North America and Europe. The main reason for the greater impact on the former
continents is their much lower average yields, so that with identical amounts of
erosion, yields decline more rapidly in relative terms. This effect may even be
amplified by one or several orders of magnitude due to inappropriate soil management, making the use of appropriate soil management techniques, those effective at
erosion control and maintaining productivity, imperative, in order to meet the needs
of the world’s present and future populations.
Soil loss, however, does not only mean the translocation of soil particles, it also
severely affects the availability of plant nutrients and water storage capability, with
consequences for both crop yields (Schmitter et al. 2012, 2011) and environmental
quality (Anyusheva et al. 2012; Lamers et al. 2011). During erosion events,
nutrients are leached (Lam et al. 2005; Dung et al. 2008; Pansak et al. 2008) and
attached on eroded sediment, then relocated in the watershed or lost in river streams
(Schmitter et al. 2012; Chaplot et al. 2005). Effective soil erosion control is;
therefore, an essential part of sustainable upland agriculture systems and can be
used to alleviate and solve the problems of agro-ecological and environmental
degradation. For more detailed information on the scale of erosion and matter
flows in mountainous regions studied by the Uplands Program, refer to Chaps.
2 and 3 of this book.
7.2.2 Soil Conservation Options
There are numerous soil conservation techniques (SCT) used to control soil loss and
run-off from agricultural land at both the field and landscape levels. Conservation,
minimum and zero tillage aim to reduce the impact of tillage on soil structures,
while contour-based cropping systems such as strip cultivation, grass barriers,
natural vegetative strips and alley cropping, reduce slope length or build a vegetative barrier against run-off. Cover crops, relay cropping, mulching and bio
or synthetic geo-textiles placed on the soil’s surface decrease the direct impact of
raindrops on the soil surface. On a larger scale, buffer strips in farming areas or
close to riparian systems, and contour terracing, are also effective at addressing this
issue.
Conservation agriculture (CA) aims to create minimum mechanical soil disturbance, and involves no-tillage seeding, the use of organic mulch cover and crop
diversity. Its potential benefits include higher productivity and incomes, climate
change adaptation and reduced susceptibility to erratic rainfall distribution, as well
as reduced greenhouse gas emissions (Kassam et al. 2012). There are three important
pillars of CA: (1) minimal tillage operations, (2) permanent soil cover, and (3) the
rotation of primary crops (Chauhan et al. 2012). Recent studies have indicated that
minimum tillage combined with cover crops has the potential to offer both improved
soil conservation in cropping systems of tropical mountainous regions, as well as
facilitate stable or even improve yields over the course of time, without the major
disadvantages found with contour hedgerow systems (Hobbs 2007; Shafi et al. 2007).
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T. Hilger et al.
continents is their much lower average yields, so that with identical amounts of
erosion, yields decline more rapidly in relative terms. This effect may even be
amplified by one or several orders of magnitude due to inappropriate soil management, making the use of appropriate soil management techniques, those effective at
erosion control and maintaining productivity, imperative, in order to meet the needs
of the world’s present and future populations.
Soil loss, however, does not only mean the translocation of soil particles, it also
severely affects the availability of plant nutrients and water storage capability, with
consequences for both crop yields (Schmitter et al. 2012, 2011) and environmental
quality (Anyusheva et al. 2012; Lamers et al. 2011). During erosion events,
nutrients are leached (Lam et al. 2005; Dung et al. 2008; Pansak et al. 2008) and
attached on eroded sediment, then relocated in the watershed or lost in river streams
(Schmitter et al. 2012; Chaplot et al. 2005). Effective soil erosion control is;
therefore, an essential part of sustainable upland agriculture systems and can be
used to alleviate and solve the problems of agro-ecological and environmental
degradation. For more detailed information on the scale of erosion and matter
flows in mountainous regions studied by the Uplands Program, refer to Chaps.
2 and 3 of this book.
7.2.2 Soil Conservation Options
There are numerous soil conservation techniques (SCT) used to control soil loss and
run-off from agricultural land at both the field and landscape levels. Conservation,
minimum and zero tillage aim to reduce the impact of tillage on soil structures,
while contour-based cropping systems such as strip cultivation, grass barriers,
natural vegetative strips and alley cropping, reduce slope length or build a vegetative barrier against run-off. Cover crops, relay cropping, mulching and bio
or synthetic geo-textiles placed on the soil’s surface decrease the direct impact of
raindrops on the soil surface. On a larger scale, buffer strips in farming areas or
close to riparian systems, and contour terracing, are also effective at addressing this
issue.
Conservation agriculture (CA) aims to create minimum mechanical soil disturbance, and involves no-tillage seeding, the use of organic mulch cover and crop
diversity. Its potential benefits include higher productivity and incomes, climate
change adaptation and reduced susceptibility to erratic rainfall distribution, as well
as reduced greenhouse gas emissions (Kassam et al. 2012). There are three important
pillars of CA: (1) minimal tillage operations, (2) permanent soil cover, and (3) the
rotation of primary crops (Chauhan et al. 2012). Recent studies have indicated that
minimum tillage combined with cover crops has the potential to offer both improved
soil conservation in cropping systems of tropical mountainous regions, as well as
facilitate stable or even improve yields over the course of time, without the major
disadvantages found with contour hedgerow systems (Hobbs 2007; Shafi et al. 2007).
232
T. Hilger et al.