Benediktas Jankauskas

Effects of land use on annual runoff and soil loss in Europe and the Mediterranean: A meta-analysis of plot data

The largest currently compiled database of plot runoff and soil loss data in Europe and the Mediterranean was analysed to investigate effects of land use on annual soil loss (SL), annual runoff (R) and annual runoff coefficient (RC). This database comprises 227 plot-measuring sites in Europe and the Mediterranean, with SL for 1056 plots (PL) representing 7024 plot-years (PY) and R for 804 PL representing 5327 PY. Despite large data variability, continental-wide trends are observed. Construction sites have the highest mean annual RC (57%) and SL (325 Mg.ha-1.yr-1). Bare soil, vineyards and tree crops have high mean annual RC (5–10%) and SL (10–20 Mg.ha-1.yr-1). Cropland and fallow show similar mean annual RC (8.0 and 7.3%), but lower SL (6.5 and 5.8 Mg.ha-1.yr-1). Plots with (semi-)natural vegetation cover show lowest mean annual RC (<5%) and SL (<1 Mg.ha-1.yr-1). Plot length and slope gradient correlations with R and SL depend on land-use type and are not concurrent for R and SL. Most land-use types show positive correlations between annual R and SL. Plots in cold climates have higher annual RC than plots in temperate and pan-Mediterranean climates. Annual SL in the pan-Mediterranean is less than in temperate zones, due to stony or clayey soils having a low erodibility. Annual RC in the pan-Mediterranean was higher than in temperate zones. Annual R increases strongly with increasing annual precipitation (P) above 500 mm.yr-1, while annual SL was found to stabilize at P > 500 mm.yr-1. For shrubland, annual SL was found to decrease for P > 250–500 mm.yr-1, which is attributed to an accompanying increase in vegetation cover. However, no such trend was found for R. The results allow a rapid assessment of the impact of land-use changes on annual R, RC and SL, based on field-measured plot data.

A comparison of measured catchment sediment yields with measured and predicted hillslope erosion rates in Europe

PurposeThis study aims to understand better the relationship between measured soil loss rates due to sheet and rill erosion (SL), predicted SL rates and measured catchment sediment yields (SY) in Europe.Materials and methodsAnalyses were based on a recently established database of measured annual SY for 1794 catchments, a database of 777 annual SL rates measured on runoff plots and two recent maps of predicted sheet and rill erosion rates in Europe (i.e. one based on empirical extrapolations of measured SL data and one based on the PESERA model). To identify regional trends, all data were grouped into eight climatic zones.Results and discussionMeasured SL rates are generally a factor of five to ten times larger than predicted SL rates and are strongly biased towards erosion-prone situations in terms of land use. Also measured SY are generally higher than predicted SL rates, especially in the Mediterranean and Alpine regions where SY is generally ten times higher than predicted SL rates. This illustrates the importance of other erosion processes contributing to SY. Regional differences in the importance of these processes and their implications are discussed.ConclusionsThis study confirms previous findings indicating the relatively low sheet and rill erosion rates compared to SY in the Mediterranean region and illustrates the importance of other erosion processes contributing to SY in most regions of Europe. This indicates that hillslope erosion rates cannot be used directly to estimate SY, and consequently soil conservation programmes should focus more on the dominant erosion processes in each catchment.

Soil erosion and changes in the physical properties of Lithuanian Eutric Albeluvisols under different land use systems

Abstract The investigations aimed to: 1) evaluate water erosion rates on undulating slopes in Lithuania under different land use systems; 2) study changes in soil physical properties on the differently eroded slopes; and 3) better understand relationships between soil physical properties and soil erodibility. Research data were obtained on loamy sand and clay loam Eutric Albeluvisols located on the undulating hilly relief of the Žemaičiai Uplands of Western Lithuania. The results of 18 years of water erosion investigations under different land use systems on slopes of varying steepness are presented. Attention is focused on changes in soil physical properties in relation to soil erosion severity. Measured water erosion rates in the field experiments were: 3.2–8.6 m3 ha−1 yr−1 under winter rye, 9.0–27.1 m3 ha−1 yr−1 under spring barley and 24.2–87.1 m3 ha−1 yr−1 under potatoes. Perennial grasses completely prevented water erosion, while erosion-preventive grass-grain crop rotations (67% grasses, 33% cereal grains) decreased soil losses by 75–80% compared to the field crop rotation, containing 17% tillage crops (potatoes), 33% grasses and 50% cereal grains. The grain-grass crop rotation (33% grasses and 67% cereal grains) decreased soil erosion rates by 23–24%. The percentage of clay-silt and clay fractions of arable soil horizons increased, while the total soil porosity and moisture retention capacity decreased with increased soil erosion. Phytocenoses, including sod-forming perennial grasses and grass-grain crop rotations, led to changes in the physical properties of eroded soils; soil bulk density decreased and percentage total porosity and moisture retention capacity increased. The grass-grain crop rotations increased the water-stable soil structure (measured as water-stable soil aggregates) by 11.03 per cent units and sod-forming perennial grasses increased aggregate stability by 9.86 per cent units compared with the grain-grass crop rotation on the 10–14° slope. Therefore, grass-grain crop rotations and sod-forming perennial grasses decreased soil erodibility and thus could assist both erosion control and the ecological stability of the vulnerable hilly-undulating landscape.

Contributions of biogeotextiles to sustainable development and soil conservation in developing countries: the BORASSUS Project.

Field and laboratory studies indicate that geotextile mats constructed from palm leaves are an effective, sustainable and economically viable soil conservation technique. The three-year (2005–08) EU-funded BORASSUS Project (Contract Number INCO-CT-2005-510745) is evaluating their long-term effectiveness in controlling soil erosion and assessing their sustainability and economic viability. These studies are in progress in 10 countries, both in the ‘industrial north’ (in Europe) and in the ‘developing south’ (Africa, South America and South-East Asia). This paper focuses on agro-environmental applications and potential in the ‘developing south’ (The Gambia, South Africa, Brazil, China, Thailand and Vietnam). Biogeotextiles offer potentially novel bioengineering solutions to environmental problems, including technologies for soil conservation, sustainable plant production and use of indigenous plants, improved ecosystem management, decreasing deforestation, improving agroforestry and cost-effective geotextile applications in diverse environments. Biogeotextiles may provide socio-economic platforms for sustainable development and the benefits for developing countries may include poverty alleviation, engagement of local people as stakeholders, employment for disadvantaged groups, small and medium enterprise (SME) development, earning hard currency, environmental education and local community involvement in land reclamation and environmental education programmes. These benefits are achieved through: (a) promotion of sustainable and environmentally-friendly palm agriculture to discourage deforestation, promoting both reforestation and agroforestry; (b) construction of palm geotextiles enabling development of a rural labour-intensive industry, particularly encouraging employment of socially-disadvantaged groups and (c) export of palm geotextiles to industrialized countries could earn hard currency for developing economies, based on the principles of fair trade.

The contribution of quality assessment of eroded agricultural soil on hilly-undulating landscapes to sustainable community development

Sustainable community development depends on different circum- stances and conditions and soil is one of the most important natural resources influencing community development. Some soil quality indicators are excep- tionally sensitive on hilly undulating relief. The results from 18 years of field experiments at the Kaltinenai Research Station of the Lithuanian Institute of Agriculture indicate that soil erosion processes under the field crop rotation (containing 17% tillage crops, 33% grasses, and 50% cereal grains), disrupt the top layer of unprotected soil, decrease soil organic matter content, impoverish soil physical-chemical properties and instigate landscape leveling. The mean annual erosion rates under the field crop rotation were 9.9, 23.4, and 32.2 Mg ha -1 year -1 , respectively, from slopes of 2-5 o , 5-10 o , and 10-14 o . Erosion- preventive grass-grain crop rotations (containing 67% grasses and 33% cereal grains), as well as the sod-forming perennial grasses for long-term use, decreased mean annual erosion rates by 75-80% compared with the field crop rotation. Both land use systems ensure increasing soil organic matter content, decreasing soil erodibility and increasing soil carbon sequestration, helping to decrease atmospheric CO2 concentrations and thus positively influencing global climate changes. These land use systems can be considered as soil conserving, sustainable systems ensuring environmental security on the vulnerable hilly undulating agricultural landscape.