不同刈割频度对绵毛优若藜地上生物量及根系的影响

采用盆栽试验,研究了不同刈割频度对绵毛优若藜地上生物量和根系的影响.结果显示:(1)不同刈割处理下绵毛优若藜地上生物量及其营养成分百分含量差异极显著(P<0.01),地上生物量随刈割频度增大呈先增大后减小,其1次刈割生物量最大,单株均值高达5.63g;随刈割次数增加其地上部分的粗脂肪和粗蛋白百分含量均极显著提高,而粗纤维和粗灰分的百分含量则均极显著降低.(2)与不刈割相比,不同频度的刈割均能使根系生物量、根系体积总量和主根直径减少,并随着刈割频度的增大显著减少.(3)刈割显著抑制植株主根伸长,也限制侧根发生,使整个根系在土壤中的分布因刈割频度增大而逐渐变浅,刈割频度≤1时,植物根系主要分布在0～30cm的土层中;刈割频度≥2时,植物根系基本分布在0～20cm的土层中.试验结果说明,绵毛优若藜在民勤沙区适应低频度刈割管理,即1年刈割1次,其地上生物量最大,而根系受影响最小.

Effect of Cutting Frequency on Overground Biomass and Root System of Ceratoides lanata (Pursh) Howell

Based on potted plant test,the effects of different cutting frequency treatments on overground biomass and root system of Ceratoides lanata(Pursh) Howell were studied.The results showed that(1) cutting had remarkable effect on biomass and nutrition percent contents of overground part of the plant.With increasing of cutting frequencies,the overground biomass augmented firstly and then minished.The biggest biomass(5.63 g per plant) was obtained by cutting one time.With the increasing of cutting frequencies,the percent contents of rough fat and rough fibre improved all through,and that of rough protein and rough ash debased contrarily.(2) Comparing with zero-cutting,all of the cutting treatments such as T1,T2,T3,made the total volume,total biomass and mean diameter of plant roots decreased,and the trend of decrease was obviously with the increasing of cutting frequencies.(3)Cutting reduced the growth of plant taproot evidently,also restrained bourgeon of the secondary roots.The distribution of root system in soil became superficial due to the increasing of cutting frequencies.Most of plant roots distributed in soil from 0 to 30 cm after zero or one time cutting,but most of the roots distributed in soil from 0 to 20 cm after cutting two or more times.It indicates that C.lanata is suitable for manegment with one time cutting each year in Minqin,the overground biomass of plant is the biggest,and the influence of root system suffered is the smallest.