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植苗造林可以弥补森林自然更新缓慢的缺陷[1],是我国主要的造林方式之一[2]。与裸根苗相比,容器苗因有容器保护,在起苗、运输和造林过程中可以有效避免根系损伤[3-4],提高造林成活率,促进苗木早期生长[5]。然而,由于容器体积有限,限制根系生长,影响苗木对水分和养分的吸收。因此,苗期水肥管理成为培育高质量容器苗的关键环节。
施肥可以促进苗木生长和养分积累[6],进而降低造林死亡率,促进苗木造林后早期生长[7],提高苗木耐胁迫的能力[8]。控释肥具有随苗木生长缓慢释放养分的特点[9],可在整个生长季持续提供养分,减少养分淋溶[10],避免水溶性肥的不利影响[11],造林后还可继续释放养分[12]。国外已将控释肥广泛应用于苗木培育[6, 13-15],国内对控释肥的研究主要集中在农作物[16]和长白落叶松(Larix olgensis Henry)[17-19]的生长及养分积累上,而在阔叶树种育苗[20-21]及对造林效果的影响方面研究报道很少。容器苗底部渗灌技术采用封闭式水分循环系统,从容器底部供水,利用基质毛细管作用吸收水分达到灌溉目的。这样苗木充分利用水分和养分,避免因养分淋溶造成环境污染,能最大限度地节水节肥[22]。由于底部渗灌系统为封闭式水分循环系统,容易引起肥料在基质和蓄水池中积累,因此,肥料种类和施肥量显得尤其重要。
栓皮栎(Quercus variabilis Bl.)是我国温带、暖温带、亚热带地区阔叶林及针阔混交林的主要树种[23]。国内对栓皮栎育苗灌溉制度和水肥需求规律开展了大量研究,确定了栓皮栎容器苗的最佳灌水量[24-26]及水溶肥的最佳施肥量[24, 27],但有关控释肥在栓皮栎容器育苗中的应用以及控释肥和灌溉方式对栓皮栎容器苗质量及造林效果的影响缺少研究。本研究以栓皮栎容器苗为试验材料,研究控释肥和灌溉方式对其容器苗生长、养分状况、基质电导率(EC)及造林效果的影响,确定适宜的控释肥施肥量,以期为高质量栓皮栎容器苗精准施肥提供参考。
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2013年9月初,在北京市平谷区四座楼栓皮栎良种基地(40.27° N,117.12° E)采集种子,带回实验室进行预处理。将栓皮栎种子浸泡在50℃温水中30 min,杀死象鼻虫,同时去除漂浮在水面的劣种。将挑选好的种子阴干后,置于2℃冰箱中贮存备用。育苗试验在北京林业大学鹫峰林场森林培育学科温室(40.05° N,116.08° E)内进行。2014年4月初,对栓皮栎种子进行催芽;4月15日,将萌发种子播种于装有泥炭(丹麦Pindstrup Mosebrug A/S公司,5号基质)和珍珠岩混合基质(3V:V)的育苗容器(D60,体积983 cm3,直径6.8 cm×长度36 cm;美国Stuewe & Sons公司,硬塑料聚丙烯材质)中,同时,基质中加入控释肥(14N-13P2O5-13K2O,释放期5~6个月,济南乐喜施肥料有限公司),充分混匀。
造林试验地位于北京林业大学鹫峰林场森林培育学科造林试验地,属于温带季风气候,年平均气温13℃,年平均降水量629 mm。土壤理化性质见表 1。
表 1 试验地土壤理化性质
Table 1. Physical and chemical characteristics of soil in the experiment
土壤深度
Soil depth/cm粘粒
< 0.002 mm Clay/%粉粒
0.002~0.02 mm Powder/%砂粒
0.02~0.20 mm Sand/%pH值 有机质含量
Organic content/(g·kg-1)全氮含量
Nitrogen content/(mg·kg-1)有效磷含量
Available phosphorus content/(mg·kg-1)速效钾含量
Effective potassium content/(mg·kg-1)0~30 7.63 31.95 60.42 7.74 7.12 843.96 112.10 373.48 30~60 7.62 33.63 58.75 7.74 3.46 479.09 80.45 329.79 -
由表 2可知:施肥量和灌溉方式二者对苗高、地径、生物量和茎根比的影响存在交互效应(P < 0.05)。多重比较发现:225-O处理的地径、根和单株生物量最大,分别为5.77 mm、11.24 g和13.81 g。225-O与125-O、175-O、125-S、175-S之间的根生物量差异不显著,225-O与175-O、125-S之间的单株生物量差异不显著。225-S的苗高、茎生物量和茎根比最大,分别为55.2 cm、2.81 g和0.36;225-S与225-O间的茎生物量差异不显著。2种灌溉方式下,苗高、地径和茎生物量均随施肥量的增加而增大;上方喷灌的根和单株生物量随施肥量的增加而增大,底部渗灌的根和单株生物量随施肥量的增加呈先增大后减小的趋势,当施肥量大于125 mg·株-1时,根和单株生物量开始下降。
表 2 施肥量和灌溉方式对栓皮栎容器苗形态指标的影响及方差分析
Table 2. Effect of fertilizer rates and irrigation methods on Q. variabilis seedling morphological attributes and associated P>F
处理组合
Combinations苗高
Height/cm地径 Root-collar diameter/mm 生物量 Biomass/g 茎根比
Ratio of S:R茎 Stem 根 Root 单株 Plant 25-O 36.2±0.8 e 3.89±0.10 f 1.09±0.08 e 6.80±0.49 e 7.89±0.53 d 0.17±0.01 de 75-O 40.2±1.1 d 4.45±0.09 e 1.42±0.10 de 9.24±0.67 bc 10.66±0.74 bc 0.16±0.01 e 125-O 43.1±1.2 c 4.78±0.09 d 1.76±0.10 d 9.98±0.58 ab 11.74±0.61 bc 0.18±0.01 cde 175-O 43.8±0.6 c 5.14±0.10 b 2.10±0.11 c 10.16±0.54 ab 12.26±0.62 ab 0.21±0.01 bcd 225-O 53.6±0.9 a 5.77±0.17 a 2.57±0.26 ab 11.24±0.55 a 13.81±0.71 a 0.23±0.02 bc 25-S 36.1±0.2 e 3.81±0.11 f 1.20±0.09 e 7.12±0.50 cd 8.32±0.55 d 0.18±0.01 de 75-S 44.1±0.6 c 4.46±0.10 e 1.60±0.06 d 8.57±0.60 bcd 10.17±0.57 c 0.20±0.02 bcde 125-S 47.9±0.8 b 4.80±0.07 d 2.77±0.09 c 10.15±0.68 ab 12.22±0.68 ab 0.21±0.02 bcd 175-S 49.5±1.2 b 4.83±0.09 cd 2.24±0.12 bc 9.62±0.46 abc 11.86±0.51 bc 0.24±0.02 b 225-S 55.2±1.4 a 5.10±0.08 bc 2.81±0.15 a 8.04±0.60 cde 10.85±0.71 bc 0.36±0.03 a 方差分析显著性(P>F) 施肥量 Fertility rates < 0.000 1 < 0.000 1 < 0.000 1 < 0.000 1 < 0.000 1 < 0.000 1 灌溉方式 Irrigation methods < 0.000 1 0.001 0.020 0.032 0.140 < 0.000 1 施肥量×灌溉方式 F × I 0.014 0.003 < 0.000 1 0.019 0.047 0.002 注:表中字母为Duncan多重比较结果,同列相同字母表示差异不显著,同列不同字母表示差异显著(P < 0.05);下同。
Notes: Column values not followed by the same letter are significantly different according to Duncan's test. The same below. -
双因素方差分析结果表明,施肥量和灌溉方式二者对苗木茎、根的氮、磷、钾浓度的影响不存在交互效应。施肥量对茎和根的氮、磷浓度影响差异显著(P < 0.05),对茎和根的钾浓度影响差异不显著;灌溉方式对苗木养分浓度均无显著影响(未列方差分析结果)。从图 1可看出:苗木的氮、磷、钾浓度均随施肥量的增加而增大,当施肥量为225 mg·株-1时,茎和根的氮浓度、茎和根的磷浓度达到最大,分别为8.9和10.2 g·kg-1、2.3和1.9 g·kg-1,明显高于其他处理。茎的磷浓度在施肥量175、225 mg·株-1间差异不显著,根的磷浓度在施肥量125、175、225 mg·株-1间差异不显著。
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双因素方差分析结果表明,施肥量和灌溉方式二者对茎、根、单株的氮、磷、钾含量的影响不存在交互效应。施肥量对茎、根、单株的氮、磷、钾含量的影响均达到显著水平(P<0.05);灌溉方式对茎的氮、钾含量影响显著(P<0.05),而对根、单株的氮、磷、钾含量影响不显著(未列方差分析结果)。苗木茎、根、单株的氮、磷、钾含量均随施肥量的增加而增大,且在施肥量225 mg·株-1时达最大。根的氮、磷、钾含量和单株的磷、钾含量在施肥量125、175、225 mg·株-1间差异不显著(图 2)。底部渗灌的茎氮、钾含量比上方喷灌的分别提高了17.2%、19.6%(图 3)。
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双因素方差分析结果表明,施肥量和灌溉方式二者对根系表面积、体积的影响不存在交互效应。施肥量对根系表面积、体积的影响差异显著(P < 0.05),灌溉方式对根系表面积、体积影响不显著(未列方差分析结果)。根系表面积和体积随施肥量的增加而增大,当施肥量增加到225 mg·株-1时,根系表面积和体积达最大,分别为184 cm2和3.18 cm3。高施肥量(125、175、225 mg·株-1)间的根系表面积、体积差异不显著,但比低施肥量(25、75 mg·株-1)分别提高了7%~25%和12%~23%(图 4)。
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双因素方差分析结果表明,施肥量、灌溉方式及二者的交互效应对容器内上层、下层基质EC值的影响均达到显著水平(P<0.05)(未列方差分析结果)。上方喷灌的下层基质EC值、底部渗灌的上层、下层基质EC值均随施肥量的增加而增大,且底部渗灌的上层、下层基质EC值显著高于上方喷灌。225-S处理的上层、下层基质EC值均最大,且明显高于其他处理组合,分别为4.69、0.56 dS·m-1(图 5)。
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双因素方差分析结果表明,施肥量和灌溉方式二者对造林成活率、幼树树高和地径的影响不存在交互效应。单独施肥或灌溉方式对栓皮栎容器苗第1年、第2年的造林成活率影响不显著;施肥量对造林第1年、第2年的幼树树高和地径均影响显著(P<0.05),灌溉方式仅对造林第1年的幼树树高和地径影响显著(P<0.05)(未列方差分析结果)。从图 6可看出:造林后树高、地径均随施肥量的增加呈增大趋势,且在施肥量225 mg·株-1时达最大,造林第1年和第2年的树高、地径比造林初期分别增加了4.0~7.6 cm、0.82~1.75 mm和26.4 ~38.5 cm、6.79~8.93 mm。造林第2年,施肥量125、175、225 mg·株-1间的树高和地径差异不显著。底部渗灌的栓皮栎容器苗造林第1年的树高、地径比上方喷灌分别显著提高了4.6%和5.0%,造林第2年的树高、地径生长速度高于第1年,但2种灌溉方式间差异不显著(图 7)。
控释肥和灌溉方式对栓皮栎容器苗苗木质量及造林效果的影响
Effect of Controlled-release Fertilizer and Irrigation Method on Seedling Quality and Outplanting Performance of Quercus variabilis
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摘要:
目的 探讨控释肥和灌溉方式对栓皮栎(Quercus variabilis Bl.)容器苗生长、养分含量、基质电导率(EC)及2年造林效果的影响,为培育高质量苗木提供参考。 方法 以栓皮栎容器苗为研究对象,采用双因素完全随机试验设计,设置5个施肥水平(以N元素含量为基准,5个施肥水平分别为:25、75、125、175、225 mg·株-1)和2种灌溉方式(上方喷灌(O)、底部渗灌(S)),测定栓皮栎容器苗形态指标、养分含量、根系生长、基质EC值及连续2年造林效果。 结果 表明:(1)施肥量和灌溉方式二者对苗木形态指标影响存在交互效应,225-O处理的苗木地径、根生物量、单株生物量最大,但根生物量、单株生物量在225-O、125-S、175-O处理之间差异不显著。225-S处理的苗高、茎生物量、茎根比最大,茎生物量在225-S与225-O之间差异不显著。(2)苗木茎、根的氮磷钾浓度和含量随施肥量的增加而增大,施肥量125、175、225 mg·株-1处理之间的根氮、磷含量及单株磷含量差异不显著。(3)增加施肥量促进苗木根系的生长,施肥量为125、175、225 mg·株-1处理之间的根系表面积、体积差异不显著。(4)基质EC值随施肥量的增加而增大,底部渗灌显著提高了基质上层、下层的EC值,基质上层、下层的最大EC值分别为4.69、0.56 dS·m-1,没有对苗木生长产生不利影响。(5)和上方喷灌相比,底部渗灌显著地促进造林第1年幼树的树高、地径生长;造林第1年、第2年的树高和地径均随施肥量的增加而增大,造林第2年,施肥量125、175、225 mg·株-1处理之间的树高、地径差异不显著。 结论 底部渗灌提高了栓皮栎容器苗体内的养分含量,促进了造林第1年幼树树高、地径的生长。施加控释肥有利于苗期苗木质量的提高及造林后苗木的快速生长。综合考虑苗木质量、经济效益、环境利益,培育栓皮栎容器苗可选择底部渗灌和控释肥量为125 mg·株-1的组合(以N元素含量为基准)。 Abstract:Objective To investigate the effects of fertilizer rate and irrigation method on morphological attributes, nutrient status, medium electrical conductivity (EC) and 2-years' outplanting performance of containerized Quercus variabilis seedlings. Method Seedlings were raised with 5 fertilizer rates (25, 75, 125, 175, and 225 mg·plant-1) and 2 irrigation methods (overhead irrigation (O) and subirrigation (S)). The experiment was a two-factor completely randomize design. Morphological attributes, nutrient status, root growth, medium EC, and 2-years' outplanting performance were measured. Result Interaction of fertilizer rate and irrigation method significantly affected seedling growth. The root-collar diameter, root and total biomass of seedling reached maximum value with 225-O treatment. There was no significant difference on root and total plant biomass among 225-O, 125-S, and 175-O. The height, stem biomass, and S/R ratio of seedling reached maximum value with 225-S treatment. There was no significant difference on stem biomass among 225-S and 225-O. The nutrient concentration and content were improved with increasing fertilizer rate. There was no significant difference on root N, P content and total P content among 125, 175, and 225 mg·plant-1. Increasing fertilizer rate promoted root growth. There was no significant difference on root surface area and volume among 125, 175, and 225 mg·plant-1. Fertilization resulted in high medium EC. Subirrigation significantly increased medium EC in upper and bottom layer. The highest medium EC reached 4.69 dS·m-1 but did not have harmful effect on seedlings. Subirrigation improved the height and root-collar diameter of seedlings 1 year after outplanting. 2 years after outplanting, the height and root-collar diameter of seedlings grew greatly with increasing fertilizer rate, but there was no significant difference on height and root-collar diameter of seedlings among 125, 175, and 225 mg·plant-1. Conclusion Subirrigation improves nutrient content and 1-year's outplanting performance. Controlled-release fertilizer increased seedlings quality, and 2-years' outplanting performance. Considering seedling quality, economic benefits and environmental value, fertilizer rate of 125 mg·plant-1 and subirrigation was the optimum combination for container seedling production of this species. -
表 1 试验地土壤理化性质
Table 1. Physical and chemical characteristics of soil in the experiment
土壤深度
Soil depth/cm粘粒
< 0.002 mm Clay/%粉粒
0.002~0.02 mm Powder/%砂粒
0.02~0.20 mm Sand/%pH值 有机质含量
Organic content/(g·kg-1)全氮含量
Nitrogen content/(mg·kg-1)有效磷含量
Available phosphorus content/(mg·kg-1)速效钾含量
Effective potassium content/(mg·kg-1)0~30 7.63 31.95 60.42 7.74 7.12 843.96 112.10 373.48 30~60 7.62 33.63 58.75 7.74 3.46 479.09 80.45 329.79 表 2 施肥量和灌溉方式对栓皮栎容器苗形态指标的影响及方差分析
Table 2. Effect of fertilizer rates and irrigation methods on Q. variabilis seedling morphological attributes and associated P>F
处理组合
Combinations苗高
Height/cm地径 Root-collar diameter/mm 生物量 Biomass/g 茎根比
Ratio of S:R茎 Stem 根 Root 单株 Plant 25-O 36.2±0.8 e 3.89±0.10 f 1.09±0.08 e 6.80±0.49 e 7.89±0.53 d 0.17±0.01 de 75-O 40.2±1.1 d 4.45±0.09 e 1.42±0.10 de 9.24±0.67 bc 10.66±0.74 bc 0.16±0.01 e 125-O 43.1±1.2 c 4.78±0.09 d 1.76±0.10 d 9.98±0.58 ab 11.74±0.61 bc 0.18±0.01 cde 175-O 43.8±0.6 c 5.14±0.10 b 2.10±0.11 c 10.16±0.54 ab 12.26±0.62 ab 0.21±0.01 bcd 225-O 53.6±0.9 a 5.77±0.17 a 2.57±0.26 ab 11.24±0.55 a 13.81±0.71 a 0.23±0.02 bc 25-S 36.1±0.2 e 3.81±0.11 f 1.20±0.09 e 7.12±0.50 cd 8.32±0.55 d 0.18±0.01 de 75-S 44.1±0.6 c 4.46±0.10 e 1.60±0.06 d 8.57±0.60 bcd 10.17±0.57 c 0.20±0.02 bcde 125-S 47.9±0.8 b 4.80±0.07 d 2.77±0.09 c 10.15±0.68 ab 12.22±0.68 ab 0.21±0.02 bcd 175-S 49.5±1.2 b 4.83±0.09 cd 2.24±0.12 bc 9.62±0.46 abc 11.86±0.51 bc 0.24±0.02 b 225-S 55.2±1.4 a 5.10±0.08 bc 2.81±0.15 a 8.04±0.60 cde 10.85±0.71 bc 0.36±0.03 a 方差分析显著性(P>F) 施肥量 Fertility rates < 0.000 1 < 0.000 1 < 0.000 1 < 0.000 1 < 0.000 1 < 0.000 1 灌溉方式 Irrigation methods < 0.000 1 0.001 0.020 0.032 0.140 < 0.000 1 施肥量×灌溉方式 F × I 0.014 0.003 < 0.000 1 0.019 0.047 0.002 注:表中字母为Duncan多重比较结果,同列相同字母表示差异不显著,同列不同字母表示差异显著(P < 0.05);下同。
Notes: Column values not followed by the same letter are significantly different according to Duncan's test. The same below. -
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