Brazil’s no-till boom fights climate change

No-till drilling into a weed-free seedbedParaquat has always played a pivotal role in the development of no-till cropping systems in Brazil, as elsewhere. Not only has no-till helped to propel Brazil to the status of an agricultural ‘superpower’, but it has also brought many sustainable benefits by improving soils and reducing erosion, increasing biodiversity

Description

The variety of life in all its forms, levels and combinations. Includes ecosystem diversity, species diversity, and genetic diversity (IUCN, UNEP and WWF, 1991).

Authoritative On-line References and Resources

http://earthtrends.wri.org/ EarthTrends is a comprehensive online database, maintained by the World Resources Institute, that focuses on environmental, social, and economic trends. Statistics on biodiversity indicators are available.
, reducing energy use and improving profitability. More recently, the contribution no-till farming can make to fighting climate change has been recognized. No-till soils sequester carbon as organic matter and because there are fewer passes over a field by machinery, considerably less fuel is used.

Brazil’s ABC Program

Plans to increase the area of no-till farming feature strongly in the Brazilian Ministry of Agriculture's ABC program (Agricultura de Baixo Carbono) launched in 2010 to target reductions in greenhouse gas emissions1. Over $1 billion worth of credit will be available to farmers to support the implementation of various approaches to reduce the impact of agriculture on climate change. The goal is to slash more than 160 million tonnes from carbon dioxide equivalent emissions per annum by 2020. Relative contributions to reducing greenhouse gas emissions by 2020 targeted in Brazil1Overall, the initiative will further increase the sustainability of Brazilian agriculture by, not only improving its environmental profile, eg by integrating crop and livestock farming and introducing more legume crops to reduce the reliance on nitrogen fertilizer, but also by increasing its profitability. No-till techniques will play an important part in this effort and the aim will be to increase the no-till area by around eight million hectares in less than 10 years.

Benefits from no-till in Brazil

The area of crops established by no-till in Brazil increased rapidly through the 1990s from one million hectares in 1990/1 to 17 million hectares by 2000 and on to more than 25 million hectares (60 million acres) in 2005/62. Nearly 70% of all cultivated land in Brazil is under no-till. A key driver in this expansion was the benefit no-till brings to the soil and positive knock-on effects. The FAO has reported the results of a number of field experiments in Brazil, comparing no-till with conventional tillage

Description

Full width tillage which disturbs all of the soil surface and is performed prior to and/or during planting. There is less than 15 percent residue cover after planting. Generally involves plowing or intensive (numerous) tillage trips. Weed control is accomplished with crop protection products and/or inter-row cultivation.

Authoritative On-line References and Resources

http://www.fao.org/News/2000/000501-e.htm A news item from FAO discussing the problems with plowing and the advantages of conservation agriculture.
using heavy discs (see table below) 3. Soil structure was clearly better after several years of no-till, especially under more diverse cropping systems. Level of organic matter increased the longer fields were kept under no-till, eg from 2.5% in the top 20 cm with tillage to 3.1% after 10 years of no-till. Earthworm populations increased dramatically under no-till, eg from an average of only 3 per square metre to a depth of 30 cm in one cultivated soil to 28 per square metre in no-till plots. Maize roots were more abundant and more evenly distributed in no-till soil. A more stable soil structure from more organic matter binding soil particles together leads to much less erosion. Greater porosity allows better water infiltration meaning far less run-off

Description

The occurrence of surplus liquid (like rain) which originates up-slope and is collected beyond the ability of the soil to absorb it. The surplus liquid then flows away over the surface to reach the nearest surface water (pond, lake, river).

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US Geological Survey's Water Science School
from fields causing flooding and blocking water courses with sediment.
  Soil Loss (t/ha/year) Water Run-Off (mm/year)
  Tillage No-till Tillage No-till
Paraná (wheat/soybean) 26 3 670 230
Cerrados (soybean)   5 1 210 120
Cerrados (maize)   3 2 280 170
Some of the other benefits of no-till including greater opportunities for biodiversity and reductions in energy use have been discussed in earlier articles.

Paraquat solution to glyphosate resistant weeds

No-till and associated cultural practices such as the use of crop rotation and cover crops

Description

Cover crops are primarily planted not to be harvested for food but to reduce soil erosion, control weeds and improve soil quality. They are usually plowed or tilled under before the next food crop is planted, in which cases the "cover crop" is used as a soil amendment and is synonymous with "green manure crop."

Authoritative On-line References and Resources

http://attra.ncat.org/attra-pub/covercrop.html ATTRA is the US National Centre for Appropriate Technology's Sustainable Agriculture Information Centre.
make sustainable farming

Description

Management and conservation of the natural resource base and the use of technological and organizational change in a manner that ensures continued agricultural production from the land for present and future generations. Such practices conserve land, water, and plant and animal genetic resources. They are environmentally non-degrading, technically appropriate, economically viable, and socially acceptable. Sustainability rests on the principle that we must meet the needs of the present without compromising the ability of future generations to meet their own needs. Therefore, stewardship of both natural and human resources is of prime importance.

Authoritative On-line References and Resources

www.nal.usda.gov Information from the USDA's Alternative Agricultural Systems Information Center.
possible. In the early days of no-till, paraquat was the key to weed control when it was no longer possible to kill weeds by plowing. Later, glyphosate was introduced and, especially following the widespread adoption of glyphosate tolerant GM soybeans, its use has dramatically escalated over three decades. However, the simplified approach to weed control an all-glyphosate system offers farmers is threatening no-till with the rise of glyphosate resistant weeds. Up to three million hectares in Brazil are now estimated to be infested with five weed species which are no longer controlled by glyphosate4. A more diversified approach to weed control is needed, including the use of cultural methods such as rotations and cover crops, and the use of herbicides with different modes of action. Although no new herbicide modes of action have been introduced for over a quarter of a century and none are in development, paraquat with its distinctive mode of action has an essential role to play. In Brazil, paraquat has been called ‘glyphosate’s bodyguard’. Using a paraquat-based herbicide to control weeds before planting glyphosate tolerant crops allows glyphosate to be used later in the growing crop with much less risk of encouraging resistant weeds than comes with more frequent use.
Using paraquat as a vital part of integrated weed management

Description

A decision support system for crop protection which focuses on long-term prevention or suppression of pest problems with minimum impact on human health, the environment, and non-target organisms. IPM takes into consideration all available pest control techniques and tactics (cultural, mechanical, biological, chemical). IPM emphasizes the growth of healthy crops for better productivity with the least possible disruption to agroecosystems.

Authoritative On-line References and Resources

http://www.ipmcenters.org "The USDA's National Site for the Regional IPM Centers' Information System provides information about US commodities, pests and pest management practices, people and issues."
systems in Brazil is helping to support the continued growth of no-till farming and making a significant contribution to fighting climate change.

References

  1. Contini, E & Martha Jr, G B (2010). Brazilian agriculture, its productivity and change. Bertebos Conference on “Food security and the futures of farms: 2020 and toward 2050”. Falkenberg: Royal Swedish Academy of Agriculture and Forestry, August 29-31, 2010.
  2. Federaçao Brasileira de Plantio Direto na Palha
  3. FAO Soils Bulletin 79. Optimising soil moisture for plant production. The significance of soil porosity.
  4. International Survey of Herbicide Resistant Weeds.

Notes

The brand names for leading paraquat products include Gramoxone and Gramocil