Volume-54 | Issue-4(October-December)| Year 2022

Weed management role in meeting the global food and nutrition security challenge
A.N. Rao

KEYWORDS:

Climate resilience, Crop yield gap, Food security, Integrated weed management, Nutrition security, Resource use efficiency, Weeds competition

Abstract:

The global agricultural production must increase by around 70% to meet the food and nutrition demands of 9.9 billion people, by 2050. It was predicted that 670 million people will still be undernourished in 2030. Hence, feasible and cost-effective strategies in the global agri-food system need to be implemented for meeting nutrition security. Weed management played a key role in achieving global food and nutrition security, till to date. In this paper the role of weed management in meeting food and nutrition security is revisited in view of the changed scenario of prevailing unintended ecological imbalance, climate change, water overuse and waste, soil degradation, loss of natural resource quality, and declines in biodiversity, increased herbicide use, and chemical runoff that are decreasing crop growth yields and raising reasonable concerns about the sustainability of the current agricultural methods in meeting the future food and nutrition security. The future role of weed management is discussed in terms of: reducing the continued losses caused by weeds and improving crops productivity and production by reducing yield gap; improving resources (land, water, light, nutrients); improving farmers income; advancement of farmers livelihood; combating climate change and balancing biodiversity. The possible role of climate resilient integrated weed management in playing the intended roles in agri-food system is discussed. In order to play much more sustainable role, the weed management, as an integral part of agricultural production, needs to move away from its mono-disciplinary perspective at targeting weeds to multidisciplinary and multifaceted technological solution to serve as a component of overall technological solutions to improve agricultural production for achieving ever increasing food and nutritional security challenges.

Email

adusumilli.narayanarao@gmail.com

Address

Consultant Scientist (Weed Science), Hyderabad, Telangana 500033, India
Weed biology: An important science to develop effective weed management strategies
Bhagirath S. Chauhan

KEYWORDS:

Genetic diversity; Phenology; Seed ecology; Weed biology; Weed emergence; Weed management

Abstract:

The world’s population is increasing at an alarming rate and to feed this population, food production needs to be increased significantly. There are several abiotic and biotic factors affecting the productivity of crops. Among biotic factors, weeds are the most important constraint to crop production throughout the world. They cause a huge yield loss in different crops and cost growers a significant amount of money. Herbicides are widely used to control weeds; however, there are concerns over the evolution of resistance in weeds, limited availability of herbicides with new modes of action, and environmental pollution. These issues suggest the need to reduce reliance on herbicides and develop sustainable weed management programs. However, to develop such programs, there is a need to gain a better understanding of weed biology. This article briefly describes the importance of weed biology in managing weeds.

Email

b.chauhan@uq.edu.au

Address

Queensland Alliance for Agriculture and Food Innovation (QAAFI), University of Queensland, Gatton, Queensland 4343, Australia
Invasive alien weeds problem in South Asia: Challenges and prospects of their management
Bharat Babu Shrestha

KEYWORDS:

Biological invasions, Invasive weeds, Invasive plants, Management strategy, Regional collaboration

Abstract:

South Asian region, like other regions of the world, is witnessing a rising problem of invasive alien weeds with wide ranging environmental and socio-economic impacts. Current policy and management responses, and national capacities of the South Asian countries are inadequate in slowing down the rate of invasion process, suggesting a need for new approaches to address the problem. Through narrative review of selected references and author’s own experiences, several challenges of invasive weed management in South Asia have been identified, including inadequate policy responses, ineffective quarantine and biosecurity rules, low national capacity, knowledge gaps on key aspects, and a lack of common and agreed standards for species categorization. Future prospects identified for effective management of invasive weeds in South Asia include improving awareness of invasive weeds problem among policy makers and other stakeholders, regional networking for information exchange, regional collaboration for biological control program, and regional collaboration among researchers to generate policy relevant information. In a nutshell, formulation of the South Asian Regional Strategy for Invasive Alien Species and its proper implementation will prevent introduction of new invasive weed species and control of established invasive weed species for the benefit of imperiled biodiversity, ecosystems and billions of people inhabiting in this region. 

Email

shresthabb@gmail.com

Address

Central Department of Botany, Tribhuvan University, Kathmandu, Nepal
Risk associated with the weed seeds in imported grain
M.C. Singh, V.C. Chalam, Dhruv Singh, Sushilkumar and S. Gnansambandhan

KEYWORDS:

Dissemination, Grain shipments, Interception, Plant Quarantine, Risk analysis, Weed seeds

Abstract:

The risk of introducing weeds to new areas through grain (cereals, oilseeds and pulses) intended for processing or consumption is considered less than that from seed or plants for planting. However, within the range of end uses for grain, weed risk varies significantly and should not be ignored. There is a need to examine the association of weed seeds with grain commodities throughout the production process from field to final end use, and inspection of representative samples for grain crops commonly imported to India. In the field, weed seed contamination of grain crops is affected by factors such as country of origin, climate, biogeography, production and harvesting practices. As it moves toward export, grain is cleaned at a series of elevators and the effectiveness and degree of cleaning are influenced by grain size, shape and density as well as by grade requirements. In cases where different grain lots are blended, uncertainty may be introduced with respect to the species and numbers of weed seed contaminants. During transport and storage, accidental spills and cross-contamination among conveyances may occur. At the point of import to India, inspection data show that grain shipments contain a variety of weed seeds including seeds of regulated weeds. However, grain cleaning and processing methods tailored to end use at destination also affect the presence and viability of weed seeds. For example, grains that are milled or crushed for human use present a lower risk of introducing weed seeds than grains that undergo minimal or no processing.  Risk analysis allows each of these stages to be evaluated in order to characterize the overall risk of introducing weeds with particular commodities, and guide regulatory decisions about trade and plant health.

Email

moolchand.singh@icar.gov.in

Address

ICAR-National Bureau of Plant Genetic Resources, New Delhi-110012, India
Biology and management of wild oat in Australia
G. Mahajan, Vivek Kumar and B.S. Chauhan

KEYWORDS:

Avena fatua, Avena ludoviciana, Herbicide resistance, Integrated weed management, Weed biology, Wild oat

Abstract:

Wild oat (Avena spp.) is one of the most serious weeds in Australian winter season crops such as wheat, barley, chickpea, etc. Avena fatua and A. ludoviciana are the dominant species of wild oat in cropping regions of Australia. Propagation of wild oat can occur through seeds. Dissemination of wild oat occurs by agricultural machinery, use of the contaminated seeds and crop residues, etc. Seed recruitment of wild oat in the soil occurs through high seed production and the shattering ability of plants. Wild oat has evolved resistance to many herbicides and continuous use of same herbicide could increase the resistance build-up in many populations on a large scale in Australia. The use of herbicides with different modes of action can provide cost-effective and sustainable control of wild oat. Non-chemical weed management practices, such as sanitation, residue burning, tillage operation, crop rotations, and improved crop competition approaches could reduce the infestation of this weed. For sustainable control of wild oat, integrated strategies involving chemical and non-chemical tactics may prove useful. Knowledge regarding the understanding of wild oat ecology could aid in strengthening the integrated management of this weed.

Email

g.mahajan@uq.edu.au

Address

Principal Agronomist, Punjab Agricultural University, Ludhiana, Punjab 141004, India
Bioavailability of allelochemicals in soil environment under climate change: Challenges and perspectives
Prasanta C. Bhowmik

KEYWORDS:

Allelopathy, Adsorption, Climate change, Cover crops, Crop residue, Microbial activity

Abstract:

Weed management is an important component in sustainable agriculture. The current agriculture is changing with climate change. Allelopathy has been recognized as a component of integrated weed management over the years. The allelopathic ideas have been used in various facets of allelopathic implications. Some of these include use of cover crops, plant residues, plant extracts, crop cultivars and others. And it is being challenged under climate change factors such as increased atmospheric CO2, temperature rise, erratic rainfall patterns and others. The relevance of allelopathy has been highly discussed due to the lack of phytotoxic concentrations of allelochemicals under field conditions. Crop residues from existing crop or rotational crops can provide selective weed suppression through their physical presence on the soil surface and/or through the release of allelochemicals. Brassica nigra, Avena fatua, Fagopyrum esculentum, Secale cereale, Sorghum bicolor, Triticum aestivum and other cover crops have been used in weed management on a limited basis. Some of the allelochemicals such as DIBOA, DIBOA-glycoside, dhurrin, isoflavonoids, isothiocyanate, juglone, momilactone, scopoletin, and sorgoleone have been reported to play a role in weed management under field conditions. The living and dynamic soil system influences the fate and functions of allelochemical activity. The bioavailability of allelochemicals in the soil is dependent on soil processes such as adsorption, leaching and degradation by abiotic and biotic factors. These processes and other related soil conditions are greatly influenced by several underlined climatic variables. Future allelopathic research should be focused on persistence and availability of allelochemicals in soil environment. The bioavailability of allelochemicals under field conditions with climate change associated rising atmospheric CO2, rising temperature and intensity and erratic rainfall must be established for its effective practical role in weed management. Currently, we face challenges and opportunities in using allelopathy as a part of weed management strategies in today’s agriculture.

 

 

 

Email

pbhowmik@umass.edu

Address

Stockbridge School of Agriculture, University of Massachusetts, Amherst MA 01003 USA
Weed management in pulse crops: Challenges and opportunities
Narendra Kumar, C.P. Nath and K.K. Hazra

KEYWORDS:

Allelopathy, Conservation agriculture, Crop-weed competition, Herbicide resistance, Integrated weed management, Soil solarization

Abstract:

Pulses are known for their role in nutritional security, and sustainability of agricultural production systems and agro-ecology. It is a main source of protein to the vegetarian population of the country. India is the largest producer, consumer and importer of pulses. But, the productivity of pulses in India is far below than several countries of the world. The low productivity of pulses in India is mainly due to several biotic and abiotic factors among which weeds are major ones since they severely affect the pulse crops yield. An estimate shows yield losses due to weeds are more than any other pests. The intensity and diversity of weed flora in pulses depends on climatic, edaphic and crop management practices. It has been observed that sedges population in cereal-cereal systems can be minimized through diversification or intensification of cropping systems with pulse crops as components. In addition, most of the pulses are grown as rainfed crops with no or minimal inputs and inadequate weed management. Limited attention was paid in the past by researchers also on development of effective strategies to manage weeds in pulses. Only a few herbicides are registered in India for use in pulses and most of the weed management recommendations in pulses are of pre-emergence herbicide application followed by manual weeding. But, due to shortage of labor for intercultural operations, the need was recognized for development of alternate methods involving post-emergence herbicides too for effective weed management in pulses. The conservation agriculture (CA) adopted acreage is increasing in India with a focus on inclusion of pulses in crop diversification component of CA. Hence, there is need to develop long-term strategies of weed management by inclusion of modern technologies in pulse crops.

Email

nkumar.icar@gmail.com

Address

ICAR-Indian Institute of Pulses Research, Kanpur, Uttar Pradesh 208024, India
Weed management in oilseed crops- a review
V.K. Choudhary, R.P. Dubey and J.S. Mishra

KEYWORDS:

Castor, Groundnut, Linseed, Niger, Oilseed crops, Sesame, Soybean, Sunflower, Weed management 

Abstract:

Oilseed crops are slow growing during the initial growth period. In oilseeds, weeds caused yield reduction by 15-60 percent. Hence it is very essential to control weeds during the critical period of crop-weed competition. Weed management options in the majority of oilseed crops are limited, therefore, adoptions of multiple options of weed management using ‘little hammers’ considering preventive, cultural, mechanical, chemical, and biotechnological approaches are important. Integrated weed management (IWM) is a system approach to minimize weed populations below the economic threshold level. Among different weed management practices, cultural practices minimized the crop-weed competition up to large extent. Further, mechanical measures and herbicidal weed management are ‘large hammers’ or single large methods of weed control, but that may lead to the development of another level of problems like shift in weed flora, development of difficult-to-control weeds, issues of herbicide resistance, establishment of perennial weeds, etc. Thus, the aforesaid problems can be overcome by suitably adopting IWM, since it mixes the use of different available weed control methods in a balanced way by managing the weeds effectively, and sustainably provides higher production without harming the environment.

Email

ind_vc@rediffmail.com

Address

ICAR-Directorate of Weed Research, Jabalpur, Madhya Pradesh 482004, India
Herbal herbicide: A low-cost and eco-friendly tool for weed management in smallholder farming
Puja Ray, Malay K. Bhowmick, Rati Kanta Ghosh and Sushil Kumar

KEYWORDS:

Crop losses, Herbal herbicide, Integrated weed management, Organic farming, Smallholder farmer, Weeds 

Abstract:

Weeds have been recognized as a major biotic constraint towards achieving higher crop productivity as well as quality. With the current crop protection measures, weeds cause nearly one-third of the crop losses among all the crop pests. The effective approach to combat the weed menace is the need-based use of herbicides. Because of widespread growing concern over the environmental aspects of commonly used herbicides as well as their untimely availability, development of weed resistance, etc., the need for the use of conveniently available and biodegradable herbicides is very much imperative. Researchers currently search for novel alternatives to the synthetic herbicides, which would be biodegradable and environment-friendly. Common plants and their metabolites become a source of compounds that can be utilized directly as natural herbicides or as lead structures for the herbicide discovery. These herbal herbicides in judicious combination with other weed management methods would be a potential tool to combat weed menace, especially by the smallholder farmers in rural areas in general, and organic or natural farming in particular.

Email

sknrcws@gmail.com

Address

Multitrophic Interactions and Biocontrol Research Laboratory, Department of Life Sciences, Presidency University, Kolkata, West Bengal 700073, India

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