Benefits for the environment
Reduces soil erosion
By killing weeds but leaving roots in place, paraquat stabilizes the soil.
Case Study
In the five year Sagip-Lupa project in the Philippines researchers have been collaborating to study approaches to reducing the serious threat to food production and the environment. posed by soil erosion
On the three experimental sites an average of more than 100 tonnes/ha of topsoil has been lost each year by farming in the traditional way. The large savings of precious topsoil from using paraquat and no-tillDescription Also known as conservation tillage or zero tillage is a way of growing crops from year to year without disturbing the soil through tillage ie cultivating the soil usually with tractor-drawn implements. Authoritative On-line References and Resources http://www.no-till.com/index.htm A portal for on-line information about no-till farming. are all statistically significant.
Crop yields have also benefited.
Increases soil organic matter
Using paraquat in conjunction with less soil tillage helps to preserve organic matter. This is good for soil health and structure, increasing fertility, improving water infiltration and retention, and locking up carbon dioxide.
Case Study
No-till crop production using paraquat for weed control is enabling the successful cultivation of one of China’s last available soil resources for food production.
In Southern China nearly 30 million hectares of red soils have been cultivated, but they are highly weathered, inherently infertile and very susceptible to erosion. Paraquat and no-till can help by stabilizing the soil.
Not tilling the soil means that less organic matter is oxidized, so building-up levels over time. Organic matter is essential for soil health and structure, increasing fertility, improving water infiltration and retention, and locking up carbon dioxide.
Reduces carbon footprint
Conservation tillage systems have higher soil organic matter content which sequesters carbon dioxide, so crops produced in this way have a lower carbon footprint.
Case Study
US farmers can now enroll in the Farmers Union Carbon Credit Program which means they will get paid for managing their cropland using conservation tillage systems like no-till and strip-till.
Conservation tillage increases the amount of organic matter in the soil, and apart from increasing fertility and improving soil structure, this sequesters large amounts of carbon dioxide.
Agricultural land has the potential to offset about 11% of US greenhouse gas emissions, equating to some 650 million tonnes of CO2 every year. Of this total, cropland could contribute 41% and half of this could be met by conservation tillage practices being adopted more widely.
Enhances biodiversity
Conservation tillage systems provide better habitats above ground, in the soil and away from fields when less run-off into waterways improves local aquatic environments.
Case Study
Leaving stubble and chaff from the previous crop on the soil surface, and undisturbed no-till soil, provides habitats for invertebrates and small wildlife. Birds are often present in greater numbers, feeding on spilled grain and weed seeds, insects or small mammals.
One bird species now thriving in no-till fields in the intensive soybean growing areas to the north and south of Sao Paulo in Brazil is the burrowing owl (Athene cunicularia). These birds nest and roost in holes in the ground, perhaps dug by prairie dogs, for instance.
During a recent ecological survey of fields in rural areas around the cities of Londrina and Uberlandia, burrowing owls and their homes were seen in many over-wintered no-till fields.
Conserves water quality
Paraquat is extremely tightly bound to soil so does not leach to groundwater. Its use in no-till systems means less soil is washed off fields and into watercourses, taking with it nutrients which cause excessive growth of algae, reducing oxygen levels and seriously impacting aquatic life.
Case Study
Scientists at Benguet State University in the north of the Philippines have worked with vegetable growers using paraquat-based systems.
These were found to reduce soil erosion and water run-off by over one third and to reduce farm input costs by 73%.
In their RED facts document, the US EPA concluded that “paraquat is not expected or considered to be a groundwater concern from normal paraquat dichloride use patterns”.
