Factors affecting N and P losses from small catchments (Lithuania)

Abstract

Most of the important factors causing differences in nutrient losses and their interaction were analysed in three small catchments that are located in partially different geographic and climatic conditions in Lithuania. The investigation revealed that climatic factors change the amount and pattern of water discharge over year (larger water discharge during winter in the catchment located closer to the sea), but nutrient leaching is more dependent on land use. Agricultural factors, such as larger cultivated area and excessive fertilisation in one catchment cause larger nitrogen losses (15 kg N ha(-1) year(-1)). Large area of non-intensively used grassland leads to very small nitrogen losses (5.7 kg N ha(-1) year(-1)) in another catchment. However, larger water discharge combined with loamy sandy soils leads to comparatively high nitrogen losses (12 kg N ha(-1) year(-1)). The highest P losses (0.318 kg P ha(-1) year(-1)) occurred in the catchment with hilly relief and clay soil texture. In summary, extensive agriculture in the post-Soviet countries has reduced the importance of agricultural activity for the extent of nutrient losses and agricultural factors (cultivation, fertilisation and livestock density) are 'responsible' for the losses only in the region of sufficient agricultural activity (N input--71.5 kg N ha(-1), livestock density--0.87 LU ha(-1)).

Nitrogen fertilization of grass leys: Yield production and risk of N leaching

“…The values predicted by the COUP model for N leaching losses after the application of mineral N fertilizer to perennial grass leys were in accordance with the low values measured, which ranged from 1.2 to 10-15 kg ha À1 yr À1 in Finland (Salo and Turtola, 2006) and in the Nordic-Baltic countries (References in Appendix B; Kutra and Aksomaitiene, 2003;Korsaeth et al, 2003;Sileika et al, 2005). Numerous studies demonstrated that N leaching losses from perennial grassland are inherently smaller than those from arable land, since N uptake covers a longer period and the soil normally remains untilled for at least three years, thereby reducing N leaching (Korsaeth and Eltun, 2000;Addiscott, 2005;Aronsson et al, 2014).…”

Plant communities as a tool in temporary ponds conservation in SW Portugal

“…Clearly, more studies on soils profiles and water tables in these ecosystems are required. The intensive land uses like overgrazing or high technology agriculture in the territory can transform vernal pools and marshlands into disturbed ponds edaphically characterised, as shown our results, by a high content in N as a consequence of cumulative effects in the catchments area (Sileika et al, 2005;Szajdak et al, 2006). The regression of vernal pool habitats, due to anthropic disturbance, affects the abundance of rare communities and species in a specific area; in particular, we can refer to I. setaceum.…”

Macronutrients along the sediment profile in a subtropical monsoonal wetland in India

“…The nutrients from the catchments are known to accumulate in wetlands (and lakes) that are known sinks (Mohanraj et al 2000). Among the nutrient elements under the study, P in particular is known to be adsorbed by soil particles and transported by erosion due to surface runoff (Sileika et al 2005). Hence, the differential water input to this wetland system could also be one of the reasons for high variability in the sedimentary nutrient content during some months.…”