紫花苜蓿根系生物量

Alfalfa(Medicago sativa L.) Root Biomass

本文综述了紫花苜蓿(Medicagosativa L.)根系生物量的影响因子和若干自然区域内的紫花苜蓿根系生物量。影响紫花苜蓿根系生物量的影响因子包括土层厚度、地下水位、土壤特性、淹水、耕作、施肥、灌溉、刈割、生长调节剂、混播、植株密度、品种和生长年限。土壤障碍(酸、碱、盐、粘重和紧实)越重、土层越薄、地下水位越高,紫花苜蓿根系生物量越小。淹水降低紫花苜蓿根系生物量。深耕可增加紫花苜蓿根系生物量,播种当年效果尤为明显。施肥可增加紫花苜蓿根系生物量。灌溉可增加紫花苜蓿根系生物量,灌溉模式及灌溉量适当时可获得相对较大的根系生物量。刈割频率越高,紫花苜蓿根系生物量越低。添加生长调节剂可增加紫花苜蓿根系生物量。混播降低紫花苜蓿根系生物量。在一定范围内,紫花苜蓿根系生物量随着植株密度的增加而增加。不同品种(材料)的根系生物量存在一定差异。生长年限越长,紫花苜蓿根系生物量越大。在每个生长季内紫花苜蓿根系生物量呈逐渐提高趋势,但在返青之初和每次刈割之后出现降低,3～4周后恢复至刈割前水平,其后则继续增加。不同自然区域紫花苜蓿的根系生物量差异较大。在相对正常的栽培管理条件下,生长1年紫花苜蓿的根系生物量约在2～7t.hm-2之间,生长2年者约为3～9 t.hm-2,生长3～5年者约为4～21 t.hm-2。

In order to provide the evidences for further research and cultivation management of alfalfa（Medicago sativa L.）,the regular pattern of alfalfa root biomass and its dominant factors in different natural regions are discussed in this review.The factors include the depth of soil layer,ground water level,soil properties,waterlogging,farming,fertilization,irrigation,cutting,growth regulating agent,mixture sowing,planting density,cultivar,and growth period.Shallow soil layers associate with high-level underground water and both contribute to diminishing root mass.Deeper plowing increased alfalfa root biomass,especially in the first growing year.Also,irrigation,fertilization,growth regulating agent,higher stubble,and longer growth period increased alfalfa root biomass.Appropriate irrigation patterns and amount increased alfalfa root biomass,but waterlogging,higher cutting frequency and mixture sowing reduced alfalfa root biomass.In some cases,alfalfa root biomass increased by increasing the planting density.Different alfalfa cultivars had different root biomass.In each growing season,alfalfa root biomass first increased gradually then decreased during its early greening period or after cutting;but 3 to 4 weeks later,recover to pre-cutting levels.Alfalfa root biomasses were different in various natural regions.With regular planting management,one-year-old alfalfa root biomass were about 2 to 7 t·hm-2,two-year-old ones about 3 to 9 t·hm-2,and three-year-old to five-year-old ones were about 4 to 21 t·hm-2.