Limmer Matt A, Linam Franklin A, Seyfferth Angelia L
University of Delaware, Department of Plant and Soil Sciences, Newark, DE 19716, United States of America.
University of Delaware, Department of Plant and Soil Sciences, Newark, DE 19716, United States of America.
Sci Total Environ. 2023 Dec 10;903:166496. doi: 10.1016/j.scitotenv.2023.166496. Epub 2023 Aug 22.
Rice production results in residues of straw and husk, and the management of these residues has implications for the sustainability of the rice agroecosystem. Rice straw is typically incorporated into soil either as fresh residue or is burned prior to incorporation. Rice husk is not typically returned to rice fields. However, rice husk contains high levels of silicon, which has been shown to decrease rice accumulation of arsenic. In this work, we studied the resulting biogeochemical changes in rice paddy soils when paddies were amended with either straw or burned straw and either no husk, husk, or burned husk over two years. Using a full-factorial design, we observed that the higher lability of rice straw carbon controlled redox-sensitive processes despite the application of husk and straw at similar carbon rates. Amending paddies with straw, rather than burned straw, increased porewater Fe and As, plant As, and methane emissions regardless of husk amendment. Husk addition provided insignificant Si to the plant despite its high concentration of Si, suggesting limited short-term mobility of Si and that long-term additions of husk or higher rates may need to be studied.
水稻生产会产生稻草和稻壳残留物，这些残留物的管理对水稻农业生态系统的可持续性具有重要意义。稻草通常以新鲜残留物的形式施入土壤，或在施入前进行焚烧。稻壳通常不会返还稻田。然而，稻壳含有大量硅，研究表明，硅可减少水稻对砷的积累。在本研究中，我们对稻田分别施用稻草或焚烧稻草，以及不添加稻壳、添加稻壳或添加焚烧稻壳的情况下，连续两年观察稻田土壤中产生的生物地球化学变化。采用全因子设计，我们观察到，尽管以相似的碳速率施用稻壳和稻草，但稻草碳的较高活性控制着对氧化还原敏感的过程。无论是否添加稻壳，用稻草而非焚烧稻草改良稻田会增加孔隙水铁和砷、植株砷含量以及甲烷排放。尽管稻壳硅含量很高，但添加稻壳向植株提供的硅量微不足道，这表明硅的短期迁移性有限，可能需要研究长期添加稻壳或更高添加速率的情况。
