Response of Cypress (Cupressusressus sempervirens var. horizontalis) Seedlings to Soil Type and Planting Depth in Plain Areas of Caspian Sea

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1 Proceedings of The Fourth International Iran & Russia Conference 1061 Response of Cypress (Cupressusressus sempervirens var. horizontalis) Seedlings to Soil Type and Planting Depth in Plain Areas of Caspian Sea Masoud Tabari 1 ; Hamid Reza Saeidi 2 ; Reza Basiri 3 1. Department of Forestry, Faculty of Natural Resources, University of Tarbiat Modarres, Noor, Iran. Fax: masoudtabari@yahoo.com ; 2. Post-graduate Student, Faculty of Natural Resources, University of Tarbiat Modarres, Noor, Iran ; 3. Faculty of Natural Resources, University of Kordestan, Sanandaj, Iran. Abstract Two-year old Cypress (Cupressus sempervirens var. horizontalis) seedlings were planted in two planting depths (20 and 40 cm) on 5 soil types in a plain area of the Caspian Sea, north of Iran. Soils consisted of 1:1 sand: clay (A), pour sand (B), 2:1 sand: clay (C), 1:1:1 sand: clay: organic matter (D), 1:1:2 sand: clay: organic matter (E). The results after one growing season revealed that soil affected survival, stem length, collar diameter and vitality; planting depth influenced only on survival and vitality. However, none of parameters were affected by soil type planting depth interaction. The same as vitality, survival was more suitable in 40-cm holes. Neither survival nor vitality differed in soil (A) with those in other soils. All characteristics respond better to soils containing organic matter (D and E). Stem length as well as collar diameter performed the least growth on pour sand soil (B). It can be concluded that deep planting, as well as adding organic matter to sandy soils, increases survival and growth and suits vitality of Cupressus seedlings. Keywords: Cupressus sempervirens, Planting depth, Seedlings, Soil type, Stem length, Survival Introduction The main objective of each plantation project is to provide the favorable growth and establishment of seedlings. For this purpose good elaboration of inhibiting factors of plantation site and careful understanding of the ecological requirements of species are unavoidable (Krasowski et al, 2000). Generally, using the low-quality seedlings in plantations reduces growth and survival and increase costs. Indeed, by high investment in nurseries and naturally high-quality seedling production, plantation costs decrease and output increases (Wightman et al., 2001). One of cases in plantation sites, particularly in dry and sandy soils, which may promote growth and survival rates, is deep planting. In reality, deep planting induces decreased effects drought stress on seedling (in dry sites); it also prevents seedlings from being turned (twisted) by wind (Schwan, 1994). Regarding to size of planting depth, some investigations have been carried out since recent decades. Among which Switzer (1960) believes that, depends on site conditions (soil texture, ground water table etc.), planting depth varies with different species. Hence, Schwan (1994) claims that deep planting improves quality and quantity of seedlings. Besides that, South (2000, on Pinus taeda) reports that shallow-planted seedlings usually are injured by windfall. In spite of above-mentioned confirmations, many primitive researchers accept that deep planting has an adverse effect on softwoods, especially on Picea sp. (Reuss, 1907; Toumey, 1916; Hosley, 1936). More recent, Mullin (1964, 1966) and Clearly et al (1978) show detrimental effects of shallow planting. In addition to planting depth, soil type is another determining factor at seedling life cycle [Korani, 1991; Sheikh-Khan et al., 1980, cited by Shahini, 1996)]. Relevant to above subjective some examinations were made with softwoods. Schwan (1994) demonstrates that peat (with 70% organic matter), compared to lower fertility soils, produces higher growth on

2 Proceedings of The Fourth International Iran & Russia Conference 1062 some of pines. Hassan et al. (1994) report that after 2 nd growing season Cupressus sempervirens seedlings grow better in environment 1:1:3 sand: clay: sphagnum. Kia-Daliri (2002) declares a non-significant difference of growth with potted seedlings Cupressus growing on sandy and sandy-clay soils when added organic matter to them. Tabari et al. (2003) exhibit that adding sand to sandy-clay soils causes increased growth and survival of 1- year bare-root Cupressus. In recent years in Iran, few investigations with aim of determination of effects of soil on conifers have been made but not on size of hole for seedling plantation. Therefore, research on planting depth and interaction between soil type and planting depth on Cupressus seedlings is needed, whereas the better planting depth and soil type for plantation of this species can be identified. Materials & Methods In February 2001, 210 bare-rooted Cupressus seedlings (1+1) in 30 ± 2.5 cm length and 4 ± 0.4 mm collar diameter, produced in a lowland nursery, were selected to be planted in a plain area of the Caspian Sea, north of Iran (Noor City), with the climate shown in Table 1. For this purpose, firstly by a rotivator soil was ploughed and weeds removed. Then on the 1-m rows and 2-m spacing two different holes in 20-cm (current method) and 40-cm depth were dug. The holes were filled by 5 soil types such as, 1:1 sand: clay (A), pour sand (B), 2:1 sand: clay (C), 1:1:1 sand: clay: organic matter (D), 1:1:2 sand: clay: organic matter (E) and occupied by seedlings. Soil properties of the study site are tabulated in Tables 2. Collar diameter, as well as stem length, was measured at intervals of two months (in late March to late November). Vitality and or discoloration of needles, according to UN/ECE & UE (1998) classification (Table 3), was recorded in late August; survival was determined in late November. The design was a randomized complete block (RCB) with three replicates. For statistical analyses, at first data was examined by one-way analysis of variance (ANOVA). Then, for comparison of means (p < 0.05), a Tukey-HSD test was analyzed among five soil treatments and an independent sample t-test between two planting depths (Cochran and Cox, 1957). Two-way analysis of variance was conducted for determining interaction of planting depth soil type, too. Table 1. Metreological census of the study site (After Tabari et al., 2002) Mean annual Mean Mean max. Mean min. Dry precipitation annual temperature of temperature of the (mm) temperature the warmest coldest month ( C) month ( C) ( C) Elevation (m) days (xerothermique index) Pluviothermique index (Q 2) Climate type (based on Emberger, 1960) Moist with cold winters Table 2. Physico-chemical properties of different soil treatments in the investigated site Soil type Organic matter ph (EC 10 3 ) N P K (%) (ppm) (ppm) (ppm) 1:1 Sand: Clay (A) Pour Sand (B) :1 Sand: Clay (C) :1:1 Sand: Clay: Organic matter (D) :1:2 Sand: Clay: Organic matter (E) Table 3. Discoloration degree of Cupressus sempervirens seedlings (based on UN/ECE & UE, 1998) Foliage discolored Discoloration degree Code of vitality up to 10 % none % slight % moderate 2 >60 % severe 1

3 Proceedings of The Fourth International Iran & Russia Conference 1063 Results Survival Measurements showed that in beginning of the growing season (March) all seedlings were alive. In other words, not any mortality could be seen in this time. Analysis of data demonstrated a high survival rate for all treatments in July but it declined gradually till November. Generally, in each month the seedlings growing on nutrient available soils (D, E) had higher survival rate when compared with those on other soils. In this regard, pour sand soil performed the poorest condition (Table 4). Two-way analysis of variance revealed that soil type and planting depth affect survival but no interaction between them can be detected (Table 5). By comparing means it appeared that at the end of the first growing season survival in soil (A) was not different with those in other soils (Table 6). The highest survival rates (87.5% and 85%) yielded in the order in soils (D) and (E) and the lowest one (61.2%) in soil (C). Deeper planting depth produced higher surviving (80.1%), compared to routine planting depth, generating lower one (69.7%). Table 4. Survival (%) of C. sempervirens seedlings at different soil types, occurred in months of the first growing season Soil type March May July Sep. Nov. 1:1 Sand: Clay (A) Pour Sand (B) :1 Sand: Clay (C) :1:1 Sand: Clay: Organic matter (D) :1:2 Sand: Clay: Organic matter (E) Table 5. Two-way analysis of variance for relationship between characteristics measured and treatments Source Survival Height Collar diameter Vitality Soil type Planting depth * ns ns * Planting depth Soil type ns ns ns ns * = Significant ns = Non significant Table 6. Average values of C. sempervirens in different soil types and planting depths Soil type 1:1 Sand: Clay (A) Pour Sand (B) 2:1 Sand: Clay (C) 1:1:1 Sand: Clay: Organic matter (D) 1:1:2 Sand: Clay: Organic matter (E) Planting depth 20 cm 40 cm Survival (%) 72.8 ± 10.7 abc 61.2 ± 10.9 c 68.2 ± 10.4 bc 85 ± 9.5 ab 87.5 ± 11.3 a 69.7 ± 14.6 b 80.1 ± 12.0 a Stem length (cm) 52.5 ± 4.2 b 45.5 ± 1.2 c 47.6 ± 2.3 c 55.8 ± 3.8 ab 59.7 ± 1.9 a 52 ± 5.8 a 52.4 ± 6.2 a Collar diameter (mm) 6.7 ± 0.6 b 5.7 ± 0.1 c 6.0 ± 0.4 b c 7.6 ± 0.6 a 8.0 ± 0.5 a 9.8 ± 0.9 a 9.8 ± 1.1 a -Within columns, values followed by different letters are significantly different at p Vitality code (discoloration degree) 1.7 ± 0.2 ab 1.1 ± 0.1 b 1.5 ± 0.1 b 2.2 ± 0.3 a 2.4 ± 0.3 a 1.6 ± 0.1 b 2.0 ± 0.2 a

4 Proceedings of The Fourth International Iran & Russia Conference 1064 Stem length Stem growth on each soil reached to its maximum at the end of July; it then appeared with a decreasing trend till November (Table 7). Contrary to planting depth, soil treatment influenced on stem length. However interaction of these factors on stem length was not significant (see Table 5). Analysis of data at the end of the growing season demonstrated a non significant difference between soils (B) and (C) (see Table 6). However, mean stem length in these soils was the least. There is no substantial difference between stem length of seedlings in soils (D) and (E) as well as between (D) and (A); However this term is greater on soil (E) than on soil (A). Table 7. Height growth (cm) of C. sempervirens seedlings at different soil types in months of the first growing season Soil type May July Sep. Nov. 1:1 Sand: Clay (A) Pour Sand (B) :1 Sand: Clay (C) :1:1 Sand: Clay: Organic matter (D) :1:2 Sand: Clay: Organic matter (E) Collar diameter Like stem growth, collar diameter growth rose in the end of July and then falls by the end of the period (Table 8). The results of data indicated the significant effect of soil treatment on this characteristic. This is while that this term was unaffected by either soil depth or interaction between soil type and soil depth (see Table 5). Collar diameter was greatest in nutrient available soils (D, E). Compared with soil (B), soil (A) produced bigger collar diameter; however neither soil (A) nor soil (B) generated collar diameter greater than that in soil (C) (see Table 6). Table 8. Collar diameter (mm) of C. sempervirens seedlings at different soil types in months of the first growing season Soil type May July Sep. Nov. Sand: Clay (1:1) (A) Pour Sand (B) Sand: Clay (2:1) (C) Sand: Clay: Organic matter (1:1:1) (D) Sand: Clay: Organic matter (1:1:2) (E) Vitality quality Soil type as well as planting depth affected vitality quality (see Table 5). According to the results demonstrated in Table 6, it can be stated that vitality or foliage discoloration was better in deeper holes. Foliage discoloration seemed to be of better status in nutritional-quality soils (D, E) than in poor ones (B, C). From this viewpoint, soil (A) exhibited an intermediate quality. Discussion By the current study it appeared that at the end of the investigation period, even-though collar diameter as well as stem length did not differ at two hole depths (20 and 40 cm) but survival, as well as vitality, was more favorable in deeper holes. This, in reality, agrees with findings

5 Proceedings of The Fourth International Iran & Russia Conference 1065 such as Sternberg et al. (2000, on coniferous), which asserts survival enhances with increasing planting depth, due to enough moisture at lower layers of soil. Similar results with Pinus banksiana, Picea mariana and Picea glauca are reported by Schawn (1994). Generally, growth and survival are influenced by some physiological and environmental factors as nutrient quality, water content, root formation, root system, soil inflammation and soil layers temperature (Schawn, 1994). As a matter of fact, some of these are interrelated and variation in one or more causes to reaction of seedlings. As a whole, on dry and drained soils increased survival and growth in deep planted seedlings is due to adequate moisture of lower parts of soil (Slocum & Maki, 1956; McGee & Hatcher, 1963; Cleary et al., 1978; Lantz et al., 1989). However, in much rainy years deep planting may have negative effect on growth and in dry season survival rate may improve (Koshi, 1960). Although fertility decreases with increased soil depth but growth and survival increase (Sutton, 1978). In literature, a few reports are referred to deep planting on moist and fertile soils. Deep planting is not advised by some people such as Switzer (1960) and Sutton (1978). In this relation, it can be also referred to the findings of Armstrong (1969), which seedlings grown on organic matter performed low (36%) and high survivorship (89%) at deep holes and normal holes, respectively. In the present review, stem length, as collar diameter, is smallest on high sand soils (B, C). This is in agreement with findings of Kia-Daliri (2002) who proved that Cupressus seedling grew poorly in sandy soil. In contrast, Tabari et al. (2003) presented shoot growth of Cupressus advanced when sand was added to sandy-clay substrate. Contrary to results made by Parde (1952, cited by Rezaei, 1992) and Hassan et al (1994), which low growth of Cupressus seedling was observed on unfertile and sandy soils, the current study corroborates high growth on nutrient available soils. Accordingly, Sheikh-Khan (1980, cited by Shahini, 1996) confirmed the positive role of N.P.K on increased seedling growth. Besides that, Shahini (1996, on Cupressus) and Khorani (1991, on Pinus taeda) reported increased growth on high nutritional quality soils. In the present research survival was not different in soil (A) with those in other soils. However, sandy soils (B, C) represented lower survivorship than fertile ones (D, E). In contradiction to Kia-Daliri observations (2002) which foliage discoloration was indifferent on less fertile and rich soils; in our research it was better on fertile soils (D, E) than on unfertile ones (B, C). However, from this viewpoint soil (A) played the intermediate role. Survival as well as vitality was more favorable in 40-cm hole. This was in accordance with those of Stenberg et al. (2000, on Cupressus) who asserted that survival with increasing planting depth elevated because seedlings used the moisture existed in lower depths of soil and overcame the drought. Conclusions As appeared in this investigation, all parameters responded poorly to high sand soils (B, C). Indeed, these characteristics, in particular growth, are often of more suitable condition on fertile soils (D, E). This implies that in nurseries or plantation sites high nutrient available soils are appropriate to raise Cupressus seedlings than high sand soils. However, due to the similar effects of soils (D) and (E) using soil (D) is more economic. Alternatively, soil (A) can be suited for this purpose, too. In addition, because survival and vitality response better to increased planting depth, deeper holes (40 cm) are recommended instead of routine holes (20 cm) for Cupressus plantation in plain areas of north of Iran. References Anonymous, Forest Condition in Europe Countries. Results of the 1997 Crown Condition Survey. Technical report prepared by Federal Research Center for Forestry and Forest Products, 140 pp.

6 Proceedings of The Fourth International Iran & Russia Conference 1066 Armstrong, R.H Experimental tree planting to compare survival and growth using various methods. Spruce Falls Pulp & Pap. Co. Ltd. File Rep. (Cited in Vincent, A. B Black Spruce: a review of its silvics, ecology and silviculture. Dept. Forestry, Canada. Pub. No. 1100, 79 p.) Cleary, B.D.; Greaves, R.D.; Hermann, R.K. Eds Regenerating Oregon s forests: A guide for the regeneration forester. Oregon State University Extension Service Corvallis, Oregon. Hassan, HA.; Mohamed., S.M. Abo-El-Ghaite-EM; Hammed-H.H Physiological studies on Cupressus sempervirens L. Seedling in response to growing media. Annals of Agricultural science, Moshtohor, Egypt. 32: 1, Hosley, N.W Norway spruce in the northeastern United States. Harvard Forest Bull p. (Cited by Sutton 1967, orig. not seen). Kia-Daliri, SH Determination of suitable soil to produce potted-seedlings Cupressus sempervirens in a lowland nursery, Scientific Report of Tarbiat Modarres Univ., Iran, 21p. Khorani, M The results of Pinus taeda growth at different soil compounds, Shafa-Rood Forest Service, Forest & Range Organization of Iran, Bulletin 110, 14p. Krasowski, M.J.; Elder, R.J.F Opportunities for improvements to reforestation success. Extension note 43. Ministry of Forest Research Program. Koshi, P.T Deep planting has little effect in a wet year. U.S. Dept. Agric., Forest Service, Tree Planter s Notes No. 40:7p. Lantz, C.W.; Brissette, J.C.; Baldwin, B.L.; Barnett, J.P Plant them deep and keep those root straight! U.S. Dept. Agric. Forest Service management Bull. RG-MB 27, 2p. McGee, C.E.; Hatcher, J.B Deep planting small slash pine on old field sites in the Carolina sandhills. J. For. 62: Mullin, R.E Influence of planting depth on survival and growth of red pine. For. Chorn. 40(3), Mullin, R.E Influence of planting depth and method of planting on white spruce J. For. 64: Rezaei, A Ecological study of natural stands of Cupressus sempervirens in north of Iran, M. Sc. Thesis, Gorgan University, Iran, 220p. Schwan, T Planting depth and its influence on survival and growth. A literature review with emphasis on jack pine, black spruce and white spruce. Technical Report TR-01. Shahini, GH Seedling production with Composts of Azola and Left-over plants, M. Sc. Thesis, University of Tarbiat Modarres, Iran, 153p. Slocum, G.K.; Maki, T.E Some effects of depth of planting upon loblolly pine in the northern Carolina Piedmont. J. For. 54: South, D A Review of the Pull up and Leave down Methods of Planting loblolly pine. School of Forestry and Wildlife Sciences of Alabama, 35pp. Sternberg, M.; Danin, A.; Noy-Meir, I Effect of clearing and herbicide treatment on coniferous seedling establishment and growth in newly planted Mediterranean forests. Forest Ecology and Management, 148: Sutton, R.F., Root system development in young outplants, particularity white spruce. P In Van Eerden E., and J.M. Kinghorn (eds) Proceedings of the rootform of planted trees Symposium. B. C. Min. of For./Can. For. Serv. Joint Report No. 8. Sutton, R.F Advantages of deep planting black spruce. Nat. Resour., Can. Ont. Rep. Tech. Note 50. Switzer, GL Exposure and planting depth effects on loblolly pine planting stock on poorly drained sites, Journal of Forestry, 58: Tabari, M.; Poormajidian, M.R.; Alizadeh, A.R Effect of soil, irrigation and weeding on survival and growth of Cupressus sempervirens, Project No. 1 in: Determining the appropriate methods of seedling production and plantation of native species for restoration of Caspian forests, Research Report of Tarbiat Modarres Univ., Iran, Tabari, M.; Djazirei, M.H.; Asadollahi, F.; Mir-Sadeghi, M.M.A Forest communities and environmental requirements of Fraxinus excelsior in forests of north of Iran, Pajouhesh & Sazandegi, 15 (2): Wightman, K.E.; Shear, T.; Goldfarb, B.; Haggar, J Nursery and field establishment techniques to improve seedling growth of three Costa Rican hardwoods. New Forests, 22:75-96.