抗重茬菌剂和双氰胺对华北夏玉米节根特性的影响

Effects of Anti-continuous Cropping Microbial Agents and Dicyandiamide on Brace Root Characteristics of Summer Maize in North China

以抗重茬微生物菌剂、双氰胺与尿素配施设置3种施肥处理(CK,常规施肥;T1,常规施肥+抗重茬微生物菌剂;T2,常规施肥+双氰胺),在夏玉米拔节期测定夏玉米节根形态、生物量、氮含量和根条数,明确不同施肥处理对夏玉米节根特性和产量的影响,为提高氮肥利用效率同时减少农业环境污染提供理论依据。结果表明:与CK处理相比,T1处理地上节根直径、生物量和数量分别显著增加25.82%、24.39%和75%,总根长显著降低50.39%;地下节根含氮量显著增加30.79%,体积显著减少23.24%。T1处理中节根生长指标仅受土壤pH值的显著影响。与CK处理相比,T2处理地上节根直径、生物量、含氮量和数量分别显著增加32.42%、57.32%、68.29%和100%,总根长显著降低30.34%;地下节根表面积、分枝数和含氮量分别显著增加36.75%、47.24%和36.07%。T2处理中节根生长指标受土壤铵态氮、有效磷和pH值的显著影响。T1和T2两处理显著改善了节根特性,提高了节根的吸收功能,其中地上节根反应更为敏感。综合比较两种模式,双氰胺的效果优于抗重茬微生物菌剂,显著提高了夏玉米有效穗数和秸秆干质量,但两种模式对产量的影响却不明显。

This study aimed to define the effects of different fertilization treatments on both nodal root characteristics and yield of summer maize. Furthermore, a theoretical basis was provided to increase nitrogen use efficiency, while simultaneously reducing agricultural environmental pollution. Anti-continuous cropping microbial agents, dicyandiamide, and urea were applied to three fertilization treatments（CK, T1, and T2）. The resulting nodal root morphology, biomass, nitrogen content, and root number of summer maize were determined at the jointing stage. The results indicated that compared to CK treatment, diameter, biomass, and number of aboveground nodal roots were significantly increased under T1 treatment by 25.82%, 24.39%, and 75%, respectively, while the total length significantly declined by 50.39%. Nitrogen content of underground nodal roots were significantly increased by 30.79%, while volume significantly declined by 23.24%. The growth indexes of nodal roots under T1 treatment were significantly affected by the soil pH value. Compared to CK treatment, diameter, biomass, nitrogen content and number of aboveground nodal roots were significantly increased under T2 treatment by 32.42%, 57.32%, 68.29% and 100%, respectively, while the total length significantly declined by 30.34%. The surface area, branch number, and nitrogen content of underground nodal roots were significantly increased by 36.75%, 47.24%, and 36.07%, respectively. The growth indexes of nodal roots under T2 treatment were significantly affected by ammonium nitrogen, available phosphorus and the pH value of soil. Treatments T1 as well as T2 significantly improved both the characteristics and the absorption function of nodal roots, while the reaction of aboveground nodal roots was more sensitive. A comprehensive comparison of the two modes showed that the effect of dicyandiamide was better than that of anti-continuous cropping microbial agents, as it significantly improved both the effective spike number and the dry weight of summer maize straw. However, both modes did not affect yield.