Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2023
Publication Date: 10/25/2023
Citation: Wuest, S.B. 2023. Soil carbon twelve years after live roots or application of plant residues or manure. Soil Science Society of America Journal. 00:1-5. https://doi.org/10.1002/saj2.20597.
Interpretive Summary: Soil was analyzed in a field where replicated plots had received a variety of carbon amendments for five years in a row. Twelve years later the effects on soil organic carbon levels have not changed in quantity or in one amendment relative to another. Municipal biosolid produced the largest gain, followed by manure and alfalfa foliage. Wheat straw, sucrose, and wood sawdust were not different than no addition. Soil which was growing a wheat crop or perennial grass still has much greater soil organic carbon than where the soil was fallow for the five-year period. Certain amendments and roots can cause durable soil organic carbon changes.
Technical Abstract: Soil organic carbon was measured after surface application of equal C amounts from various carbon sources to fallow soil or a winter wheat crop for five consecutive years. Municipal biosolid produced the largest gain, followed by manure and alfalfa (Medicago sativa L.) foliage. Wheat (Triticum aestivum L.) straw, sucrose, and wood sawdust were not different than no addition. These effects were additive to and independent from the effect of fallow soil versus cropped soil. Soil cropped to winter wheat increased in carbon comparable to the biosolid application or to plots planted to perennial grass. Measurements 4, 6, and 12 years after a return to normal farming practices produced no change in relative or quantitative differences. These results illuminate the durability of above- and below-ground contributions to soil carbon.