Effects of mowing time of rice in main season on yield, quality and economic benefit of forage-grain dual-purpose ratoon rice

【Objective】To explore the effects of mowing time of rice in main season on yield,quality,and economic benefit of forage-grain dual-purpose ratoon rice,so as to provide theoretical and technical support for production of this rice cropping system with high yield, quality, and efficiency and balancing cereal production and livestock farming in southern China. 【Method】Two rice cultivars widely grown for ratoon rice in southern China,Liangyou 6326 and Taoyouxiangzhan,were used as materials. The field experiment was carried out in three mowing time treatments,namely flowering,milk,and dough stages. The yield and quality of forage in the main season and those of rice in the ratoon season were determined,and the economic benefits of two seasons were evaluated. 【Result】With the postponement of mowing time,the yield of dry forage in the main season increased,and the highest yield of Liangyou 6326 and Taoyouxiangzhan(9.17and 10.35 t/ha) reached when the main season was mowed at the dough stage. The change of quality of silage forage was consistent with the yield of dry forage. The later the mowing time was,the better the fermentation qualities were and the higher the relative feed value was. The fermentation qualities such as detergent fiber content neutral of silage forage reached the second grade according to the standard of GB/T 25882-2010 Silage Maize Quality Grade when the main season was mowed at the dough stage. The yield of rice in the ratoon season decreased with the postponement of mowing time,and the highest yield of Liangyou 6326 and Taoyouxiangzhan(8.94 and 8.92 t/ha) reached when the main season was mowed at the flowering stage. Although inconsistent differences in qualities of rice in the ratoon season were found among different mowing times as mowing time postponed,the head rice rate,amylose content and chalkiness of all treatments reached or closed to the second grade according to the standard of GB/T 17891-2017 High Quality Rice. The economic benefit of rice in the ratoon season was much higher than that of forage in the main season,resulting in the total income,net income,and output-input ratio of the two seasons for two varieties were decreased with the postponement of the mowing time,and the highest total income,net income,and output-input ratio reached 36755 yuan/ha,17450 yuan/ha,and 1.90,respectively,when the main season was mowed at the flowering stage. 【Conclusion】The main season should be mowed at the dough stage if the goal is to produce forage with high yield and high quality,whereas the mowing time should be advanced to the flowering stage if the goal is changed to produce rice grain with high yield and high quality.When the main season is mowed at the flowering stage,the economic benefit is the highest for the forage-grain dualpurpose ratoon rice system.