坡向和建植年限对3种冷季型草坪草重要值和相对生物量的影响

Effects of slope aspect and growth years on theimportant value and relative yield of threecold season turfgrasses

摘要:

在紫色土丘3个坡向(A-半阴坡EN 40°,B-阳坡WS 33°,C-阴坡WN 29°)上,以建植的高羊茅、多年生黑麦草和草地早熟禾混播草坪为研究对象,于建成后1~5 a分析3种草坪草相对密度、重要值、相对生物量及生长特点的变化,研究坡向和建植年限对草坪草重要值和相对生物量及根冠比的影响。结果表明:1)坡向和建植年限影响草坪草比例,入侵杂草种类和数量受坡向影响,建植年限决定草坪草退化速度,B坡群落组成高于A和C,3种草坪草比例逐年下降。2)坡向和建植年限影响草坪草相对密度和重要值(P＜0.05),建植2~3年相对密度下降约60个百分点,重要值下降约70个百分点,C坡相对密度和重要值在建植1~2年大于A和B坡(P＜0.05),B坡在建植3~5年大于A和C坡(P＜0.05)。3)坡向和建植年限影响草坪草绝对生物量和相对生物量,建植年限对草坪草绝对生物量和相对生物量影响的大小顺序为多年生黑麦草＞草地早熟禾＞高羊茅,坡向对相对生物量影响的大小顺序为草地早熟禾＞多年生黑麦草＞高羊茅,相对生物量均逐年降低(P＜0.05);建植2~5年高羊茅绝对生物量B坡大于A和C坡,多年生黑麦草和草地早熟禾的相对生物量C坡大于A和B坡(P＜0.05)。4)坡向和建植年限影响草坪草单株生物量(P＜0.05),3种草坪草单株生物量在2~3年增加而4~5年下降(P＜0.05),建植2~3年高羊茅单株生物量B坡大于A和C坡,多年生黑麦草和草地早熟禾则C坡大于A和B坡(P＜0.05);第4年C坡3种草坪草单株生物量最大,B坡最小。5)坡向和建植年限影响草坪草根冠比,坡向对根冠比影响的大小顺序为草地早熟禾＞多年生黑麦草＞高羊茅,建植年限对根冠比影响大小顺序为高羊茅＞草地早熟禾＞多年生黑麦草,B坡3种草坪植物的根冠比大于A和C坡。综上,坡向主要影响群落组成和优势种种类,建植年限主要影响草坪生物量及单株生物量,坡向和年限共同作用降低了草坪草重要值、相对密度、相对生物量及生长能力,导致草坪严重退化。

Abstract:

The mixed-sown turf with 3 cold season turfgrasses (Festuca arundinacea,Lolium perenne and Poa pratensis,1∶1∶1,3 g/cm2) located on the three slope aspects (A,semi-shading slope EN 40°;B,sunny slope WS33°;C,shady slope WN 29 °) in purple soil in hilly area was selected to measure the community composition,relative density,important value,relative yield in 1 to 5 years after sowing.The results showed that 1) The slope aspect and growth year affected community composition of turf and proportion of 3 turfgrasses (P＜0.05).The slope aspect affected the species and quantity of invasive weeds,and the growth year determined the rate of turf degradation.The community composition of slope B was higher than that of slope A and slope C,and the proportion of 3 turfgrasses decreased year by year.2) The slope aspect and growth year affected the relative density and important value of turfgrasses (P＜0.05),the relative density and important value decreased by about 60% and 70% within 2 to 3 years,respectively.In 1 to 2 years,the relative density and important value of slope C were greater than that of slope A and slope B (P＜0.05).In 3rd to 5th years,the relative density and important value of slope B was greater than that of slope A and slope C (P＜0.05).3) Slope aspect and growth year affected the absolute and relative yield of turfgrasses (P＜0.05).The influence degree of growth year on absolute and relative yield was L.perenne ＞P.pratensis＞ F.arundinacea,and it was P.pratensis ＞ L.perenne ＞ F.arundinacea for the slope aspect on relative yield.The relative yield all decreased year by year (P＜0.05).In 2 nd to 5 th years,the absolute yield of F.arundinacea on slope B was higher than that on slope A and slope C,and the relative yield of L.perenne and P.pratensis on slope C was higher than that on slope A and B (P＜0.05).4) The slope aspect and growth year affected the biomass of single turfgrass (P＜0.05).The biomass of 3 turfgrasses increased in 2nd and 3rd years,and decreased in 4th and 5th years (P＜0.05).In 2 nd and 3rd years,the single plant biomass of tall fescue in slope B was higher than that in slope A and C,while those of ryegrass and bluegrass in slope C were higher than those in slope A and B (P＜0.05).In 4th year,the biomass of 3 turfgrasses in slope C all reached the highest and that of slope B was the lowest.5) The slope aspect and growth year affected the root-shoot ratio of turfgrasses (P＜0.05).The influence degree of slope aspect on root-shoot ratio was F.arundinacea ＜ L.perenne ＜ P.pratensis,and it was F.arundinacea ＞ P.pratensis ＞ L.perenne for growth year.The root-shoot ratio of 3 turfgrasses in slope B was higher than that on slope A and C.In conclusion,the slope aspect mainly affected community composition and dominant species,and the growth year mainly affected the biomass.The combination of slope direction and year reduced the important value,relative density,relative yield and growth of turfgrass,which lead to serious turf degradation.