FAO stresses need for sustainable land use

Soil erosion seriously limits productivityThe United Nations Food and Agriculture Organisation (FAO) has recently published a report emphasising that to meet global food security needs it will be essential to adopt best practices in soil and water management. By 2050, rising population and consumption are expected to demand up to 70% more food production globally, and 100% more in developing countries, compared to current production levels.1

Higher yields … at a price

In the report, ‘The state of the world’s land and water resources for food and agriculture’, FAO point out that over the past 50 years agricultural productivity has grown by 150 – 200%, despite the total area of cultivated land increasing by only 12%. Yields have increased, but the cropland available per head of the burgeoning population has steadily reduced (Fig. 1).2 Figure 1. Global average yields of wheat, rice and maize since 1961 and cropland per head every 5 years (FAOSTAT).Moreover, the achievements of higher crop yields in some regions have been associated with degradation of land and water resources. According to FAO, soil degradation issues include erosion, loss of organic matter, compaction and loss of 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.
. Soil degradation is also closely associated with poverty. Some 40% of the world’s degraded land is found in areas with high degrees of poverty.
In future, more than 80% of productivity gains will have to come from existing farmland through sustainable intensification

Description

United Nations Food and Agriculture Organisation (FAO) defines Sustainable Crop Production Intensification as optimizing crop production per unit area, taking into account social, political, economic and environmental impacts.

Authoritative On-line References and Resources

Sustainable intensification of crop production is one of FAO's core themes.
, making effective use of soil and water resources without causing them harm.

Conservation agriculture

FAO recommend the wider adoption of conservation agriculture as one important means of addressing these issues of land degradation. Conservation agriculture is based on the three principles of minimal soil disturbance; permanent soil cover by crops, other vegetation or harvest waste; and crop rotations.

Three pillars of conservation agriculture

  • Minimal soil disturbance:  Soil structure is allowed to build naturally, eg through the action of earthworms; organic matter is protected from oxidation
  • Permanent soil cover:  Soil is protected from the action of wind and rain causing erosion; habitats for beneficial insects, etc are preserved
  • Crop rotations:  Soil organic matter levels, fertility and structure are improved
Moving to conservation agriculture will especially benefit smallholder farmers who are facing acute labor shortages as workers migrate to cities. This is because under conservation agriculture field operations with high labor requirements, such as plowing and hand weeding, are reduced or eliminated. In conservation agriculture, tillage systems such as no-till

Description

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

No-till.com:  A portal for on-line information about no-till farming.
involve seeds being planted directly into uncultivated stubble after weeds have been controlled by a non-selective

Description

A chemical product used for eliminating all types of weeds (annual and perennial grasses and broadleaved weeds).

Authoritative On-line References and Resources

http://www.weeds.iastate.edu/ An invaluable source of contemporary information about herbicides and weeds from Iowa State University.
herbicide such as paraquat.

Paraquat: past, present and future

Modern no-till systems were pioneered in Brazil in the 1970s.3 The availability of paraquat for weed control and the development of suitable seed drills made crop establishment without plowing possible. Paraquat’s broad spectrum, fast action and soil properties, being deactivated immediately on contact with soil, made it the ideal herbicide for no-till. Paraquat is not systemic, so weed roots remain intact for some time, anchoring the soil and resisting erosion. It has no soil residual properties, so new flushes of weeds may emerge and be allowed to provide ground cover while they are small and not competing with the crop.  More recently, when glyphosate became a cheap generic herbicide it often replaced paraquat. However, paraquat is now a key tool for weed control once more for many farmers in Brazil and elsewhere facing the serious problem of glyphosate resistant weeds. The widespread adoption of GM glyphosate tolerant soybeans and corn meant that many farmers came to rely almost totally on glyphosate for weed control. This has resulted in shifts to more tolerant species or resistant populations in the weed flora, posing a dilemma for Brazilian farmers A solution for many farmers has been to spray a paraquat based herbicide at or shortly after planting, following a burndown application of glyphosate. As paraquat has a distinctive mode of action this controls any weeds that have survived the glyphosate spray and any newly emerged weeds, extending the period of weed control. Glyphosate resistant weeds are prevented from setting seed, halting the advance of resistant populations. An article on this system can be read here. Paraquat has a number of important benefits, which make it an essential tool for farmers to ensure sustainable land use.

References

  1. FAO (2011). The state of the world’s land and water resources for food and agriculture
  2. FAOSTAT 
  3. FAO (2012). No-till agriculture in Southern Brazil
    NB Portuguese version available.

Notes

The brand names of the leading paraquat products are Gramoxone and Gramocil.