短轮伐期毛白杨S86纸浆林生长对沟灌水肥耦合的响应

杨红青; 王亚飞; 贾黎明

doi:10.12171/j.1000-1522.20210465

短轮伐期毛白杨S86纸浆林生长对沟灌水肥耦合的响应

Response of pulp plantation growth of Populus tomentosa S86 in short rotation period to coupling of water and fertilizer in furrow irrigation

摘要

摘要:
目的研究沟灌水氮耦合对三倍体毛白杨S86高密度短轮伐期纸浆林林木生长和林分生产力的影响，旨在为选择适合当地的高效沟灌−施肥技术制度提供科学理论依据。
方法以山东省高唐县三倍体毛白杨S86为研究对象，采用完全随机区组试验设计，监测3个灌溉水平，即土壤水势值达到−20 kPa（W1）、−33 kPa（W2）、−45 kPa（W3）时开始灌溉，和4个施氮水平（N1，120 kg/（hm²·a）；N2，190 kg/（hm²·a）；N3，260 kg/（hm²·a）；N4，0 kg/（hm²·a））组合下短轮伐期内（2017—2020年）胸径、相对生长率、蓄积、生产力的变化规律，并设置无灌溉施肥作为对照处理（CK）。
结果三倍体毛白杨S86的胸径生长速生期持续较长，生长季内各处理不同林龄林分胸径生长均符合Logistic函数（R² > 0.99），各沟灌施肥处理的差异主要表现在6月份。沟灌施氮处理对2年生毛白杨S86林木胸径增长量、相对生长率有显著影响（P < 0.05），而对3 ~5年生毛白杨S86林木影响不显著。水肥耦合措施对2 ~ 3年生林木平均蓄积量和平均生产力促进作用较强，而对4 ~5年生林木促进作用不显著。毛白杨S86林木4年的年均生产力为19.65 ~ 25.31 m³/（hm²·a），其中年均生产力最大的处理W1N1，显著高于CK 28.41%（P < 0.05）；5年生林分W1N1处理下林木生长最优，单位面积蓄积和平均生产力分别达到104.39 m³/hm²和27.42 m³/（hm²·a），较CK处理分别提高28.15%和11.74%。
结论沟灌水肥耦合措施对2 ~ 3年生三倍体毛白杨林木的单位面积蓄积和年度生产力有不同程度的提高，而对4 ~ 5年生毛白杨S86单位面积蓄积和年度生产力无明显作用，其中W1N1沟灌施氮处理生长最优；在气候和土壤条件相近条件下，保持水分充足（灌溉阈值为−20 kPa）以及较低的施氮量（120 kg/（hm²·a））时最有利于以纸浆林为培育目标的高密度短轮伐期毛白杨林木的生长。

Abstract:
Objective This paper aims to research the coupling effects of furrow irrigation and nitrogen fertigation on the growth and stand productivity of high-density and short-rotation triploid Populus tomentosa S86 pulp plantations, in order to provide scientific theoretical basis for selecting efficient furrow irrigation-fertilization technology system suitable for the local area.
Method The plant materials were triploid P. tomentosa S86 in Gaotang County, Shandong Province of eastern China. A completely random block experiment design was adopted to monitor three irrigation levels, i.e. irrigation started when the soil water potential reached −20 kPa (W1), −33 kPa (W2) and −45 kPa (W3), and four fertigation levels (N1, 120 kg/(ha·year); N2, 190 kg/(ha·year); N3, 260 kg/(ha·year); N4, 0 kg/(ha·year)), and the control treatment was with no irrigation and no fertigation set (CK).
Result It took a long time for the fast-growing period of DBH growth of triploid P. tomentosa S86. The DBH growth of different stand ages in the growing season conformed to the Logistic function (R² > 0.99), and the difference of furrow irrigation and fertilization treatments was mainly manifested in June. Nitrogen application in furrow irrigation significantly affected the DBH increment and relative growth rate of 2-year-old P. tomentosa S86 plantations (P < 0.05), but had no significant effect on 3−5-year-old P. tomentosa S86 plantations. The coupling measures of water and fertilizer had a strong promotion effect on the average volume and average productivity of 2−3-year-old trees, but had no significant promotion effect on 4−5-year-old P. tomentosa S86 plantations. The average annual productivity of triploid P. tomentosa S86 stands was 19.65−25.31 m³/(ha·year) in four years, among which, W1N1 had the highest annual productivity, which was significantly higher than CK by 28.41% (P < 0.05). Under the treatment of 5-year-old stand W1N1, the tree growth was optimal, with unit area volume and average productivity reaching 104.39 m³/ha and 27.42 m³/(ha · year), respectively, which were 28.15% and 11.74% higher than CK treatment, respectively.
Conclusion The furrow irrigation and fertilizer coupling measures have different degrees of improvement on the unit area storage and annual productivity of 2−3-year-old triploid P. tomentosa S86 stand, but have no significant effect on the unit area storage and annual productivity of 4−5-year-old P. tomentosa S86 plantation. Among them, W1N1 furrow irrigation and nitrogen application treatment has the best growth. Under similar climatic and soil conditions, maintaining sufficient water (irrigation threshold of −20 kPa) and a lower nitrogen application rate (120 kg/(ha · year) is most conducive to the growth of high-density short-rotation triploid P. tomentosa targeting pulp forests.

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