Zentgraf Isabel, Hoffmann Mathias, Augustin Jürgen, Buchen-Tschiskale Caroline, Hoferer Sara, Holz Maire
Leibniz Center for Agricultural Landscape Research (ZALF) e.V., Group of Isotope Biogeochemistry and Gas Fluxes, Eberswalder Str. 84, 15374, Müncheberg, Germany.
Humboldt-Universität zu Berlin, Thaer-Institute of Agricultural and Horticultural Sciences, Invalidenstraße 42, 10099, Berlin, Germany.
Heliyon. 2024 Jul 19;10(15):e34822. doi: 10.1016/j.heliyon.2024.e34822. eCollection 2024 Aug 15.
Erosion-induced topsoil dilution strongly affects cropland biogeochemistry and is associated with a negative effect on soil health and crop productivity. While its impact on soil C cycling has been widely recognized, there is little information about its impact on soil N cycling and N fertilizer dynamics. Here, we studied three factors potentially influencing N cycling and N fertilizer dynamics in cropping systems, namely: 1.) soil type, 2.) erosion-induced topsoil dilution and 3.) N fertilizer form, in a full-factorial pot experiment using canola plants. We studied three erosion affected soil types (Luvisol, eroded Luvisol, calcaric Regosol) and performed topsoil dilution in all three soils by admixing 20 % of the respective subsoil into its topsoil. N fertilizer dynamics were investigated using either mineral (calcium ammonium nitrate) or organic (biogas digestate) fertilizer, labeled with N. The fertilizer N recovery and the distribution of the fertilizer N in different soil fractions was quantified after plant maturity. Fertilizer N dynamics and utilization were influenced by all three factors investigated. N recovery in the plant-soil system was higher and fertilizer N utilization was lower in the treatments with diluted topsoil than in the non-diluted controls. Similarly, plants of the organic fertilizer N treatments took up significantly less fertilizer N in comparison to mineral fertilizer treatments. Both topsoil dilution and organic fertilizer application promoted N recovery and N accumulation in the soil fractions, with strong differences between soil types. Our study reveals an innovative insight: topsoil dilution due to soil erosion has a negligible impact on N cycling and dynamics in the plant-soil system. The crucial factors influencing these processes are found to be the choice of fertilizer form and the specific soil type. Recognizing these aspects is essential for a precise and comprehensive assessment of the environmental continuum, emphasizing the novelty of our findings.
侵蚀导致的表土稀释对农田生物地球化学有强烈影响，并与土壤健康和作物生产力的负面影响相关。虽然其对土壤碳循环的影响已得到广泛认可，但关于其对土壤氮循环和氮肥动态的影响却知之甚少。在此，我们在一项使用油菜植株的全因子盆栽试验中，研究了可能影响种植系统中氮循环和氮肥动态的三个因素，即：1.）土壤类型，2.）侵蚀导致的表土稀释，以及3.）氮肥形态。我们研究了三种受侵蚀影响的土壤类型（淋溶土、侵蚀淋溶土、石灰性初育土），并通过将各自20%的底土混入表土，对所有三种土壤进行表土稀释。使用标记氮的矿物肥料（硝酸钙铵）或有机肥料（沼气消化液）来研究氮肥动态。在植株成熟后，对肥料氮的回收率以及肥料氮在不同土壤组分中的分布进行了量化。所研究的所有三个因素均影响肥料氮的动态和利用。与未稀释的对照相比，表土稀释处理的植物 - 土壤系统中氮回收率更高，肥料氮利用率更低。同样，与矿物肥料处理相比，有机肥料氮处理的植株吸收的肥料氮显著更少。表土稀释和有机肥料施用均促进了土壤组分中氮的回收和积累，不同土壤类型之间存在显著差异。我们的研究揭示了一个创新性的见解：土壤侵蚀导致的表土稀释对植物 - 土壤系统中的氮循环和动态影响可忽略不计。发现影响这些过程的关键因素是肥料形态的选择和特定的土壤类型。认识到这些方面对于精确和全面评估环境连续体至关重要，凸显了我们研究结果的新颖性。
