College of Environment and Resources, College of Carbon Neutrality, Zhejiang A&F University, Hangzhou, 311300, China; The State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China.
College of Environment and Resources, College of Carbon Neutrality, Zhejiang A&F University, Hangzhou, 311300, China; The State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China.
J Environ Manage. 2024 Nov;370:122488. doi: 10.1016/j.jenvman.2024.122488. Epub 2024 Sep 12.
The widespread utilization of straw return was a popular practice straw disposal for highly intensive agriculture in China, which has brought about some negative impacts such as less time for straw complete biodegradation, aggravation of greenhouse gas evolution, and lower efficient of carbon accumulation. It was urgent to find an eco-friendly N-rich organic fertilizer instead of mineral N as activator to solve the above problems and lead a carbon accumulation in long tern management. Besides, microbial necromass was considered as a crucial contributor to persistent soil carbon (C) and nitrogen (N) pool. How organic fertilizer activators influence microbial residue under different amount of crop residues input remained unclear. Thus, soils incorporating moderate and high rate of rice straw residue with additions of half and full of organic activators (fish protein hydrolysates vs. manure) were incubated for measuring carbon dioxide (CO) and nitrous oxide (NO) emission, microbial community and necromass. It was found that soil CO emission was rapidest during the first 13 days of straw decomposition but remained lowest in the treatments of 50% mineral N substituted by fish protein hydrolysate. There were that 81%-89% of total CO release and 59%-65% of total NO emission occurred within 60 days of incubation period, and bacterial community and nitrate positively affected soil CO and NO release respectively. Straw incorporation amount and organic activator application interactively influenced soil CO emission but not affected soil NO emission. After 360 days of incubation, the difference of bacterial necromass was noticeable but fungal necromass remained almost unaltered across all treatments. All treatments showed generally comparable contribution of microbial necromass N to the total N pool. The treatment of 50% mineral N substituted by fish protein hydrolysate under high rate of straw input (HSF50) promoted the highest proportion of microbial necromass C in soil organic C because of alleviating N limitation for microorganisms. Finally, HSF50 was recommended as an eco-friendly strategy for enhancing microbial necromass C and N storage and climate benefits in agroecosystems.
秸秆还田在中国集约化农业中是一种广泛应用的秸秆处理方式，但也带来了一些负面影响，如秸秆完全生物降解的时间减少、温室气体排放加剧以及碳积累效率降低等。因此，迫切需要寻找一种环保的富氮有机肥料来替代矿物氮作为激活剂，以解决上述问题，并在长期管理中实现碳积累。此外，微生物残体被认为是土壤中持续碳（C）和氮（N）库的重要贡献者。然而，有机肥料激活剂在不同作物秸秆输入量下如何影响微生物残体仍不清楚。因此，本研究在添加半量和全量有机激活剂（鱼蛋白水解物与粪肥）的情况下，培养添加中量和高量水稻秸秆残体的土壤，以测量二氧化碳（CO）和氧化亚氮（NO）排放、微生物群落和残体。结果表明，在秸秆分解的前 13 天内，土壤 CO 排放最快，但在 50%矿物 N 用鱼蛋白水解物替代的处理中最低。在培养期的 60 天内，有 81%-89%的总 CO 释放和 59%-65%的总 NO 排放发生，细菌群落和硝酸盐分别对土壤 CO 和 NO 释放有积极影响。秸秆添加量和有机激活剂应用交互影响土壤 CO 排放，但不影响土壤 NO 排放。培养 360 天后，不同处理间细菌残体的差异明显，但真菌残体几乎不变。所有处理的微生物残体 N 对总 N 库的贡献大致相当。在高量秸秆输入下（HSF50），用鱼蛋白水解物替代 50%的矿物 N 的处理促进了土壤有机碳中微生物残体 C 的最高比例，因为这缓解了微生物的氮限制。因此，HSF50 被推荐为一种环保策略，用于增强农业生态系统中微生物残体 C 和 N 的储存和气候效益。
