Sustainable Soil Management Is More than What and How Crops Are Grown - Principles of Sustainable Soil Management in Agroecosystems - page 360

To achieve and sustain the necessary intensification of these production systems
to meet the increasing demand for food and other ecosystem services, productivity
needs to be optimized by applying best management practices such as good-quality
adapted seeds, adequate nutrition, and protection from pests and diseases (weeds,
insects, and pathogens) and avoiding soil compaction. In addition, efficient water
management and timely operations are required within suitable cropping systems to
achieve desirable and acceptable outcomes.
In light of the above, it is clear that sustainable soil management depends on both
what and how crops are grown, as well as on additional aspects of soil and landscape
management, which includes the horizontal integration of other production sectors
such as livestock and forestry. The special role of deep-rooted legumes such as pigeon
pea ( Cajanus cajan ), lablab ( Dolichos lablab ), and Mucuna ( Stizolobium cinereum )
in building soil structure and biopores for drainage and aeration, in contributing bio-
logically fixed nitrogen to improved nitrogen stocks in soils, and in generating both
biomass and edible products is a case in point. Beneficial effects of cover crops on
soil and water quality, ecological sustainability, and crop and livestock productivity
have been known for many years (e.g., Hargrove 1991). Similarly, species diversi-
fication as the third principle of CA is related to integrated management of insect
pests, pathogens, and weeds, and the effectiveness of control of pests, pathogens,
and weeds depends on both what and how crops are grown. Species diversification
involving crops of different durations and complementarity is also related to the use
and management of resources of different crops in space and time to maximize and
optimize the production during the growing season every year to its fullest poten-
tial in an increasingly variable and unpredictable climate. Furthermore, in order to
establish diversity of soil biological activity, it is necessary to include in the cropping
system a diversity of crops instead of monocropping or reduced crop diversity.
CA is now adopted on about 125 million ha of arable land worldwide, which
corresponds to nearly 10% of the total cropland (Friedrich et al. 2012). Some 50%
of this area is located in the developing regions. During the past decade, it has
been expanding with an average rate of more than 6 million ha/year. The highest
adoption levels, exceeding 50% of the cropland, are found in the southern part of
South America, the Canadian prairies, and Western Australia. Fast adoption rates
are now being seen in Central Asia and China, alongside increasing policy support
and early large-scale adoption taking place across Africa, particularly in Zambia,
Zimbabwe, South Africa, Tanzania, Kenya, Morocco, and Tunisia. Europe now
has some few pockets of adoption, particularly in Finland, Spain, France, Italy,
the United Kingdom, and Switzerland (Kassam et al. 2010; Derpsch and Friedrich
2009; Friedrich et al. 2012).
14.5.2 l linkage with l anDScaPe h ealth
Soil forming factors include topography, climate (microclimates), and parent materi-
als, all of which vary by landscape type and magnitude (Jenny 1980). Soils are vari-
able according to their positions in the landscape. Landscapes distribute water and
energy according to landform characteristics. In the northern hemisphere, the north-
facing side of a hill, in contrast to the south-facing side, will receive less radiation