rural labor-intensive industry in which particularly socially disadvantaged groups
can be employed for the production of bio-geotextiles that could be exported to
industrialized countries based on fair trade principles (Booth et al. 2007). The
IWAM approach consists of three pillars: (1) contour furrow cultivation,
(2) mulching, and (3) multiple cropping. The first pillar – contour furrow cultivation, breaks the water flow down slopes, to decrease surface run-off and soil loss as
well as increase water infiltration and; hence, the amount of soil water available for
plant growth. The second mulching decreases the impact of rain drop energy on the
soil surface during the wet season and reduces soil water evaporation during the dry
season, while the third, multiple cropping, achieves both – a permanent soil cover
and a continuous income flow for farmers (Panomtaranichagul et al. 2010).
7.2.3.1 Study Sites and Experimental Set-Up
Field experiments for this study were carried out between 2007 and 2009. Two sites
were established, one at Bor Krai in Pang Mapa district, Mae Hong Son Province
(site 1: 19
33
0 6
00 N, 98
12
0 52
00 E; altitude 697–719 m.a.s.l.; slope gradients 38–48
),
and the other at Jabo Village in Pang Mapa District, also in Mae Hong Son Province
(site 2: 19
33
0 51
00 N, 98
12
0 10
00 E; altitude 896–910 m.a.s.l.; slope gradients
16–18
), using complete randomized block designs with three replications. Both
sites had a clayey soil texture. Climate in the area is influenced by tropical
monsoons with a hot dry season lasting from mid-March to mid-May. Intermittent
rain showers occur towards the end of April and until the arrival of the monsoonal
rains at the end of May. The wet season lasts until the end of October or early
November, followed by a cool and dry season. Total rainfall amounts at the study
site were 1,642 mm in 2007, 1,717 mm in 2008 and 1,579 mm in 2009.
The treatments applied were: (1) conventional contour planting (CP),
(2) cultivated contour furrow planting with alley cropping (CF-AL), (3) cultivated
contour furrow planting with alley cropping mulched with bio-geotextiles (CFBGT-AL), and (4) contour planting with alley cropping and bio-geotextiles (CPBGT-AL). The following bio-geotextiles were available at the field site: bamboo
mats, banana leaves (Musa acuminata), imperata grass (Imperata cylindrica),
bamboo grass (Thysannolaena maxima), vetiver grass (Vetiveria nemoralis) and
forking fern (Dicranopteris linearis). For this study, banana leaves, bamboo grass
and vetiver grass were used. As differences between the bio-geotextiles were
marginal, these treatments were averaged and presented as one treatment. In the
alley cropping treatments, a mixture of fruit trees was set up, these being mango
(Mangifera indica), lemon (Citrus aurantifolia) and jujube (Ziziphus jujuba). In
addition, Graham stylo (Stylosanthes guianensis) was sown as a cover crop below
the fruit trees. Sweetcorn (Zea mays var. saccharata) was planted as the first crop,
followed by groundnuts (Arachis hypogea) or upland rice (Oryza sativa), and
chilies (Capsium frutescens) or kidney beans (Phaseolus vulgaris) as a second
crop. As a third crop lablab beans (Lablab purpureus) were sown. All the crops
were relay cropped, making it possible to establish three crops a year.
7 Soil Conservation on Sloping Land: Technical Options and Adoption Constraints
235
can be employed for the production of bio-geotextiles that could be exported to
industrialized countries based on fair trade principles (Booth et al. 2007). The
IWAM approach consists of three pillars: (1) contour furrow cultivation,
(2) mulching, and (3) multiple cropping. The first pillar – contour furrow cultivation, breaks the water flow down slopes, to decrease surface run-off and soil loss as
well as increase water infiltration and; hence, the amount of soil water available for
plant growth. The second mulching decreases the impact of rain drop energy on the
soil surface during the wet season and reduces soil water evaporation during the dry
season, while the third, multiple cropping, achieves both – a permanent soil cover
and a continuous income flow for farmers (Panomtaranichagul et al. 2010).
7.2.3.1 Study Sites and Experimental Set-Up
Field experiments for this study were carried out between 2007 and 2009. Two sites
were established, one at Bor Krai in Pang Mapa district, Mae Hong Son Province
(site 1: 19
33
0 6
00 N, 98
12
0 52
00 E; altitude 697–719 m.a.s.l.; slope gradients 38–48
),
and the other at Jabo Village in Pang Mapa District, also in Mae Hong Son Province
(site 2: 19
33
0 51
00 N, 98
12
0 10
00 E; altitude 896–910 m.a.s.l.; slope gradients
16–18
), using complete randomized block designs with three replications. Both
sites had a clayey soil texture. Climate in the area is influenced by tropical
monsoons with a hot dry season lasting from mid-March to mid-May. Intermittent
rain showers occur towards the end of April and until the arrival of the monsoonal
rains at the end of May. The wet season lasts until the end of October or early
November, followed by a cool and dry season. Total rainfall amounts at the study
site were 1,642 mm in 2007, 1,717 mm in 2008 and 1,579 mm in 2009.
The treatments applied were: (1) conventional contour planting (CP),
(2) cultivated contour furrow planting with alley cropping (CF-AL), (3) cultivated
contour furrow planting with alley cropping mulched with bio-geotextiles (CFBGT-AL), and (4) contour planting with alley cropping and bio-geotextiles (CPBGT-AL). The following bio-geotextiles were available at the field site: bamboo
mats, banana leaves (Musa acuminata), imperata grass (Imperata cylindrica),
bamboo grass (Thysannolaena maxima), vetiver grass (Vetiveria nemoralis) and
forking fern (Dicranopteris linearis). For this study, banana leaves, bamboo grass
and vetiver grass were used. As differences between the bio-geotextiles were
marginal, these treatments were averaged and presented as one treatment. In the
alley cropping treatments, a mixture of fruit trees was set up, these being mango
(Mangifera indica), lemon (Citrus aurantifolia) and jujube (Ziziphus jujuba). In
addition, Graham stylo (Stylosanthes guianensis) was sown as a cover crop below
the fruit trees. Sweetcorn (Zea mays var. saccharata) was planted as the first crop,
followed by groundnuts (Arachis hypogea) or upland rice (Oryza sativa), and
chilies (Capsium frutescens) or kidney beans (Phaseolus vulgaris) as a second
crop. As a third crop lablab beans (Lablab purpureus) were sown. All the crops
were relay cropped, making it possible to establish three crops a year.
7 Soil Conservation on Sloping Land: Technical Options and Adoption Constraints
235