{"type": "FeatureCollection", "features": [{"id": "10.1007/s10021-008-9154-z", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-13T16:14:44Z", "type": "Journal Article", "created": "2008-05-27", "title": "Reversibility Of Soil Productivity Decline With Organic Matter Of Differing Quality Along A Degradation Gradient", "description": "In the highlands of Western Kenya, we investigated the reversibility of soil productivity decline with increasing length of continuous maize cultivation over 100\u00a0years (corresponding to decreasing soil organic carbon (SOC) and nutrient contents) using organic matter additions of differing quality and stability as a function of soil texture and inorganic nitrogen (N) additions. The ability of additions of labile organic matter (green and animal manure) to improve productivity primarily by enhanced nutrient availability was contrasted with the ability of stable organic matter (biochar and sawdust) to improve productivity by enhancing SOC. Maize productivity declined by 66% during the first 35\u00a0years of continuous cropping after forest clearing. Productivity remained at a low level of 3.0\u00a0t\u00a0grain\u00a0ha-1 across the chronosequence stretching up to 105\u00a0years of continuous cultivation despite full N\u2013phosphorus (P)\u2013potassium (K) fertilization (120\u2013100\u2013100\u00a0kg ha\u22121). Application of organic resources reversed the productivity decline by increasing yields by 57\u2013167%, whereby responses to nutrient-rich green manure were 110% greater than those from nutrient-poor sawdust. Productivity at the most degraded sites (80\u2013105\u00a0years since forest clearing) increased in response to green manure to a greater extent than the yields at the least degraded sites (5\u00a0years since forest clearing), both with full N\u2013P\u2013K fertilization. Biochar additions at the most degraded sites doubled maize yield (equaling responses to green manure additions in some instances) that were not fully explained by nutrient availability, suggesting improvement of factors other than plant nutrition. There was no detectable influence of texture (soils with either 11\u201314 or 45\u201349% clay) when low quality organic matter was applied (sawdust, biochar), whereas productivity was 8, 15, and 39% greater (P\u00a0<\u00a00.05) on sandier than heavier textured soils with high quality organic matter (green and animal manure) or only inorganic nutrient additions, respectively. Across the entire degradation range, organic matter additions decreased the need for additional inorganic fertilizer N irrespective of the quality of the organic matter. For low quality organic resources (biochar and sawdust), crop yields were increasingly responsive to inorganic N fertilization with increasing soil degradation. On the other hand, fertilizer N additions did not improve soil productivity when high quality organic inputs were applied. Even with the tested full N\u2013P\u2013K fertilization, adding organic matter to soil was required for restoring soil productivity and most effective in the most degraded sites through both nutrient delivery (with green manure) and improvement of SOC (with biochar).", "keywords": ["Soil nutrients", "2. Zero hunger", "Soil management", "Soil organic matter", "Chronosequence", "Sustainable agriculture", "Green manure crops", "04 agricultural and veterinary sciences", "15. Life on land", "Soil fertility", "Soil degradation", "Soil productivity", "Soil erosion", "0401 agriculture", " forestry", " and fisheries", "Biochar addition", "Clay concentration", "Agroecosystems", "Field Scale"]}, "links": [{"href": "https://doi.org/10.1007/s10021-008-9154-z"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Ecosystems", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s10021-008-9154-z", "name": "item", "description": "10.1007/s10021-008-9154-z", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s10021-008-9154-z"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2008-05-28T00:00:00Z"}}, {"id": "10.1111/brv.12949", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-13T16:19:16Z", "type": "Journal Article", "created": "2023-03-14", "title": "Trade\u2010offs in carbon\u2010degrading enzyme activities limit long\u2010term soil carbon sequestration with biochar addition", "description": "ABSTRACT

Biochar amendment is one of the most promising agricultural approaches to tackle climate change by enhancing soil carbon (C) sequestration. Microbial\uffe2\uff80\uff90mediated decomposition processes are fundamental for the fate and persistence of sequestered C in soil, but the underlying mechanisms are uncertain. Here, we synthesise 923 observations regarding the effects of biochar addition (over periods ranging from several weeks to several years) on soil C\uffe2\uff80\uff90degrading enzyme activities from 130 articles across five continents worldwide. Our results showed that biochar addition increased soil ligninase activity targeting complex phenolic macromolecules by 7.1%, but suppressed cellulase activity degrading simpler polysaccharides by 8.3%. These shifts in enzyme activities explained the most variation of changes in soil C sequestration across a wide range of climatic, edaphic and experimental conditions, with biochar\uffe2\uff80\uff90induced shift in ligninase:cellulase ratio correlating negatively with soil C sequestration. Specifically, short\uffe2\uff80\uff90term (<1\uffc2\uffa0year) biochar addition significantly reduced cellulase activity by 4.6% and enhanced soil organic C sequestration by 87.5%, whereas no significant responses were observed for ligninase activity and ligninase:cellulase ratio. However, long\uffe2\uff80\uff90term (\uffe2\uff89\uffa51\uffc2\uffa0year) biochar addition significantly enhanced ligninase activity by 5.2% and ligninase:cellulase ratio by 36.1%, leading to a smaller increase in soil organic C sequestration (25.1%). These results suggest that shifts in enzyme activities increased ligninase:cellulase ratio with time after biochar addition, limiting long\uffe2\uff80\uff90term soil C sequestration with biochar addition. Our work provides novel evidence to explain the diminished soil C sequestration with long\uffe2\uff80\uff90term biochar addition and suggests that earlier studies may have overestimated soil C sequestration with biochar addition by failing to consider the physiological acclimation of soil microorganisms over time.Biochar amendment is one of the most promising agricultural approaches to tackle climate change by enhancing soil carbon (C) sequestration. Microbial\uffe2\uff80\uff90mediated decomposition processes are fundamental for the fate and persistence of sequestered C in soil, but the underlying mechanisms are uncertain. Here, we synthesise 923 observations regarding the effects of biochar addition (over periods ranging from several weeks to several years) on soil C\uffe2\uff80\uff90degrading enzyme activities from 130 articles across five continents worldwide. Our results showed that biochar addition increased soil ligninase activity targeting complex phenolic macromolecules by 7.1%, but suppressed cellulase activity degrading simpler polysaccharides by 8.3%. These shifts in enzyme activities explained the most variation of changes in soil C sequestration across a wide range of climatic, edaphic and experimental conditions, with biochar\uffe2\uff80\uff90induced shift in ligninase:cellulase ratio correlating negatively with soil C sequestration. Specifically, short\uffe2\uff80\uff90term (<1\uffc2\uffa0year) biochar addition significantly reduced cellulase activity by 4.6% and enhanced soil organic C sequestration by 87.5%, whereas no significant responses were observed for ligninase activity and ligninase:cellulase ratio. However, long\uffe2\uff80\uff90term (\uffe2\uff89\uffa51\uffc2\uffa0year) biochar addition significantly enhanced ligninase activity by 5.2% and ligninase:cellulase ratio by 36.1%, leading to a smaller increase in soil organic C sequestration (25.1%). These results suggest that shifts in enzyme activities increased ligninase:cellulase ratio with time after biochar addition, limiting long\uffe2\uff80\uff90term soil C sequestration with biochar addition. Our work provides novel evidence to explain the diminished soil C sequestration with long\uffe2\uff80\uff90term biochar addition and suggests that earlier studies may have overestimated soil C sequestration with biochar addition by failing to consider the physiological acclimation of soil microorganisms over time.