Conservation agriculture | SESL Australia

Conservation agriculture | SESL Australia




Conservation Agriculture


SESL Australia

Soybeans planted into winter wheat stubble. Photo: Colette Kessler, USDA ARS. Used under Creative Commons licence.


Agriculture as we know it in the West has proved a destructive force, especially here in Australia, even as we depend on it for our food.

The ever-increasing human population of Earth means that more food must be produced. The traditional solution has been to clear more land and plant more crops. But there is an upper limit to how much land can be cleared before no more suitable land remains. Many farmers around the world are now resorting to clearing marginal land for many reasons, including dispossession through corruption, displacement by war, loss of water by upstream damming, overpopulation and soil loss. The short-term need to eat causes a cycle of further degradation that threatens the long-term ability to live. An extreme example is seen in North Korea, where the almost totally denuded landscape is close to environmental collapse (Bowers 2012).

The Green Revolution supplied a temporary reprieve from the Malthusian constraint on continuous growth, but its gains have now been swallowed up by more consumers, soil loss and pest resistance, and the spiralling costs of fertilisers and fuels mean that yield potentials can often not be realised.
Sustainable food production

One promising solution is conservation agriculture (CA), which the UN’s Food and Agriculture Organization defines as “an approach to managing agro-ecosystems for improved and sustained productivity, increased profits and food security while preserving and enhancing the resource base and the environment” (FAO 2007).

CA relies on three key principles:
Continuous minimum mechanical soil disturbance.
Permanent organic soil cover.
Diversification of crop species grown in sequences and/or associations.

By loosening the soil, tillage enhances soil loss through wind and water erosion. The problem is particularly serious on sloping lands, such as hillsides, where many poor farmers in developing countries are pushed. The need to cultivate steep hillsides to grow enough to eat regularly leads to the loss of soil and the need to move further away and to clear even poorer land. In contrast, by encouraging minimum tillage, CA vastly reduces soil loss, making even marginal lands more productive.

As we’ve said many times over the years, organic matter (OM) is crucial to soil productivity. OM has a greater cation exchange capacity than clay and is critical to maintaining nutrient availability in the soil. OM returned to the soil from the crop returns nutrients and encourages soil organisms, which benefit soil fertility and resilience. OM left on the surface (rather than being incorporated) additionally insulates the soil against extremes of temperature and minimises soil loss through wind and rain. In addition, it inhibits the germination of weeds, reducing the need for both physical and chemical weed control.

Growing crops in rotation and association achieves both financial and ecosystem benefits. Crop rotation has long been known to reduce pests and diseases by breaking the continuity of food supply for pests and diseases. For example, growing wheat in rotation with soybean leaves no opportunity for wheat diseases to grow on soybean or soybean pests to multiply on wheat. Further, rotating cereals with legumes alternates a nitrogen user with a nitrogen supplier, reducing the need for fertiliser. In addition, intercropping of two different crops diversifies the farmers’ income, hedges against crop failure and achieves higher yields than either crop alone.
Drawbacks

Although CA has proven its worth many times in many different countries, it can face difficulties in gaining acceptance. The most serious problem is that farmers in dire poverty cannot afford the 3 or more years it can take for CA to yield benefits. Another problem is the conservativeness of farmers worldwide, who need persuasive reasons to abandon a traditional farming system for an entirely unfamiliar idea. Another is that in some countries, so much forest has been cleared for firewood for cooking that the only cooking fuel left is straw or cow manure, both of which are vital to CA; and eating has to come first.

Aid agencies can often make matters worse, not better: funding is often tied to political ideals or short-term increases in yields. And aid workers often arrive with the intention of supplying a solution rather than engaging with farmers and understanding what they want.

Not surprisingly, then, CA has had its greatest success in developed nations, where farmers can afford the time and money to experiment. In fact, in Australia, up to 90% of growers have adopted CA practices in some form or another (Llewellyn and D’Emden 2010).
Not a magic bullet

CA is not a panacea, however. It requires effort and a long-term commitment to adapting strategies to local conditions, including social, financial and environmental, and to persevering, as it does not offer a quick fix. Instead, by gradually increasing soil fertility, decreasing soil erosion, increasing water infiltration and diversifying income, it can restore stability of production and livelihoods, in both developing and developed countries.
Further reading

Bowers K. 2012. Inside the secret state. New Scientist 24 Nov: 38–41.

FAO. What is conservation agriculture? Food and Agriculture Organization of the United Nations.

Hauswirth D et al. 2012. Conservation agriculture and sustainable upland livelihoods: innovations for, with and by farmers to adapt to local and global changes. Proc 3rd Int Conf Conserv Agric in SE Asia, Hanoi, 10–15 Dec. CIRAD, NOMAFSI, Univ Qld.

Llewellyn R, D’Emden FH. 2010. Adoption of no-till cropping practices in Australian grain growing regions. Grains Research and Development Corporation, Canberra.




SESL Australia
SESL Australia has evolved over 30 years as an environmental, soil, water and plant science laboratory and consultancy service. Established in Sydney in 1984 by Simon Leake, SESL has expanded into the ACT, QLD and VIC. The SESL team of environmental consultants have a clear company objective to provide accurate and timely sampling, analysis and interpretive reporting to solve client problems.