Experimental Design

Two rice cultivation treatments were established in the experiment: conventional rice cultivation without frogs (CR) and rice-frog cultivation (RF). In both the CR and RF fields, the same amount (300 kg N ha^–1) of nitrogen fertilizer was applied for each treatment. A randomized complete block experimental design was used with three replicates. A total of 12,000 frogs/ha were introduced into the RF paddy fields. Tiger frogs (Rana tigrina rugulosa), which are highly adaptable to the environment, were introduced and raised by the Zizaiyuan Agricultural Development Co., Ltd., Shanghai. At 15 days after rice transplantation, frogs large enough (≥20 g) to prey on pests were released into the paddy fields. In addition, the tiger frogs used in this study were managed in accordance with relevant guidelines and regulations of the Guide for the Care and Use of Laboratory Animals of the Ministry of Health, China. We domesticated and bred the tiger frogs with the permission of the Shanghai Forestry Bureau, and the license permission number was (2008) 419.