施肥方式对核桃楸容器苗生长及根系养分累积的影响

建立合理的施肥制度是培育优质苗木、提高造林表现的重要措施之一。以当年生核桃楸幼苗为研究对象，分别设置对照（CK）、平均施肥（AF）、直线施肥（LF）、指数施肥（100E）、0.5倍指数施肥（50E）、2倍指数施肥（200E）、4倍指数施肥（400E）等处理，探究幼苗根系形态和养分累积对不同施肥处理的响应。在生长结束时，100E处理下的苗高和地径表现较好，增长量分别为21.35 cm和3.66 mm。在施肥初期（5周后），LF处理下的幼苗比根长（SRL）、比根表面积（SRA）、平均直径（AD）、组织密度（RTD）和生物量达到最高，在施肥9周后，各处理中100E处理下幼苗根系的SRL、SRA和AD达到最高，分别比CK高77.93%、50.59%和54.84%（P<0.05）。随着幼苗生长节律的变化，不同收获时间对核桃楸幼苗根系形态存在显著影响，施肥显著降低了核桃楸根系的SRL、SRA和AD，增加了RTD和生物量（P<0.05）。100E处理和200E处理下的幼苗根系分别有较高的K和N浓度，总体上，根系养分浓度随着时间的变化而降低。各施肥处理显著提高了幼苗根系养分含量，生长结束时，100E处理下的幼苗根系N、P和K含量分别为106.41、11.00 mg·株^-1和14.43 mg·株^-1。指数施肥方式下100 mg·株^-1的施肥量更有利于核桃楸幼苗的根系发育。

Effects of Fertilization Methods on the Growth and Root Nutrient Accumulation of Juglans mandshurica Container Seedlings

Establishing a reasonable fertilization regime is one of the important management measures for breeding high-quality seedlings and improving afforestation performance.The annual seedlings of Juglans mandshurica were used as research objects,and an experiment was conducted to set control (CK),average fertilization (AF),linear fertilization (LF),exponential fertilization (100E),0.5-fold exponential fertilization (50E),2-fold exponential fertilization (200E),and 4-fold exponential fertilization (400E),respectively.The object of this study was to explore the response of root morphology and nutrient accumulation of the seedlings in different fertilization treatments.At the end of growth,seedling height and ground diameter in 100E were better than others,and the increment of them were 21.35 cm and 3.66 mm,respectively.At the early stage of fertilization (after 5 weeks),the seedlings in LF treatment had the highest root length (SRL),specific root surface area (SRA),average diameter (AD),root tissue density (RTD) and biomass.After 9 weeks of fertilization,the SRL,SRA and AD of the seedlings in 100E reached the highest values among fertilization treatments,which were 77.93%,50.59% and 54.84% higher than the control,respectively (P<0.05).With the change of seedling growth dynamic,different harvest time had significant effects on the root morphology.The fertilization treatment significantly reduced the SRL,SRA and AD,and increased RTD and biomass (P<0.05).The roots in 100E and 200E had higher K and N contents,respectively.In general,the root nutrient contents decreased with fertilization time.The fertilization treatment significantly increased the nutrient contents of the roots.At the end of the growth,the N,P and K contents of the roots in 100E were 106.41,11.00,and 14.43 mg·plant^-1,respectively.The application amount of 100 mg·plant^-1 by exponential fertilization method was more beneficial for the root development of J.mandshurica seedlings.