The operationally defined fraction of soil organic matter (SOM), glomalin‐related soil protein (GRSP), has been reported to be particularly stable. This is the first study to test this hypothesis. Archived soil has been used from the long‐term bare fallow trial, known as the 42‐Plots, in Versailles, France. With no input from plants for 80 years, changes in GRSP must result from either turnover of SOM or net mineralization. Intrinsically, stability of protein would lead to progressive enrichment in GRSP. Soils from treatments that influenced pH, soil C:N ratio and physical stability were studied. Soil having received manure amendment was also studied to give contrasting microbial activity. Both GRSP and soil organic carbon (SOC) contents declined over the 80‐year period, with the exception of the manure treatment. GRSP and SOC contents were positively correlated. SOC was continuously enriched in GRSP in the control treatment, suggesting greater stability of GRSP. The SOC in manure‐amended soil was also progressively enriched in GRSP, but this can be attributed to the GRSP content of added manure. For the other treatments, the ratio GRSP:SOC fell continuously (CaCO₃ amendment) or fell to a minimum value after 45 years (KCl amendment) or levelled off after a progressive increase ((NH₄)₂SO₄ amendment). Trends are compared with measured soil properties and changes in microbial activity inferred from soil pH. No reliable independent assessment of microbial composition of these archived soils is possible. The results cannot be explained by inherent chemical or physicochemical stability of GRSP. We conclude that recycling of SOM continually produces soil protein. The net change in GRSP content is a complex function of SOM cycling and protein mineralization. These findings add to the increasing body of evidence that the operationally defined fraction of SOM known as GRSP does not predominantly originate from arbuscular mycorrhizal fungal activity.

中文翻译：

---

在土壤中可操作定义的部分土壤有机质“ GRSP”（与球蛋白有关的土壤蛋白）是否稳定？长期裸露土壤趋势的证据

据报道，土壤有机质（SOM）的操作定义部分是格洛马林相关的土壤蛋白（GRSP），它特别稳定。这是检验该假设的第一项研究。法国凡尔赛的长期裸露休耕试验（称为42地块）已使用了已存档的土壤。在80年没有任何植物投入的情况下，必须通过SOM的周转或净矿化来改变GRSP。本质上，蛋白质的稳定性会导致GRSP逐渐富集。研究了影响pH，C：N比和物理稳定性的处理土壤。还研究了接受粪肥改良的土壤，以提供相反的微生物活性。在80年期间，除粪便处理外，GRSP和土壤有机碳（SOC）均下降。GRSP与SOC含量呈正相关。在对照处理中，SOC不断丰富GRSP，表明GRSP的稳定性更高。粪肥改良土壤中的SOC也逐渐富含GRSP，但这可以归因于添加粪肥中GRSP的含量。对于其他处理，GRSP：SOC之比连续下降（CaCO₃修正案）或在45年后降至最小值（KCl修正案）或在逐渐增加（（NH ₄）₂ SO ₄后趋于稳定修正案）。将趋势与测得的土壤性质以及从土壤pH值推断出的微生物活性变化进行比较。无法对这些存档土壤的微生物组成进行可靠的独立评估。结果不能用GRSP固有的化学或物理化学稳定性来解释。我们得出的结论是，回收利用SOM会不断产生土壤蛋白质。GRSP含量的净变化是SOM循环和蛋白质矿化的复杂功能。这些发现增加了越来越多的证据，即被称为GRSP的SOM的操作定义部分并非主要来自丛枝菌根真菌活性。