Arable and Livestock Corporation Trial in the Upland Fields of the Southern Kyushu Region: Confirmation of Nematode-Suppression by Introducing the Tropical Forage Palisade Grass into the Crop Rotation System

Nematode-suppressive tropical forage palisade grass （Urochloa brizantha） was introduced into the upland field crop rotation system, which was conducted in two fields in the southern Kyushu region. The crop rotation system was palisade grass–spinach–sweet potato–cabbage, hence this was a trial of arable and livestock corporation in the region. During the field crop rotation system experiments, conditions of fertilization and inter-row spacing, methods of seeding and inter-row management, and cultivation duration for palisade grass were modified. By these modifications, the forage nitrate content was improved, and the suitable cultivation system was clarified. After the cultivations of nematode-susceptible sweet potato cultivar “Koganesengan”, the root-knot nematode densities were increased. However, after every palisade grass cultivations, the nematode densities were suppressed to suitably low densities. The control manure of plant-parasitic nematode density by the introduction of forage crop palisade grass to the crop rotation system was demonstrated and confirmed.