不同生态蔗区气候土壤差异对甘蔗生产的影响

Effects of key climate and soil factors on sugarcane production in different ecological regions in China

通过分析中国主产蔗区甘蔗综合实验站的气候和土壤差异、甘蔗产量和糖分差异,明确影响甘蔗大田生产的关键气候、土壤要素,探讨如何通过土壤改良和水肥优化管理提高甘蔗生产潜力,为促进甘蔗产业提质增效提供依据。通过收集云南、广西和广东3个主产蔗区5个代表站点2018~2019年甘蔗产量和糖分数据,测定土壤指标14项:有机质、碱解氮、有效磷、速效钾、pH、容重、总孔隙度、毛管孔隙度、饱和度、充气孔隙度、初始含水量、饱和含水量、田持含水量、有效含水量,比较耕作层(0~40 cm)、深层(40~80 cm)和底层(80~120 cm)各项土壤指标差异;综合分析不同生态蔗区气候、土壤因子与甘蔗产量和糖分间的相关性,明确影响甘蔗大田生产的关键指标,建立数学模型对甘蔗产量和糖分进行预测。不同生态蔗区站点的昼夜温差、降水量、蒸发量和日照时数年际变异显著,同一站点不同土层的养分指标差异显著,耕作层的有机质和有效氮、磷、钾含量显著高于其它两层;蔗区土壤为红壤,偏酸性(4.5<pH<6.0),各层土壤容重1.15~1.61 g·cm^(-3),有效含水量83~206 g·kg^(-1);土壤有机质含量6.67~22.48 g·kg^(-1),碱解氮含量37.56~96.97 mg·kg^(-1),有效磷含量0.42~37.84 mg·kg^(-1),速效钾含量58.90~171.12 mg·kg^(-1)。采用偏最小二乘回归分析筛选出对甘蔗产量、糖分综合影响较大且重要变量投影值>0.8的6个关键指标,分别为土壤萎蔫含水量、有效含水量、速效钾含量以及种植地海拔、降水量和蒸发量。上述变量构建的回归预测模型对甘蔗产量、糖分的拟合优度为0.79~0.97,相对误差为4.54%~5.61%。基于偏最小二乘法数学模型,采用种植地海拔、降水量和蒸发量等气候环境关键变量,以及土壤速效钾含量、萎蔫含水量和有效含水量等土壤水肥关键变量,可以对中国主产蔗区甘蔗产量和糖分进行较准确的预测。另外,建议今后除更新甘蔗良种外,还应注重提高蔗区土壤pH,加强中耕培土、合理施肥并提高钾肥比例,有利于实现甘蔗高产高糖。

By analyzing the climate and soil differences,sugarcane yield and sugar content differences of representative experiment stations in major sugarcane producing areas of China,the key climate and soil factors affecting sugarcane field production were clarified.Meanwhile,how to improve sugarcane production potential through soil improvement and optimal management of water and fertilizer was discussed,so as to provide reference for improving the quality and efficiency of sugarcane industry.By collecting sugarcane yield and sugar data from 5 representative sites in 3 main sugarcane producing areas i.e.,Yunnan,Guangxi,and Guangdong from 2018 to 2019,14 soil indicators were determined:organic matter,alkaline nitrogen,available phosphorus,available potassium,pH,bulk density,total porosity,capillary porosity,saturation,aerated porosity,initial water content,saturated water content,field holding water content and effective water content.These soil indicators in tillage layers(0~40 cm),deep layer(40~80 cm)and bottom layer(80~120 cm)were compared.The correlation between climatic and soil factors of different ecological sugarcane regions and sugarcane yield and sugar content,and the key indicators affecting sugarcane field production were analyzed comprehensively.A mathematical model to predict sugarcane yield and sugar content was established.The inter-annual variability of temperature difference,precipitation,evaporation and sunshine duration between different ecological sugarcane sites was significant,and the nutrient indicators of different soil layers at the same site were significantly different.The organic matter and available nitrogen,phosphorus and potassium contents of the farming layer were significantly higher than the other two layers.The soil in the sugarcane area is red soil,which is slightly acidic(4.5-3,and the effective water content was 83~206 g·kg^(-1),the soil organic matter content was 6.67~22.48 g·kg^(-1),the content of alkaline hydrolyzed nitrogen was 37.56~96.97mg·kg^(-1),the content of available phosphorus was 0.42~37.84 mg·kg^(-1),and the content of available potassium was 58.90~171.12 mg·kg^(-1).Partial least squares regression analysis was used to screen out six key indicators,including soil withering water content,effective water content,available potassium content,and planting altitude,precipitation and evaporation,which had a greater impact on sugarcane yield and sugar content and the important variable projection value>0.8.The regression prediction model constructed by the above variables had a goodness of fit for the sugar content of sugarcane yield which was 0.79 to 0.97,and the relative error was from 4.54%to 5.61%.Based on the mathematical model of the partial least squares method,the use of key climate and environmental variables such as altitude,precipitation,and evaporation,as well as key soil water and fertilizer variables such as soil available potassium content,wilting water content and effective water content,can predict relatively accurately the sugarcane field and sugar content.In addition,it is recommended that in addition to updating sugarcane varieties in the future,attention should also be paid to increasing the soil pH in the sugarcane area,strengthening soil cultivation,rational fertilization and increasing the proportion of potassium fertilizer,which is conducive to achieving high sugarcane yield and high sugar.