Abstract:

To solve the failure of coexistence between rice and earthworm in conventional flat planting, we proposed an earthworm raising technique under rice ridge cultivation and explored its effects on rice growth and grain yield. A field experiment was conducted with the treatments of conventional rice ridge cultivation (CK), rice ridge planting with earthworm raising at a density of 20 g·m^-2 (RE1), 40 g·m^-2 (RE2) and 60 g·m^-2 (RE3). The growth properties of shoots and roots of the plants, grain yield, and the formation of yield were investigated. The results showed that, during grain filling stage, aboveground biomass of RE3, RE2, and RE1 was increased by 10.81%-13.70%, 9.14%-12.44%, and 7.23%-8.82%, while leaf area index was increased by 8.39%-14.40%, 6.33%-10.94%, and 7.02%-10.34%, respectively. Rice ridge planting with earthworm raising increased root biomass, root/shoot ratio and the number and volume of roots, decreased malonaldehyde content in flag leaves after full heading, and enhanced SOD and POD activities in flag leaves. The SPAD of flag leaves after earing and bleeding sap in roots were kept at a higher level, and the aging of flag leaves was retarded. The plant dry matter after earing was effectively enhanced, laying the foundation for a stable and high yield. Moreover, RE2 and RE3 had better performance than RE1 in belowground and aboveground growth of rice plants.

Key words: rice, ridge planting, earthworm, yield, leaf area index, root growth.