Western Region Agricultural Research Center, NARO

In order to produce high quality mandarin oranges, controlling the soil moisture for increasing the sugar content of fruit and applying moderate drought stress are necessary. Therefore, the Western Region Agricultural Research Center has developed Marudori cultivation technology that combines drip fertigation with sheet mulching and has been working towards its popularization. However, there are some orchards where the fruit has low sugar content because the effect of mulch sheet is not sufficiently obtained when rain water enters the root part of citrus even if it is covered with mulch sheet or when the root spreads outside of mulch sheet. To enable the production of high-quality fruits even in such orchards, a shielding and mulching cultivation system (NARO S. Mulch) was developed by the Citrus Research Center (Shizuoka), NIFTS, NARO. In this cultivation technology, sheets that are waterproof and root-proof are buried in the ground surrounding rows of citrus trees. This prevents the inflow of rainwater into the root area and allows the root area to be collected within a controllable range of soil moisture. We are conducting verification tests to apply NARO S. Mulch to citrus orchards in the Chugoku and Shikoku regions.