The final disposal of sewage sludge (SS) in agricultural areas is considered economically and environmentally viable, but few studies on the effects of sludge stabilization processes on SS fertilizing potential are available. The present study evaluated two forms of SS stabilization on the shoot biomass, yield, and concentration of nutrients in the soil and plants in three successive maize croppings. The raw sludge was chemically stabilized (CSS) and composted (TSS) through the addition of calcium oxide and co-composting with plant residues, respectively. Five rates of each type of SS (0, 10, 20, 30, and 40 t ha −1 dry weight) were applied to the soil in a family farm of NE Brazil. A mineral fertilization treatment was used to assess the SS fertilizer potential. Changes in soil chemical characteristics (pH, organic matter, and nutrient available contents), plant mineral composition, and maize biomass and yield were assessed at each crop cultivation. Applying sewage sludge to the soil elevated the soil organic matter and the availability of N, P, Fe, Mn, Zn, and Cu, reflecting in higher accumulation of these nutrients by plants. The CSS was more efficient in increasing soil pH than SS composting. In the first harvest, maize yield in CSS was 34% higher than that obtained with mineral fertilization. The two types of sludges had different effects on soil characteristics, plant mineral composition, and maize yield. The CSS residual effect on soil pH can dismiss soil liming. Composted sludge maintained higher soil organic matter levels in the soil with the successive croppings and promoted higher soil N concentrations in the first two croppings. Both sludges increased and maintained adequate available P concentrations in the soil throughout the successive crops. The results support SS’s efficiency in providing nutrients to plants, improving soil properties, and boosting crop productivity in low-input agriculture systems.

中文翻译：

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污水污泥稳定化工艺对连作玉米土壤肥力、矿物质成分和籽粒产量的影响

农业地区污水污泥 (SS) 的最终处置被认为在经济和环境上都是可行的，但关于污泥稳定过程对 SS 施肥潜力的影响的研究很少。本研究在三个连续的玉米作物中评估了两种形式的 SS 稳定对土壤和植物中地上部生物量、产量和养分浓度的影响。原料污泥分别通过添加氧化钙和与植物残渣共同堆肥进行化学稳定 (CSS) 和堆肥 (TSS)。在巴西东北部的一个家庭农场中，将每种类型的 SS（0、10、20、30 和 40 吨公顷 -1 干重）的五种比率施用于土壤。矿物施肥处理用于评估 SS 肥料潜力。土壤化学特征（pH、有机质、和养分有效含量）、植物矿物质组成、玉米生物量和产量在每种作物种植中进行评估。将污水污泥施用于土壤提高了土壤有机质和 N、P、Fe、Mn、Zn 和 Cu 的可用性，这反映在植物对这些养分的更高积累上。CSS 在提高土壤 pH 值方面比 SS 堆肥更有效。在第一次收获中，CSS 中的玉米产量比矿物施肥高 34%。两种污泥对土壤特性、植物矿物成分和玉米产量有不同的影响。CSS 对土壤 pH 的残留效应可以消除土壤石灰。随着连续种植，堆肥污泥在土壤中保持较高的土壤有机质水平，并在前两次种植中促进了更高的土壤氮浓度。在整个连续作物期间，两种污泥都增加并保持了土壤中足够的有效磷浓度。结果支持 SS 在为植物提供养分、改善土壤特性和提高低投入农业系统作物生产力方面的效率。