Nitrogen fertilizer and harvest management will alter soils under bioenergy crop production and the long\uffe2\uff80\uff90term effects of harvest timing and residue removal remain relatively unknown. Compared to no\uffe2\uff80\uff90tilled corn (NT\uffe2\uff80\uff90C, Zea mays L.), switchgrass (Panicum virgatum L.) is predicted to improve soil properties [i.e. soil organic C (SOC), soil microbial biomass (SMB\uffe2\uff80\uff90C), and soil aggregation] due to its perennial nature and deep\uffe2\uff80\uff90rooted growth form, but few explicit field comparisons exist. We assessed soil properties over 9\uffc2\uffa0years for a rainfed study of N fertilizer rate (0, 60, 120, and 180\uffc2\uffa0kg N\uffc2\uffa0ha\uffe2\uff88\uff921) and harvest management on switchgrass (harvested in August and postfrost) and NT\uffe2\uff80\uff90C (with and without 50% stover removal) in eastern NE. We measured SOC, aggregate stability, SMB\uffe2\uff80\uff90C, bulk density (BD), pH, P and K in the top 0\uffe2\uff80\uff9330\uffc2\uffa0cm. Both NT\uffe2\uff80\uff90C and switchgrass increased SMB\uffe2\uff80\uff90C, SOC content, and aggregate stability over the 9\uffc2\uffa0years, reflecting improvement from previous conventional management. However, the soils under switchgrass had double the percent aggregate stability, 1.3 times more microbial biomass, and a 5\uffe2\uff80\uff938% decrease in bulk density in the 0\uffe2\uff80\uff935 and 5\uffe2\uff80\uff9310\uffc2\uffa0cm depths compared to NT\uffe2\uff80\uff90C. After 9\uffc2\uffa0years, cumulative decrease in available P was significantly greater beneath NT\uffe2\uff80\uff90C (\uffe2\uff88\uff9224.0\uffc2\uffa0kg P\uffc2\uffa0ha\uffe2\uff88\uff921) compared to switchgrass (\uffe2\uff88\uff925.4\uffc2\uffa0kg P\uffc2\uffa0ha\uffe2\uff88\uff921). When all measured soil parameters were included in the Soil Management Assessment Framework (SMAF), switchgrass improved soil quality index over time (\uffce\uff94SQI) in all depths. NT\uffe2\uff80\uff90C without residue removal did not affect \uffce\uff94SQI, but 50% residue removal decreased \uffce\uff94SQI (0\uffe2\uff80\uff9330\uffc2\uffa0cm) due to reduced aggregate stability and SMB\uffe2\uff80\uff90C. Even with best\uffe2\uff80\uff90management practices such as NT, corn stover removal will have to be carefully managed to prevent soil degradation. Long\uffe2\uff80\uff90term N and harvest management studies that include biological, chemical, and physical soil measurements are necessary to accurately assess bioenergy impacts on soils.
", "keywords": ["2. Zero hunger", "harvest timing", "no-till corn", "N fertilizer", "soil C sequestration", "switchgrass", "P", "04 agricultural and veterinary sciences", "15. Life on land", "K", "7. Clean energy", "630", "residue removal", "soil organic C", "0401 agriculture", " forestry", " and fisheries"]}, "links": [{"href": "https://doi.org/10.1111/gcbb.12142"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/GCB%20Bioenergy", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/gcbb.12142", "name": "item", "description": "10.1111/gcbb.12142", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/gcbb.12142"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2014-01-15T00:00:00Z"}}, {"id": "10.1111/gcbb.12326", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:17:51Z", "type": "Journal Article", "created": "2015-12-18", "title": "N Fertilizer And Harvest Impacts On Bioenergy Crop Contributions To Soc", "description": "AbstractBelowground root biomass is infrequently measured and simply represented in models that predict landscape\uffe2\uff80\uff90level changes to soil carbon stocks and greenhouse gas balances. Yet, crop\uffe2\uff80\uff90specific responses to N fertilizer and harvest treatments are known to impact both plant allocation and tissue chemistry, potentially altering decomposition rates and the direction and magnitude of soil C stock changes and greenhouse gas fluxes. We examined switchgrass (Panicum virgatum L.) and corn (Zea mays L.,) yields, belowground root biomass, C, N and soil particulate organic matter\uffe2\uff80\uff90C (POM\uffe2\uff80\uff90C) in a 9\uffe2\uff80\uff90year rainfed study of N fertilizer rate (0, 60, 120 and 180\uffc2\uffa0kg\uffc2\uffa0N\uffc2\uffa0ha\uffe2\uff88\uff921) and harvest management near Mead, NE, USA. Switchgrass was harvested with one pass in either August or postfrost, and for no\uffe2\uff80\uff90till (NT) corn, either 50% or no stover was removed. Switchgrass had greater belowground root biomass C and N (6.39, 0.10\uffc2\uffa0Mg\uffc2\uffa0ha\uffe2\uff88\uff921) throughout the soil profile compared to NT\uffe2\uff80\uff90corn (1.30, 0.06\uffc2\uffa0Mg\uffc2\uffa0ha\uffe2\uff88\uff921) and a higher belowground root biomass C:N ratio, indicating greater recalcitrant belowground root biomass C input beneath switchgrass. There was little difference between the two crops in soil POM\uffe2\uff80\uff90C indicating substantially slower decomposition and incorporation into SOC under switchgrass, despite much greater root C. The highest N rate decreased POM\uffe2\uff80\uff90C under both NT\uffe2\uff80\uff90corn and switchgrass, indicating faster decomposition rates with added fertilizer. Residue removal reduced corn belowground root biomass C by 37% and N by 48% and subsequently reduced POM\uffe2\uff80\uff90C by 22% compared to no\uffe2\uff80\uff90residue removal. Developing productive bioenergy systems that also conserve the soil resource will require balancing fertilization that maximizes aboveground productivity but potentially reduces SOC sequestration by reducing belowground root biomass and increasing root and soil C decomposition.
", "keywords": ["roots", "2. Zero hunger", "harvest timing", "N fertilizer", "soil C sequestration", "04 agricultural and veterinary sciences", "15. Life on land", "soil fractions", "7. Clean energy", "630", "6. Clean water", "residue removal", "13. Climate action", "soil organic C", "0401 agriculture", " forestry", " and fisheries"]}, "links": [{"href": "https://doi.org/10.1111/gcbb.12326"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/GCB%20Bioenergy", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/gcbb.12326", "name": "item", "description": "10.1111/gcbb.12326", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/gcbb.12326"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2016-05-03T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=harvest+timing&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=harvest+timing&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=harvest+timing&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=harvest+timing&offset=2", "hreflang": "en-US"}], "numberMatched": 2, "numberReturned": 2, "distributedFeatures": [], "timeStamp": "2026-09-23T03:35:58.015453Z"}