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 The Bolivian highland plateau region (Altiplano) plateau region (Altiplano) is a semi-arid region in is a semi-arid region in the Andes Mountains that the Andes Mountains that occupies approximately occupies approximately 27% of the area of Bolivia 27% of the area of Bolivia and has a range in and has a range in elevation of between elevation of between 3600 and 4300 m.a.s.l. 3600 and 4300 m.a.s.l.

STUDY AREASTUDY AREA

Primarily potato-based Primarily potato-based cropping systems and cropping systems and livestock rearing of livestock rearing of cows, sheep and cows, sheep and camelids (e.g., alpaca camelids (e.g., alpaca and lama) 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 The Altiplano region’s climate is characterized by climate is characterized by high diurnal temperature high diurnal temperature variations, frost risks, low variations, frost risks, low and irregular precipitation and irregular precipitation and high risks of drought and high risks of drought during the growing season during the growing season (Garcia et al., 2007).(Garcia et al., 2007).

CLIMATE CHANGECLIMATE CHANGE

The region will experience The region will experience temperature increases of temperature increases of up to 6up to 6C by the end of the C by the end of the century (Bradley et al., century (Bradley et al., 2006, IPCC, 2007).2006, IPCC, 2007).

A consequence of global A consequence of global climate change has and climate change has and will be a higher incidence will be a higher incidence of extreme weather of extreme weather events (Haylock et al., events (Haylock et al., 2006; Thibeault 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

Annual RainfallAnnual Rainfall DistributionDistribution

OBJECTIVES OF SOILS RESEARCHOBJECTIVES OF SOILS RESEARCH

To survey representative To survey representative indigenous farming communities indigenous farming communities in the Altiplano of Bolivia to in the Altiplano of Bolivia to determine perceived changes in determine perceived changes in cropping practices in potato-cropping practices in potato-based cropping systems due to based cropping systems due to global climate change and socio-global climate change and socio-economic factors.economic factors.To assess the effects of these To assess the effects of these changes on soil total organic C changes on soil total organic C and other soil properties to and other soil properties to determine if soil degradation has determine if soil degradation has occurred. occurred.

MATERIALS AND METHODSMATERIALS AND METHODS

Village-level surveys and participatory workshops were Village-level surveys and participatory workshops were conducted in 4 to 5 villages situated at different relative conducted in 4 to 5 villages situated at different relative altitudes in the communities of Umala and Ancoriames. altitudes in the communities of Umala and Ancoriames.

MATERIALS AND METHODSMATERIALS AND METHODS

Replicated soil samples Replicated soil samples were collected in Umala to were collected in Umala to a 20 cm depth from a 20 cm depth from agricultural fields of the agricultural fields of the same cropping system and same cropping system and sandy soil type (locally sandy soil type (locally classified as “cha’lla” soil) classified as “cha’lla” soil) to determine changes in to determine changes in soil properties with fallow soil properties with fallow length.length.

MATERIALS AND METHODSMATERIALS AND METHODS

Replicate soil samples were Replicate soil samples were collected to a 20 cm depth collected to a 20 cm depth directly underneath or directly underneath or between “th’ola” between “th’ola” (Parastrephia lepidophylla), (Parastrephia lepidophylla), a common component of a common component of fallow vegetation, to fallow vegetation, to determine its effects on soil determine its effects on soil properties during fallow.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 (e.g. Increase in production of some cash crops (e.g. onion) and other income-generating activities onion) and other income-generating activities (e.g. dairy production, day labor)(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.

CHANGES IN SOIL CHANGES IN SOIL MANAGEMENT PRACTICESMANAGEMENT PRACTICES

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 Loss of native species (e.g., th’ola) that have multiple uses to restore soil fertility have multiple uses to restore soil fertility during fallow period and are a fuel source. during 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.

• Soil management problems identified were:Soil management problems identified were:

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

Exchangeable

Community Soil typeTextural

classOrganicmatter pHs Bray1

PK Ca Mg CEC EC

-- % -- ---------------- mg kg-1 ----------------- cmolc

kg-1

dS cm-1

San José Sandy/ Cha’lla Sand 0.3 5.5 35.0 166 311 44 3.1 0.1

Clayey/ Ňeq’e Silt loam 2.4 7.5 20.5 424 4520 279 26.0 0.5

Silty/ Kaima Silt loam 0.5 7.5 14.8 158 2337 125 13.1 0.3

Vinto Coopani

Sandy/ Cha’lla Loam 1.3 5.7 46.8 271 1102 148 8.9 0.3

Sandy/ clayey /Jach’oca

Sandy loam 1.2 5.5 45.2 240 580 70 5.8 0.2

Clayey/ Ňeq’e oraque

Clay loam 1.5 6.9 3.0 159 3763 578 24.3 0.2

EFFECTS OF FALLOW AND CROPPING EFFECTS OF FALLOW AND CROPPING ON SOIL ORGANIC C IN UMALAON SOIL ORGANIC C IN UMALA

y = -0.0004x2 + 0.0299x + 0.7586R² = 0.868

y = 0.0052x + 0.5403R² = 0.8085

y = 0.0017x + 0.4387R² = 0.4908

y = 0.0141x + 1.0671R² = 0.3649

0.200

0.400

0.600

0.800

1.000

1.200

1.400

1.600

-5 5 15 25 35 45 55

Soiltotal

organicC (%)

Years of fallow

Vinto Coopani

SJ Circa

San Jose

Kellhuiri

Years ofcropping

Uncropped land

Uncropped land

Uncropped land

EFFECTS OF TH’OLA AND CROPPING EFFECTS OF TH’OLA AND CROPPING ON SOIL PROPERTIESON SOIL PROPERTIES

EExxcchhaannggeeaabbllee

LLooccaattiioonn ooff ssaammpplliinngg TToottaall oorrggaanniicc CC

TToottaall NN

ppHHss

NNeeuutt.. aacciiddiittyy

SSooiill tteesstt BBrraayy11 PP

SSooiill tteesstt KK

CCaa

MMgg

CCEECC

---------------------------------- %% ---------------------------- ccmmoollcc kkgg--11 -------------------------------------------------------- mmgg kkgg--11 ------------------------------------------------------ ccmmoollcc kkgg--11 UUnnddeerrnneeaatthh tthh’’oollaa 11..8822 00..114455 77..2200 00..00 4444..55 552299 33115522 220088 1188..88 BBeettwweeeenn tthh’’oollaa 11..5577 00..115522 77..5500 00..00 2288..77 336655 33448855 118855 1199..99 11sstt yyeeaarr ccrrooppppiinngg 00..4433 00..002244 55..5555 00..55 2233..22 112211 332222 5544 22..88 DDMMRRTT((00..0055))** 00..8811 00..004477 00..4422 00..11 1177..88 226611 11006688 6666 66..11 **DDuunnccaann’’ss MMuullttiippllee RRaannggee TTeesstt ((PP << 00..0055))..

““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 factors in the Altiplano region have led to changes in soil and led to changes in soil and management practices that have management practices that have generally reduced soil fertility and generally reduced soil fertility and soil organic matter. soil organic matter.

The decreasing length of the fallow The decreasing length of the fallow period and reduction in native period and reduction in native vegetation (e.g. “th’ola”) caused vegetation (e.g. “th’ola”) caused by competing uses and mechanized by competing uses and mechanized tillage, may be removing an tillage, may be removing an important mechanism by which soil important mechanism by which soil fertility and soil organic matter are fertility and soil organic matter are restored.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 increase soil fertility and soil organic matter by adding organic matter by adding conventional and alternative conventional and alternative organic soil amendments (e.g. organic soil amendments (e.g. compost, biofertilizers).compost, biofertilizers). Additional research is needed to Additional research is needed to identify suitable plants that could identify suitable plants that could be introduced for improved fallow be introduced for improved fallow management. management.

QUESTIONS?QUESTIONS?COMMENTS?COMMENTS?

SUGGESTIONS?SUGGESTIONS?