Agricultural Soil Erosion Research Articles

고랭지 경사 밭 콩 재배지에서 토양유실경감을 위한 피복방법 평가

There is relatively high vulnerability of soil erosion in slope highland agriculture due to a reclamation of mountain as well as low surface covering in early summer season with high rainfall intensity time. The aim of this study was to evaluate various surface covering methods for reducing soil loss in highland radish cultivation in highland. The experiment was conducted in 17% sloped lysimeter () with 8 treatments including covering with cut rye, sod culture of rye, Ligularia fischeri var. spiciformis Nakai, Arachniodes aristata Tindale, Aster koraiensis Nakai, Festuca myuros L. and mulching with black polyethylene film, and runoff water, eroded soil and radish growth were investigated. Surface covering with sod culture and plant residue, especially cut rye treatment, had lower runoff water than non-covering, whereas black polyethylene film mulching had the reverse. The amount of eroded soil was also lowest in cut rye treatment, , and increased in the order of rye sod culture, Ligularia fischeri var. spiciformis Nakai, Aster koraiensis Nakai, Festuca myuros L., Arachniodes aristata Tindale, black polyethylene film, and non-covering, . The results showed that surface covering with sod culture or plant residue could be effective for reducing runoff water and soil erosion in the radish field, significantly in cut rye treatment. On the other hand, in sod culture of rye, Aster koraiensis Nakai and Ligularia fischeri var. spiciformis Nakai, radish yields were lower than in the non-covering. Unlike this, covering with cut rye, sod culture of Festuca myuros L. had similar radish yield to the non-covering radish yield. In conclusion, covering with cut rye and sod culture of Festuca myuros L. were beneficial for reduction of soil loss without decreasing in radish yield in highland sloped fields.

Towards constraining the magnitude of global agricultural sediment and soil organic carbon fluxes

ABSTRACTReliable quantitative data on the extent and rates of soil erosion are needed to understand the global significance of soil‐erosion induced carbon exchange and to underpin the development of science‐based mitigation strategies, but large uncertainties remain. Existing estimates of agricultural soil and soil organic carbon (SOC) erosion are very divergent and span two orders of magnitude. The main objective of this study was to test the assumptions underlying existing assessments and to reduce the uncertainty associated with global estimates of agricultural soil and SOC erosion. We parameterized a simplified erosion model driven by coarse global databases using an empirical database that covers the conterminous USA. The good agreement between our model results and empirical estimates indicate that the approach presented here captures the essence of agricultural erosion at the scales of continents and that it may be used to predict the significance of erosion for the global carbon cycle and its impact on soil functions. We obtained a global soil erosion rate of 10.5 Mg ha‐1 y‐1 for cropland and 1.7 Mg ha‐1 y‐1 for pastures. This corresponds to SOC erosion rates of 193 kg C ha‐1 y‐1 for cropland and 40.4 kg C ha‐1 y‐1 for eroding pastures and results in a global flux of 20.5 (±10.3) Pg y‐1 of soil and 403.5 (±201.8) Tg C y‐1. Although it is difficult to accurately assess the uncertainty associated with our estimates of global agricultural erosion, mainly due to the lack of model testing in (sub‐)tropical regions, our estimates are significantly lower than former assessments based on the extrapolation of plot experiments or global application of erosion models. Our approach has the potential to quantify the rate and spatial signature of the erosion‐induced disturbance at continental and global scales: by linking our model with a global soil profile database, we estimated soil profile modifications induced by agriculture. This showed that erosion‐induced changes in topsoil SOC content are significant at a global scale (an average SOC loss of 22% in 50 years) and agricultural soils should therefore be considered as dynamic systems that can change rapidly. Copyright © 2011 John Wiley & Sons, Ltd.

고랭지 경사 밭 무 재배지에서 토양유실경감을 위한 피복방법 평가

There is relatively high vulnerability of soil erosion in slope highland agriculture due to a reclamation of mountain as well as low surface covering in early summer season with high rainfall intensity time. The aim of this study was to evaluate various surface covering methods for reducing soil loss in highland radish cultivation in highland. The experiment was conducted in 17% sloped lysimeter () with 8 treatments including covering with cut rye, sod culture of rye, Ligularia fischeri var. spiciformis Nakai, Arachniodes aristata Tindale, Aster koraiensis Nakai, Festuca myuros L. and mulching with black polyethylene film, and runoff water, eroded soil and radish growth were investigated. Surface covering with sod culture and plant residue, especially cut rye treatment, had lower runoff water than non-covering, whereas black polyethylene film mulching had the reverse. The amount of eroded soil was also lowest in cut rye treatment, , and increased in the order of rye sod culture, Ligularia fischeri var. spiciformis Nakai, Aster koraiensis Nakai, Festuca myuros L., Arachniodes aristata Tindale, black polyethylene film, and non-covering, . The results showed that surface covering with sod culture or plant residue could be effective for reducing runoff water and soil erosion in the radish field, significantly in cut rye treatment. On the other hand, in sod culture of rye, Aster koraiensis Nakai and Ligularia fischeri var. spiciformis Nakai, radish yields were lower than in the non-covering. Unlike this, covering with cut rye, sod culture of Festuca myuros L. had similar radish yield to the non-covering radish yield. In conclusion, covering with cut rye and sod culture of Festuca myuros L. were beneficial for reduction of soil loss without decreasing in radish yield in highland sloped fields.

Large Shift in Source of Fine Sediment in the Upper Mississippi River

Although sediment is a natural constituent of rivers, excess loading to rivers and streams is a leading cause of impairment and biodiversity loss. Remedial actions require identification of the sources and mechanisms of sediment supply. This task is complicated by the scale and complexity of large watersheds as well as changes in climate and land use that alter the drivers of sediment supply. Previous studies in Lake Pepin, a natural lake on the Mississippi River, indicate that sediment supply to the lake has increased 10-fold over the past 150 years. Herein we combine geochemical fingerprinting and a suite of geomorphic change detection techniques with a sediment mass balance for a tributary watershed to demonstrate that, although the sediment loading remains very large, the dominant source of sediment has shifted from agricultural soil erosion to accelerated erosion of stream banks and bluffs, driven by increased river discharge. Such hydrologic amplification of natural erosion processes calls for a new approach to watershed sediment modeling that explicitly accounts for channel and floodplain dynamics that amplify or dampen landscape processes. Further, this finding illustrates a new challenge in remediating nonpoint sediment pollution and indicates that management efforts must expand from soil erosion to factors contributing to increased water runoff.

Poverty Implications of Agricultural Land Degradation in Ghana: An Economy‐wide, Multimarket Model Assessment

Abstract: An economy‐wide, multimarket model is applied for Ghana and is used to assess the aggregate economic cost of agricultural soil erosion. To fill a gap in the literature regarding economic cost analysis of soil erosion, this paper also analyzes the poverty implications of land degradation. The model predicts that land degradation reduces agricultural income in Ghana by a total of US$4.2 billion over the period 2006–2015 and the national poverty rate will increase in 2015 by 5.4 percentage points. Moreover, soil loss causes a slowing of poverty reduction over time in the three northern regions, which currently have the highest poverty rates in the country. Sustainable land management (SLM) is the key to reducing agricultural soil loss. The present findings indicate that through the adoption of conventional SLM practices, the declining trend in land productivity can be reversed, and that use of a combination of conventional and modern SLM practices would generate an aggregate economic benefit of US$6.4 billion over the period 2006–2015. SLM practices would therefore substantially reduce poverty in Ghana, particularly in the three northern regions.

Three Alternative Crops to Reduce Soil Erosion for Mountain Agriculture

One of the problems for cultivating crops in the mountainous highland is soil erosion and nutrients runoff. Alternative cropping ways were searched to reduce soil erosion and to ensure farm income in the mountainous highland agricultural region. Three edible wild plants including goatsbeard, Korean thistle, and aster, were selected to test as alternative crops to reduce soil erosion in mountain agriculture of highland area. In the first year, the soil losses from the alternative cropping were 26 to 63 percents of the soil loss from summer radish cultivated by conservation tillage with contour and plastic film mulching. The relative soil losses in the second year ranged from 2.8 to 5.5 percents in comparison with radish cultivation. Rapid surface coverage contributed to successive soil loss protection by these alternative crops. Farm net profit of these crops was greater than that of radish. Monitoring of yields of Korean thistle or aster for further experiments, however, might be necessary for economic cultivation due to yield reduction caused by consecutive production.

Environmental impact of introducing plant covers in the taluses of terraces: Implications for mitigating agricultural soil erosion and runoff

Abstract South-eastern Spain, and in particular the coastal areas of Granada and Malaga, feature a large area under subtropical crops, with orchards established on terraces built along the slopes of the mountainous areas. The climate, characterized by periodically heavy rainfall, variable in space and time, and with the common agricultural practice of leaving the taluses with bare soil, are the main factors encouraging soil erosion, runoff, and subsequent transport of pollutants. Over a two-year period, six plant covers were applied [( Thymus mastichina (Th), Lavandula dentata (La), native spontaneous vegetation (Sv), Anthyllis cytisoides (An), Satureja obovata (Sa), Rosmarinus officinalis (Ro)] in comparison to a control of bare soil (Bs) to determine the effectiveness of the covers in reducing soil erosion, runoff, and potential pollution risk by agricultural nutrients (N, P, and K) and heavy metals. Also, carbon losses were monitored in the transported sediments by runoff and in eroded soils. For this purpose, 16 m 2 erosion plots (4 m × 4 m) were laid out in the taluses of the terraces. When the yearly data were compared, the control plot (Bs) showed significantly higher soil erosion and runoff rates (26.4 t ha − 1 yr − 1 and 55.7 mm yr − 1 , respectively) than the treatments with plant covers. The plant covers studied registered the following results in runoff: Ro > Sa > An > Th ≈ La > Sv (41.7, 38.2, 35.5, 16.9, 16.1, and 12.4 mm yr − 1 , respectively) while annual soil erosion gave the following results: Sa > An > Ro > Th > Sv > La (18.0, 13.5, 13.4, 5.5, 4.4, and 3.2 Mg ha − 1 yr − 1 , respectively). This means that Sv reduced runoff and soil-erosion rates compared to Bs by not less than 78 and 83%, respectively. Nevertheless, La and Th plots were also very effective plant covers in reducing runoff and soil erosion (71.2 and 87.8; 69.5 and 79.2%, respectively) in comparison with the Bs plot. The heaviest nutrient losses in runoff and eroded soils were found in Bs and the lowest in the La, Th, and Sv plots. Bs and Ro plots registered the highest carbon losses (829.9 and 652.1 kg ha − 1 , respectively), the lowest carbon-loss rates being measured in La, Sv, and Th plots (145.2, 140.3, and 109.3 kg ha − 1 , respectively). The results indicate that heavy metals (Mn, Cr, Co, Ni, Cu, Zn, Mo, Cd, and Pb) in these types of agroecosystems may also be a potential pollutant due to transport by agricultural runoff. There was a major reduction of heavy-metal transport by plant covers in relation to the control of bare soil. The results of this research support the recommendation of using plant covers with multiple purposes (aromatic–medicinal–culinary) on the taluses of subtropical-crop terraces in order to reduce erosion and pollution risk.

The impact of agricultural soil erosion on biogeochemical cycling

Soils are the main terrestrial reservoir of nutrients, such as nitrogen and phosphorus, and of organic carbon. Synthesizing earlier studies, we find that the mobilization and deposition of agricultural soils can significantly alter nutrient and carbon cycling. Specifically, erosion can result in lateral fluxes of nitrogen and phosphorus that are similar in magnitude to those induced by fertilizer application and crop removal. Furthermore, the translocation and burial of soil reduces decomposition of soil organic carbon, and could lead to long-term carbon storage. The cycling of carbon, nitrogen and phosphorus are strongly interrelated. For example, erosion-induced burial of soils stabilizes soil nutrient and carbon pools, thereby increasing primary productivity and carbon uptake, and potentially reducing erosion. Our analysis shows soils as dynamic systems in time and space.

Agricultural soil erosion and global carbon cycle: controversy over?

AbstractRecent research on the contribution of soil erosion on agricultural land to atmospheric carbon dioxide (CO2) emphasizes either the contribution of soil organic matter (SOM) mineralization during transport as source for atmospheric CO2, or the deep burial of SOM‐rich sediment in agricultural landscapes as a sink. The contribution of either process is subject to a controversial debate. In this letter, we present preliminary results on our research on interrill carbon (C) erosion, SOM transport by rill erosion and the stationarity of C erosion during the Holocene. None of those issues has been incorporated comprehensively and with global coverage in the debate on the role of C erosion in the global C cycle. Therefore, we argue that only an eco‐geomorphologic perspective on organic C movement through landscapes can reconcile the two positions. Copyright © 2009 John Wiley & Sons, Ltd.

Land use history and historical soil erosion at Albersdorf (northern Germany) — Ceased agricultural land use after the pre-historical period

Abstract The Holocene landscape history and historical soil erosion were reconstructed at Albersdorf (Schleswig-Holstein, Germany) from soils and colluvial layers. In contrast to many landscapes in central Europe, agricultural land use and soil erosion were more frequent during pre-historical times, whereas it has almost ceased after the advent of history. Pre-historical soil erosion rates from about 0.1 to 6.9 t ha− 1 a− 1 were reconstructed with no significant differences between the prehistoric cultural phases. The study of buried soils within the soil/soil-sediment-sequences provided evidence for an acceleration of soil formation processes probably as a consequence of excessive prehistoric woodland pasture on poor sandy soils.

Stream sediment geochemistry of the Upper Mahaweli River Basin of Sri Lanka—Geological and environmental significance

Stream sediment geochemical maps serve as a tool for mineral exploration, identifying pollutant sources and providing information on weathering and transport processes. This paper presents geochemical maps of the upper catchment of the Mahaweli River of Sri Lanka, with interpretations based on geochemistry, geology and environmental conditions. For the construction of these maps, stream sediment geochemical data of 1585 samples, collected from 05 main tributaries of the Mahaweli River, was used. Elemental concentrations of 19 major and trace elements were determined by X-ray fluorescence spectrometry. Geochemical maps were prepared and existing geological maps, discriminant analysis, factor analysis, and correlation coefficients were used to recognize the relationship between spatial distribution patterns and the geological and environmental factors. These maps and statistical analysis clearly show the identical geochemical behavior of K, Rb, Ba and Sr. Even Mg and Ca show a similar distribution in different basins, the lack of correlation with metacarbonates probably being due to dissolution of Ca–Mg bearing minerals. The anomalous concentrations of these elements observed in the Anda Oya of Belihul Oya basin may indicate the existence of a Fe–Cu ore body and a Ni–Cr deposit in the upstream tributary of Badulu Oya. This however needs further detailed geological investigations. High Al levels in some streams seem to be controlled by high silt and clay contents released due to agricultural soil erosion in the upstream areas. Similarly, Pb enrichment in the vicinity of some cities may also be anthropogenic. Na, Mn, Ti, Nb, Y, Zn, Zr distribution in the stream sediment shows a relationship with the underlying lithologies of the area.

Agricultural slope management and soil erosion at La Laguna, Tlaxcala, Mexico

Several superimposed systems of agricultural terracing are preserved at the archaeological site of La Laguna in central Mexico. Excavations uncovered complex stratigraphic sequences of terrace fills and colluvial deposits. Their chronology was established by radiocarbon, optically stimulated luminescence (OSL), and the presence of diagnostic features and artifacts. The Formative occupations of the site (ca. 600–400 BC and 100 BC–AD 100) resulted in severe erosion and exposure of indurated subsoil horizons. In the Middle to Late Postclassic (AD 1150–1520) stone-walled terraces were built to recover the degraded slopes for cultivation. Renewed reclamation works have been undertaken since the Colonial period, eventually taking the form of sloping-field terraces with berms planted in maguey. The reconstructed sequence of local land use underscores the risks of dating agricultural features by association with sherd scatters, as well as the complexity of the relationships between demographic variables, agricultural intensity and terracing.

The Impact of Agricultural Soil Erosion on the Global Carbon Cycle

Agricultural soil erosion is thought to perturb the global carbon cycle, but estimates of its effect range from a source of 1 petagram per year(-1) to a sink of the same magnitude. By using caesium-137 and carbon inventory measurements from a large-scale survey, we found consistent evidence for an erosion-induced sink of atmospheric carbon equivalent to approximately 26% of the carbon transported by erosion. Based on this relationship, we estimated a global carbon sink of 0.12 (range 0.06 to 0.27) petagrams of carbon per year(-1) resulting from erosion in the world's agricultural landscapes. Our analysis directly challenges the view that agricultural erosion represents an important source or sink for atmospheric CO2.

Acoustic to seismic signatures of layered near-surface soil

The near‐surface soil structure, which strongly influences agricultural productivity and soil erosion, is amenable to study by acoustic to seismic techniques. These techniques utilize the coupling between airborne sound and seismic vibrations of the soil to investigate the distribution of soil’s mechanical properties. Two field sites were chosen over which the acoustic to seismic coupling signature of the ground, was measured. A predictive model, assuming acoustic plane waves incident on a vertically stratified ground was developed to predict the acoustic to seismic response. In this presentation, the acoustic to seismic signatures from these sites are compared to model results using the ground truth from seismic refraction and cone penetrometer surveys as input to the model.

Agricultural land-use patterns and soil erosion vulnerability of watershed units in Vietnam’s northern highlands

Since the mid eighties, agricultural development and increased population growth in Vietnam’s northern highlands have modified land use patterns and thus, increased the runoff process and soil degradation induced by water erosion. In the last decade, Vietnamese literature has focused on the computation of soil losses over large areas. Most of these spatial and quantitative soil erosion studies do not consider the impact of agricultural land use diversity (spatial heterogeneity), particularly at the watershed scale, and the annual variability of seasonal landscape factors on soil erosion vulnerability and hence, landscape dynamics. We present an integrated approach combining field measurements and observations, GIS and modeling to determine the spatial and temporal dynamics of soil erosion vulnerability according to watershed units and hence, the impact of physical environment components and agricultural land use patterns on landscape evolution. Tables and graphics showing the cropping systems, the periods within a year, and the watershed units that are most vulnerable are presented. The double cultivation cycles for paddy rice fields not only imply two periods of land preparation and establishment that expose the soil surface to raindrop impacts, but also increased soil management practices that decrease the soil’s resistance to detachment. Despite the low levels of soil management practices for the shifting cultivation system, the near absence of soil conservation practices clearly increases their vulnerability. Hence, rainfed cropping systems, mainly soya and cassava, cultivated on sloping lands (hills and mountains) where soil erosion vulnerability is the highest represent the watershed units which are the most prone to soil loss.

Measurement and distribution of runoff and soil losses from selected watersheds in the Hindu-Kush Himalayan region

The sediment loads of Himalayan Rivers are amongst the highest in the world, resulting in problems such as siltation of reservoirs, blockage of river channels and poor quality of water supplies. The aim of the study was to develop total sediment calculation and distribution on different land uses and thus to provide information for planning the quantification of sediment loads to rivers and reservoirs. Hydrological, meteorological and soil erosion data were collected from four watersheds, the Jhikhu Khola, the Hilkot, the Bhetagad and the Xizhuang, all of which featured several types of land use. Runoff and sediment losses were monitored. Total annual rainfall in the region ranged between 972 to 2400 mm. About 44 to 66 percent of rainfall occurred from June to August, which is mostly the Monsoon season in the region. Results show that runoff and soil losses were higher in the months of May to September, when rainfall duration and intensity were higher in all the watersheds. Large rainfall events contributed most of annual runoff and soil loss in the area. The highest annual runoff was generated in the Jhikhu Khola watershed under all conditions of land use while it was very low in the Bhetagan and Hilkot watersheds. The highest runoff and soil loss was recorded from degraded land plots because there less vegetation was available and the soil was loose and susceptible to erosion. In agricultural plots runoff and soil erosion was higher during the periods when there was no crop canopy and soil was not compacted after ploughing. During the months when crop cover was good there was less runoff and soil erosion. In pasture and forest plots runoff and soil loss was minimal throughout because of good vegetation and higher concentrations of organic matter that increased water infiltration and reduced runoff and soil loss.

Strategies to increase agricultural productivity and reduce land degradation: evidence from Uganda

AbstractThis paper estimates a structural econometric model of household decisions regarding income strategies, participation in programs and organisations, crop choices, land management, and labour use, and their implications for agricultural production and soil erosion; based upon a survey of over 450 households and their farm plots in Uganda. Many factors have context‐specific impacts and involve trade‐offs between increasing production and reducing land degradation. Government agricultural extension and training programs contribute to higher value of crop production in the lowlands, but to soil erosion in the highlands. By contrast, non‐governmental organization (NGO) programs focusing on agriculture and environment help to reduce erosion, but have less favourable impacts on production in the lowlands. Education increases household incomes, but also reduces crop production in the lowlands. Poverty has mixed impacts on agricultural production, depending on the nature of poverty: smaller farms obtain higher crop production per hectare, while households with fewer livestock have lower crop production. Population pressure contributes to agricultural intensification, but also to erosion in the densely populated highlands. Several household income strategies contribute to increased value of crop production, without significant impacts on soil erosion. We find little evidence of impact of access to markets, roads and credit, land tenure or title on agricultural intensification and crop production and land degradation. In general, the results imply that the strategies to increase agricultural production and reduce land degradation must be location‐specific, and that there are few ‘win‐win’ opportunities to simultaneously increase production and reduce land degradation.

Strategies to increase agricultural productivity and reduce land degradation: evidence from Uganda

This paper estimates a structural econometric model of household decisions regarding income strategies, participation in programs and organisations, crop choices, land management, and labour use, and their implications for agricultural production and soil erosion; based upon a survey of over 450 households and their farm plots in Uganda. Many factors have context-specific impacts and involve trade-offs between increasing production and reducing land degradation. Government agricultural extension and training programs contribute to higher value of crop production in the lowlands, but to soil erosion in the highlands. By contrast, non-governmental organization (NGO) programs focusing on agriculture and environment help to reduce erosion, but have less favourable impacts on production in the lowlands. Education increases household incomes, but also reduces crop production in the lowlands. Poverty has mixed impacts on agricultural production, depending on the nature of poverty: smaller farms obtain higher crop production per hectare, while households with fewer livestock have lower crop production. Population pressure contributes to agricultural intensification, but also to erosion in the densely populated highlands. Several household income strategies contribute to increased value of crop production, without significant impacts on soil erosion. We find little evidence of impact of access to markets, roads and credit, land tenure or title on agricultural intensification and crop production and land degradation. In general, the results imply that the strategies to increase agricultural production and reduce land degradation must be location-specific, and that there are few ‘win-win’ opportunities to simultaneously increase production and reduce land degradation.

Two hundred years of a diverse Daphnia community in Lake Naivasha (Kenya): effects of natural and human‐induced environmental changes

Summary1. We used fossil diapausing eggs extracted from 210Pb‐dated sediment cores to reconstruct historical changes in the Daphnia community of Lake Naivasha, a climate‐sensitive lake in Kenya which over the past 200 years has experienced a series of well‐documented natural and anthropogenic environmental changes.2. Contiguous sampling and analysis of four cores yielded ephippial capsules of eight Daphnia species. Only two of these had been recorded previously in live collections from Lake Naivasha, and one species is new to science. The four more common species (Daphnia barbata, D. laevis, D. magna, and D. pulex) show striking differences in abundance patterns and population dynamics through time. Four other species (D. lumholtzi, D. curvirostris, D. longispina s.l., and Daphnia sp. nov. type Limuru.) appear to have been present only occasionally. Nevertheless, between 1895 and 1915 seven species of Daphnia inhabited Lake Naivasha simultaneously.3. Despite considerable natural environmental change associated with climate‐driven lake‐level fluctuations, the Daphnia community of Lake Naivasha has been severely affected by human activities over the past century, especially the introduction of exotic fishes and water‐quality changes because of agricultural soil erosion. The recent reappearance of large‐bodied Daphnia species (D. magna, D. barbata, D. lumholtzi, Daphnia sp. nov. type Limuru) after 20–110 years of absence can be explained by their release from fish predation, following a dramatic increase in turbidity caused by excess clastic sediment input from eroded catchment soils. The small‐bodied species D. laevis has fared less well recently, presumably because the benefit of lowered predation pressure is counteracted by more pronounced negative effects of increased turbidity on this species and loss of submerged macrophyte beds which formerly served as predation refuge.4. Our results suggest that, despite considerable environmental instability and the absence of specialised zooplanktivores, top‐down control of fish on large zooplankton is important in Lake Naivasha. Predation pressure from fish has led to clear‐cut shifts in local Daphnia species composition, but failed to drive the larger taxa to extinction.

The Use of Pollen, Magnetic and Carbon Analyses in Identifying Agricultural Activity and Soil Erosion from the Neolithic to the Iron Age – A Study of Two Lake Sediment Cores from Jæren, South-Western Norway

Sediment cores from two small lakes, Alvevatn and Hanalandstjønn, both situated in the coastal heathland in Jceren, south-western Norway, were investigated with respect to microfossil analyses of pollen, spores and charcoal. The two lakes are situated close to prehistoric sites and monuments ranging in time from the Mesolithic to the Medieval Age. The microfossil analyses clearly reflect abrupt deforestation from closed mixed deciduous forest to heathland at approximately 3800 BP (ca. 2500–2200 cal BC). This event coincides with the generally accepted introduction of an agro-pastoral economy in the area at the Middle Neolithic II/Early Late Neolithic transition (MN II/ELN). However, at both localities, weak signals of agrarian impact are traced earlier by palynology. In recent years conclusions based on weak palynological signals have been criticised severely. In this investigation the tenability of the palynological method has been tested by applying independent methods to sediments from the same cores, viz. mineral magnetic and carbon analyses, which are likely to be proxy records for anthropogenic activity. The close agreement between the different methods support the conclusion that an agrarian economy was introduced prior to 4300 BP in the coastal heathland in Jæren.