DIFFERENCES IN CROPPING SYSTEMS AND SOIL ORGANIC CARBON DUE TO CLIMATE CHANGE AND SOCIOECONOMIC FACTORS IN POTATO-BASED CROPPING SYSTEMS IN THE BOLIVIAN HIGHLANDS. Peter Motavalli, Jorge Cusicanqui, Javier Aguilera, Corinne Valdivia, Magali Garcia, Elizabeth Jiménez , and Roberto Miranda. - PowerPoint PPT Presentation
Peter Motavalli, Jorge Cusicanqui, Peter Motavalli, Jorge Cusicanqui, Javier Aguilera, Corinne Valdivia, Javier Aguilera, Corinne Valdivia, Magali Garcia, Elizabeth Jiménez, and Magali Garcia, Elizabeth Jiménez, and Roberto Miranda Roberto Miranda DIFFERENCES IN CROPPING SYSTEMS AND DIFFERENCES IN CROPPING SYSTEMS AND SOIL ORGANIC CARBON DUE TO CLIMATE SOIL ORGANIC CARBON DUE TO CLIMATE CHANGE AND SOCIOECONOMIC FACTORS IN CHANGE AND SOCIOECONOMIC FACTORS IN POTATO-BASED CROPPING SYSTEMS IN THE POTATO-BASED CROPPING SYSTEMS IN THE BOLIVIAN HIGHLANDS BOLIVIAN HIGHLANDS
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Peter Motavalli, Jorge Cusicanqui, Javier Peter Motavalli, Jorge Cusicanqui, Javier Aguilera, Corinne Valdivia, Magali Garcia, Aguilera, Corinne Valdivia, Magali Garcia, Elizabeth Jiménez, and Roberto MirandaElizabeth Jiménez, and Roberto Miranda
DIFFERENCES IN CROPPING SYSTEMS AND DIFFERENCES IN CROPPING SYSTEMS AND SOIL ORGANIC CARBON DUE TO CLIMATE SOIL ORGANIC CARBON DUE TO CLIMATE
CHANGE AND SOCIOECONOMIC FACTORS IN CHANGE AND SOCIOECONOMIC FACTORS IN POTATO-BASED CROPPING SYSTEMS IN THE POTATO-BASED CROPPING SYSTEMS IN THE
BOLIVIAN HIGHLANDSBOLIVIAN HIGHLANDS
STUDY AREASTUDY AREA
• The Bolivian highland plateau The Bolivian highland plateau region (Altiplano) is a semi-arid region (Altiplano) is a semi-arid region in the Andes Mountains that region in the Andes Mountains that occupies approximately 27% of the occupies approximately 27% of the area of Bolivia and has a range in area of Bolivia and has a range in elevation of between 3600 and 4300 elevation of between 3600 and 4300 m above sea level. m above sea level.
• Primarily potato-based cropping Primarily potato-based cropping systems and livestock rearing of systems and livestock rearing of cows, sheep and camelids (e.g., cows, sheep and camelids (e.g., alpaca and lama) alpaca and lama)
AltiplanoAltiplano
A.A.B.B.
C. AncoraimesC. Ancoraimes D. UmalaD. Umala
LakeLakeTiticacaTiticaca AncoraimesAncoraimes
UmalaUmala
ChinchayaChinchaya
KellhuiriKellhuiri
San JosSan Joséé de Llanga de Llanga
San Juan CercaSan Juan Cerca
Vinto CoopaniVinto Coopani
ChojChojňňapataapata
CohaniCohani
KarkapataKarkapata
CalahuancaneCalahuancane
Lake TiticacaLake Titicaca
La PazLa Paz
SANREM STUDY AREA IN BOLIVIASANREM STUDY AREA IN BOLIVIA
CLIMATE CHANGECLIMATE CHANGE
• The Altiplano region’s climate is The Altiplano region’s climate is characterized by high diurnal characterized by high diurnal temperature variations, frost risks, low temperature variations, frost risks, low and irregular precipitation and high and irregular precipitation and high risks of drought during the growing risks of drought during the growing season (Garcia et al., 2007).season (Garcia et al., 2007).
• The region will experience temperature The region will experience temperature increases of up to 6increases of up to 6CC by the end of the by the end of the century (Bradley et al., 2006, IPCC, century (Bradley et al., 2006, IPCC, 2007).2007).
• A consequence of global climate A consequence of global climate change has and will be a higher change has and will be a higher incidence of extreme weather events incidence of extreme weather events (Haylock et al., 2006; Thibeault et al., (Haylock et al., 2006; Thibeault et al., 2008).2008).
STUDY AREA IN BOLIVIASTUDY AREA IN BOLIVIA
ºC yr-1
Average annual rainfall(mm yr-1)
Garcia and Seth (in prep.)Garcia and Seth (in prep.)
Change in MinimumChange in Minimum TemperatureTemperature
OBJECTIVES OF SOILS RESEARCHOBJECTIVES OF SOILS RESEARCH
• To survey representative indigenous To survey representative indigenous farming communities in the Altiplano of farming communities in the Altiplano of Bolivia to determine perceived changes Bolivia to determine perceived changes in cropping practices in potato-based in cropping practices in potato-based cropping systems due to global climate cropping systems due to global climate change and socio-economic factors.change and socio-economic factors.
• To assess the effects of these changes To assess the effects of these changes on soil total organic C and other soil on soil total organic C and other soil properties to determine if soil properties to determine if soil degradation has occurred. degradation has occurred.
MATERIALS AND METHODSMATERIALS AND METHODS
• Village-level surveys and participatory Village-level surveys and participatory workshops were conducted in 4 to 5 villages workshops were conducted in 4 to 5 villages situated at different relative altitudes in the situated at different relative altitudes in the communities of Umala and Ancoriames. communities of Umala and Ancoriames.
• Replicated soil samples were collected in Replicated soil samples were collected in UmalaUmala to a 20 cm depth from agricultural fields to a 20 cm depth from agricultural fields of the same cropping system and sandy soil of the same cropping system and sandy soil type (locally classified as “cha’lla” soil)type (locally classified as “cha’lla” soil) to to determine changes in soil properties with determine changes in soil properties with fallow length.fallow length.
• Replicate soil samples were collected to a 20 Replicate soil samples were collected to a 20 cm depth directly underneath or between cm depth directly underneath or between “th’ola” (“th’ola” (Parastrephia lepidophylla),Parastrephia lepidophylla), a common a common component of fallow vegetation, to determine component of fallow vegetation, to determine its effects on soil properties during fallow. its effects on soil properties during fallow.
CHANGES IN SOIL MANAGEMENT PRACTICESCHANGES IN SOIL MANAGEMENT PRACTICES
(Yucra and Gilles, unpublished)
20 years ago in Chinchaya20 years ago in Chinchaya PresentPresent
CHANGES IN SOIL CHANGES IN SOIL MANAGEMENT PRACTICESMANAGEMENT PRACTICES
• Increase in production of some cash crops Increase in production of some cash crops (e.g. onion) and other income-generating (e.g. onion) and other income-generating activities (e.g. dairy production, day labor)activities (e.g. dairy production, day labor)
• Decrease in the length of the fallow period in Decrease in the length of the fallow period in the crop rotation.the crop rotation.
• Reduction in planting of early season crops Reduction in planting of early season crops (e.g., fava beans and quinoa) due to early (e.g., fava beans and quinoa) due to early season rainfall uncertainty.season rainfall uncertainty.
• Greater tractor use for tillage in lower Greater tractor use for tillage in lower elevation communities.elevation communities.
• Loss of native species (e.g., th’ola) that have Loss of native species (e.g., th’ola) that have multiple uses to restore soil fertility during multiple uses to restore soil fertility during fallow period and are a fuel source. fallow period and are a fuel source.
COMMUNITY PERCEPTIONS OF SOIL RESOURCES COMMUNITY PERCEPTIONS OF SOIL RESOURCES
AND SOIL-RELATED PROBLEMSAND SOIL-RELATED PROBLEMS
• Soil-related problems are only one of several Soil-related problems are only one of several factors limiting crop production.factors limiting crop production.
Low soil quality and soil fertilityLow soil quality and soil fertility((low soil nutrient content, high clay content and stoniness)low soil nutrient content, high clay content and stoniness)
Excessive water and wind-induced soil erosionExcessive water and wind-induced soil erosion Insufficient soil moisture due to lower rainfallInsufficient soil moisture due to lower rainfall Inadequate soil management practicesInadequate soil management practices
((Inappropriate tractor tillage practices, lack of a suitable crop Inappropriate tractor tillage practices, lack of a suitable crop rotation strategy, insufficient soil fertility inputs, and rotation strategy, insufficient soil fertility inputs, and overgrazing by sheep)overgrazing by sheep)
EXAMPLES OF LOCAL SOIL CLASSIFICATION SYSTEM AND EXAMPLES OF LOCAL SOIL CLASSIFICATION SYSTEM AND PERCEIVED CHANGES IN SOIL PROPERTIES PERCEIVED CHANGES IN SOIL PROPERTIES
* Observed changes in use of soil over the last 10 years.* Observed changes in use of soil over the last 10 years.
Vinto Coopani community (Relative high elevation)Vinto Coopani community (Relative high elevation)
Soil typeSoil typeNative Native namename CharacteristicsCharacteristics Changes in use over time*Changes in use over time*
1.White soil Pajre oraque
Soft soil; spiny plants grow in it. Before it was used for agriculture and now it is not.
2.Clayey soil Ňeq’e oraque
The surface soil can be cultivated but with erosion the soil becomes hard like cement
The soil used to be much stronger but it has been washed away.
3.Sandy/clayey soil
Jach’oca The soil has both clay and large stones
The moisture content is decreasing and there are more rocks.
4.Hard clay soil Karpa Has clay that is used for making ceramics.
It has become less fertile.
5.Sandy soil Saj’e Little soil on surface and below has gravel. Dries out quickly and is a very good for production.
Used to be more fertile because it was maintained in fallow longer.
6.Black soil Chiar laqa The clay is neither hard or soft Used to be more fertile because it was maintained in fallow longer.
7.Fine sand soil Laqa Oraque
Good soil with the color of skin; it has very fine sand
It appears to have more rocks.
EXAMPLES OF SOIL PROPERTIES OF SOIL TYPES BASED ON EXAMPLES OF SOIL PROPERTIES OF SOIL TYPES BASED ON LOCAL SOIL CLASSIFICATION SYSTEMLOCAL SOIL CLASSIFICATION SYSTEM
““Th’ola” is an evergreen shrub (Th’ola” is an evergreen shrub (Parastrephia lepidophylla) Parastrephia lepidophylla) that re-grows during fallow periodsthat re-grows during fallow periods
Selected soil properties of sandy (ch’alla) soil collected directly underneath or between th’ola Selected soil properties of sandy (ch’alla) soil collected directly underneath or between th’ola plants or in farm field during first year of cropping plants or in farm field during first year of cropping in San José de Llanga in Umala.in San José de Llanga in Umala.
CONCLUSIONSCONCLUSIONS
• Climate change and socioeconomic Climate change and socioeconomic factors in the Altiplano region have led to factors in the Altiplano region have led to changes in soil and management practices changes in soil and management practices that have generally reduced soil fertility that have generally reduced soil fertility and soil organic matter. and soil organic matter.
• The decreasing length of the fallow period The decreasing length of the fallow period and reduction in native vegetation (e.g. and reduction in native vegetation (e.g. “th’ola”) caused by competing uses and “th’ola”) caused by competing uses and mechanized tillage, may be removing an mechanized tillage, may be removing an important mechanism by which soil fertility important mechanism by which soil fertility and soil organic matter are restored.and soil organic matter are restored.
CONCLUSIONS (CONT.) CONCLUSIONS (CONT.)
• Ongoing research is examining soil Ongoing research is examining soil management practices that may management practices that may increase soil fertility and soil organic increase soil fertility and soil organic matter by adding conventional and matter by adding conventional and alternative organic soil amendments alternative organic soil amendments (e.g. compost, biofertilizers).(e.g. compost, biofertilizers).
• Additional research is needed to Additional research is needed to identify suitable plants that could be identify suitable plants that could be introduced for improved fallow introduced for improved fallow management. management.
