Inter-row

Weeds and weed control

Paraquat is used to control a huge range of weeds worldwide, but to control weeds effectively and sustainably it is important to understand them.
Why does a plant become a weed? How can different types of weeds be described? What are the features of weeds and the way they grow which can be targeted by herbicides for successful control?

Will farming and soil quality collide?

Will farming and soil quality collide?
World Agriculture and the Environment is an important new book addressing the fear that increasing demand for food and fiber is on a “collision course” with soil quality.
This article is in two parts. In Part One, some of the main issues discussed in the book are reviewed. Part Two then explains how more than 50 years of research and practical use have shown that controlling weeds with paraquat can help provide improved and sustainable crop management practices to improve soil quality.
Part One: What ‘World Agriculture and the Environment’ says
In World Agriculture and the Environment authorJason Clay (World Wildlife Fund-US vice president, Center for Conservation Innovation) reviews the production and environmental impact of 21 of the world’s major food commodities. The main threats to the environment posed by crops, fish and meat are identified and explored, as well as the trends that shape those threats.
Major Issues
A fundamental acknowledgement in the book is that low intensity cropping can not support current, let alone future, levels of world population. There are two underlying reasons. First, using more land for farming destroys natural forests and grasslands.

Safety to the environment

Extensive long-term field studies confirm - and governments and regulatory authorities, worldwide, agree - that normal use of paraquat in accordance with the approved label instructions does not cause an unacceptable environmental impact.
These studies have shown that:
Paraquat is inactive in soil
When paraquat residues come into contact with the soil the paraquat active ingredient rapidly becomes adsorbed and strongly bound to clay and organic matter in the soil. It becomes biologically inert and as a result it cannot be taken up by plant roots or other organisms. Paraquat treated soils still maintain an active soil ecosystem with no adverse effects on soil microbes, microorganisms and earthworms. Paraquat cannot be released from the soil or re-activated by the application of water or other agrochemicals.
All agricultural soils, not only those with high clay content, have a high capacity to absorb paraquat.

Paraquat - a unique contributor to agriculture

Mr. Prasanna Srinivasan of New Dehli, India, is a recognized expert in the field of economics, policy and regulatory development and specializes in the impact of global environmental treaties on developing countries. Syngenta commissioned Mr. Srinivasan to provide a balanced assessment of the benefits and risks of pesticides in general and paraquat in particular. Mr. Srinivasan recently completed this review entitled, “Paraquat: A unique contributor to agriculture and sustainable development.
Please click on this link to download a copy of the review:
Paraquat: A Unique Contributor to Agriculture and Sustainable Development

Paraquat in perspective

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.
 

Tea cropping

Next time you are relaxing with a nice cup of tea, remember that this beverage once sparked a revolution. In 1773, a group protesting against unfair taxes, dressed as Mohawk Indians and tipped the cargo of tea carried by ships of the British East India Company into Boston Harbor. The Boston Tea Party rallied support for the revolutionaries in the 13 Colonies and, some say, started the American War of Independence. Now, tea is a crop leading another revolution, one in sustainable agriculture.
The major environmental issues in growing tea include (Clay, 2004):

Loss of habitats and effects on biodiversity
Soil erosion on the often hilly terrain
Water pollution and reduction in soil health by agrochemicals
Deforestation as a result of the need for wood for drying tea leaves

Using the non-selective herbicide paraquat for weed control can address three of these four issues. 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.
Paraquat is an essential tool in tea
Paraquat is a broad-spectrum herbicide. Its mode of action is to inhibit photosynthesis, an essential process in plants, and means that paraquat destroys all green tissue.

Soybean cropping

Soybean stands out from other major crops: broad leaved rather than a grass; a legume, so plants supply their own needs for nitrogen fertilizer while increasing the fertility of the land; soybeans are rich in oil, protein and carbohydrate; and the crop has been highly developed by plant breeders and agronomists. This makes soybean arguably the world’s most versatile crop.
With such a broad nutritional base, soybeans are a staple food and animal feed. Whole beans provide flours; soya oil is used in cooking and food; protein-rich soya meal left after oil extraction is an important livestock feed; and soya protein is used in drinks, baby food, noodles, and as a meat and dairy substitute.
A significant amount of soybean production in the US, in particular, now goes to make biodiesel (5 to 10% each year). Biodiesel is not soya’s first connection with motor vehicles. In 1941, Henry Ford’s enthusiasm for finding industrial uses for crops resulted in the manufacture of the ‘Biological Car’ made for an exhibition. The vehicle’s entire bodywork was made from plastic derived from soybeans!
Paraquat is an essential tool for soybean farmers
Paraquat is an important tool in the soybean farmer’s battle against weeds, while also having a good environmental profile and creating opportunities in rural communities.

Paraquat for vegetables

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.

Paraquat for coffee

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.
Although it is termed ‘non-selective’, paraquat is safe to coffee crops for several reasons. Firstly, it is immobilised on contact with the soil meaning that it cannot move to roots and be taken up into plants. Secondly, it is sprayed around the coffee plants which are protected by their bark which paraquat cannot penetrate.

Paraquat for tea

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

3.1 million ha grown worldwide, mainly in Asia
117%: 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.