Manure application and no‐till management improve soil quality, crop yields and C inputs, but little specific knowledge is available regarding the combined effect of long‐term dairy liquid manure (DLM) application and no‐till management on soil organic matter status and soil structure in topsoils. Here, we assess the impacts of surface‐applied DLM for a 10‐year period on soil total organic carbon (TOC) and nitrogen (TN) concentrations and stocks, on organic matter fractions and on soil physical‐structural attributes in a no‐till crop rotation system on clayey Ferralsol under no‐till crop rotation management in a subtropical climate. Four rates of DLM (0, 60, 120 and 180 m³ ha⁻¹ year⁻¹) were applied in a randomized block design with four replications. Soil samples were collected to calculate TOC and TN stocks to 100‐cm depth and organic matter fractions in the 0–5‐cm layer, and physical indicators of soil quality: bulk density, macroporosity and microporosity and aggregate stability. The largest DLM rates (120 and 180 m³ ha⁻¹ year⁻¹) added 3.8–5.8 Mg C ha⁻¹ year⁻¹ as manure, increased crop residue input by 0.6 Mg C ha⁻¹ year⁻¹, and increased TOC stock by 17% and TN stock by 27% in the top 10 cm of soil, at annual accumulation rates that averaged 0.72 Mg C ha⁻¹ year⁻¹ and 86 kg N ha⁻¹ year⁻¹. Stocks of TOC and TN in the sand‐POM (particulate organic matter) fraction under the 180 m³ ha⁻¹ year⁻¹ rate increased by 49 and 63%, and in the silt‐MOM (mineral‐associated organic matter) fraction by 30 and 47%, respectively. In the clay‐MOM fraction, the change in TOC was not significant, but the TN increased by 16%. Soil physical‐structural attributes (bulk density, porosity and aggregates) were improved by DLM application in the 10‐cm layer and followed the soil carbon and nitrogen increments. Overall, the DLM amendment applied on the soil surface of no‐till proved to be a strategy to ameliorate soil organic matter status, an important factor for agronomic and environmental benefits, besides improving crop biomass production.

中文翻译：

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在免耕条件下长期将乳液肥料表面施用到土壤中可改善碳和氮储量

施用肥料和免耕管理可改善土壤质量，作物产量和碳输入量，但关于长期使用奶液肥料（DLM）和免耕管理对土壤有机质状况和土壤的综合影响的具体知识很少表土结构。在这里，我们评估了免耕耕作表面施用DLM 10年对土壤总有机碳（TOC）和氮（TN）浓度和储量，有机质含量以及土壤物理结构属性的影响。亚热带气候下免耕作物轮作下黏土Ferralsol的作物轮作系统。DLM的四种速率（0、60、120和180 m ³ ha - ¹年^-1）应用于四次重复的随机区组设计中。收集土壤样品以计算TOC和TN储量（深度为100cm）和0-5cm层中的有机物含量，以及土壤质量的物理指标：堆积密度，大孔隙度，微孔隙度和团聚体稳定性。最大的DLM速率（120和180 m ³ ha - ¹年^-1）增加了3.8-5.8 Mg C ha - ¹年^-1作为粪肥，增加了0.6 Mg C ha - ¹年^-1的农作物残渣输入量，并增加了TOC在土壤表层10 cm的年平均累积率分别为0.72 Mg C ha - ¹年^-1和86 kg N ha^-1年^-1。在180 m ³ ha - ¹年^-1以下的沙子-POM（颗粒有机物）部分中的TOC和TN存量含沙量增加了49％和63％，粉砂-MOM（矿物质相关有机物）的比例分别增加了30％和47％。在粘土-MOM分数中，TOC的变化不显着，但TN增加了16％。通过在10厘米厚的土壤层中施用DLM可以改善土壤的物理结构特征（堆积密度，孔隙率和聚集体），并随土壤碳和氮的增加而增加。总体而言，在免耕土壤表面应用DLM修正案被证明是改善土壤有机质状况的一种策略，这是改善农作物生物量生产的重要因素，对农业和环境效益具有重要意义。