TOWARDS THE CIRCULAR ECONOMY | 91
FIGURE 25 Regenerative agricultural practices greatly reduce soil losses and quality deterioration Example of wheat-maize rotation grown in Red Ferralsol1 soil 29 Soil nutrient losses (t/ha/year)
2
196
Soil nutrient losses (kg/ha/year)
10
700 Water losses (m3/ha/year)
33 Conventional agriculture
Conventional agriculture using zero tillage
1 These soils occur mainly under tropical climates, and cover extensive areas on flat, generally well-drained land. They are considered strongly weathered and associated with old geomorphic surfaces. SOURCE: Castro (1991) as reported in FAQ Concepts and impacts of conservation available at http://www.fao.org/docrep/003/ Y1730E/y1703e03.htm#P194_29413
A broad range of regenerative farming practices
184 IFDC (http://www.ifdc. org/Technologies/Fertilizer/ Fertilizer_Deep_Placement_ (UDP)) 185 ‘Ducks replace paddy-field pesticides’, The Guardian, 24 January, 2012
Nutrient waste can be cut while maintaining productivity. According to the IFDC, twothirds of the nitrogen applied as chemical fertiliser often remains unabsorbed by crops and becomes an environmental pollutant, either in the form of potent greenhouse gases or runoff that pollutes streams and lakes. Less than 30% of the phosphate mined to produce phosphorus fertiliser becomes part of the food chain as a result of inefficiencies in its production and use. There are several ways to use chemical fertilisers more effectively, allowing smaller doses, such as slow-release fertilisers or deep placement and precision agriculture. Improving the effectiveness of nutrient use does not just reduce pressure on the fertiliser supply; reduced runoffs also protect the environment against the formation of aquatic ‘dead zones’ overloaded with oxygen-depleting chemicals, encouraging algae to bloom where rivers run into the ocean. One successful example is the urea deep-placement (UDP) technology project in Bangladesh (2008/2009), which has delivered a 20% increase in crop yields and a 40% decrease in nitrogen losses. Farmers who used this technique had additional annual
net returns of USD 188/ha and the higher rice production resulted in food security for an additional 4.2 million Bangladeshis. In 2008 Bangladesh was able to cut its urea import needs by 50,000 Mt, saving not only USD 22 million in fertiliser imports but also a further USD 14 million in government subsidies.184 Similar practices to select more carefully and apply more precise quantities can also reduce pesticides. As James Lomax of UNEP’s Sustainable Consumption and Production Branch summarises it: ‘The aim is to use fewer “bad” agricultural inputs and to use the “good” inputs better’. ‘Integrated farming systems’ refers to integrating livestock and crop farming to make it easier to return nutrients to the soil. Crops and livestock interact to create a synergy that can go beyond using the ‘waste’ products from animals as fertiliser for crops. One example is the ‘aigamo method’. Keeping ducks on rice paddies was rediscovered by the Japanese farmer Takao Furuno in 1989. The droppings from the ducks are a natural fertiliser, but the ducks also keep insects and weeds under control and their wading and paddling oxygenates the water and stirs up the soil. The concept has been refined to integrate the nitrogen-fixing fern Azolla, further reducing the need for fertiliser. Furuno’s rice output is reportedly a third higher than that of his neighbours, who use pesticides,185 and in 2011, the technique was successfully tested in Camargue in southern France. Another example is ‘pasture cropping’. This is a technique of growing crops symbiotically with existing pastures. The mix of shallowrooted crops and deep-rooted perennial pastures results in reduced wind and water erosion, improved soil structure, fewer weeds, greater nutrient availability and increased levels of organic carbon in the soil. Measurements in the NSW Central Highlands of Australia show that in such a system organic soil carbon levels can double over a 10-year period, and many crops there are now being sown without any chemicals or fertilisers. The application of integrated farming and other permaculture principles has a measurable impact on the preservation of natural capital in terms of reduced nutrient and soil carbon losses, and it typically improves water retention too (Figure 25).