Recycling nutrients in agroecosystems is becoming increasingly important to promote agricultural sustainability. Struvite and nitrogen (N)-enriched zeolites produced via wastewater treatment offer the potential for nutrient recycling. However, their effects on soil properties, particularly on microbial physiology, remain largely unknown; especially regarding microbial feedback, from which losses or sequestration of essential elements may result. This study investigates the short-term (three days) physiological responses of soil microorganisms, changes in available nutrients, and the immediate effects on soil organic matter (SOM) and carbon dioxide (CO2) emissions following the application of struvite and N-enriched zeolites derived from liquid digestate, alongside natural zeolites amendments in an acidic sandy soil. All treatments increased soil pH, which emerged as a driving factor in the dissolution of labile organic carbon (C) and the microbial production of N-, C-, and phosphorus (P)-acquiring extracellular enzymes. As soil pH increased, the stoichiometric ratio of microbial biomass C (Cmic) to microbial biomass N (Nmic), along with the enzymatic C:N ratio decreased, suggesting a superior effect on microbial N-cycling compared to C-cycling. Carbon dioxide emissions increased, particularly with the application of organic fertilizer (digestate), where the highest microbial metabolic quotient reflected increased catabolic activity due to the immediate availability of organic C. Overall, zeolitized tuffs demonstrated the potential to mitigate CO2 emissions, likely due to CO2 adsorption capacity.

中文翻译：

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鸟粪石和沸石的农业回收利用改善土壤微生物生理学和减少 CO2 排放的潜力


在农业生态系统中回收养分对于促进农业可持续性变得越来越重要。通过废水处理生产的鸟粪石和富含氮 （N） 的沸石具有养分回收的潜力。然而，它们对土壤特性的影响，特别是对微生物生理学的影响，在很大程度上仍然是未知的;特别是关于微生物反馈，这可能会导致基本元素的损失或封存。本研究调查了土壤微生物的短期（三天）生理反应、有效养分的变化，以及在酸性沙质土壤中施用来自液体沼渣的鸟粪石和富氮沸石以及天然沸石改良剂后对土壤有机质 （SOM） 和二氧化碳 （CO2） 排放的直接影响。所有处理都提高了土壤 pH 值，这成为不稳定有机碳 （C） 溶解和微生物产生获得 N、C- 和磷 （P） 的细胞外酶的驱动因素。随着土壤 pH 值的增加，微生物生物量 C （Cmic） 与微生物生物量 N （Nmic） 的化学计量比以及酶 C：N 比降低，表明与 C 循环相比，微生物 N 循环的影响更优。二氧化碳排放量增加，尤其是使用有机肥料（沼渣）时，其中最高的微生物代谢商反映了由于有机 C 的即时可用性而增加的分解代谢活性。总体而言，沸石凝灰岩显示出减少 CO2 排放的潜力，这可能是由于 CO2 吸附能力。