保护地蔗田对土壤优先流与根系生物量及产量品质的影响

为探明保护性耕作对蔗田土壤及甘蔗生长的影响,该研究设置2种耕作方式(常规耕作、粉垄耕作)与2种施肥水平(减量施肥20%、常规施肥),并于甘蔗苗期后在甘蔗行间近根部覆盖豆科秸秆,以第二年宿根蔗为研究对象,采用染色示踪法测定秸秆覆盖下蔗田土壤优先流特征,同时测定分析甘蔗株高、茎围、地下根系生物量、产量及品质等重要农艺性状。结果表明:(1)粉垄耕作方式下蔗田土壤优先流发生速度快且活跃,添加秸秆覆盖降低了土壤优先流发生程度,增加了土壤水分在10～25 cm土层的横向运移能力,在一定程度上提高了土壤蓄水能力。(2)粉垄保护性耕作在秸秆覆盖下提高了甘蔗根系生物量和产量,秸秆覆盖下粉垄免耕宿根蔗根系生物量提高了8.97%～25.54%,并且减量施肥处理中秸秆覆盖宿根蔗伸长期地下根系生物量显著高于无秸秆覆盖,秸秆覆盖下甘蔗株高提高了4.2%～13.1%; 在减量施肥处理中,粉垄耕作添加秸秆覆盖甘蔗产量提高了16.27%,并且添加秸秆覆盖较常规施肥中无秸秆覆盖,产量提高了5.95%。(3)粉垄保护性耕作利于提高甘蔗品质,对比无秸秆覆盖处理,粉垄耕作下秸秆覆盖后显著提高了甘蔗蔗汁视纯度,并且宿根蔗纤维分、蔗汁锤度、转光度和蔗糖分均有提升。综上认为,免耕秸秆覆盖可作为粉垄红壤坡耕地蔗田保护性生产调控方式。

Effects of protected sugarcane field on soil preferential flow and root biomass and yield quality of sugarcane

In order to investigate the effects of conservation tillage on the soil and sugarcane growth in sugarcane field, the study set up two farming methods(conventional farming, smash ridging)and two fertilization levels(reduced fertilization by 20%, conventional fertilization), and covered leguminous straw near the roots between sugarcane rows after the sugarcane seedling stage, taking the second-year stubble cane as the object. The dyeing tracer method was used to determine the characteristics of preferential flow in the sugarcane field under straw mulching, and the study also determined and analyzed sugarcane plant height, stem circumference, underground root biomass, yield and quality and other important agronomic characteristics. The results were as follows:(1)The soil preferential flow in the sugarcane field under the smash ridging was fast and active. The addition of straw mulch reduced the degree of soil preferential flow, increased the lateral transport capacity of soil moisture in the 10-25 cm soil layer, and improved the soil water storage capacity to a certain extent.(2)Conservation tillage of smash ridging under straw mulching improved the root biomass and yield of sugarcane. The root biomass of no-tillage stubble cane under straw mulching increased by 8.97%-25.54%. Compared without straw mulching, the biomass of the underground root system during the elongation period of the straw mulching stubble cane increased by 4.2%-13.1% under the reduced fertilization treatment; In the weight loss treatment, the sugarcane yield increased by 16.27% under adding straw mulch and smash ridging coupling, and compared with conventional fertilization without straw mulching, the yield increased by 5.95% under adding straw mulching.(3)Smash ridging conservation tillage was beneficial to improve the quality of sugarcane. Compared with the treatment without straw mulching, the straw mulching under smash ridging tillage significantly improved the apparent purity of sugarcane juice, and the fiber, brix, pol and sucrose content were all improved. In summary, no-tillage straw mulching can be used as a protective production regulation method for sugarcane fields in smash ridging red soil slope farmland.