Poultry litter composting and its effects on the occurrence of clubroot

This study aimed to evaluate the effects of the application of poultry litter with different composting times on the occurrence of clubroot and the development of cauliflower plants. Plots inoculated with Plasmodiophora brassicae (Pb) and fertilized with non-composted poultry litter (PL-0 + Pb) and with poultry litter composted for 15 (PL-15 + Pb) and 30 days (PL-30 + Pb), were tested. As control treatments, we used inoculated plots without poultry litter (Control + Pb), non-inoculated plots (NI) and treated with composted poultry litter for 30 days (PL-30 - NI), and without poultry litter (Control - NI). The degree of stabilization and maturation of the poultry litter affected the severity of the clubroot, the volume and mass of healthy roots and galls, and shoot growth. The treatments PL-15 + Pb and PL-30 + Pb were equivalent to Control + Pb in terms of disease intensity. In the presence of the pathogen (Pb), the application of PL-15 resulted in the lowest volume and mass of healthy roots and shoot mass. The PL-0 treatment was equivalent to the non-inoculated treatments. Further studies are needed to elucidate the processes and interactions related to the effect of maturation of poultry litter composts on root infection and the occurrence of clubroot.