2015 International Year of Soils

No-till: a great way to care for our soilSoil is critical to life on earth. It comprises mineral particles, organic matter, water, air, flora and fauna. Soil formation is an extremely slow process, so soil is essentially a non-renewable resource and must be valued, respected and treated with great care. Agronomic techniques such as no-till 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.
, which involve the use of 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.
herbicides like paraquat for weed control, can preserve and improve the quality of our soils.
The UN Food and Agriculture Organisation (FAO) held a forum in Rome to mark World Soils Day on 5 December 2014 and to launch the International Year of Soils. Speakers at the event emphasised the critical importance, complexity and fragility of this thin layer covering the earth.1

Soil degradation and agriculture

It takes 1000 years to form about three centimetres of topsoil and the planet is losing an area equivalent to 30 soccer fields every minute. About one third of all the world’s soil is now considered to be degraded. Figure 1. Contribution of agricultural and industrial activities to soil degradation (Gruver, 2013).Soil degradation is caused by a number of factors, most particularly erosion by water and wind. Farming and associated deforestation are by far the main causes of degradation (Fig. 1). Intensive livestock production in the form of over-grazing, deforestation in the pursuit of more land and conventional cropping using deep cultivations each cause similar amounts of soil degradation. Overall, the loss of soil cover by vegetation, which exposes soil to wind and rain resulting in the erosion of topsoil, is to blame.2

FAO Global Soil Partnership

At the current rate of soil degradation and population growth, the area of agricultural land per person in 2050 will be only one quarter of what it was in 1960. A heavy burden of responsibility rests on the soil. We expect this thin layer to provide or facilitate many essentials:
  • Food security: increasing production of food, fodder and fibre
  • Water storage and provision
  • Climate change adaptation and mitigation (soil contains twice as much carbon as the atmosphere and three times as much as vegetation)
  • Sustain 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.
  • Bioenergy production
  • Base for urban expansion and supply of construction materials

Food security challenges for soil

  • 805 million people are hungry and malnourished in 2015
  • 60% more food will be needed by 2050
  • 33% of soil resources are degrading
These imperatives, especially in the face of soil degradation, have led FAO to establish the Global Soil Partnership. Partners are being drawn from international, regional and national institutions or organizations working on soil, including government organizations, universities, soil science societies, NGOs, private companies and farmer associations. They will bring not only scientific and technical expertise, but will also advise on practical issues and help to secure sponsorship and funding. Regional Soil Partnerships are being established to develop programs and to work with FAO and national organizations, building on existing networks and projects. The Global Soil Partnership will address soil needs through several main pillars of action. These include:
  • Soil management: promote the protection, conservation and sustainable productivity of soil resources
  • Policy: encourage the coordinated development and implementation of policy related to soil, including education, extension services and investment
  • Research and development: promote soil science focusing on identified knowledge gaps and opportunities for synergies
  • Data and information: support the generation, analysis and reporting of data, and subsequent monitoring and multidisciplinary use
Besides activities directly involving agriculture, Global Soil Partnership actions will be directed towards or involve issues with impact on society other than food security, including flood and drought management and land use.

Role of paraquat and conservation agriculture

Figure 2. Comparison of soil erosion rates in US cropping systems (Montgomery, 2007).The key to maintaining a healthy soil and avoiding erosion is to keep a substantial vegetative cover throughout the year and to replenish or increase soil organic matter levels. Conventional methods of cultivating the soil, especially plowing, bury weeds and the remains of the previous crop leaving soil bare. In conservation tillage

Description

Any tillage and planting system that covers 30 percent or more of the soil surface with crop residue after planting to reduce soil erosion by water.

Authoritative On-line References and Resources

Purdue University-based Conservation Technology Information Centre.
systems soil disturbance is minimal, or totally avoided as in no-till.
Studies on erosion rates have demonstrated the very significant impact on soil loss by keeping a vegetative cover (Fig. 2).3 Paraquat enabled the development of no-till because it is a very broad-spectrum, fast-acting, non-selective herbicide, which is deactivated immediately on contact with soil. This means that it can be used to burndown all weeds or a cover crop just before the next crop is planted. The desiccated weeds stay rooted to the soil, providing protection from the erosive effects of wind and rain while the crop establishes. The use of paraquat to control weeds is best integrated with cultural approaches including the use of cover crops, crop rotation, and varying sowing dates. Paraquat has other advantages as a herbicide including outstanding rainfastness and, because of its distinctive mode of action, it provides a vital means of combatting weed resistance

Description

The inherited ability of a plant/weed to survive a dose of a herbicide normally lethal to that species.

Authoritative On-line References and Resources

http://www.weedscience.org/in.asp The International Survey of Herbicide Resistant Weeds monitors the evolution of resistant species and assesses their impact. All confirmed instances of new cases are listed.
to other herbicides, especially glyphosate.

Symphony of the soil

A film has been produced to provide the essential background to the International Year of the Soil. The importance, complexity and mystery of the soil is explored and a trailer can be watched here

References

Arsenault, C (2014). Only 60 years of farming left if soil degradation continues. Scientific American, 5 December 2014. Gruver, J B (2013). Prediction, prevention and remediation of soil degradation by water erosion. Nature Education Knowledge, 4, (12), 2 Montgomery, D R (2007). Soil erosion and agricultural sustainability. Proceedings of the National Academy of Sciences USA, 104, (3), 13268-13272

Notes

The brand name of the leading paraquat herbicide is Gramoxone.