Soil properties

Worldwide, paraquat's use brings substantial benefits to food production and sustainable agriculture; farmers remain enthusiastic about the value that it adds. In contrast to this, some groups have been very vocal in their demands for its restriction or banning and this has led to the production of a large number of reports that contain allegations regarding its safety in use.  Syngenta, the leading manufacturer, treats any expression of concern over safety very seriously and continues to work with authorizing bodies, academics and local organizations to understand and improve the safe handling of pesticides, including paraquat.  The objective of this paper in Outlooks on Pest Management is to consider the need for and benefits of paraquat alongside the issues raised by its critics and thereby to put paraquat in perspective. 
Click here to download the PDF.
Paraquat has an important role to play in vegetable cropping because its unique characteristics are particularly suited to the challenges posed by controlling weeds in these diverse crops. Growing vegetables also helps with growing other crops in a sustainable way. Legume vegetables have bacteria associated with their roots which convert nitrogen from the air into forms which can be used by plants as nutrients and these remain in the soil to fertilize following crops. A vegetable break crop, such as peas or potatoes, prevents the build-up of pests and diseases in cereal rotations and provides an opportunity to control weeds by alternative approaches.
Using paraquat for weed control helps to address many of the challenges to vegetable production including soil erosion, leaching of agrochemicals, early harvests for best prices. Paraquat is used to prepare the land for sowing or transplanting and is safe to use for inter-row weed control in growing crops by careful application with knapsack sprayers or from tractor mounted sprayers with shielded spray nozzles. Unlike systemic herbicides which are too dangerous to use, even if small amounts of paraquat land on crop plants they cannot move within the plant to cause damage.
Vegetables fact file 70 million hectares grown worldwide
70% grown in Asia
5 portions a day recommended for health
Millions of people around the world wake-up each day with a cup of freshly brewed coffee and later meet their friends or do business in fashionably expensive coffee houses.
But for many farmers there has been a coffee crisis. Although consumption is growing in some markets, coffee is a victim of its own success, and recently there has been considerable over-supply.
In 1970 the average US consumer drank 36 gallons of coffee and 23 gallons of soft carbonated drinks. In 2000 these figures were 17 gallons and 53 gallons, respectively.
The key to success and the way out of the coffee crisis lies in quality through a sustainable approach to production. Best quality speciality coffee growers can get twice the regular price. Paraquat has a key role to play by controlling weeds that would otherwise seriously reduce productivity, in conjunction with other agronomic practices that protect the environment.
Tea is one of the leading crops in the move towards a more sustainable agriculture.
The major environmental issues in growing tea include:
Loss of habitats and effects on biodiversity
Soil erosion on the often hilly terrain
Water pollution and reduction in soil health by agrochemicals
Paraquat can be used to maintain a managed, non-competitive weed flora which provides habitats to encourage biodiversity and helps prevent soil erosion. Paraquat does not affect soil health and does not pollute soil or surface waters. The Tea Research Institute of Sri Lanka recommends using paraquat as a weed management solution allowing reduced use of glyphosate, stating:
“Manual weeding and chemical weeding with paraquat in rotation could be advocated to sustain productivity and maintain an eco-friendly environment in tea plantations.”
Tea fact file 3.5 million ha grown worldwide, mainly in Asia
133%: increase in area harvested in Vietnam, one of the top five producing countries, since 1995
75 tonnes/ha of soil eroded annually from hilly tea estates in Sri Lanka
3 main varieties: Assam, China, Cambodian
Paraquat only removes the top growth of well-established weeds and does not affect the germination of new seedlings.
Global production of palm oil has now overtaken soybean oil to be the world’s leading vegetable oil. The Roundtable on Sustainable Palm Oil (RSPO) is a multi-stakeholder not-for-profit association designed to promote the growth and use of sustainable palm oil. RSPO has published a set of Principles and Criteria for Sustainable Palm Oil Production. These include that growers: Minimise erosion
Ensure the quality of surface and groundwater
Use integrated pest management (IPM) techniques to protect crops from weeds, pests and diseases
Use agrochemicals in a way that does not damage health or the environment
Soil erosion on sloping ground is especially serious. Up to 14 tonnes per hecatre of soil have been estimated as being removed every year. Plantations affected cannot be re-planted and new land must be found. “Paraquat has always given good value, with fast and effective weed control, especially of difficult weeds like ferns, woody shrubs and volunteer oil palm seedlings, even in the rainy season. These days, it is important to use paraquat to prevent weed succession problems caused by glyphosate.”
- Professor Gembira Sinuraya, North Sumatra University, Indonesia
Citrus fruit make-up a vast family including not only oranges, lemons, limes and grapefruit, but also calamondins, citrons, pomelos and ugli fruit.
Integrated pest management (IPM) systems have been introduced to minimize the impact of citrus growing on soil, water, air and biodiversity.  Paraquat has a key role in sustainable citrus production by controlling weeds that would otherwise seriously reduce productivity.  It can be used in conjunction with other techniques to manage soil erosion, particularly the use of strips of grass or legume cover crops between trees.
Paraquat can be safely sprayed to manage the weed flora along the crop rows between the grass or legume strips without fear of damaging the citrus trees.  Paraquat is immobile in soil and cannot move to the roots and up into the shoots.  Tree bark cannot be penetrated by paraquat meaning that it can be sprayed right up to the base of the trees.  Even if paraquat drifts onto citrus leaves there is little or no damage because paraquat does not move through plants like glyphosate does.
Citrus fact file 1:  Brazil is the leading citrus growing country
8.7 million ha of citrus are grown worldwide
43% are oranges, 27% mandarin types, 11% lemons and limes, 3% grapefruit
33% of crops are grown for juice
Ever wonder what fuels the impressive size and power of the awesome Pacific Island rugby players? Look no further than taro. Taro is a tropical starchy root crop which is a staple food in many subsistence communities, particularly in the Pacific islands. And while the rugby team members most likely have a broad selection of meals from which to choose, for many people living in these areas taro is an essential part of their diet.
Often called “the potato of the tropics,” its role is so significant that taro is celebrated in festivals and on coins in many Pacific Island cultures. And it is no wonder: taro makes up almost 20% of peoples’ daily calorific intake in some areas, compared to only 3-5% represented by potatoes for people in the US and Europe. Economically, it is an important source of export revenue, mainly to supply ex-patriot islanders living in Australia, New Zealand and the west coast of the US.
As a tropical crop, protecting taro from weeds is critical. Weeds thrive in such hot and humid climates, robbing yield. Hand hoeing crops is one option, but, not only is this time consuming and labour intensive, but it means other opportunities, particularly for education in poorer communities, may be missed. Using the right choice of herbicide provides an effective alternative. 
Paraquat is an essential tool for taro farmers
In this section you will find articles about paraquat's environmental profile. One of paraquat's key chemical properties, fundamental to the way it is used in sustainable farming systems, is that it is inactivated immediately on contact with soil.
Paraquat has been an essential tool for farmers in protecting sustainable cropping systems for more than 50 years. Its unique properties have enabled the development of vital new crop production techniques, especially no-till.
This section includes in-depth features that cover topics including:
Paraquat's role in sustainable agriculture
All about weeds and weed control
Important crops and their production systems
Find out more about the science of paraquat in this section. How does it work as a herbicide?
What are its chemical properties?