摘要: 目的研究带状采伐毛竹林中氮、磷、钾养分变化特征，为伐后竹林的养分管理策略提供科学依据、�/sec> 方法�? m带宽采伐样地（SC）及其保留样地（RB）为研究对象，以传统经营毛竹林（CK）为对照，调查伐�?年内不同处理样地毛竹生物量、林下灌草生物量、凋落物产量及各组分相应的养分含量，量化养分流通量，计算不同处理样地的养分循环系数，比较不同处理样地的养分流动及循环特征的差异、�/sec> 结果�?）伐后第1年，不同处理样地内毛竹氮、磷、钾的留存量无显著差异；采伐样地中氮、磷的归还量减少；（2）伐�?年，保留样地中氮的留存量小于采伐样地和对照样地；采伐样地和保留样地中氮的归还量显著低于对照样地。（3）伐�?年，保留样地中氮的留存量小于采伐样地和对照样地；采伐样地中氮、磷、钾的归还量、养分贮量均与对照样地无显著差异；（4）带状采伐显著增加了氮、磷、钾的利用系数（ P< 0.05），随着样地的恢复各养分的利用系数逐渐下降，与对照无差异；保留样地中各养分的利用系数随竹林生长显著降低＇�i>P< 0.05）；采伐对氮、磷、钾的循环系数无显著影响，保留样地中养分循环系数随时间逐渐增加、�/sec> 结论伐后5年氮、磷、钾养分贮量达到伐前和现期对照样地水平，从养分循环的角度证明伐后5年带状采伐样地能够恢复到对照样地水平。保留样地养分利用系数和循环系数从伐后第二个大年开始逐渐降低，需要进行密度调控，从而提高养分利用效率、�/sec>

关键诌�
• 毛竹枖�/a> /
• 带状采伐/
• 自然恢复/
• 养分循环

Abstract: ObjectiveTo study the dynamics of nitrogen (N), phosphorus (P), and potassium (K) nutrients in moso bamboo forest after strip cut, so as to provide a scientific basis for nutrient management strategies in the post cut bamboo forest. MethodWe selected the plots that strip cut with 8 m width (SC) and its reserved belts (RB) as the research object and the traditional management forest (CK) as control. The biomass of moso bamboo, understory vegetation, litter yield, and corresponding nutrient contents of each component was investigated for five years after cutting. Therefore, nutrient flux was quantified, and the nutrient cycling coefficient of the moso bamboo forest was calculated. The characteristics of nutrient flow and cycling were compared among different treatment plots. Result(1) In the first year after cutting, there was no significant difference in the retention of N, P, and K among different treatment plots. The return of nitrogen in SC was decreased; (2) Three years after cutting, the retention of nitrogen in the RB was less than that in the SC and CK; The return of nitrogen in SC and RB was significantly lower than that in CK. (3) Five years after cutting, the retention of nitrogen in RB was less than that in SC and CK; There was no significant difference in the amount of N, P and K returned and nutrient storage between the SC and CK. (4) Strip cutting significantly increased the utilization coefficients of N, P and K ( P< 0.05). With the restoration of the plots, the utilization coefficient of each nutrient gradually decreased, and there was no difference with CK; The utilization coefficients of nutrients in RB decreased significantly with the growth of bamboo forest ( P< 0.05); Cutting had no significant effect on the cycling coefficients of N, P and K, but the cycling coefficients of nutrients in RB gradually increased with time. ConclusionFive years after cutting, nitrogen, phosphorus, and potassium nutrient storage reached the level of the pre-cutting and CK. From the perspective of the nutrient cycle, it was proved that SC could recover to the level of CK after 5 years. However, the nutrient use coefficient and recycling coefficient of RB gradually decreased from the second On-year after cutting, and density control management was needed to improve the nutrient use efficiency.

Key words:
• Moso bamboo forest/
• Strip clearcutting/
• Natural restoration/
• Nutrient cycling

�?nbsp; 1不同处理样地毛竹地上、地下生物量变化动�?/p>

横坐标上部的柱状图代表毛竹地上部分新增生物量占比；横坐标下部的柱状图代表毛竹地下部分新增生物量占比。不同小写字母表示相同时间不同处理样地毛竹生物量存在显著差异＇�i>P< 0.05）；不同大写字母表示同一处理样地不同时间毛竹生物量存在显著差异（P< 0.05）。The column at the top of the abscissa represents the biomass of Moso bamboo in the aboveground part; The column at the bottom of the abscissa represents the biomass of Moso bamboo in the underground part. Different lowercase letters indicate a significant difference in biomass between the different treatment plots at the same times (P< 0.05); Different capital letters indicate a significant difference in biomass between the different times in the same treatment plot (P< 0.05).

Figure 1.Dynamics of above and underground biomass of Moso bamboo under different treatments

下载: 全尺寸图牆�/a> 幻灯牆�/a>

�?nbsp; 2不同处理样地养分留存年变化动�?/p>

星号表示研究地点在不同显著性水平上的差异，***�?*�?分别表示P< 0.001�?i>P< 0.01咋�i>P< 0.05� 下同。Asterisks indicate differences between study sites at different levels of significance. ***, **and * representP< 0.001,P< 0.01 andP< 0.05, respectively. The same below.

Figure 2.The annual changes of nutrient retention in the different treatment plots

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�?nbsp; 3不同处理样地养分归还年变化动�?/p>

Figure 3.The annual changes of nutrient return in different treatment plots

下载: 全尺寸图牆�/a> 幻灯牆�/a>

�?nbsp; 4不同处理样地养分贮量年变化动�?/p>

D图横坐标上、下部的柱状图分别代表毛竹地上、地下部分新增生物量占比。不同小写字母表示同一养分循环系数在不同处理样地间存在显著差异＇�i>P< 0.05）。The bar chart above and at the bottom of the abscissa represent the nutrient storage of the aboveground and underground part of Moso bamboo, respectively. Different lowercase letters indicate a significant differences in the same nutrient cycling coefficient between the different treatment plots (P< 0.05).

Figure 4.The annual changes of nutrient storage in different treatment plots

下载: 全尺寸图牆�/a> 幻灯牆�/a>

�?nbsp; 5不同处理样地养分循环系数

不同小写字母表示同一养分循环系数在不同处理样地间存在显著差异＇�i>P< 0.05）。Different lowercase letters indicate a significant differences in the same nutrient cycling coefficient between the different treatment plots (P< 0.05).

Figure 5.Nutrient cycling coefficient in different treatment plots

下载: 全尺寸图牆�/a> 幻灯牆�/a>

�?nbsp; 1试验样地基本信息

Table 1.Basic information of sample plots

样地 Plot	坡度 Slope/(°)	海拔 Altitude/m	密度/（株·hm�?� Density (individual·hm�?)	竹龄结构 Age structure Ⅰ∶Ⅱ∶Ⅱ�/td>	平均胸径 Mean DBH/cm	平均枝下� Mean height to crown base/m	平均竹高 Mean tree height/m
SC1	5	113	3 250	18�?7�?7	8.68	4.10	12.91
SC2	6	113	3 861	17�?3�?2	9.13	4.60	13.75
SC3	6	113	3 187	16�?8�?7	8.49	5.09	13.21
RB1	6	113	3 452	19�?0�?6	8.83	4.76	12.85
RB2	6	114	3 815	21�?8�?2	8.88	4.06	13.22
RB3	5	114	3 687	19�?1�?9	9.38	5.07	13.53
CK1	6	113	3 657	17�?2�?0	9.06	4.23	13.33
CK2	6	113	3 756	20:22:18	8.77	4.43	13.63
CK3	5	114	3 948	21�?3�?9	8.90	4.40	13.21
注：SC.采伐样地；RB.保留样地；CK. 对照。下同。Note: SC, strip cut plot; RB, reserved belts plot; CK, control. The same below.

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�?nbsp; 2采伐移出养分总量 kg/hm²

Table 2.The total amount of nutrients removed from cutting kg/ha

组分 Components	全氮 Total nitrogen	全磷 Total phosphorus	全钾 Total potassium
竹秆 Bamboo clum	189.07 ± 20.49	7.10 ± 0.65	112.60 ± 36.45
竹枝 Bamboo branch	41.69 ± 8.75	2.15 ± 0.46	19.04 ± 3.16
竹叶 Bamboo leaf	100.75 ± 6.92	5.79 ± 0.39	41.89 ± 7.39
合计 Total	331.51 ± 32.50	15.04 ± 0.53	173.54 ± 32.72

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�?nbsp; 3竹蔸生物量全干质量对胸径的拟合模型及养分含量

Table 3.The model of bamboo rhizome dry weight to DBH and nutrient content

竹龄 Age	模型 Model	全氮 Total nitrogen (TN)/(g·kg�?)	全磷 Total phosphorus (TP)/(g·kg�?)	全钾 Total potassium (TK)/(g·kg�?)
⅟�/td>	W= �?.858 2 + 1.319 6DDBH	4.140 ± 0.181	0.318 ± 0.027	3.466 ± 0.732
Ⅰ�/td>	W= �?.217 8 + 1.582 2DDBH	3.610 ± 0.214	0.502 ± 0.057	2.995 ± 0.382
Ⅱ�/td>	W= �?.455 1 + 1.628 8DDBH	3.472 ± 0.171	0.670 ± 0.019	2.112 ± 0.127
注：单株毛竹的竹蔸干质量单位为kg。Note：The unit of rhizome dry weight of single bamboo is kg.

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�?nbsp; 4不同处理样地养分循环年变化动态特�?/p>

Table 4.Dynamic characteristics of nutrient cycling in different treatment plots

养分循环系数 Nutrient cycling coefficient	元素 Element	样地 Plots	年份 Year
			2017	2018	2019	2020	2021
利用系数 Utilization coefficient	N	SC	0.51 ± 0.06Aa	0.25 ± 0.02Ac	0.43 ± 0.04Ab	0.16 ± 0.01Ad	0.28 ± 0.02Ac
		RB	0.26 ± 0.02Ca	0.12 ± 0.01Bc	0.18 ± 0.04Cb	0.10 ± 0.010Bc	0.13 ± 0.01Bc
		CK	0.34 ± 0.03Ba	0.10 ± 0.01Bc	0.31 ± 0.04Bab	0.10 ± 0.02Bc	0.27 ± 0.02Ab
	P	SC	0.50 ± 0.06Aa	0.30 ± 0.01Abc	0.39 ± 0.09Ab	0.24 ± 0.02Ac	0.28 ± 0.03Ac
		RB	0.25 ± 0.02Ba	0.21 ± 0.02Bb	0.25 ± 0.02Ba	0.13 ± 0.01Bc	0.11 ± 0.01Cc
		CK	0.31 ± 0.04Ba	0.18 ± 0.02Bbc	0.35 ± 0.03ABa	0.15 ± 0.01Bc	0.21 ± 0.04Bb
	K	SC	0.54 ± 0.06Aa	0.20 ± 0.01Acd	0.38 ± 0.03Ab	0.16 ± 0.02Ad	0.26 ± 0.05Ac
		RB	0.32 ± 0.02Aa	0.10 ± 0.00Bc	0.17 ± 0.05Bb	0.08 ± 0.01Bc	0.16 ± 0.02Bb
		CK	0.41 ± 0.05Aa	0.09 ± 0.02Bd	0.31 ± 0.04Ab	0.10 ± 0.02Bd	0.26 ± 0.05Ac
循环系数 Cycle coefficient	N	SC	0.16 ± 0.04Ac	0.43 ± 0.05Ab	0.14 ± 0.02Bc	0.53 ± 0.03Aa	0.19 ± 0.02Bc
		RB	0.13 ± 0.02Ad	0.29 ± 0.04Bb	0.20 ± 0.02Ac	0.45 ± 0.02Ba	0.29 ± 0.03Ab
		CK	0.15 ± 0.03Ab	0.44 ± 0.06Aa	0.17 ± 0.02ABb	0.45 ± 0.04Ba	0.19 ± 0.01Bb
	P	SC	0.11 ± 0.03Abc	0.21 ± 0.06Aa	0.08 ± 0.02Ac	0.16 ± 0.03Aab	0.10 ± 0.02Bbc
		RB	0.08 ± 0.01Abc	0.10 ± 0.03Bb	0.07 ± 0.00Ac	0.16 ± 0.02Aa	0.14 ± 0.01Aa
		CK	0.09 ± 0.02Aab	0.11 ± 0.01Ba	0.07 ± 0.00Ab	0.11 ± 0.02Ba	0.11 ± 0.02Ba
	K	SC	0.10 ± 0.03Abc	0.20 ± 0.03Aa	0.09 ± 0.01Cc	0.14 ± 0.04Ab	0.10 ± 0.02Bbc
		RB	0.08 ± 0.02Ac	0.18 ± 0.03Aab	0.16 ± 0.01Ab	0.21 ± 0.04Aa	0.17 ± 0.03Aab
		CK	0.08 ± 0.01Ab	0.18 ± 0.02Aa	0.11 ± 0.01Bb	0.16 ± 0.02Aa	0.10 ± 0.02Bb
注：不同大写字母表示相同时间同一养分循环系数在不同处理样地间存在显著差异＇�i>P< 0.05）；不同小写字母表示同一养分循环系数在同一样地内不同时间存在显著差异（P< 0.05）。Note: Different capital letters indicate a significant differences in the same nutrient cycling coefficient between the different treatment plots (P< 0.05); Different lowercase letters indicate that the cycling coefficient of the same nutrient is significantly different at different times in the same place (P< 0.05).

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