水肥耦合对‘聊红’椿幼苗根系形态特征的影响

Effects of Water and Fertilizer Coupling on Root Morphological Characteristics of Ailanthus altissima‘Liaohong’Seedlings

为探明‘聊红’椿幼苗根系生长对水肥耦合的响应规律,以确定最佳的灌溉施肥组合,本试验以一年生‘聊红’椿幼苗为对象,采用双因素试验设计,设置3个水分处理梯度(低水,W1:田间持水量的30%~40%;中水,W2:田间持水量的50%~60%;高水,W3:田间持水量的70%~80%)及4个施肥水平(无肥,F0:N、P_(2)O_(5)、K_(2)O施用量均为0;低肥,F1:N、P_(2)O_(5)、K_(2)O施用量分别为2.0、1.0、1.5 g·株^(-1);中肥,F2:N、P_(2)O_(5)、K2_(O)施用量分别为4.0、2.0、3.0 g株^(-1);高肥,F3:N、P_(2)O_(5)、K2_(O)施用量为6.0、3.0、4.5 g·株^(-1))共组合成12个处理,通过盆栽试验比较不同水肥耦合处理对‘聊红’椿幼苗根系性状(根长、根表面积、根体积、根平均直径、比根长和比表面积)的影响。结果显示,水分处理和施肥处理对粗根各个性状均有显著影响;对细根的影响除比表面积不显著外其余性状均显著;水肥交互作用对粗根的根表面积和根体积有显著影响,对细根的根长、根表面积、根体积和比根长均有显著影响。在F0和F1施肥水平下,粗根、细根的根长、根体积和根平均直径随着灌水量增加而上升,而在F2和F3施肥水平下则先升后降,说明F0W3和F2W2处理对根系生长的促进作用较为明显。综上,高肥抑制根系生长,且细根较粗根对高肥的耐受性更强,水肥耦合对细根影响更为显著,F2W2组合最利于‘聊红’椿幼苗根系生长。

In order to explore the response characteristics of root growth of Ailanthus altissima‘Liao-hong’seedlings to the coupling of water and fertilizer,and determine the best combination of irrigation and fertilization,one-year-old A.altissima‘Liaohong’seedlings were used as the object and two-factor design was conducted in this experiment.Three water treatments were set as low water(W1:30%~40%of field water holding capacity),reclaimed water(W2:50%~60%of field water holding capacity)and high water(W3:70%~80%of field water holding capacity),and four fertilizer levels were set as no fertilizer(F0:no applica-tion of N,P_(2)O_(5),K_(2)O),low fertilizer(F1:2.0,1.0,1.5 gplant^(-1)of N,P_(2)O_(5),K_(2)O respectively),medium fertilizer(F2:4.0,2.0,3.0 gplant^(-1)of N,P_(2)O_(5),K_(2)O respectively);and high fertilizer(F3:6.0,3.0,4.5 gplant-1 of N,P_(2)O_(5),K_(2)O respectively),which formed 12 treatments.The effects of different water and fer-tilizer coupling treatments on root traits(root length,root surface area,root volume,average root diameter,specific root length and specific surface area)of A.altissima‘Liaohong’seedlings were compared by pot ex-periment.The results showed that both water and fertilization treatments had significant effects on each trait of coarse roots and all the traits of fine roots except for the specific surface area.The interaction of water and ferti-lization had significant effects on the surface area and volume of coarse roots and the length,surface area,vol-ume and specific root length of fine roots.Under F0 and F1 treatments,the length,volume and average diame-ter of both coarse and fine roots increased with the increase of irrigation amount,but they increased first and then decreased under F2 and F3 treatments,indicating more obviously promotion effects of F0W3 and F2W2 on root growth.Above all,high fertilizer inhibited the growth of roots,and fine roots had stronger tolerance than coarse roots.The coupling of water and fertilizer had more significant effects on fine roots.The combina-tion of F2W2 was most beneficial to root growth of A.altissima‘Liaohong’seedlings.