A three-year field study was conducted to evaluate the impact of two different agro-industrial byproducts on soil properties, provisioning services, olive quality and production in a traditional rainfed olive grove to assess suitable management options for recycling organic wastes and reduce the use of inorganic fertilizers. The organic amendments consisted of compost (AC), made from residues from the olive oil industry (“alperujo”), and biosolid compost (BC), constituted of wastewater sludge and green waste from parks and gardens. The compost addition enhanced carbon storage, available phosphorous and potassium content overtime, whereas no effect was detected on soil hydraulics, yield and olive trees growth, partly due to the high variability encountered among plots. Beneficial effects, especially carbon storage, were more evident during the fourth sampling, where carbon content increased by almost 40% for BC, suggesting that compost effects need to be evaluated in the long term. Strong seasonal changes of most of the physico-chemical parameters were detected, and therefore the effect of the compost could have been partly masked. Establishing a non-climatic variation scenario would be advisable to fully detect compost effects. Our results suggest that different agro-industrial byproducts could be potentially viable and valuable source of fertilization, favoring in this way a circular economy of zero waste.

中文翻译：

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农业工业和城市堆肥作为地中海条件下传统雨养橄榄林中无机肥料的替代品

进行了一项为期三年的实地研究，以评估两种不同的农工业副产品对传统雨养橄榄林中土壤特性、供应服务、橄榄质量和产量的影响，以评估回收有机废物的合适管理方案并减少使用无机肥料。有机添加物包括堆肥 (AC)，由橄榄油工业 (“alperujo”) 的残留物制成，以及生物固体堆肥 (BC)，由来自公园和花园的废水污泥和绿色废物构成。堆肥添加增加了碳储存、有效磷和钾含量随时间的推移，而没有检测到对土壤水力学、产量和橄榄树生长的影响，部分原因是地块之间遇到的高度可变性。有益效果，尤其是碳储存，在第四次采样期间更明显，其中 BC 的碳含量增加了近 40%，这表明需要长期评估堆肥效果。检测到大部分物理化学参数的强烈季节性变化，因此堆肥的影响可能被部分掩盖。建议建立非气候变化情景以充分检测堆肥效应。我们的研究结果表明，不同的农工业副产品可能是可行且有价值的施肥来源，以这种方式有利于零浪费的循环经济。因此，堆肥的影响可能会被部分掩盖。建议建立非气候变化情景以充分检测堆肥效应。我们的研究结果表明，不同的农工业副产品可能是可行且有价值的施肥来源，以这种方式有利于零浪费的循环经济。因此，堆肥的影响可能会被部分掩盖。建议建立非气候变化情景以充分检测堆肥效应。我们的研究结果表明，不同的农工业副产品可能是可行且有价值的施肥来源，以这种方式有利于零浪费的循环经济。