Mulching with Cynara cardunculus Residues Affects Selected Soil Properties, Weed Pressure and Potato Yield

The current trend toward sustainable agricultural practices requires to investigate alternatives to conventional soil management, which is mainly based on the intensive use of external inputs with high environmental impact. In this view, mulching with a layer of organic material on topsoil seems an attractive and sustainable alternative for soil management in different open-field crops. It shows several advantages, such as adding organic matter, regulating the soil's microclimatic conditions (temperature, moisture), and suppressing spontaneous weeds. However, there is no information on its impact on the 'early' potato (Solanum tuberosum L.), appreciated for its nutritional characteristics. To address this gap, a 2-year field experiment was conducted to evaluate the effect of organic mulching with Cynara cardunculus crop residues, a common herbaceous species in the Mediterranean Basin with high biomass production and allelopathic activity, on selected soil properties, weed control and tuber yield performances of two 'early' potatoes cultivars. The soil's total polyphenol content (TPC) was also taken into account to assess the presence of allelochemicals in the soil. The mulched plots maintained more soil humidity (+ 21%) and reduced both soil salinity (- 39%) and temperature (- 5%) compared with the no-mulched ones (control). Mulching enhanced also the soil TPC compared with the control (2.16 vs. 0.83 mg kg-1 of soil). Moreover, C. cardunculus mulching decreased both weed biomass and species richness, respectively by - 72 and - 40%, compared to the control. These positive effects probably allowed the increase of marketable tuber yield and mean tuber weight (+ 12 and + 39%, respectively) in mulched plots compared with the control. Overall, this research contributes to the development of a sustainable soil management practice by using C. cardunculus residues, with the purpose of improving organic 'early' potato cultivation.