- tively. The diseased plant rate and disease index of rice sheath blight in late rice were 17.7% and 13.3% lower than those in treatments with continuous cropping mode, respectively. The diseased plant rate and disease index of rice false smut in both early rice and late rice under rotation treatments were lower than those in treatments with continuous cropping mode. White leaf rate caused by rice leaf roller and dry heart rate caused by striped rice borer under rotation treatments were significantly lower than those under continuous cropping treatment. The growth status of weeds under rotation treatments was weaker than that under continuous cropping treatment. [ Conclusion] The paper has important significance on alleviating diseases, pests and weeds of rice and improvement of ecological environment of farmland, and provides theoretical basis for sustainable development of agriculture.

Control Effects of 3 Kinds of Herbicides against Weeds in Dogbane (Apocynum venetum) Field

[ Objective] The paper was to explore the control effects of 3 kinds of herbicides against weeds in dogbane （Apocynum venetum） field. [ Method ] Using haloxyfop-R-mithyl and quizalofop-ethyl EC specifically killing monagenns gramineous weeds and chipton specifically killing dicotyledonous broad-leaf weeds, the control test against weeds in 2-year-old dogbane field was carried out. [ Result ] Haloxyfop-R-mithyl had good control effect against gramincous weeds, and its control effect against both barnyard weed （ Echinochloa crusgalli） and green bristleweed （ Setaria viridis ） was greater than 35.0% ; the control effects of quizalofop- ethyl EC against barnyard weed and green bristleweed were 14.8% and 28.6%, respectively; chipt0n had good control effect against Chenopodium album, and the control effect reached 30.8%. Moreover, 3 herbicides did not cause damage to dogbane. [ Conclusion] The study provide theoretical basis for completing cultivation technique of dogbane.

A Review on Reasons of Increasing Perennial Weeds and Control Technology of Perennial Weeds in Heilongjiang Province

The main reasons that perennial weeds has becoming the dominant weeds in Heilongjiang Province were summarized. The biological mechanism that explained why it was difficult to control perennial weeds was analyzed. During dormancy course, variation regularity of some inner matters in perennial weeds was researched and new tentative for controlling the perennial weeds was pointed out.

Preliminary Report on Species and Occurrence Regularity of Diseases,Pests and Weeds of Corn in Angola

[ Objective] The paper was to understand species of diseases, pests and weeds and their occurrence periods and dynamic changes of quantity during corn growing period in rainy and dry seasons in Angola. [ Method] Using systematic investigation method, the species and occurrence regularity of diseases, pests and weeds of corn in Pedras Negras farm （ Malanje）, Sanza Pombo farm （Uige） and Catete farm （Luanda） in the Mrican continent, the Republic of Angola, were studied in two dry seasons and a rainy season from 2011 to 2012. [ Result] The occurrence status of pests and diseases of corn during dry and rainy seasons were basically similar, and only individual diseases and pests had different incidence degrees. The corn varieties from the United States and Brazil had prominent advan- tages in resistance to diseases and barren. Due to different climate environments in dry and rainy seasons, the unearthed rate of weeds in fields was also different. Soil moisture had great impact on weed population and density. Soil layer depth greatly influenced unearthed speed and unearthed rate of weeds. [ Conclusion ] The study cleared species, occurrence period and harmful levels of pests, diseases and weeds of corn in three provinces of Angola.

Occurrence, Damage and Control Strategies of Major Pests, Diseases and Weeds in Sugarcane Areas of Lincang Nanhua Sugar Industry Co., Ltd.

The pests, diseases and weeds in sugarcane areas of Lincang Nanhua Sugar Industry Co.,Ltd. were investigated at seedling stage, growth stage and maturity stage of sugarcane from 2012 to 2016. The occurrence and damage of diseases, pests and weeds were analyzed, and the problems in prevention and control were discussed based on the local conditions of sugarcane production. The species, occurrence and damage characteristics of diseases, pests and weeds were ascertained, and the corresponding strategies and technical measures were proposed.

Effectiveness of Cyhalofop-butyl EW for Control of Poaceae Weeds in Transplanted Rice in China

[Objective] This study aimed to investigate the effectiveness of different rates of 10% cyhalofop-butyl EW for control of Poaceae weeds in transplanted rice in China. [Method] The experimental and eco-friendly herbicide, 10% cyhalofop-butyl EW, was applied in field trials in 2013 to investigate its efficacy in five representa-tive rice producing areas, one in each of the provinces Anhui, Hunan, Zhejiang, Jiangsu and Liaoning. [Result] The results showed that 10% cyhalofop-butyl EW could effectively control Poaceae weeds in transplanted rice without negative effects on the rice crop. The optimal application rate of 10% cyhalofop-butyl EW was found to be 750-1 500 ml/hm2. [Conclusion] The study confirmed that 10% cyhalofop-butyl EW has clear potential for wide-spread adoption in rice production systems.

Evaluation of soil flame disinfestation(SFD) for controlling weeds,nematodes and fungi

Soil flame disinfestation(SFD) is a form of physical disinfestation that can be used both in greenhouses and on field crops. Its use for soil disinfestation in different crop growing conditions makes it increasingly attractive for controlling soilborne pathogens and weeds. But little is known about the effect on weeds and soilbrone diseases. This study reports on greenhouses and field crops in China that determined the efficacy of SFD to control weeds, nematodes and fungi. It also determined the impact of SFD on the soil physical and chemical properties(water content, bulk density, NO3^–-N content, NH4^+-N content, conductivity and organic matter) in three field trials. A second generation SFD machine was used in these trials. SFD treatment significantly reduced weeds(>87.8%) and root-knot nematodes(Meloidogyne incognita)(>98.1%). Plant height and crop yield was significantly increased with SFD treatment. NO3^–-N and NH4^+-N increased after the SFD treatment, and there was also an increase in soil conductivity. Water content, bulk density and organic matter decreased significantly in the soil after the SFD treatment compared to the control. Soil flame disinfestation is a potential technique for controlling weeds and diseases in greenhouses or in fields. SFD is a non-chemical, safe, environmentally-friendly soil disinfection method.

Herbicidal activity of Aureobasidium pullulans PA-2 on weeds and optimization of its solid-state fermentation conditions

Fungal strain PA-2 was isolated from infected poplar leaves from the Ping’an District, Haidong City of Qinghai Province, China. Based on the culture characteristics and the internal transcribed spacer(ITS) sequence of its 16S r DNA, the strain was identified as Aureobasidium pullulans. The culture and metabolites of strain PA-2 showed high herbicidal potential to five tested weeds Galium aparine var. tenerum, Chenopodium album, Malva crispa, Polygonum lapathifolium and Avena fatua. For the in vitro test, 5 days after the detached leaves were inoculated with PA-2 culture, all leaves infected by the hyphae and became black and rotten. For the in vivo test, a metabolite filtrate of PA-2 culture was sprayed over the living weed plants, and five days after inoculation, the weed plants became withered and necrotic. Seven days after inoculation, the fresh weight reductions of G. aparine var. tenerum, C. album, M. crispa, P. lapathifolium and A. fatua were 87.25, 78.46, 82.25, 62.11, and 80.27%, respectively. Galium aparine var. tenerum and M. crispa exhibited significant reductions in fresh weight. The bio-safety test on the five crops showed no significant plant height reductions, which was also observed for wheat(Triticum aestivum), faba bean(Vicia faba), and barley(Hordeum vulgare). By contrast, oilseed rape(Brassica napus) and pea(Pisum sativum) exhibited light spots but no significant reductions in plant height. These results indicated that A. pullulans could be a potential microbial herbicide for the control of the target weeds in crops. Optimization of the carbon and nitrogen sources for cultural media and substances for solid-state fermentation indicated that PA-2 had better colony growth and spore production with the optimal carbon source of glucose(C4), nitrogen source of soybean flour(N2), and the optimal substance was wheat bran. The results in this study provide useful information for the development ofA. pulluans PA-2 as an herbicide for bio-control of the weed.

Al elopathic Effects of Melilotus officinalis Desr. against Weeds

In this study, the allelopathic effects of 100 g/L water extract of Melilotus offtcinalis Desr. on seed germination and seedling growth of Melilotus offwinalis Desr., Trifolium pretense L. , Medicago sativa L. cv. Victoria, Echinochloa crusgalli （ L. ） Beauv., Lxer/s chinensis （ Thunb. ） Nakai and Plantago asiatica L. were investigated by biological assay. Dried powder of Melilotus officinalis Desr. was applied to the field in spring and winter to verify the inhibitory effects of Me- lilotus officinalis Desr. on weed biomass in the experimental field and compare the effects between Melilotus offwinalis Desr. and a variety of commonly used chemi- cal herbicides on weed suppression. The results showed that water extract of Melilotm officinalis Desr. posed significant effects on seed germination and seedling growth of Trifolium pretense L. , Echinochloa crusgalli （ L. ） Beauv. , Lxeris chinensis （ Thunb. ） Nakm, Plantago asiatica L. , Melilotus o^tcinalis Desr. and Medi- cago sativa L. cv. Victoria, exhibiting strong allelopathic effects, but the inhibition rate varied greatly among different plant species. Therefore, the allelopathic effects of Melilotus o^winalis Desr. should be utilized appropriately in practical applieatians. Dried powder of Melilotus officinalis Desr. significantly reduced weed quantity in the field for a short duration, which should be administered multiple times in a sufficient amount for weed control in the production.

Suppression of weeds and weed seeds in the soil by stubbles and no-tillage in an arid maize-winter wheat-common vetch rotation on the Loess Plateau of China

Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, high abundances of weeds in reduced tillage systems cause significant yield losses. In this study, we explored the effects of no-tillage and stubble retention on the number and density of weeds and weed seeds in a 12-year maize-winter wheat-common vetch rotation on the Loess Plateau. Four treatments including conventional tillage, no-tillage, conventional tillage＋stubble retention and no-tillage＋stubble retention were designed and applied. We found that no-tillage increased the number of weed species and weed density in most of the crops, while stubble retention decreased weed density in maize and tended to suppress weeds in both no-tillage treatments（no-tillage and no-tillage＋stubble retention）. No-tillage led to an increase in the number of weed species in the weed seedbank and tended to increase seed density during the spring growth of winter wheat, but it decreased seed density during post-vetch fallow. Stubble retention tended to reduce seed density during the spring growth of winter wheat and post-vetch fallow. We concluded that no-tillage can promote weeds in the experimental crop rotation, while stubble retention suppresses weeds in untilled fields. The combined effects of stubble retention and no-tillage on weed suppression varied among the three crops. Based on these results, we recommend stubble retention in untilled legume-crop rotations on the Loess Plateau to improve the control of weeds.

Control Efficacy of Pyroxasulfone on Weeds in Corn Field

To explore the control efficacy of 85%pyroxasulfone water-dispersible granule(WG)on annual weeds in corn field as well as its safety,a randomized block design was used to conduct a field plot test of efficacy at four different test sites.After sowing before seedling,85%pyroxasulfone WG at the doses of 10,15,20,and 40 g/667 m^(2),and 55%acetochlor+atrazine suspension concentrate(SC,control agent)at the dose of 170 g/667 m^(2)in summer corn area and 260 g/667 m^(2)in spring corn area were applied,respectively.The test site without herbicide application was used as the blank control.The results revealed that after 40 d of application,the control efficacy of 85%pyroxasulfone WG reached 83.75%~98.23%on Gramineae weeds,55.22%~98.33%on broadleaf weeds,and 88.03%~98.46%on Cyperaceae weeds,but without toxicity to corns.Compared with 55%acetochlor+atrazine SC,85%pyroxasulfone WG at the dose of more than 10 g/667 m^(2)had higher control efficacy on Gramineae weeds,lower efficacy on broadleaf weeds and similar efficacy on Cyperaceae weeds.To sum up,spraying 85%pyroxasulfone WG at the dose of 15~20 g/667 m^(2)(an active component dose of 191.3~255.0 g/hm^(2))after sowing before seedling could effectively control some annual weeds in corn fields and had no toxicity to corns.The herbicide dose was greatly reduced,and thus 85%pyroxasulfone WG was recommended as an effective mean to control the main weeds in corn fields.

Synergistic Effects of Herbicide Adjuvants on Weeds Control and Safety Determination in Field Application

The effects of 9 plant adjuvants on the control of Stellaria japonica and Poa pratensis by 3 herbicidesor mixtures,including MCPA-Na+Clethodim,Atrazine and Bentazon,were studied by pot experiments.The results showed that all these 9 plant adjuvants could significantly promote the control effects of MCPA-Na+Clethodim on 2 weeds,except Jiabajin for Poa pratensis.The control effect on plant number and fresh weight of Stellaria japonica increased by 90.6%~100.0%and 47.6%~56.2%respectively 10 d after the treatment,and 25.1%~96.4%and 17.7%~90.4%for Poa pratensis respectively.Pharmacodynamics,Doctor lemon oil,Pamiere,Beirunsu and Wynote had better synergistic effects.Plant adjuvants had little synergistic effect on Atrazine and Bentazon in the early stage which was 10 d after the treatment.However,when it was 20 d after the treatment,adjuvants like Yaoxiaoling,Pamiere and Beirunsu could significantly increase the control effect of Atrazine on Stellaria japonica.Yaoxiaoling,Jiabajin and Beirunsu could promote the synergistic effect of Bentazon on Poa pratensis.Adding herbicide Yaoxiaoling could increase the herbicide control effect,fresh weight control effect,plant height and fresh weight inhibition rate of weeds in maize and flax fields.And the herbicide phytotoxicity was not obvious.The combinations of plant adjuvants with 4 herbicides including Atrazine,Nicosulfuron Mesotrione Atrazine,Nicosulfuron Atrazine,and Bentazon;had better control effects on weeds in maize fields,while MCPA-Na+Clethodim+adjuvants had better control over weeds in flax fields.

Impacts of Different Weeding Methods on Weeds Control in Tobacco Fields in Anshun City

[Objective] The paper was to explore weed control measures in tobacco fields in Anshun City. [Method] Different treatments on weed control were conducted in tobacco fields in Anshun City, Guizhou Province, from 2017 to 2019. [Result] Various treatments had no negative effect on tobacco plant growth in the field, and had different degrees of control effects on five dominant weeds, including Digitaria sanguinalis, Setaria viridis, Fagopyrum dibotrys, Commelina communis and Chenopodium album. White mulching film and 50% butralin·clomazone EC 160 m L/667 m^(2) + white mulching film had the worst performance, which had extremely significant or significant differences with other treatments. There was no sig-nificant difference among most treatments, and the overall effects were comprehensive(multi-factor) treatment > double factor treatment > single factor treatment. [Conclusion] Combination control is recommended in practical tobacco production.