黄土丘陵区不同种植行距下柳枝稷根系分布特征研究

明确旱区作物根系生长与行距的关系可为合理选择种植密度提供依据。以梯田种植第7年的柳枝稷(Pancium virgatum L.)草地为研究对象,采用根钻法于2016年4月和10月对0~150cm土层进行根系取样,比较研究了3种种植行距下(20cm,40cm和60cm)柳枝稷根系生物量和根长密度分布特征。结果表明:柳枝稷根系主要分布在0~40cm土层,20cm和40cm行距下0~20cm土层根系生物量显著高于60cm行距(P0.05);在40~150cm土层,根系生物量和根长密度在20cm行距下最低。行上与行间根系生物量均随种植行距增大而增大,均以40cm行距下根长密度较高。细根(d≤0.5mm)根长密度为40cm行距下显著最高,20cm行距下最低(P0.05)。总体表明,40cm行距下柳枝稷根系生物量较高,平均根长密度与细根根长密度最高。

Characteristics of Switchgrass Root Distribution under Different Row Spacings in Loess Hilly-gully Region of China

To know the relationship between root growth and row spacing can offer evidence for choosing rational crop density in dry region.The roots of switchgrass (Pancium virgatum L.) were sampled down to 150 cm deepth using soil core method under different row spacings in April and October,2016.The measurements were conducted on a terrace field under three row spacings (20 cm,40 cm and 60 cm,respectively) after switchgrass has grown for 6 years in semiarid loess hilly-gully region.Results showed that root biomass of switchgrass mainly distributed in the 0～40 cm soil profile.In the 0～20 cm soil profile,root biomass decreased as the row spacing enlarged and root biomass under 60 cm was significantly higher than that under 20 cm and 40 cm row spacing (P＜0.05).In the 40～150 cm soil profile,the root biomass and root length density were the smallest under 20 cm row spacing.Root biomass upon or between rows increased as row spacing enlarged.Root length density upon the row increased with increasing row spacing in April,and the highest root length density under 40 cm row spacing appeared in October.Under 40 cm row spacing,the root length density between rows showed the highest value in both months.Row spacing affected root length density of fine roots (d≤0.5 mm) significantly (P＜0.05),and it was the biggest and smallest under 40 cm and 20 cm row spacing,respectively.Our results showed that higher root biomass production and the biggest averaged root and fine root (d≤0.5 mm) length density were obtained under 40 cm row spacing,which would be the appropriate row spacing for planting switchgrass in the region.