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.

Influence of Adjuvants on the Efficacy of Tolpyralate plus Atrazine for the Control of Annual Grass and Broadleaf Weeds in Corn with and without Roundup WeatherMAX^®

Tolpyralate is a new HPPD-inhibiting herbicide that is efficacious on annual grass and broadleaf weed species in corn. For maximum herbicide performance of tolpyralate, it is recommended that atrazine is tank mixed with tolpyralate along with the adjuvants methylated seed oil concentrate (MSO) plus urea ammonia nitrate (UAN). A common use pattern of tolpyralate plus atrazine will be in a tank mix with Roundup WeatherMAX®due to the high proportion of corn acres that are seeded to Roundup Ready®hybrids in Eastern Canada. There is no information in the peer-reviewed literature if the adjuvant system in Roundup WeatherMAX®is adequate for optimal herbicide performance of tolpyralate plus atrazine, or if MSO and UAN are still required. Six field trials were conducted over two years near Ridgetown and Exeter, ON, Canada to determine if adjuvants are still required when tolpyralate plus atrazine is tank mixed with Roundup WeatherMAX®in corn. Tolpyralate plus atrazine plus MSO and Roundup WeatherMAX®plus tolpyralate plus atrazine provided excellent control of velvetleaf, pigweed spp, common ragweed, lambsquarters, ladysthumb, wild mustard, flower-of-an-hour, barnyardgrass and green foxtail in this study. Results of this study show that in the absence of Roundup WeatherMAX®, weed control with tolpyralate plus atrazine was improved substantially with the addition of MSO;however, there was little to no increase in weed control with the addition of UAN. When tolpyralate plus atrazine was co-applied with Roundup WeatherMAX®, there was no improvement in weed control with the addition of MSO and/or UAN.

Chlorobenzenes in waterweeds from the Xijiang River (Guangdong section) of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes （CBs） in both water and waterweeds collected from 4 stations in the Xijiang River （Gangdong section） of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs （ZCBs） in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ZCBs in waterweeds ranged from 13.53×10^2μg/g to 38.27×10^2μg/g dry weight （dw）. There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs （DCBs）, whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip （bioconcentration factor） of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was： Fengkai County 〈 Yunan County 〈 Yun＇an County 〈 Gaoyao County according to the ZCBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River .

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.

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.

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.

A Review of Research Directions and Research Methods of Farmland Weeds

Farmland weeds are an important part of farmland ecosystems.Research on farmland weeds is one of the major research fields in agricultural ecology.It is of great significance for achieving high yield,high quality and high efficiency in agriculture.In recent years,research on farmland weeds has focused on investigation of weed communities,research on weed seed banks,and research on weed control.These three research directions complement each other.Among them,the investigation work of weed communities and the research of weed seed banks are helpful for us to grasp the occurrence of farmland weeds more accurately and provide references for the control of farmland weeds.This article summarizes the research directions of farmland weeds in recent years(weed community investigation,weed seed bank,weed control)and the research methods used,provide reference value for the follow-up research work of farmland weeds,and provide theoretical support for promoting the development of rural ecological industry and building beautiful villages.

Several Exotic Harmful Weeds in Beilun Port of Ningbo

An investigation was carried out in wharves, inspection yards, processing plants in Beilun Port and the surrounding areas. Five kinds of exotic harmful weeds were discovered and collected, and they were described and analyzed.

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.

Technical Regulations for Integrated Prevention and Control of Weeds in Millet Fields in Hebei Province

According to the summary of experiments for many years, application scope, prevention and control principle and objects of technical regulation for integrated prevention and control of weeds in millet fields, as well as integrated control technologies including agricultural control, physical control and chemical control were studied, and the specific methods and technical indicators were determined.

Use of Gramoxone 20SL (Paraquat) Prior to Land Preparation in Controlling Aquatic Weeds in Wetland Areas of Bangladesh

Emergent aquatic weeds present in the monocropped fresh water wetland area of Bangladesh create a hazard in land preparation by developing dense stands. A field experiment was conducted at the farmers’ field of two villages namely Mahilara and Kashemabad under Gournadi Upazila of Barisal district, Bangladesh during October 2012 to evaluate the efficacy of Gramoxone 20SL (Paraquat) in controlling emergent aquatic weeds and to find out an appropriate dose of this herbicide. Three doses of Gramoxone 20SL at 1.96 l·ha-1, 2.00 l·ha-1 and 2.04 l·ha-1 were tried with an untreated control. All treatments were laid out in a randomized complete block design and replicated thrice. There were 8 different emergent weed species infesting the field among which the most dominant weed species were Eichhornia crassipes, Pistia stratiotes, Enhydra fluctuans, Monochoria vaginalis, Echinochloa crus-galli. The results revealed that, weed control efficiency was significantly affected by different herbicidal treatments. The treatments, Gramoxone 20SL at 2.00 l·ha-1 and 2.04 l·ha-1 were controlled in all the emergent aquatic weeds more than 85% infesting both the sites. Application of non-selective herbicide Gramoxone 20SL at 2.00 l·ha-1 prior to land preparation was most effective to suppress weed dry masses in both the site resulting reduced land preparation cost up to 78.93% as compared to manual weed control.

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.

Study on Analysis Model of Millet Yield Loss Caused by Weeds in Summer Season Millet Field

Weed management in summer season foxtall millet field was studied by evaluating weed damage and exploring competition between weeds and foxtail millet, and a few fitting models were simulated and compared by employing field plot experiment and nonlinear regression analysis. The results showed that the millet yield losses and weed density were extremely significantly correlated. Among the tested models, the determination coefficient （ R2 ） of hyperbolic model was 0.997 12, and minimum residual sum of squares was 16.174, which was considered the optimal model to simulate the competition relation between weeds and millet. The predicted equation was Y = d/（ 1. 733 ＋ 0. 018d） ; the interspecific competitiveness of weeds was 0. 577 0 and the intraspecific competitiveness was 0.010 3 ; the maximum loss rate of millet yield was 55.56%. This study had established an analysis model with high gcodness-of-fit and practical prediction which could help weed management in summer season millet field.

Weeds of Wheat Crop and Their Control Strategies in Dera Ismail Khan District, Khyber Pakhtun Khwa, Pakistan

This study is based on research work conducted during 2008-2010 inDera Ismail Khan, KPK,Pakistan. The research area was extensively surveyed to investigate weed species. About 32 weed species, belonging to two monocot and thirteen dicot families, were collected from the study area. Plants were identified with the help of available literature and by comparing with the already identified plant specimens of the herbarium ofQuaid-i-AzamUniversity,Islamabad,Pakistan. Data inventory constitutes botanical name, vernacular name, English name, family, and flowering and fruiting period. Phalarus minor, Rumax dentatus, and Chenopodium album were the dominant weeds in the study area having comparatively higher relative weed density. Weeds having tough competition with wheat crop for light, moisture, and nutrients adversely affect wheat production. Hence, a constant effort is needed to keep the weed population under control. Many methods of weed control and eradication have been devised but chemical control is the most effective one. However, it may have some environmental consequences if not handled properly.

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.

Occurrence and Control of Weeds in Abandoned Fields in Central Hunan

[Objectives]This study was conducted to clarify the occurrence of weeds,and give relevant comprehensive control suggestions accordingly.[Methods]The species and community characteristics of weeds in abandoned rice fields in central Hunan were investigated and analyzed.[Results]There were 75 species of weeds in the abandoned farmland in central Hunan,belonging to 66 genera,27 families.Among them,22 species had a relative abundance of more than 5%.According to the different water environments of abandoned fields,there were differences in the types and structures of weeds.They succeeded to wetland vegetation types and dryland vegetation types respectively.Species grown in the original farmland still exist in abandoned fields,but they were mainly invaded by field weeds,such as Digitaria sanguinalis,Eleusine indica,Panicum acroanthum,Bidens pilosa,and Xanthium sibiricum.[Conclusions]This study lays a foundation for fully guaranteeing the actual results of re-cultivation of abandoned land in rural areas.

Farmers’ Understandings of Weeds and Herbicide Usage as Environmental Influences on Agricultural Sustainability

Little comparative research has specifically used farmers’ understandings of agricultural weeds and herbicides usage as important indicators of their environmental decision making and behaviours. This paper proposes that “organic’ farmers”, already attuned to environmental ideas, may be more likely to have favourable understandings and behaviours towards agricultural weeds as an integral part of environmentally sustainable agricultural farming systems than “conventional” farmers. Using a behavioural approach, the ways in which farmers’ (situated in central-southern England) understandings influence their environmental behaviours were examined. Most “conventional” farmers’ fields were kept relatively weed-free through herbicide usage. This contrasted with “organic” farmers having less concern about removal of weeds (with their associated invertebrates and seeds) which they understood contributes significantly towards biodiversity and agricultural sustainability. A remarkably high 92 per cent of “organic” farmers were critical of “conventional” farmers’ using herbicides and pesticides, asserting that lack of pesticide and herbicide usage as core reasons for their sustainability. This contrasted with most “conventional” respondents who claim they used as few chemicals as practicable to minimise environmental damage to soil and water, while maintaining adequate crop levels. Nevertheless, such environmental understandings and behaviours may not always be indicative of any differences that may be found between those farmers commonly classified as “organic” and “conventional” in the UK as a whole.

Analysis of the Impact of Aquatic Weeds in the Shire River on Generation of Electricity in Malawi: A Case of Nkula Falls Hydro-Electric Power Station in Mwanza District, Southern Malawi

A study was carried out to analyse the extent to which diverse species of aquatic weeds that have proliferated in the Shire River in Malawi in recent years affect the generation of electricity at Nkula Hydro-Electric Station in Mwanza District of the southern region of the country. Specifically, the study endeavoured to establish whether frequent power interruptions that Malawi is facing are the result of the problems caused by aquatic weeds in the Shire River which are believed to disturb proper functioning of the machines at the power station. Study results revealed that as much as the aquatic weeds impede power generation such as blocking the turbines, problems of low power generation that result into frequent and persistent load shedding are not entirely due to aquatic weeds. Problems of inefficient machines and shut down of machines are due to serving, which appeared to be the major cause.