刈割和施氮对饲用玉米生物量构成与可溶性糖分配的影响

Effects of Defoliation and Nitrogen Application on Biomass Composition and Soluble Sugar Distribution of Forage Maize

本试验采用田间裂区试验结合室内分析方法,研究了不同刈割强度和施氮水平对中原单32号饲用玉米生物量构成与可溶性糖分配的影响。结果表明,玉米根、茎、鞘及地上累积生物量随刈割强度增大显著降低(P<0.05),而叶的累积生物量在轻度刈割条件(20%)下略有增加。随着刈割强度增大,玉米茎的可溶性糖含量逐渐下降,而叶片可溶性糖含量却呈现上升趋势,根和鞘的可溶性糖含量先增加后减少。刈割处理下施氮8g能够在一定程度上弥补玉米地上部分营养物质的损失。二因素方差分析结果表明,刈割对玉米各器官累积生物量都有极显著影响(P<0.01),施氮仅对地上累积生物量影响不显著(P>0.05),而刈割和施氮的互作效应仅对玉米根、茎、叶累积生物量有极显著影响(P<0.01)。不论何种处理,均对玉米根冠比有极显著影响(P<0.01)。综上所述,刈割对饲用玉米生物量构成和可溶性糖的分配有显著影响,并最终影响玉米产量形成;刈割后高水平施氮有助于玉米进行补偿性生长。

In this study,field split block design and laboratory analysis were used to determine the biomass composition and soluble sugar distribution of forage maize(Zhong yuandan 32)under different defoliation intensities and nitrogen application levels.The results indicated that defoliation treatments significantly decreased the accumulative biomass of root,stem,sheath and total accumulative aboveground biomass(P<0.05),while the accumulative biomass of leaf increased slightly in the condition of light defoliation.With the increase of defoliation intensity,the content of soluble sugar in stem gradually decreased but increased in leaf.In addition,the soluble sugar content in root and sheath firstly increased and then decreased.The loss of nutrient substances in aboveground part of maize by defoliation resulted could be partly compensated by nitrogen application(8g/plant).Two-way ANOVA analysis showed that defoliation had a significant(P<0.01)effect on the accumulative biomass of each organ of maize.Nitrogen application had a significant effect on the accumulative biomass of each organ except accumulative aboveground biomass(P>0.05).But the interaction effects of defoliation and nitrogen application only had a significantly effect on the accumulative biomass of root,stem and leaf of maize(P<0.01).The root/shoot ratio of maize was significantly affected by all treatments(P<0.01).In general,defoliation had a great influence on the biomass composition and soluble sugar distribution of forage maize,and could finally affect the maize yield formation.High nitrogen application after defoliation treatment could help to establish compensatory growth of maize.