Diversity of shifting cultivation cycles among small-scale farmers in Peruvian Amazon

doi:10.4236/as.2011.22011

Paper Menu >>

Journal Menu >>

Vol.2, No.2, 68-77 (2011)

doi:10.4236/as.2011.22011

Agricultural Sciences

Diversity of shifting cultivation cycles among

small-scale farmers in Peruvian Amazon

Bohdan Lojka1*, Jan Banout1, Lucie Banoutova1, Vladimir Verner1, Patrick Van Damme2

1Institute of Tropics and Subtropics, Czech University of Life Sciences, Prague, Czech Republic;

2Laboratory of Tropical and Subtropical Agriculture and Ethnobotany, Ghent University, Ghent, Belgium;

*Corresponding Author: lojka@its.czu.cz

Received 25 November 2010; revised 16 February 2011; accepted 15 March 2011.

ABSTRACT

Although shifting cultivation is practiced by mil-

lions of farmers, it is often blamed for causing

deforestation and keeping farmers in poverty.

Our study focused on the Amazon basin, where

small-scale farmers widely practice shifting cul-

tivation. The objective w as to identify the diver-

sity in land use after initial slash-and-burn land

clearing among migrant peasants. Our research

aimed at documenting typical crop sequences,

plant species composition and specific lengths

of particular phases of shifting cultivation cy-

cles on the basis of farmers related field histo-

ries. Land use was examined in two settlements:

Antonio Raimondi and Pimental in Ucayali re-

gion, Peru. Data was gathered via semi-struc-

tured questionnaires that focused on the socio-

demographic characterization of agriculture-de-

pendent households and their land use charac-

teristics. More in-depth a ssessments of crop oc-

currence, cropping sequence and length of the

different shifting cultivation cycles were con-

ducted on 114 fields in Pimental and 44 fields in

Antonio Raimondi. Interview analysis showed

that in both villages, forest cover has substan-

tially decreased over the last 10 years. Results

also indicate considerable variation in swid-

den-fallow systems. Whereas settlers in Anto nio

Raimondi plant annual crops after slashing and

burning the forest, settlers in Pimental gave

more importance to perennial crops. Progress

in deforestation and land degradation is rela-

tively more pronounced in the younger settle-

ment (Antonio Raimondi). These differences are

likely caused by the different social back-

grounds of settlers and histories of each site.

Small-scale farmers in the study area are now

facing a problem with the transition from shift-

ing cultivation to sedentary farming. Farmers in

areas with a prevalence of annual cropping use

a significantly shorter fallow period, which causes

a higher rate of forest degradation. As annual

cropping seems to be unsustainable in relation

with forest degradation, farmers should either

use a longer natural fallow to sust ain longer cro -

pping cycles, or shift to tree-based land use sy-

stems.

Keywords: Agroforestry; Deforestation; Land

Degradation; Slash-And-Burn; Swidden-Fallow

1. INTRODUCTION

Despite rapid economic development in many tropical

countries, shifting cultivation is practiced by millions of

farmers and has been blamed for causing deforestation

and keeping farmers in poverty [1]. Exact figures about

the total area under shifting cultivation are not available,

but it is still applied in at least some 40 - 50 countries [2];

and shifting cultivation constitutes an important part of

the 850 million hectares of secondary forest manage-

ment in tropical Africa, America and Asia [3]. Some

researchers have claimed that shifting cultivation is

practiced on as much as 30% of the world’s exploitable

soils [4]. Figures for the number of people depending on

this system are also uncertain and range between 40 to

500 million [4-7].

Slash-and-burn agriculture can only be sustainable

when population densities are low enough to allow re-

establishment of the forest within slash-and-burn fields.

However, under the pressure of increasing populations,

fallow periods are drastically reduced and the system

degrades, resulting in serious soil erosion and a decline

in soil fertility and productivity [8]. This assumption is

commonly accepted, however, empirical evidence is

scarce. Mertz et al. [1] have demonstrated that fallow

length is a weak predictor of crop yields and that other

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

factors such as fertilizer inputs, drought, flooding or

pests and diseases are more important determinants of

yield. Thus, fallow length is not the best proxy for as-

sessing sustainability of the system.

Shifting cultivation is thought to account for about

one third of deforestation in the Amazon, while cattle

ranching is responsible for at least half of the forest re-

treat [9]. After the annual crop stage of the slash-and-

burn cycle, farmers leave the land for short fallow, or

convert is to other uses, including pastures for cattle and

perennial crops [10].

Although a relatively large amount of literature has

been generated on the subject, a number of aspects of the

system is still poorly understood [1]. More applied re-

search to explain local complexities of the system and to

demonstrate to what extent shifting cultivation contrib-

utes to local livelihoods and environmental (mis)mana-

gement is still needed.

Our study focused on the slash-and-burn system in the

Ucayali region of the Peruvian Amazon. Between 1999

and 2005, disturbance and deforestation rates throughout

the Peruvian Amazon averaged 632 and 645 km2·yr–1,

respectively, whereby 64% of all damage was concen-

trated in the area around the Ucayali logging centre of

Pucallpa and along the road network emanating from it

[11]. In this region, colonists or migrating landless pea-

sants lacking the traditional knowledge required for

maintaining sustainability of their shifting cultivation

system predominate. Generally, crop yields are decreas-

ing and soil degradation is rapidly increasing. On such

degraded land extensive grasslands have developed, do-

minated by Imperata spp. The latter is considered to be

one of the world's worst weeds and a reliable indicator

of land degradation [12,13]. These grasslands are mostly

formed following annual bushfires that hinder the re-

generation of woody vegetation [14]. Such landscape is

considered as the final stage in the process of land deg-

radation with an irreversible loss of forest cover and a

permanent loss of agricultural income [15].

Our objective was to identify the diversity in land use

after initial slash-and-burn among migrant peasants and

to identify traditional technologies used in the cropping

cycles (from original forest, through cropping sequence

to secondary fallow), in order to understand the factors

influencing the changes in local agricultural systems.

Our research aimed at documenting and characterising

typical crop sequences, plant species composition and

lengths of particular phases of shifting cultivation cycles

on the basis of collecting data about field history. Th-

rough this documentation, we can quantify how local

households change original natural environment on their

farming land. One of the most striking features of land

use practices in tropical environments is their great di-

versity (use of plant species, varieties, cropping se-

quences). Therefore, by examining local differences,

such research could provide valuable information about

the varied economic opportunities, constraints on pro-

duction, and land use decisions perceived by local farm-

ers [16]. On the basis of these findings, new alternative

land use methods can be proposed in order to improve

sustainability of their farming.

2. METHODS

2.1. Site Description

Pucallpa, the capital of Ucayali region, is situated on

the Ucayali River, 860 km from Lima, the capital of

Peru, at 154 m above sea level, 8°23' S and 74°31' W.

Ucayali region borders Brazil to the east. Annual rainfall

ranges 1500 - 3000 mm (with rainfall increasing in a

western direction) with a mean annual precipitation of

approximately 1600 mm around Pucallpa. Intense pre-

cipitation prevails during the wet months from February

to May and from September to November [17]. Average

annual temperature is around 25˚C, with a maximum of

31˚C and a minimum of 19.5˚C. Soils include more fa-

vourable alluvial, seasonally-flooded riverine system

entisols, where pH is about 7.7, available P is 15 ppm

and upland, well-drained ultisols of forested areas with

an acid pH around 4.4 and low in P (around 2 ppm) [17].

In general, these soils have low quality for agriculture

[18]. The upland terrain is usually flat or undulating. The

original, natural vegetation is a tropical semi-evergreen

seasonal forest, now mixed with palm forest, dominated

by Mauritia spp. palms. Settlement around Pucallpa

started in the 1940s after construction of the road linking

the cities of Pucallpa and Lima, and was promoted by

road improvements in the late 1960s.

For our study, two representative settlements (Antonio

Raimondi and Pimental), located near the city of Pu-

callpa, were chosen. Both villages are situated in the

Campo Verde district, which came into existence in 1982,

and are connected with the Lima-Pucallpa highway. An-

tonio Raimondi is located 25 km west of Pucallpa. Ac-

cording to the head of the local municipality, this com-

munity was established in 1990 and, in 2005, there were

27 households (about 200 inhabitants). Due to slash-and-

burn farming, most of the forest has already been cut

down and vast areas around the village are degraded and

covered by Imperata grass. Farmers establish their fields

either on already degraded plots, or else they go further

to clear the primary or secondary forest and open a new

field. Secondary forest (so-called purma) is a previously

cultivated area that was left under fallow for 25 - 40

years. The most important crop is cassava (Manihot es-

culenta), which is considered the only crop which can be

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

economically grown on degraded land infested by Im-

perata. Cassava mainly serves for household subsistence,

but is often sold on the local market in Pucallpa as well.

Other staple crops are rice (Oryza sativa), maize (Zea

mays), bananas, plantains (Musa spp.) and cowpea (Vi-

gna ungiculata), mainly grown on fields with better soil

fertility, and usually planted after slashing and burning

the secondary forest. In addition, nearly each household

is surrounded by a homegarden with many fruit and

timber trees mixed with vegetable and medicinal plants.

Local households also depend on collecting non-timber

forest products (medicinal plants, honey and fruit) from

adjacent forests, whereas they also fish and hunt. All these

products are sold on the local market in Pucallpa, which

can be reached within one hour by local transport. How-

ever, this transport is expensive. Farmers usually own a

few heads of cattle (on average 2 - 3 heads), sometimes

pigs and horses, and most only raise poultry. They have

very limited opportunity for any off-farm employment.

The second village, Pimental, located 35 km west of

Pucallpa, is not very different from the previous site, but

the community is older (established in 1972) and more

prosperous, as farmers are more focused on cash crop

growing. This community was established when the hi-

ghway linking Lima with Pucallpa was improved in the

1970s. There were 56 households (about 400 inhabitants)

in 2005. Large areas are covered by weedy grassland

species such as Imperata spp. and Brachiaria spp. The

land use system is based on the same methods of slash-

and-burn farming, although cultivation of the more eco-

nomically-viable pepper (Piper nigrum) has a tradition

in this zone. Farmers also grow (semi-) perennial crops

such as pineapple (Ananas comosus), native fruit tree

species and various citruses (Citrus spp.). Furthermore,

settlers also have more opportunities for off-farm in-

come generation.

2.2. Data Collection and Evaluation

Our methodology of data collection and evaluation

was based on the similar study of Coomes and Burt [16]

made in traditional community near Iquitos, Peru. In the

period from June to October 2005, a survey was con-

ducted in both above-mentioned villages. Data on gen-

eral household characteristics were collected via semi-

structured interviews with local farmers. In each village,

a sample of households practicing agriculture as their

main activity was randomly chosen. Altogether, 27

households were interviewed: 11 in Antonio Raimondi

(40% of total number of households) and 16 in Pimental

(29%). The questionnaire was usually filled in by the

household head, typically a male. The household inter-

view focussed on demographic characteristics (e.g. size

and composition through time), methods of shifting cul-

tivation used, history of their agricultural practice, basic

socio-economic data and additional information related

to main crops and trees grown, land tenure and problems

with agriculture. In addition, each respondent was ac-

companied to each of his/her fields where we assessed

vegetation type, field size, crop composition and previ-

ous use. Each visit started with an initial delineation of

the whole farm area. Then the area was divided into

smaller parts according to current vegetation type and

crop composition. The history of each field was recon-

structed by asking the respondent to recall type and dura-

tion of each crop and forest fallow, beginning with pre-

sent field cover and working backward through time. A

total of 163 and 94 fields were thus inventoried Pimental

and Antonio Raimondi, respectively. Generally, farmers

were able to recall most of their experiences over the

time they had lived in their particular location, though

occasionally with some difficulty. By knowing crop/fal-

low durations in the sequence back through time, we

were able to reconstruct, using manual spreadsheet, the

history of each field held by the respective farmer. Based

on this, data we were able to calculate various current and

past land-use system sizes, their proportion of total farm-

ing land, and assess the changes in time. The data served

for identification of several shifting cultivation cycles and

determination of the most frequently planted crop and

tree species. We used the independent two-sample t-test

to reveal the statistically significant differences between

both settlements. Household and field surveys afford a

comprehensive and systematic analysis of variation and

diversity in local shifting cultivation systems.

3. RESULTS

3.1. General Household and Farm

Characteristics

Respondents have been living, on average, for 13 and

18 years in Antonio Raimondi and Pimental, respectively.

In Pimental, 56 of respondents were born (or had lived)

there since the community was established. Each house-

hold consists of, on average, four to five members (Ta-

ble 1). On average, three household members work on a

farm as their main activity (child labour was not counted

but occurs). Average farm size is about 20 ha. We tried

to assess farm size changes over the last 10 years. Only

respondents living in their village since before 1995

were included in this attribute, 8 households from Anto-

nio Raimondi and 9 from Pimental. For simplification,

this group of respondents will be further referred to as

“old residents”. In both villages, farm size has slightly

decreased over the last 10 years. There is an increasing

trend in acquiring land tenure rights over this period.

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

Table 1. Household demography and land availability in Antonio Raimondi and Pimental.

Unit Pimental Antonio Raimondi T-test (0.05)

Mean SD Mean SD p

Total members of household* pers. 4.81 ± 1.91 4.09 ± 1.22 0.279

Age of household head* year 43.2 ± 13.7 49.4 ± 15.9 0.291

Farm size actual* ha 18.5 ± 11.0 20.7 ± 13.4 0.645

Farm size per family member* ha 4.7 ± 4.10 5.4 ± 3.81 0.645

Farm size 10 years ago** ha 21.4 ± 8.55 24.1 ± 12.5 0.243

% of fields with land tenure actual* % 84.8 75.6

% of fields with land tenure 10 years

ago** % 82.0 46.1

*Values for all sampled respondents in Antonio Raimondi (n = 11) and Pimental (n =16); **Values only for sampled older respondents living

in Antonio Raimondi (n = 8) and Pimental (n = 11) since before 1995.

Currently, more than 84 of the total area in Pimental

and 75 in Antonio Raimondi is protected by land ten-

ure rights. Especially in Antonio Raimondi, private land

ownership has increased significantly over the last 10

years, although almost one fifth of all respondents in

Pimental and one third in Antonio Raimondi does not

have any land tenure rights at all.

3.2. Land use Classification and Changes

Based on farmers’ responses, we identified nine dif-

ferent land use system, based on current plant species

composition and use (Table 2). According to this classi-

fication, we assessed changes in land use within both

villages over the last 10 years (Table 3). In 1995, a total

of 64% of the farm land in Pimental was forested (re-

sidual forest or fallow) or covered by tree-dominated

land use systems (tree crop plantation, agroforestry and

homegardens); 36% was covered by pastures and only

small parts were cropped by non-wood crops (3%), or

were degraded (2%). In Antonio Raimondi, 73% of the

farmed land was forested or covered by tree-dominated

land use systems in 1995; pastures and degraded land

covered 13% and 11%, respectively; only 3% was

cropped by non-wood crops. Differences between vil-

lages could be explained by the fact settlements in Pi-

mental are older and so that farmers had already defor-

ested higher proportion of their land.

After 10 years, there has been an important decrease

in forested land in both villages. In Pimental, reduction

in forested area amounted to 23% whereas in Antonio

Raimondi it reached as much as 47%. Currently, forests

and fallows cover only 21% and 11% of farm land in

Pimental and Antonio Raimondi, respectively. In both

villages, we see the same trend of land use transition:

decrease in forest cover and increase in grass cover, evi-

denced by higher proportion of pasture and degraded

land (44% increase in Antonio Raimondi). Generally,

land classified as pasture is used extensively having very

low stocking rate. During this period, there have been

only slight changes in proportion of farming area occu-

pied by young fallow, homegardens, tree plantation,

agroforestry systems and non-wood crops. It seems that

households did not increase their total cropped extension

substantially over the last 10 years.

3.3. Field Characteristics and

Swidden-Fallow Cycles

A total of 163 and 94 fields were studied for assess-

ment of current land use and specific shifting cycles in

Pimental and Antonio Raimondi, respectively (Table 4 ).

Each household in the sample possesses a collection of

plots in different phases, which, together, represent its

swidden-fallow agroforestry portfolio. On average, ho-

useholds in Pimental hold a total of 10 plots (7 in crops,

1 in forest or fallow and 2 under pasture or degraded

land). About 27% of household land holding is currently

used for annual or perennial cropping, 20% is forested or

under fallow, whereas the remaining 53% is pasture or

degraded land. Households in Antonio Raimondi hold,

on average, a total of 8 plots (5 in crops, 1 in forest or

fallow and 2 under pasture or degraded land). Nearly

20% of household land holdings is used for cropping,

11% is under forest or fallow; the remaining 69% is

pasture and degraded land. It is evident that land in An-

tonio Raimondi is currently more deforested and de-

graded than in Pimental.

Altogether, 87 complete swidden-fallow cycles were

documented from the field histories in Pimental: 62

fields were claimed from residual forest, 16 originated

from old fallow, 4 from young fallow, whereas the re-

maining 5 fields were established from pasture. We

identified seven principal cropping cycles established

after slashing and burning of residual forest (Figure 1)

and four most frequent crops; i.e. rice, cassava, banana

and pepper. After clearance, the deforested land was

used for planting various crops. Rice and pepper inter-

planted with bananas were first planted on 51% and 41%

of all fields, respectively. On the remaining 8% of fields,

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

Table 2. Classification of land use systems.

Land use type Local name Characteristics

Residual forest Monte

An old primary forest that was not slashed and burnt in recent history but can

be used for timber, game, medicinal plants and fruit collection. People often

refer to monte alto or monte virgen. Monte virgen is considered as a virgin

forest untouched by timber exploitation while monte alto is a logged-over

forest, but never slashed or burnt.

Old fallow Purma alta

High-grown secondary forest 6 years old or more, which was formerly

slashed and burnt and which has continuously turned into a secondary forest

over time.

Young fallow Purma baja Young secondary forest up to 5 years old.

Tree plantation Plantación Plantation of citruses, native fruit trees or timber trees.

Agroforestry Agroforestería Plots covered by trees and/or shrubs along with non-wood annual or perennial

crops.

Homegardens Huerto familiar Plots adjacent to the house consisting of a mix of annual and semi-perennial

plants and trees with different uses, mainly for household consumption.

Non-wood crops Chacra Annual crops such as cassava, maize, rice, vegetable etc. and non-wood per-

ennials such as pineapple, banana and plantains, pepper (Piper nigrum).

Pasture Pasto Plot assumed to be entirely used for livestock. It is covered with other grasses

than Imperata spp., like Brachiaria spp. etc.

Degraded land Pasto degradado Plots covered by noxious grassy weeds, mainly Imperata spp.

Table 3. Land use ( area) and total area of specific land use type in 1995 and 2005.

Pimental Antonio Raimondi

1995** 2005* Difference1995** 2005* Difference

[ha][%] [ha] [%] [%] [ha][%] [ha] [%] [%]

Residual forest 29.814 22.5 8 –6 47.027 12.05 –22

Old fallow 59.528 34.5 12 –16 49.8 29 7.0 3 –26

Young fallow 5.0 2 3.6 1 –1 4.252 6.0 3 1

Tree plantation 26.512 36.6 12 0 12.87 10.55 –2

Agroforestry 10.25 20.4 7 2 10.06 14.36 0

Homegarden 5.8 3 6.9 2 –1 3.0 2 6.0 3 1

Non-wood crops 6.5 3 14.4 5 2 4.853 15.47 4

Pasture 68.332 140.0 47 15 23.613 76.033 20

Degraded land 4.0 2 17.5 6 4 18.811 80.935 24

*Values for all sampled respondents in Pimental (n=16) and Antonio Raimondi (n=11). ** Values only for sampled older respondents

living in Pimental (n = 11) and Antonio Raimondi (n = 8) since before 1995.

Table 4. Field size by land use type in 2005.

Pimental Antonio Raimondi

T-test

(0.05)

No. of

plots

Total

(ha)

Mean

(ha)

(ha) Range (ha)No. of

plots

Total

(ha)

Mean

(ha)

Range

(ha) p

Residual forest 4 22.5 5.63 ± 6.610.5 - 15.04 12.03.00± 4.06 0.5 - 9.0 0.524

Old fallow 10 34.5 3.45 ± 2.701.0 - 9.55 7.0 1.40± 0.82 0.5 - 2.5 0.127

Young fallow 4 3.6 0.89 ± 0.830.06 - 2.03 6.0 2.00± 1.73 1.0 - 4.0 0.305

Tree plantation 46 36.6 0.79 ± 0.720.1 - 4.510 10.51.05± 0.95 0.25 - 3.3 0.334

Agroforestry 31 21.7 0.70 ± 0.670.18 - 3.014 14.31.02± 0.65 0.25 - 2.0 0.146

Homegarden 14 6.9 0.49 ± 0.330.1 - 1.09 6.0 0.67± 0.25 0.5 - 1.0 0.190

Non-wood crops 26 13.6 0.52 ± 0.510.02 - 2.023 14.40.63± 0.79 0.1 - 4.0 0.585

Pasture 22 141.0 6.40 ± 6.810.5 - 25.012 75.96.33± 4.48 0.7 - 13.0 0.975

Degraded land 6 17.5 2.92 ± 2.010.5- 5.0 14 80.95.78± 5.96 0.1 - 17.0 0.272

Total 163 298.0 94 227.0

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

Figure 1. Typical swidden-fallow cycles on fields in Pimental village after clearing of the forest (No. of

fields 87, no. of cycles 7, no. of crops 4, mean cycle length 12 years, mean fallow length 6 years).

other crops such as maize, pineapple, sugar cane or

vegetables were planted. After harvesting rice subsequent

crops planted were typically cassava, banana/ plantain,

cowpeas or again rice. The second most common cycle

started by an initial crop mixture of pepper with bananas.

Pepper is grown for 8 years on average; at the end of this

cycle, the field is usually left to pasture, tree plantation,

or fallow. In general, one cycle length varied from 1.5 to

27 years, with a mean duration of 6 years of fallow and a

mean total cycle length of 12 years. The shortest cycle

was “rice-short fallow-rice” with a minimum of 18

months and a mean duration of 2.7 years.

In Antonio Raimondi, 48 complete swidden-fallow

cycles were identified from the field histories: 28 fields

were established from forest, 9 originated from old fal-

low, 8 from degraded land whereas 2 fields were estab-

lished from pasture. We identified eight principal crop-

ping cycles established after slashing and burning of

residual forest (Figure 2) and five most frequent crops;

i.e. rice, cassava, banana, maize and cowpea. Rice and

cassava/banana were planted on 56% and 31% of all

fields originating from forest, respectively. Rice (56%),

cassava/bananas (31%) and maize/cowpeas (12%) were

the first crops to be grown after forest clearance. After

rice, crop mixtures that followed were typically cas-

sava/banana (33%) and maize/cowpea (11%); 45% of

the land was left fallow; and pasture was established in

11% of the cases. In addition to rice, cassava/bananas

were also grown as the first crops after forest clearing.

Very often, farmers repeat planting of a cassava/banana

mixture subsequently for several years. Cycle length

varied from 17 months to 10 years, with a mean duration

of 3 years of fallow and a mean total cycle length of 5

years. The shortest cycle was “rice - short fallow - rice”,

with a minimum duration of 17 months. In both villages,

the final land use system in the cycle is either tree-based

(fallow, tree plantation or agroforestry) or, as in the ma-

jority of cases, the soil is so severely depleted and is left

as a low-grade pasture or degraded land without any

economic use.

3.4. Crop and Tree Species Diversity

A total of 100 tree and crop species (90 in Pimental

and 55 in Antonio Raimondi) were found on 158 fields

(114 in Pimental and 44 in Antonio Raimondi). The

largest variety of species was encountered in tree planta-

tions (70 and 37 species in Pimental and Antonio Rai-

mondi, respectively). Plots with non-wood crops were

generally the least diverse (13 and 16 species in Pimen-

tal and Antonio Raimondi, respectively). Despite the rich

overall diversity of crops observed across fields, most

individual plots contained relatively high densities of a

small number of crops. As farmers mentioned, banana,

cassava, pineapple and rice are the most widely planted

crop species, whereas citruses, guaba (Inga edulis) and

peach palm (Bactris gasipaes) are the most widely

planted tree species (Table 5).

4. DISCUSSION

In both villages, it was observed that, over the last 10

years, mean farm size decreased while percentage of

land with secure tenure significantly increased. Shifting

cultivation patterns are different in each settlement. In

both villages, we found a large decrease in forest cover

over the last 10 years. In 1995, residual forest covered

14% and 27% of farmers’ fields in Pimental and Antonio

Raimondi, respectively, while 30% and 31% of farm

land, respectively, was kept fallow. Fujisaka and White

[10], while conducting their study around Pucallpa in

Openly accessible at

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

Figure 2. Typical swidden-fallow cycle on fields in Antonio Raimondi village after clearing of the forest.

(No. of fields 48, no. of cycles 8, no. of crops 5, mean cycle length 5 years, mean fallow length 3 years).

Table 5. Most frequently cultivated crop and tree species on fields in Pimental (PIM) and Antonio

Raimondi (AR).

Vernacular name Scientific name Product Frequency of occurrence

Total PIM AR

(n = 158)(n = 114) (n = 44)

Crop species

Banana Musa spp. Fruit 42 26 16

Cassava Manihot esculenta Tuber 40 22 18

Rice Oryza sativa Grain 25 12 13

Pepper Piper nigrum Condiment 21 21 0

Pineapple Ananas comosus Fruit 20 12 8

Sugar cane Saccharum o fficinarum Juice/sugar 15 8 7

Coca Erythroxylum coca Stimulant 8 6 2

Cocona Solanum sessiliflorum Fruit 8 0 8

Bijao Calathea sp. Vegetable 7 7 0

Cowpea Vigna ungiculata Bean 7 4 3

Maize Zea mays Grain 7 4 3

Tree species

Citrus Citrus spp. Fruit 88 75 13

Guaba Inga edulis Fruit 38 23 15

Peach palm Bactris gasipaes Fruit 33 27 6

Caimito Pouteria caimito Fruit 22 12 10

Tahuari Tabebuia sp. Timber 21 18 3

Sangre de grado Croton l ech le ri Latex 20 18 2

Caoba Swietenia macrophylla Timber 19 15 4

Cedro Cedrela odorata Timber 19 15 4

Mango Mangifera indica Fruit 19 8 11

Aguaje Maurici flexuosa Fruit 15 11 4

Umari Pouraqueiba sericea Fruit 13 11 2

Capirona Calicophyllum

spruceanum Timber 13 10 3

Ishpingo Amburana clarensis Timber 13 10 3

Shebon Scheelea bassleriana Thatch 12 10 2

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

Bolaina Guzama crinita Timber 13 8 5

Carambola Averrhoa carambola Fruit 11 8 3

Anona Rollinia mucosa Fruit 9 5 4

Coconut Cocos nucifera Nut 9 5 4

Camu-camu Myrciaria dubia Fruit 8 7 1

Macambo Theobroma bicolor Fruit 8 5 3

Mamey (poma

rosa) Syzygium sp. Fruit 8 7 1

Avocado Persea americana Fruit 8 7 1

Shimbillo Inga spp. Fruit 8 7 1

Guanabana Anona muricata Fruit 7 5 2

1996, found slightly higher numbers: 27% forest and

39% fallow. In 2005, about 12% of the land was covered

by forest, 13% by fallow and 53% by grass vegetation

(pasture and degraded land) in Pimental, whereas only

about 5% was forest, 6% fallow and about 68% grass

vegetation in Antonio Raimondi. Furthermore, in Pi-

mental we find more tree plantations (either fruit or tim-

ber trees) than in Antonio Raimondi. This is probably

due to the divergent histories of the sites. Pimental was

established immediately after timber exploitation of the

forest by logging companies, whereas Antonio Raimondi

was established as a consequence of increasing popula-

tion pressure in Pucallpa. It would seem that, in the older

Pimental settlement, cultivation has acquired more per-

manent character and whereas land use systems are

based on tree cultivation, especially of citruses.

Even though the ratio of land degradation and forest

destruction in 1995 was higher in Pimental, further de-

forestation proceeded relatively slowly, as compared to

what happened in Antonio Raimondi. This could proba-

bly be explained by a relatively better agricultural and

socio-economic situation in Pimental. In the letter com-

munity, planting of pepper and fruit trees has a long tra-

dition and this makes the village more prosperous. As a

consequence, settlers prefer long-term plantation crops,

while in Antonio Raimondi they prefer annual or

short-term perennial crops.

We found that shifting cultivation cycles are very di-

verse in our study area from the points of view of cycle

length, plot and crop composition. In both villages, basic

cycle components are staple crops such as rice, cassava,

banana, maize and cowpeas. In Pimental, farmers also

grow pepper, but the mean length of a complete shifting

cultivation cycle there was 12 years, while in Antonio

Raimondi it was only five years. We also found that

mean duration of fallow in Pimental is twice as long (six

years, as compared to three years in Antonio Raimondi).

Although Mertz et al. [1], in their case study from Kali-

mantan, wrote that fallow length is a weak predictor of

crop yield (and thus sustainability of the system), we

found a positive relationship between the length of the

fallow and the length of the subsequent cropping period.

When fallow period is longer, subsequent cropping can

also be longer and more diversified. It seems that larger

area taken by pastures and degraded land in Antonio

Raimondi could be a consequence of a shorter fallowing

period and the subsequent rapid weed proliferation and

soil degradation.

According to Boserup [19], shifting cultivation sys-

tems usually evolve toward “annual cropping” and

“multiple cropping” systems through a progressive re-

duction in fallow length and fire intensity. Woody vege-

tation is eliminated from the fields and interplanting of

trees and crops only occurs in the later stages of intensi-

fication, when there is no more space to establish a pure

plantation. The small farmers around Pucallpa now find

themselves in this transition period. The question arises

whether the system of annual cropping can be sustained

in such an environment of low soil fertility and noxious

weeds. It seems that fallowing remains a very important

part of the local shifting cultivation cycle, but a transi-

tion to more intensified land use systems could be

achieved through tree-based systems such as perennial

fruit or timber tree plantations, or an agroforestry mix-

ture. These systems could substitute for the biological

role of natural fallow (soil fertility maintenance and

weed control) and bring the farmers the necessary return

on their investment (fruit, timber and non-timber prod-

ucts). Development agencies should not provide farmers

with complete, fixed technological packages, but should

design technologies in a less specific manner, thus al-

lowing for flexibility in their appropriation by farmers

[20].

5. CONCLUSIONS

Based on our results, we can conclude that, although

land use patterns after initial slash-and-burn were similar

in both study areas, considerable local diversity as well

as variations in principal crop composition and fallow

length occur in local shifting cultivation system. This is

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

due to the different backgrounds and histories of the

settlers. The rate of land degradation and forest conver-

sion to other uses is much higher in the more re-

cently-established settlement as a consequence of popu-

lation pressure and population structure, consisting pre-

dominantly of migrant peasants. Due to this fact and the

shorter fallow period (lack of perennial cropping tradi-

tion), the process of forest destruction is much more

pronounced in Antonio Raimondi than in the older study

site. Small-scale farmers in both study areas are now

facing a problem with the transition from shifting culti-

vation to sedentary farming.

The settlement where cultivation of market-oriented

perennials was introduced by its founders seems to be

permanent and more sustainable. The rate of forest de-

struction and land degradation is relatively slower in

settlements where perennials are planted than in settle-

ments where annual crops prevail. Fallow length is pri-

marily influenced by the type of principal crop composi-

tion and access to available land. Farmers focused

mainly on annual cropping employ a significantly

shorter fallow period and thus higher rate of forest deg-

radation occurs. As annual cropping seems to be unsus-

tainable, farmers should either continue using a longer

natural fallow period to sustain longer cropping cycles,

or shift to perennial tree-based land use systems that

require a higher initial investment, but brings larger

benefits in the future. Moreover, according to our study,

farmers in the study area use a considerable variety of

useful tree species; this could be an advantage for wider

use of them. We have to agree with the hypothesis pre-

sented by Fujisaka and White [10], that diminishing

pioneer conditions favour mixed systems that include

perennial crops with high-value products (e.g. coffee,

cocoa, fruit, timber). However, there is the risk of failure

of such an establishment as promoted by development

projects, when market projections are incomplete.

6. ACKNOWLEDGEMENTS

This research was conducted with financial support from the Foun-

dation Nadání Josefa, Marie a Zdeňky Hlavkových, Czech Republic,

Youth Activity Fund Of Explorers Club, USA and the Czech Ministry

of Agriculture within the Czech Republic Development Cooperation

program, project number 23/MZE/B/07-10.

REFERENCES

[1] Mertz, O., Wadley, R.L., Nielsen, U., Bruun, B.T., Col-

fer, C.J.P., de Neergaard, A., Jepsen, M.R., Martinussen,

T., Zhao, Q., Noweg, G.T. and Magid, J. (2008) A fresh

look at shifting cultivation: Fallow length and uncertain

indicator of productivity. Agricultural Systems, 96 , 75-84.

doi:10.1016/j.agsy.2007.06.002

[2] Mertz, O. (2009) Trends in shifting cultivation and the

REDD mechanism. Current Opinion in Environmental

Sustainability, 1, 156-160.

doi:10.1016/j.cosust.2009.10.002

[3] FAO. (2005) State of the World’s Forest. Food and Ag-

riculture Organization of the United Nations, Rome,

Italy.

[4] Warner, K. (1991) Shifting cultivators—Local technical

knowledge and natural resource management in the

humid tropics. Food and Agriculture Organization’s

Community Forestry Note, 8, Rome, Italy.

[5] Russell, W.M.S. (1988) Population, swidden farming and

the tropical environment. Population and Environment,

10, 77-94. doi:10.1007/BF01359134

[6] Kleinman, P.J.A., Pimentel, D. and Bryant, R.B. (1996)

Assessing the ecological sustainability of slash-and-burn

agriculture through soil fertility indicators, Agronomic

Journal, 88, 122-127.

doi:10.2134/agronj1996.00021962008800020002x

[7] Sanchez, P.A., Palm, C.A., Vosti, S.A., Tomich, T. and

Kasyoki, J. (2005) Alternatives to slash and burn. Ch-

allenges and approaches of an international consor- tium.

In: Palm, C.A., Vosti, S.A., Sanchez, P.A. and Ericksen,

P.J. Eds., Slash-and-Burn Agriculture. The Search for

Alternatives, Columbia University Press, New York,

3-37.

[8] Nair, P.K.R. (1993) An introduction to agroforestry.

Kluwer Academic Publishers, Dordrecht, The Nether-

lands.

[9] Serrao, E.A.S., Nepstad, D. and Walker, R. (1996) Up-

land agricultural and forestry development in the Am-

azon: sustainability, criticality and resilience. Eco-

logical Economics, 18, 3-13.

doi:10.1016/0921-8009(95)00092-5

[10] Fujisaka, S. and White, D. (1998) Pasture or permanent

crops after slash-and-burn cultivation? Land use choice

in three Amazon colonies. Agroforestry Systems, 42,

45-59. doi:10.1023/A:1006195810077

[11] Olivera, P.J.C., Asner, G.P., Knapp, D.E., Almeyda, A.,

Galván-Gildemeister, R., Keene, S., Raybin, R.F. and

Smith, R.C. (2007) Land use allocation protects the

peruvian amazon. Science, 317, 1233-1237.

doi:10.1126/science.1146324

[12] Holm, L.G., Plucknett, D.L., Pancho, J.V. and Herberger,

J.P. (1997) The World’s Worst Weeds: Distribution and

Biology. University Press of Hawaii, Hawaii, USA.

[13] Garrity, D.P., Soekardi, M., De La Cruz, R., Pathak, P.S.,

Gunasena, H.P.M., Van So, N., Huijin, G. and Majid,

N.M. (1997) The Imperata grasslands of tropical Asia:

area, distribution, and typology. Agroforestry Systems, 36,

3-29. doi:10.1007/BF00142865

[14] Hartemink, A.E. (2001) Biomass and nutrient accumu-

lation of Piper aduncum and Imperata cylindrica fallows

in the humid lowlands of Papua New Guinea. Forest

Ecology and Management, 144, 19-32.

doi:10.1016/S0378-1127(00)00655-1

[15] Albers, H.J. and Goldbach, M.J. (2000) Irreversible

ecosystem change, species competition, and shifting

cultivation. Resource and Energy Economics, 22, 261-

280. doi:10.1016/S0928-7655(00)00034-8

[16] Coomes, O.T. and Burt, G.J. (1997) Indigenous market-

oriented agroforestry: Dissecting local diversity in we-

stern Amazonia. Agroforestry Systems, 37, 27-44.

B. Lojka et al. / Agricultural Sciences 2 (2011) 68-77

doi:10.1023/A:1005834816188

[17] Fujisaka, S., Escobar, G. and Veneklaas, E. (1999) Plant

community diversity relative to human land uses in an

Amazon forest colony. Biodiversity Conservation, 7,

41-57. doi:10.1023/A:1008855612209

[18] de Jong, W. (1995) Diversity, variation and change in

Ribereno agriculture and agroforestry. Doctoral Thesis,

Wageningen University for Life Sciences, The Nether-

lands.

[19] Boserup, E. (1965) The Conditions of Agricultural Gr-

owth: The Economics of Agrarian Change Under Po-

pulation Pressure. Earthscan Publication Ltd., London.

[20] Pollini, J. (2009) Agroforestry and the search for alterna-

tives to slash-and-burn cultivation: From technological

optimism to a political economy of deforestation. Agri-

culture, Ecosystems and Environment, 133, 48-60.

doi:10.1016/j.agee.2009.05.002