Abstract: A doubleseason rice field trial was carried out in Liuyang City of Hunan to explore the effects of different cultivation methods on rice root characteristics and soil physical properties, with the aim to provide a basis for rice ridge cultivation techniques. The results showed that, compared with flat cultivation, ridge cultivation significantly increased total root length and root volume of early rice at the booting stage and root bleeding intensity at each stage of early rice and the peak tillering stage of late rice. The total length of roots, root surface area, and root volume of late rice at the full heading stage were significantly increased by 36.9%, 41.1%, and 44.9%. Furrow cultivation significantly reduced total root length and root volume of early rice at the peak tillering stage and full heading stage, and reduced root surface area at each stage of early rice by 40.6%-44.5%. Root bleeding intensity was significantly increased at the full heading stage of early rice, while significantly reduced at the booting stage of late rice. Compared with flat cultivation, soil bulk density of early rice in ridge cultivation and furrow cultivation was significantly reduced by 6.8%-10.6%, while total soil porosity and capillary porosity was increased by 7.2%-10.6% and 6.5%-10.4%, respectively. Ridge cultivation and furrow cultivation increased the average mass diameter of soil aggregates in early rice. Ridge cultivation and furrow cultivation increased the content of 0.25-2 mm water-stable aggregates in the soil of early rice and late rice, respectively, and reduced the content of water-stable aggregates of <0.053 mm in the soil of early rice and late rice, respectively. Ridge cultivation and furrow cultivation improved soil physical properties and increased yield of late rice. Ridge cultivation promoted and furrow cultivation hindered root growth and development of rice.

Key words: double-cropping rice, ridge cultivation, furrow cultivation, soil bulk density, soil aggregate, yield.