Mitigating salt stress in “Friariello Napoletano” (Brassica rapa subsp. sylvestris L. Janch. var. esculenta Hort.): The potential of biochar for sustainable agriculture

Abstract

The agricultural sector is therefore called upon to seek efficient and sustainable strategies to improve plant resilience and tolerance to sub-optimal growth conditions. In many coastal areas of the Mediterranean, saline stress causes serious problems to vegetable crops. In this scenario, the use of upgraded agrochemicals such as plant biostimulants, biochar and plant nutrition regulators could be beneficial. The aim of the study was to evaluate the effects of amending the soil with different concentrations of poplar-derived biochar (0 %, 1 % and 2 % by volume), on the productive and qualitative response of an ecotype of “Friariello Napoletano” (Brassica rapa subsp. sylvestris L. Janch. var. esculenta Hort.) under different levels of saline irrigation (0, 30, 60 and 120 mM NaCl, giving an electrical conductivity values of 0.05, 2.09, 6.09 and 9.70 dS m–1). The experiment was conducted in an unheated greenhouse, using pot plants grown in soil with a randomized complete-block experimental design arranged in a 4 × 3 factorial scheme with three replications. Productive and physiological results (ACO2, gs, E, SPAD index) highlighted a highly glycophytic response of Friariello. Biochar integration, besides increasing total production and glucosinolate content, led to a significant reduction in toxic ion content (Na+and Cl−) under saline conditions compared to control plants. Regardless of salinity effect, the application of biochar resulted in an increase in fresh yield and photosynthetic activity (ACO2) of 12.8 % and 29.3 % respectively. The promising results underscore the potential role of biochar as a sustainable strategy for mitigating salt stress in Friariello Napoletano and potentially other vegetable crops in salt-affected regions. However, it needs to be clarified which adaptive mechanisms triggered by biochar improves production performance even and especially under sub-optimal growing conditions.