تأثیر کوبیدگی خاک بر متغیر زی‌توده و رشد نهال بلندمازو در شرایط گلخانه‌ای

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده منابع طبیعی دانشگاه تهران، دکترای جنگلداری

2 دانشگاه تهران

3 گروه جنگلداری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران

چکیده

استفاده از ماشین‌آلات سنگین برای فعالیت‌های جنگل مانند عملیات بهره‌برداری در طول چند دهۀ گذشته افزایش یافته است که همین امر پیامدهای منفی بر اکوسیستم خاک جنگل شامل کوبیدگی، به‌هم‌خوردگی و شیاری شدن خاک را در پی داشته است. این تحقیق در پی اثبات این فرضیه است که افزایش مقاومت به نفوذ با تحت تأثیر قراردادن الگوهای اندام هوایی و زیرزمینی، سبب ایجاد اثرهای منفی بر متغیرهای مورفولوژی نهال (اندازه) و رشد (زی‌توده) می‌شود. در این تحقیق چهار تیمار کوبیدگی خاک اعمال شده تا یک طیف پیوسته از کوبیدگی با استفاده از افزایش وزن مخصوص ظاهری ایجاد شود (تیمار شاهد بدون کوبیدگی و سطح دوم تا سطح چهارم کوبیدگی به ترتیب با 3، 5 و 7 ضربه چکش). اثرهای کوبیدگی خاک در خاکی با بافت لومی تا رسی- لومی با شرایط بهینه از نظر آب (آبیاری روزانه) در یک مقیاس پیوستۀ مقاومت به نفوذ (1/0 تا 0/1 مگاپاسکال) بر متغیرهای رشد نهال‌های گونه بلندمازو در شرایط گلخانه بررسی شد. با افزایش مقاومت به نفوذ، متغیرهای رشد شامل اندازۀ نهال (طول و قطر ساقه، طول برگ، طول و قطر ریشۀ اصلی و طول ریشۀ جانبی) و زی‌توده (اندام هوایی و ریشه) از نظر آماری به‌طور معنی‌داری کاهش یافتند. پارامترهای رشد با افزایش کوبیدگی خاک به‌صورت رابطه‌ای غیرخطی تغییر یافتند. به‌طور کلی می‌توان نتیجه‌گیری کرد که رشد ریشه و ارتفاع نهال بلندمازو با هر گونه افزایش در مقاومت خاک محدود می‌شود.
 

کلیدواژه‌ها


عنوان مقاله [English]

The Effects of Soil Compaction on Morphology and Biomass Variables of Chestnut-leaved Oak (Quercus castaneifolia C.A.M.) in Greenhouse Situations

نویسنده [English]

  • Meghdad Jourgholami 1
چکیده [English]

The use of heavy machinery in forestry operations such as logging has increased worldwide during the last decades. However, these machines may seriously influence the soil ecosystem as they induce rutting, disturbing the upper soil layers, and soil compaction. Severe compaction of soil adversely affects the growth of plants.This study was done by using a penetration resistance experiment in a greenhouse to test the hypotheses that increasing soil strength would affect adversely the seedling morphology (size) and growth (biomass) by changing the above- and below-ground patterns. We created four soil compaction intensity treatments. The lowest compaction intensity (no compaction, control), low, moderate, and high intensities of compaction were achieved by manually applying 3, 5 and 7 blows with a compaction hammer from a height of 20 cm above the soil surface, respectively. We studied the effects of soil compaction in a loam to clay-loam textured soil with optimal conditions of water on a continuous scale (0.1–1.0 MPa penetration resistance) on the growth responses of the deciduous Quercus castaneifolia (C.A.M.). Above- and below-ground metrics of seedling size (i.e., stem length and diameter, leaf length, main root length and diameter, and lateral root length) and biomass (i.e., total, shoot, and total root) were negatively affected by soil compaction. Seedling sizes and growth parameters responded nonlinearly to increasing the soil strength. We conclude that growth of roots and height of oak seedlings are restricted with any increases in soil strength.

کلیدواژه‌ها [English]

  • Hyrcanian forest
  • penetration resistance
  • seedling morphology
  • relative growth rate
[1]. Kolowski, T.T. (1999). Soil Compaction and growth of woody plants. Scandinavian Journal of Forest Research, 4: 596–619.
[2]. Conlin, T.S.S., and Van den Driessche, R., (1996). Short-term effects of soil compaction on growth of Pinus contarta seedlings. CandaianJournalForest Research, 26: 727–739.
 [3]. Gómez, A., Powers, R.F., Singer, M.J., and Horwath, W.R. (2002). Soil compaction effects on growth of young ponderosa pine following letter removal in California’s Sierra Nevada. Soil Science Society of American Journal, 66: 1334–1343.
[4]. Bassett, I.E., Simcock, R.C., Mitchell, N.D. (2005). Consequences of soil compaction for seedling establishment: implications for natural regeneration and restoration. Australian Ecolology, 30: 827–833.
[5]. Blouin, V.M., Schmidt, M.G., Bulmer, C.E., and Krzic, M. (2008). Effects of compaction and water content on lodgepole pine seedling growth. Forest Ecolology and Management, 255: 2444–2452.
[6]. Greacen, E.L., and Sands, R. (1980). A reviw of compaction of forest soils. Australian Journal of Soil Research, 18: 163-189.
 [7]. Alameda, D., and Villar, R. (2009). Moderate soil compaction: implications on growth and architecture in seedlings of 17 woody plant species. Soil & Tillage Research, 103: 325–331.
[8]. Verdu, M., and Garcıa-Fayos, P. (1996). Nucleation processes in a Mediterranean bird dispersed plant. Functional Ecolology, 10: 275–280.
[9]. Bejarano, L., Murillo, A.M., Villar, R., Quero, J.L., and Zamora, R. (2005). Crecimiento de pla´ ntulas de Quercus pyrenaica bajo distintos niveles de adiacio´n y compactacio ´n del suelo. Resumen de Actas del 48 Congreso Forestal. Zaragoza. 16pp.
[10]. Lloret, F., Casanovas, C., and Peñuelas, J. (1999). Seedling survival of Mediterranean shrubland species in relation to root, shoot ratio, seed size and water and nitrogen use. Functional Ecology, 13: 210–216.
[11]. Van Andel, J., and Biere, A. (1989). Ecological significance of variability in growth rate and plant productivity. In: Lambers, H., Cambridge, M.L., Konings, H., Pons, T.L. (Eds.), Causes and Consequences of Variation in Growth Rate and Productivity of Higher Plants. SPB Academic Publishins B.V., The Hague, pp. 257–267.
[12]. Grime, J.P. (1977). Evidence for the existence of three primary strategies in plants and its relevance to ecological and evolutionary theory. American Naturalist, 982: 1169–1194.
[13]. Poorter, H., and Nagel, O. (2000). The role of biomass allocation in the growth response of plants to different levels of light, nutrients and water: a quantitative review. Australian Journal of Plant Physiology, 27: 595–607.
[14]. Bejarano, M.D., Villar, R., Murillo, A.M., and Quero, J.L. (2010). Effects of soil compaction and light on growth of Quercus pyrenaica Willd. (Fagaceae) seedlings. Soil and Tillage Research, 110: 108–114
[15]. Alameda, D., and Villar, R. (2012). Linking root traits to plant physiology and growth in Fraxinus angustifolia Vahl. seedlings under soil compaction conditions. Environmentsl and Experimental Botany, 79: 49–57.
[16]. Wasterlund, I. (1988). Damages and growth effects after selective mechanical clearing. Scandinavian Joural of Forest Research, 3: 259–272.
[17]. Corns, G.W. (1988). Compaction by forestry equipment and effects on coniferous seedling growth on four soils in the Alberta foothills. Candaian Journal of Forest Research, 18: 75–84.
[18]. Misra, R.K. and Gibbons, A.K. (1996). Growth and morphology of eucalypt seedling roots in relation to soil strength arising from compaction. Plant and Soil, 182: 1–11.
[19]. Jamshidi, R. (2004). Effects of ground-based skidding on soil physical properties in skid trails and stand growth. Department of forestry, Faculty of Natural Resources and Marine Sciences, TarbiatModaresUniversity, 75pp. 
[20]. Hunt, R. (1990). Basic Growth Analysis. Unwin Hyman Ltd., London, p. 112.