Sustainable Soil Management Is More than What and How Crops Are Grown - Principles of Sustainable Soil Management in Agroecosystems - page 371

problems, various kinds of CA practices have been developed in northern China,
such as no-till, controlled traffic, and PRBs, leading to a range of beneficial effects
on soil quality, including increase in SOM, decrease in bulk density and improve-
ment in soil structure, higher infiltration rate, greater soil moisture holding capacity,
and reduced runoff and erosion (Bai et al. 2008; Gao et al. 2008; Chen et al. 2008).
Effect of CA on wind erosion: Research measuring springtime wind erosion losses
in the Yanggao region of the Loess Plateau has shown that CA treatments reduced
topsoil loss by 44.7% compared to CT ( Table 14.3 ). At nine other sites across north-
ern and north central China, from the dry, windy conditions of the far west to the
relatively temperate plains in the Beijing area, CA treatments consistently reduced
springtime wind erosion losses from 12% to 93% depending upon the measurement
duration, ambient conditions, and erosive winds (Table 14.3).
14.6 INTEGRATING SUSTAINABLE SOIL MANAGEMENT
PRINCIPLES INTO FARMING SYSTEMS
Sustainable soil management and crop production principles of CA can be integrated
into most if not all types of production or farming systems. This is because they
provide the ecological underpinnings to production and farming systems to generate
greater productivity and environmental benefits. Below are some examples.
Organic agriculture based on CA can lead to greater soil health and productivity,
increased efficiency of use of organic matter, and reduction in use of energy. Organic
CA farming is already being practiced on a smaller scale in the United States, Brazil,
and Germany, as well as by subsistence CA farmers in Africa and elsewhere. Tillage-
based organic farming is often characterized more by what practices it excludes from
its production systems than by what it actually does to harness sustainable produc-
tion intensification and ecosystem services. Introducing CA principles into organic
farming would reduce soil disturbance, improve weed control with mulch cover and
crop diversification, and generate greater amounts of organic matter from in situ
sources within a more diversified cropping system involving legumes (Altieri et al.
2011).
Agroforestry systems involve the cultivation of woody perennials and annual
crops together in a sustainable manner and are increasingly practiced in degraded
areas with perennial legumes (Saha et al. 2010). CA works well with trees and shrubs
and within agroforestry and related systems. In fact, several tree crop systems in
the developing and developed regions already practice some form of CA, but these
systems can be further enhanced with improved crop associations including legumes
and integration with livestock. Alley cropping has been one innovation in this area
that is beginning to offer productivity, economic, and environmental benefits to pro-
ducers (Sims et al. 2009).
CA with trees has now become an important option for many farming situations,
particularly in the tropics. These CA systems incorporate varying densities of fertil-
izer trees in order to enhance biological nitrogen fixation, increase biomass produc-
tion for surface residue, and conserve moisture. They have become the basis for major
scaling-up programs with hundreds of thousands of farmers in Zambia, Malawi,
Niger, and Burkina Faso (Garrity et al. 2010; Garrity 2011). The incorporation of the