Phosphorus (P) eutrophication in the water bodies is of global concern. The role of biochar in the mitigation of (P) eutrophication has recently received substantial attention. Agriculture is the main source of P in the water bodies, as a result of excessive fertilizer and manure application. Excessive P results in excessive primary production in the water bodies, leading to anoxic conditions, growth of toxic algae blooms, altering plant species composition and biomass. Therefore, resulting in food web disruption, fish kill, toxins production and recreation areas degradation. When biochar is applied on farm, it has potential to sorb/adsorb P, immobilizing it, slowing its translocation to the water bodies. However, biochar effectiveness in P sorption is influenced by both feedstock type and pyrolysis temperature. The interaction between feedstock type and pyrolysis temperature influences the biochar pH, surface area, aromatic carbon, cation exchange capacity, surface charge density, biochar internal porosity and polar and nonpolar surface sites that promote nutrient absorption. Hence, biochar properties have a broad spectrum that influences how biochar reacts with P sorption; therefore, it is not appropriate to extrapolate observed results to different materials. Biochar that promote P sorption rather than desorption should be considered and designed to meet specific management practices.
Part of the book: Biochar
Nitrogen (N) and phosphorus (P) eutrophication in marine ecosystems is a global problem. Marine eutrophication has a negative impact on food security, ecosystem health and economy through disruptions in tourism, fisheries and health industries. Both N and P have known point and non-point sources. Control of point sources has been easier than non-point sources particularly agricultural sources for both N and P as well as fossil fuel combustion for N, which remains a major challenge. Implementing mitigation strategies for N has been reported to be effective for P mitigation; however, the converse is not true due to mobility and volatility of N. Excessive N and P cause algae blooms, anoxic conditions, and ocean acidification with these conditions leading to dead zones, fish kill, toxin production, altered plant species diversity, food web disruption, tourism disruption and health issues. Management of N and P pollution includes reduction of leaching from farms through crop selection, timely and precise application of fertilizer and building artificial wetlands, proper management of animal waste, reduction of fossil fuel N emission, mitigating N and P from urban sources and restoration of aquatic ecosystem. Mitigation measures need to focus on dual nutrient strategy for successful N and P reduction.
Part of the book: Monitoring of Marine Pollution