Browsing by Subject "nutrient loads"

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  • Lötjönen, Sanna Annika; Ollikainen, Markku Martti Olavi (2017)
    We investigate crop rotation with legumes from economic and environmental perspectives by asking how effective they are at providing profits and reducing nutrient runoff and greenhouse gas emissions compared with monoculture cultivation. We study this effectiveness in three alternative policy regimes: the free market optimum, the Finnish agri-environmental scheme, and socially optimal cultivation, and also design policy instruments to achieve the socially optimal outcomes in land use and fertilization. We first develop an analytical model to describe crop rotation and the role of legumes, and examine its implications for water and climate policies. Drawing on Finnish agricultural data, we then use numerical simulations and show that shifting from monoculture cultivation to crop rotation with legumes provides economically and environmentally better outcomes. Crop rotation with legumes also reduces the variability in profits caused by stochastic weather. The optimal instruments implementing the social optimum depend on nutrient and climate damage (nitrogen tax), as well as carbon sequestration and nutrient reduction benefits (buffer strip subsidy).
  • Laurén, Annamari (Ari); Guan, Mingfu; Salmivaara, Aura; Leinonen, Antti; Palviainen, Marjo; Launiainen, Samuli (2021)
    Responsible forest management requires accounting for adverse environmental effects, such as increased nutrient export to water courses. We constructed a spatially-distributed nutrient balance model NutSpaFHy that extends the hydrological model SpaFHy by introducing a grid-based nutrient balance sub-model and a conceptual solute transport routine to approximate total nitrogen (N) and phosphorus (P) export to streams. NutSpaFHy uses openly-available Multi-Source National Forest Inventory data, soil maps, topographic databases, location of water bodies, and meteorological variables as input, and computes nutrient processes in monthly time-steps. NutSpaFHy contains two calibrated parameters both for N and P, which were optimized against measured N and P concentrations in runoff from twelve forested catchments distributed across Finland. NutSpaFHy was independently tested against six catchments. The model produced realistic nutrient exports. For one catchment, we simulated 25 scenarios, where clear-cuts were located differently with respect to distance to water body, location on mineral or peat soil, and on sites with different fertility. Results indicate that NutSpaFHy can be used to identify current and future nutrient export hot spots, allowing comparison of logging scenarios with variable harvesting area, location and harvest techniques, and to identify acceptable scenarios that preserve the wood supply whilst maintaining acceptable level of nutrient export.