耕作措施对宿根甘蔗产量、碳排放及经济效益的影响

Effects of tillage practices on yield,carbon emissions and economic benefits of ratoon sugarcane

以宿根甘蔗生产体系为研究对象,探讨不同耕作措施对甘蔗产量、碳排放和经济效益的影响,为指导甘蔗绿色低碳高效生产提供科学依据。2021—2023年在粤西蔗区进行了连续两年宿根甘蔗生产试验,设置4种耕作措施:CK(不施肥对照)、FP(常规施肥)、DF(水肥一体化)、DF+S(水肥一体化+蔗叶覆盖还田),分析不同耕作措施下土壤理化性质、甘蔗产量、肥料偏生产力、碳排放量及经济效益等指标。结果表明:与基础土壤相比,FP处理的土壤氮磷钾有效养分出现一定程度的盈余。DF+S处理的土壤有机质、速效钾和交换性镁含量较DF处理分别增加16.1%、16.1%和28.8%,表明蔗叶覆盖还田能一定程度培肥地力。与FP相比,DF和DF+S处理的甘蔗产量(两年平均)分别显著提高15.2%和27.8%,氮肥、磷肥和钾肥偏生产力分别显著提高107.6%和130.3%、41.6%和57.1%、145.7%和172.5%,氮肥、磷肥和钾肥利用率分别显著提高92.6%和127.7%、30.1%和48.3%、85.3%和119.6%,碳排放量分别减少22.3%和75.6%,碳足迹分别显著降低32.8%和80.9%,净收益分别增加4.3倍和9.8倍。与DF相比,DF+S处理的甘蔗产量和经济效益分别增加10.9%和103.2%,而碳排放和碳足迹分别显著降低68.6%和71.7%,净生态系统经济效益得到进一步提升。综上,水肥一体化较常规施肥管理既能减少肥料施用量,还能提高肥料利用率和产量、增加收益、降低碳排放,是一种绿色低碳高效的栽培措施。另外,水肥一体化结合蔗叶覆盖还田的增产增效减排效果显著,净生态系统效益增强,在有条件的蔗区可作为宿根甘蔗减排增效的一种重要耕作管理措施。

The sugarcane yield,carbon emissions,and economic benefits of the ratoon sugarcane production system were studied under different tillage practices to provide a scientific basis for guiding the green,low-carbon,and efficient production of sugarcane.A field ratoon sugarcane experiment was conducted on two consecutive ratoon sugarcane crops from 2021 to 2023 in the western Guangdong sugarcane farming area under four tillage practices:control treatment with no fertilizer(CK),farmer practice(FP),integration of water and fertilizer(DF),and integration of water and fertilizer+sugarcane leaf return and mulching(DF+S).In addition,the following were analyzed:soil physical and chemical properties,sugarcane yield,partial factor productivity,fertilizer use efficiency,carbon emissions and footprint,and economic benefits.The results showed that,after two years,the available nutrients of nitrogen,phosphorus,and potassium increased in soils on the sample farms,indicating that the amount of fertilizer applied through farmer practice may be excessive,posing an environmental pollution risk.Compared with the DF treatment,the soil organic matter,available potassium,and exchangeable magnesium content in the DF+S treatment increased by 16.1%,16.1%,and 28.8%,respectively,indicating that sugarcane leaf mulching can improve soil fertility.Compared with the FP treatment,the yield(over an average of two years)significantly increased by 15.2%and 27.8%in DF and DF+S treatments,respectively.Meanwhile,the partial factor productivity of nitrogen,phosphorus,and potassium fertilizers for the DF and DF+S treatments significantly increased by 107.6%and 130.3%,41.6%and 57.1%,and 145.7%and 172.5%,respectively.For the same treatments,the use efficiency of nitrogen,phosphorus,and potassium fertilizers significantly increased by 92.6%and 127.7%,30.1%and 48.3%,85.3%and 119.6%,respectively.However,carbon emissions decreased by 22.3%and 75.6%,respectively,and carbon footprints significantly decreased by 32.8%and 80.9%,respectively.Consequently,net income increased by 4.3 and 9.8 times,respectively.Moreover,compared with the DF treatment,the yield and net income of the DF+S treatment increased by 10.9%and 103.2%,respectively,whereas carbon emissions and carbon footprints significantly decreased by 68.6%and 71.7%,respectively,which improved the net economic ecosystem budget.Compared to FP,this demonstrated that the integration of water and fertilizer not only reduced fertilizer application but also improved fertilizer use efficiency and yield,resulting in higher profits and lower carbon emissions,indicating a green,low-carbon,and high-efficiency tillage practice.In addition,the integration of water and fertilizer+sugarcane leaf return and mulching significantly increased yield and net income and reduced carbon emissions,consequently improving the net economic ecosystem budget.This tillage practice in ratoon sugarcane production could,therefore,be recommended for simultaneously low carbon emissions,high efficiency,and resultant environmental and economic benefits.