College of Agronomy, Anhui Agricultural University, Hefei, 230036, China.
School of Engineering, Anhui Agricultural University, Hefei, 230036, China.
Environ Sci Pollut Res Int. 2021 Jun;28(23):29332-29343. doi: 10.1007/s11356-020-12038-7. Epub 2021 Feb 8.
Nitrite oxidation as the second step of nitrification can become the determining step in disturbed soil systems. As a beneficial fertilization practice to maintain high crop yield and soil fertility, partial substitution of chemical fertilizer (CF) by organic fertilizer (OF) may exert a notable disturbance to soil systems. However, how nitrite oxidation responds to different proportions of CF to OF is still unclear. We sampled soils from a 4-year field experiment subject to a gradient of increasing proportions of OF to CF application. Activity, size, and structure of Nitrospira-like and Nitrobacter-like nitrite-oxidizing bacteria (NOB) community were measured. The results revealed that with increasing proportion of OF to CF application, potential nitrite oxidation activity (PNO) showed a marked decreasing trend. PNO was significantly correlated with the abundance of Nitrobacter-like but not Nitrospira-like NOB. The abundance of Nitrobacter-like was significantly influenced by soil organic matter, organic nitrogen (N), and available N. In addition, PNO was also affected by the structure of Nitrobacter-like NOB. The relative abundance of Nitrobacter hamburgensis, alkalicus, winogradskyi, and vulgaris responded differently to the proportions of OF to CF application. Organic N, organic matter, and available N were the main factor shaping their community structure. Overall, Nitrobacter-like NOB is more sensitive and plays a more important role than Nitrospira-like NOB in responding to different proportions of OF to CF application.
亚硝酸盐氧化作为硝化作用的第二步，可以成为受干扰土壤系统的决定性步骤。作为维持高作物产量和土壤肥力的有益施肥实践，部分替代化学肥料（CF）的有机肥料（OF）可能会对土壤系统产生显著干扰。然而，亚硝酸盐氧化对 CF 与 OF 不同比例的响应仍不清楚。我们从一个 4 年的田间实验中采集了土壤样本，该实验中 OF 对 CF 的应用比例呈梯度增加。测量了硝化螺旋菌和硝化杆菌样亚硝酸氧化菌（NOB）群落的活性、大小和结构。结果表明，随着 OF 对 CF 应用比例的增加，潜在的亚硝酸盐氧化活性（PNO）呈显著下降趋势。PNO 与硝化杆菌样但不是硝化螺旋菌样 NOB 的丰度显著相关。硝化杆菌样的丰度受土壤有机质、有机氮（N）和有效氮的显著影响。此外，PNO 还受到硝化杆菌样 NOB 结构的影响。硝化杆菌 hamburgensis、alkalicus、winogradskyi 和 vulgaris 的相对丰度对 OF 对 CF 应用比例的响应不同。有机氮、有机质和有效氮是塑造其群落结构的主要因素。总的来说，硝化杆菌样 NOB 比硝化螺旋菌样 NOB 更敏感，在响应 CF 与 OF 不同比例的应用方面发挥着更重要的作用。
