Aggregate stability strongly affects many soil processes and is critical to maintain sustainable agriculture. Aggregate breakdown is controlled by the interaction between soil intrinsic properties and solution characteristics. Nitrogen fertilization including different forms is well known to influence aggregate stability; however, relative to their long-term effects, there is little recognition on the rapid response of aggregate breakdown to nitrogen solutions. This study aimed to examine the effects of nitrogen form and concentration on aggregate stability for different types of soils. Aggregate breakdown against slaking of three soil types (Phaeozem, Luvisol, and Acrisol) and three horizons (organo-mineral (A), illuvium (B), and parent material horizons (C)) was determined subjected to nitrogen solutions of three forms (CO(NH2)2, NH4+, NO3–) and five concentrations (0.05 ∼ 1.0 mol/L). Among nitrogen forms, urea solution almost had non-significant effect irrespective of soil type and horizon (p > 0.05); for NH4+ and NO3– solutions, aggregate stability showed little variations (MWD of 0.19 ∼ 0.26 mm) with electrolyte concentration for Phaeozem in B and C horizons, overall increased for Luvisol and Phaeozem in A horizon, and decreased first and then reached a steady state for Acrisol. The effects of nitrogen forms on aggregate breakdown were dependent on soil aggregation status or cementing agents (mainly organic matter, clay mineralogy). Electrolyte nitrogen solutions (NH4+ and NO3–) inhibited aggregate breakdown mainly through reducing electrostatic repulsive forces for moderately developed soils rich in swelling clays, and promoted aggregate breakdown by both weakening particle cohesion and enhancing compression pressure of entrapped air for highly developed soils rich in non-swelling clays and Fe/Al oxides. These results facilitate an improvement of fertilizer management and irrigation to improve soil quality on different soil types.

中文翻译：

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不同土壤类型在溶液中分解成氮形式的聚集体分解的不同响应


骨料稳定性强烈影响许多土壤过程，对于维持可持续农业至关重要。骨料分解由土壤内在特性和溶液特性之间的相互作用控制。众所周知，氮肥（包括不同形式的氮肥）会影响骨料稳定性;然而，相对于它们的长期影响，人们对聚集体分解对氮溶液的快速响应知之甚少。本研究旨在研究氮形式和浓度对不同类型土壤团聚体稳定性的影响。在三种形式 （CO（NH2）2、NH4+、NO3–） 和五种浓度 （0.05 ∼ 1.0 mol/L） 的氮溶液下，测定三种土壤类型 （Phaeozem、Luvisol 和 Acrisol） 和三个层 （有机矿物 （A）、illuvium （B） 和母质层 （C）） 的团聚体分解。在氮形式中，尿素溶液几乎不考虑土壤类型和层级，影响不显著（p > 0.05）;对于 NH4+ 和 NO3– 溶液，聚集体稳定性随 B 和 C 层 Phaeozem 的电解质浓度变化不大（MWD 为 0.19 ∼ 0.26 mm），Luvisol 和 Phaeozem 在 A 层总体上增加，Acrisol 先下降然后达到稳定状态。氮形式对团聚体分解的影响取决于土壤聚集状态或胶结剂（主要是有机质、粘土矿物学）。 电解质氮溶液（NH4+ 和 NO3–）主要通过降低富含溶胀粘土的中等发育土壤的静电排斥力来抑制骨料分解，并通过削弱颗粒内聚力和提高滞留空气的压缩压力来促进骨料分解对于富含非溶胀粘土和 Fe/Al 氧化物的高度发育土壤。这些结果有助于改进肥料管理和灌溉，以改善不同土壤类型的土壤质量。