Sustainable Soil Management Is More than What and How Crops Are Grown - Principles of Sustainable Soil Management in Agroecosystems - page 363

Sustainable soil management as practiced in CA systems has resulted in the
enhancement or rehabilitation of the soil resource base and its agroecological poten-
tials, thus enabling the avoidance of soil degradation and repair of lands, leading to
sustainable intensification and the harnessing of ecosystem services. This is illus-
trated in the examples for Brazil, Australia, and China given in the next sections.
14.5.3.1 Brazil
The soil degradation in South Brazil was reverted initially by reducing tillage inten-
sity. This involved the use of a chisel in substitution of the moldboard plow and the
reduction in the number of disc operations. The first no-till experimental plots were
set up in the early 1970s in Rio Grande do Sul and Paraná States. However, the suc-
cessful diffusion of no-till systems on a broader scale remained erratic until late
1980s. The first obstacles that had to be overcome were control of weeds without soil
tillage or a hoe, as well as unavailability of planters able to work with crop residues.
There was also the need to select appropriate cover crop options to intensify the
cropping system in substitution of fallow, to produce enough crop residue to protect
the soil and deal with the scarce technical assistance, high price of herbicides, and
many technical doubts about the efficiency of lime and fertilizer surface broadcast
instead of soil placement (Amado and Reinert 1998; Bernoux et al. 2006; Bolliger
et al. 2006).
In the 1980s, farmers began to organize themselves into no-till-promoting asso-
ciations, such as the “Clube da Minhoca” (“Earthworm Clubs”) and the “Clubes
Amigos da Terra” (“Friends of the Soil” clubs or “Earth” clubs), as well as private
research institutions, such as the “Fundacão ABC” (ABC Conglomerate of Farmers'
Cooperatives) to promote the adoption and diffusion of no-till (Borges Filho 2001;
Dijkstra 2002).
The initial drive to expand the adoption of no-till was led by pioneer farmers,
who also organized the first Brazilian no-till conference in 1981 (Steiner et al. 2001).
No-till technologies and systems subsequently spread fairly rapidly from Paraná to
other Southern Brazilian states and neighboring Paraguay, where similar environ-
mental conditions existed.
A steady interregional migration of farmers from Southern Brazil to tropical
Brazil brought a transfer of the basic zero-till principles in its wake, but the different
agroecological conditions of humid subtropical Southern Brazil compared to those
of frost-free, seasonally dry, tropical Brazil, as well as the different scales of large
cerrado farms compared to generally smaller farms in the South, meant that no-till
systems had to undergo scale and regional adaptation (Spehar and Landers 1997;
Bolliger et al. 2006). The first records of mechanized no-till in South America were
in the Brazilian state of Goiás dating from 1981/1982 (Landers et al. 1994). In Brazil,
especially, no-till-type land management expanded from an estimated less than 1000
ha in 1973/1974 to nearly 26 million ha in 2010/2011 (Bolliger et al. 2006; Kassam
et al. 2010).
More than 45% of total cultivated land in Brazil is now estimated to be managed
with no-till (Scopel et al. 2004), although in Southern Brazil, this figure is reported
to exceed 80% (Amado et al. 2006; Denardin and Kochhann 1999; Bolliger et al.
2006). Among the leading no-till nations, Brazil is purportedly the only one with