Impact of fertilization and crop type on horticultural soil quality: A 3‐year, open‐field experiment

In many regions worldwide, horticulture is a soil‐based production system closely tied to small family farmers who often face socio‐economic challenges. In the peri‐urban area of Buenos Aires (Argentina), horticultural soils face significant degradation because of inadequate agricultural practices. At the same time, efforts are underway to design and implement alternative sustainable practices. Evaluating the effect of current and alternative practices on soil quality under controlled conditions is essential for ensuring food security and supporting the livelihoods of family farmers. In this area, family farmers commonly use poultry litter (PL) as a sole nutrient source or combined with mineral fertilizers (MF). Agroecological practices such as crop rotation, intercropping, and diversification with legumes and flowers are also being adopted. This study aimed to assess the effects of fertilization strategies and crop types on the physical, chemical and biological quality of an Aquic Argiudol soil under continuous horticultural use. A 3‐year open field experiment compared the impacts of the fertilization strategies, PL, MF and no fertilization (CRL), and the crop types, vegetables (lettuce, beet and fava beans) and flowers (snapdragon and stock). Treatments were assigned to 4 m 2 plots, and soil samples (0–10 cm deep) were collected annually at harvest. Key indicators were monitored, including bulk density, aggregate stability (AS), pH, electrical conductivity, soil organic carbon (SOC), total nitrogen (TN), extractable phosphorus (EP), basal respiration (BR) and microbial biomass (MCB). Compared to CRL, PL significantly improved ( p < .05) SOC (15.8%), TN (18.0%), BR (53.6%) and MCB (76.4%), but also elevated EP (180.9%) to excessive levels and increased pH. In contrast, MF caused soil acidification. Legume inclusion improved ( p < .05) AS (18.6%) and MCB (31.0%), while reducing the pH (3.7%). These findings highlight the benefits of organic amendments and crop diversification for soil quality in intensive horticultural systems, while also underscoring the need for careful management to address risks such as nutrient accumulation and environmental impacts.