头季稻刈割时期对粮饲型再生稻饲草和再生稻产量、品质及经济效益的影响

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

【目的】探究头季稻不同刈割时期对粮饲型再生稻饲草和再生稻产量、品质及经济效益的影响,为粮饲型再生稻的高产优质高效种植及南方稻区解决粮饲争地、实现粮饲统筹提供理论依据和技术支撑。【方法】以我国南方稻区大面积作为再生稻种植的品种两优6326和桃优香占为试验材料,设开花期、乳熟期和蜡熟期3个头季刈割时期,分析头季饲草和再生季稻米的产量和品质差异,并对粮饲型再生稻模式的经济效益进行综合评价。【结果】随着刈割时期的推迟,头季干饲草产量逐渐增加,在蜡熟期刈割时最高,两优6326和桃优香占分别达9.17和10.35 t/ha。青贮饲草的饲用品质变化趋势与干饲草产量一致,刈割时期越晚,发酵品质越优,相对饲用价值越高,且在蜡熟期刈割时青贮饲草的中性洗涤纤维含量等发酵品质指标均达GB/T 25882—2010《青贮玉米品质分级》优质二级标准。再生季水稻产量在开花期刈割时最高,两优6326和桃优香占分别达8.94和8.92 t/ha,之后随着刈割时期的推迟逐渐降低。随刈割时间推迟,再生季稻米各品质指标变化趋势不尽相同,但各刈割处理下的整精米率、直链淀粉含量和垩白度表现达到或接近GB/T 17891—2017《优质稻谷》二级标准。再生季稻谷经济收益大幅高于头季饲草,2个品种的总收益、净收益和产出投入比在开花期刈割时最高,平均分别达36755元/ha、17450元/ha和1.90,并随着刈割时期的推迟逐渐降低。【结论】以高产优质饲草生产为目的,头季宜在蜡熟期刈割;以高产优质稻米生产为目的,头季宜在开花期刈割,且该模式在开花期刈割时的总体经济效益最高。

【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 Taoyou-xiangzhan,were used as materials.The field experiment was carried out in three mowing time treatments,namely flowe-ring,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(9.17 and 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 sea-son 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 treat-ments reached or closed to the second grade according to the standard of GB/T 17891-2017 High Quality Rice.The eco-nomic benefit of rice in the ratoon season was much higher than that of forage in the main season,resulting in the total in-come,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 dual-purpose ratoon rice system.