Organic amendment and minimum tillage in winter wheat grown in Mediterranean conditions: effects on yield performance, soil fertility and environmental impact

The experiment was conducted to evaluate the agronomic benefit of the application of organic fertilizerscombined with different soil tillage on quantitative and qualitative components of winter wheat (Triticumdurum Desf., cv. ‘Simeto’) and on chemical soil fertility parameters. The environmental impact, due toheavy metals introduced in soil-plant system, was further investigated. Soil tillage treatments consistedof conventional (CT) and minimum tillage (MT). Fertilization treatments were: mineral at 100 kg N ha−1(Nmin); municipal solid waste compost at 100 kg N ha−1(Ncomp); 50 kg N ha−1of both compost and min-eral fertilizers (Nmix); sewage sludge at 100 kg N ha−1(Nss). These treatments were compared with anunfertilized control (N0). No significant difference was observed between the two soil tillage treatmentsfor quantitative yield production, while among the fertilization treatments Nssdid not show any signif-icant difference compared to Nmin. At the end of the research, the fertility of the soil (oxidable carbon,total nitrogen, available phosphorus) was on average higher in Ncompand Nsstreatments compared to theN0and Nminones. The overall distribution of heavy metals in soil-plant system respect to the differentfertilizer treatments has not allowed to grouped their effects with Principal Components Analysis. Thisresult showed that the amount of potential pollutants applied by organic amendments did not modifiedthe dynamic equilibrium of the soil–plant system. The MT, as well as the fertilization with the applicationof sewage sludge (Nss), allowed to reach productive performance similar to conventional management(CT with Nmin). Here we demonstrate that, in the short term period, sustainable agronomical techniquescan replace the conventional one with environmental benefit.