Effects of repeated organic amendment applications on soil and crop qualities

WOS:000392711300011

anglais. Soil application of organic waste products (OWP) favors the increase of soil organic matter (SOM) and biological activity, the recycling of nutrients and crop production, but it may also lead to soil contamination. All these effects may occur simultaneously and must be considered in the evaluation of the practice. Various urban composts and manure have been applied every second year in a long-term field experiment during 15 years. A soil sampling assessing the cumulative residual effects of seven applications was used to compare the impact on soil and crop quality of four OWP: a municipal solid waste compost (MSW), a co-compost of sewage sludge and green waste (GWS), a biowaste compost (BIO) and a farmyard manure (FYM). More than 100 different soil indicators were measured (including organic C, N availability, pH, POlsen, plasticity, microbial biomass, enzymatic activity, trace elements and crop yield) and classified in categories to explain soil functioning including crop production: soil fertility, soil biological activity, soil biodiversity, soil physical stability, soil sanitary status (available and total) and crop productivity. Based on these categories, seven minimum data sets (MDS) were defined using statistical analysis, in order to eliminate overlapping parameters and select significant indicators highlighting the effects of OWP compared with a mineral fertilization. The aim of this study was to evaluate the long-term effects of repeated OWP applications on the seven categories of indicators. The OWP were characterized by different qualities and properties of organic matter (OM), which drove their potential effects after application on cropped soils. The GWS and BIO were the most efficient OWP at increasing SOM content, which was one of the major drivers of the effects.