氮、磷添加对亚热带毛竹林土壤水稳性团聚体及有机碳分布的影响

doi:10.11707/j.1001-7488.LYKX20220803

摘要/Abstract

摘要：

目的: 研究氮（N）、磷（P）添加对亚热带毛竹林土壤水稳性团聚体及土壤有机碳（SOC）分布的影响，揭示毛竹林SOC对N、P添加的响应特征，为N沉降背景下毛竹林固碳增汇提供数据支持。方法: 以NH₄NO₃为N源、NaH₂PO₄为P源，设置不同N、P添加量的4个处理：CK（0 kg·hm^?2a^?1 N+0 kg·hm^?2a^?1 P）、N（120 kg·hm^?2a^?1 N）、P（120 kg·hm^?2a^?1 P）和NP（120 kg·hm^?2a^?1 N+120 kg·hm^?2a^?1 P），3年后分析N、P添加对毛竹林土壤0~20、20~40 和40~60 cm土层不同粒级（>2、0.25~2、0. 053~0.25和<0.053 mm）团聚体含量、平均重量直径（MWD）、几何平均直径（GMD）及其SOC分布的影响。结果: 1）各土层土壤水稳性团聚体均以大团聚体（>0.25 mm）为主，各处理大团聚体含量均随土层加深而降低，微团聚体（<0.25 mm）含量随土层加深而增加。在0~20 cm土层，N处理显著增加微团聚体含量，对大团聚体含量无显著影响；P处理对团聚体组成无显著影响；NP处理显著增加微团聚体含量、降低大团聚体含量；各处理对水稳性团聚体MWD和GMD均无显著影响。在20~40和40~60 cm土层，与CK相比，各处理均呈大团聚体含量降低、微团聚体含量增加的趋势。在20~40 cm土层，P处理显著降低水稳性团聚体MWD和GMD，N处理对水稳性团聚体MWD和GMD无显著影响，NP处理显著降低水稳性团聚体MWD，对水稳性团聚体GMD无显著影响；在40~60 cm土层，各处理均显著降低水稳性团聚体MWD和GMD。2）与CK相比，N、P处理显著降低各土层SOC含量；NP处理对0~20和20~40 cm土层SOC含量均无显著影响，但显著降低40~60 cm土层SOC含量。3） N处理对0~20和40~60 cm土层土壤团聚体SOC贡献率均无显著影响，仅增加20~40 cm土层土壤大团聚体SOC贡献率、降低微团聚体SOC贡献率；NP处理显著降低各土层大团聚体SOC贡献率、增加微团聚体SOC贡献率；P处理对团聚体SOC贡献率的影响在20~40和40~60 cm土层与NP处理对其的影响趋势一致，对0~20 cm土层无显著影响。结论: N、P同时添加可在一定程度上减缓N或P单独添加引起的毛竹林SOC含量降低；P添加可促进SOC由大团聚体向微团聚体转移，增加SOC稳定性。在N素相对富集、P限制的亚热带森林土壤中，P添加可缓解N沉降引起的SOC含量降低，并在一定程度上促进SOC固定。

关键词: 氮沉降, 磷添加, 水稳性团聚体, 有机碳

Abstract:

Objective: This study aims to investigate the effects of nitrogen (N) and phosphorus (P) addition on soil water-stable aggregates and soil organic carbon (SOC) distribution in moso bamboo forest in subtropical China, and reveal the response of soil SOC in bamboo forest to N and P addition, providing data support for carbon sequestration and sink enhancement in bamboo forest under N deposition background. Method: In this study, NH₄NO₃ was used as N source, NaH₂PO₄ was used as P source and 4 treatments (CK: 0 kg·hm^?2a^?1N+0 kg·hm^?2a^?1P, N: 120 kg·hm^?2a^?1N, P: 120 kg·hm^?2a^?1P, NP: 120 kg·hm^?2a^?1N+120 kg·hm^?2a^?1P) were set. After N and P addition for 3 years, changes of different particle size (>2, 0.25?2, 0.053?0.25, and <0.053 mm) composition, mean weight diameter (MWD), geometric mean diameter (GMD) and SOC content were investigated. Result: 1) The content of water-stable aggregates in each soil layer was mainly macro-aggregates (>0.25 mm), and the content of macro-aggregates decreased with the increase of soil depth, while the content of micro-aggregates (<0.25 mm) increased with the increase of soil depth. In 0?20 cm soil layer, N treatment significantly increased the content of micro-aggregates, but had no significant effect on the content of macro-aggregates; P treatment had no significant effect on aggregate composition; NP treatment significantly increased the content of micro-aggregates and decreased the content of macro-aggregates; each treatment has no significant effect on MWD and GMD of water-stable aggregates. In 20?40 and 40?60 cm soil layer, the content of macro-aggregate decreased and the content of micro-aggregate increased in each treatment. In 20?40 cm soil layer, P treatment significantly reduced the MWD and GMD of water-stable aggregates, N treatment had no significant effect on MWD and GMD of water-stable aggregates, NP treatment significantly reduced the MWD of water-stable aggregates, and had no significant effect on GMD of water-stable aggregates. In 40?60 cm soil layer, each treatment significantly reduced the MWD and GMD of water-stable aggregates. 2) Compared with CK, N, and P treatment significantly reduced SOC content in each soil layer; NP treatment significantly reduced SOC content in 40?60 cm soil layer, but had no significant effect on SOC content in 0?20 and 20?40 cm soil layer. 3) N treatment only increased the SOC contribution rate of soil macro-aggregates in 20?40 cm soil layer, decreased the SOC contribution rate of soil micro-aggregates, but had no significant effect on the SOC contribution rate of soil aggregates in 0?20 and 40?60 cm soil layer; NP treatment significantly reduced the SOC contribution rate of macro-aggregates and increased the SOC contribution rate of micro-aggregates in each soil layer; the effect of P treatment on SOC contribution rate of aggregates in 20?40 and 40?60 cm soil layers was consistent with that of NP treatment, but there was no significant effect on 0?20 cm soil layer. Conclusion: NP addition could mitigate the decrease of SOC content caused by N and P addition to a certain extent. P addition could promote the transfer of SOC from macro-aggregates to micro-aggregates and increase the stability of soil carbon. Therefore, in subtropical forest soils where N is relatively rich and P is limited, P addition can alleviate the decrease of SOC content caused by N deposition and promote the sequestration of SOC to a certain extent.

Key words: nitrogen deposition, phosphorus addition, water-stable aggregate, organic carbon

中图分类号:

S714

臧艳,向宇轩,刘娟,姜培坤,吴家森,李永夫. 氮、磷添加对亚热带毛竹林土壤水稳性团聚体及有机碳分布的影响[J]. 林业科学, 2024, 60(7): 8-16.

Yan Zang,Yuxuan Xiang,Juan Liu,Peikun Jiang,Jiasen Wu,Yongfu Li. Effects of Nitrogen and Phosphorus Addition on Soil Water-Stable Aggregates and Organic Carbon Distribution in Moso Bamboo Forests in Subtropical China[J]. Scientia Silvae Sinicae, 2024, 60(7): 8-16.

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土层 Soil layer	处理 Treatments	pH	有机碳含量 Soil organic carbon content/（g·kg^?1）	有效磷含量 Available phosphorous content/（mg·kg^?1）	全氮含量 Total nitrogen content/（g·kg^?1）	全磷含量 Total phosphorus content/（g·kg^?1）
0~20 cm	CK	5.19±0.13Aa	28.64±0.33Aa	2.10±0.20Ca	1.80±0.01Ca	0.28±0.01Ba
	N	3.66±0.05Cb	23.76±0.77Ba	2.43±0.17BCa	1.66±0.03Da	0.27±0.02Ba
	P	3.81±0.02Cb	25.53±1.12Ba	12.57±1.01ABa	1.94±0.02Ba	0.32±0.01Aa
	NP	4.32±0.11Bb	29.32±0.91Aa	11.29±0.63Aa	2.33±0.03Aa	0.35±0.02Aa
20~40 cm	CK	4.58±0.13Aa	19.11±0.27Ab	0.65±0.07Cb	1.12±0.01Ab	0.26±0.01Aa
	N	4.04±0.07Ba	12.80±0.25Cb	0.92±0.20Cb	0.98±0.02Ab	0.22±0.01Bb
	P	4.52±0.24ABa	16.11±0.22Bb	1.64±0.17Bb	1.06±0.08Ab	0.27±0.01Ab
	NP	4.73±0.12Aa	18.11±0.57Ab	4.21±0.17Ab	1.08±0.06Ab	0.28±0.00Ab
40~60 cm	CK	4.81±0.46ABa	16.06±0.31Ac	0.65±0.13Bb	1.02±0.05Ab	0.24±0.00Bb
	N	4.30±0.15ABb	12.25±0.21Cb	0.19±0.07Cc	0.77±0.02Bc	0.20±0.00Cb
	P	3.90±0.04Bb	13.04±0.47Bc	1.38±0.13Ab	0.81±0.03Bc	0.26±0.02Bb
	NP	4.71±0.03Ab	11.58±0.20Cc	0.78±0.17Bb	1.07±0.04Ab	0.31±0.00Ab

土层 Soil layer	处理 Treatment	大团聚体Macro-aggregate			微团聚体Micro-aggregate
土层 Soil layer	处理 Treatment	>2 mm	0.25~2 mm	总和Sum	0.053~0.25 mm	< 0.053 mm	总和Sum
0~20 cm	CK	27.7±1.1ABa	57.3±0.7Aa	85.1±0.6Aa	8.0±0.8Bc	6.9±0.5Ac	14.9±0.6Bc
	N	27.1±2.9Aab	55.3±1.1Aa	82.3±2.7Aab	12.0±2.1ABc	5.7±1.6Ab	17.7±2.7Abc
	P	35.1±6.5Aa	52.3±6.7Aa	87.3±0.5Aa	7.4±0.2Bc	5.3±0.4Ac	12.7±0.5Bc
	NP	20.5±0.7Ba	58.9±2.3Aa	79.4±1.6Ba	13.8±1.7Ac	6.7±0.1Ab	20.6±1.6Ac
20~40 cm	CK	26.7±2.0Aa	51.1±1.8ABb	77.7±0.2Ab	11.7±0.9Bb	10.6±0.7Ab	22.3±0.2Bb
	N	25.4±0.9ABa	49.4±0.7Bb	74.8±0.6ABb	17.9±0.6Ab	7.3±0.3Bb	25.2±0.6ABb
	P	21.7±1.4ABab	51.3±1.6ABa	73.0±1.2Bb	16.3±1.2Ab	10.7±1.2Ab	27.0±1.2Ab
	NP	20.6±1.4Ba	54.5±0.7Aa	75.1±0.8ABb	17.7±0.7Ab	7.2±0.3Bb	24.9±0.8ABb
40~60 cm	CK	15.7±0.7Ab	46.4±1.0Ac	62.0±0.5Ac	20.9±1.0Ca	17.0±0.5Ca	38.0±0.5Ca
	N	15.6±0.1Ab	43.9±0.2ABc	59.5±0.2Bc	23.1±0.3BCa	17.4±0.4Ca	40.5±0.2Ba
	P	13.4±0.4Bb	41.5±0.6Ba	54.9±0.8Cc	26.1±0.6Aa	19.0±0.5Ba	45.1±0.8Aa
	NP	10.8±0.4Cb	43.3±0.7Bb	54.0±0.7Cc	24.6±0.5ABa	21.3±0.3Aa	46.0±0.7Aa

项目 Item	MWD	GMD	SOC	大团聚体含量Macro-aggregate content	微团聚体含量 Micro-aggregate content	大团聚体有机碳含量SOC content of macro-aggregate	微团聚体有机碳含量SOC content of micro-aggregate	大团聚体有机碳贡献率 SOC rate of macro-aggregate	微团聚体有机碳贡献率SOC rate of micro-aggregate
NA	14.21^***	15.11^***	33.59^***	15.11^***	15.11^***	42.74^***	0.56	1.79	5.30^*
PA	13.07^***	20.96^***	0.57	20.96^***	20.96^***	12.40^**	42.10^***	9.83^**	37.67^***
SL	251.43^***	573.01^***	667.66^***	573.01^***	573.01^***	731.24^***	1.57	40.36^***	154.75^***
NA×PA	2.07	0.01	106.73^***	0.01	0.01	21.79^***	83.92^***	3.34	14.72^***
NA×SL	5.25^*	4.86^*	4.56^*	4.86^*	4.86^*	0.94	21.22^***	1.63	4.79^*
PA×SL	3.77^*	7.40^**	8.86^***	7.40^**	7.40^**	3.74^*	17.45^***	0.71	2.35
NA×PA×SL	5.99^***	5.60^**	9.14^***	5.60^**	5.60^**	3.53^*	24.03^***	2.69	11.87^***

土层 Soil layer	处理Treatment	大团聚体Macro-aggregate			微团聚体Micro-aggregate
土层 Soil layer	处理Treatment	>2 mm	0.25~2 mm	总和Sum	0.053~0.25 mm	<0.053 mm	总和Sum
0~20 cm	CK	8.19±0.16ABa	15.98±0.30Aa	24.17±0.17Aa	2.15±0.11Bb	2.32±0.66Ba	4.47±0.70Ba
	N	6.40±1.13BCa	14.57±0.18Aa	20.97±1.16Ba	1.56±0.30Ba	1.23±0.19Ba	2.79±0.42Bb
	P	9.99±0.10Aa	11.86±0.50Ba	21.85±0.57ABa	2.17±0.11Bb	1.51±0.09Bb	3.68±0.08Bb
	NP	5.23±0.39Ca	14.70±0.77Aa	19.93±0.60Ba	4.91±0.55Aa	4.48±0.22Aa	9.39±0.71Aa
20~40 cm	CK	5.50±0.24Ab	8.21±0.42Ab	13.71±0.22Ab	2.46±0.20BCb	2.94±0.14Aa	5.40±0.06Aa
	N	3.67±0.10Bb	5.94±0.14Bb	9.61±0.22Cb	1.87±0.07Ca	1.31C±0.04a	3.18±0.10Cb
	P	4.93±0.35Ab	6.35±0.25Bb	11.27±0.13Bb	2.72±0.26ABa	2.11±0.23Ba	4.84±0.26Ba
	NP	5.50±0.42Ab	6.76±0.16Bb	12.26±0.55Bb	3.24±0.14Ab	2.61±0.01Ab	5.85±0.14Ab
40~60 cm	CK	3.27±0.08Ab	6.93±0.26Ac	10.19±0.18Ac	3.47±0.20Aa	2.40±0.04Aa	5.87±0.19Aa
	N	3.31±0.03Ab	4.64±0.19Bc	7.95±0.22Bb	2.62±0.02Ba	1.67±0.03Ba	4.30±0.01Ca
	P	2.63±0.22Bb	4.81±0.31Bc	7.44±0.48BCc	3.22±0.09Aa	2.38±0.17Aa	5.60±0.20Aa
	NP	2.45±0.13Bb	4.21±0.07Bc	6.67±0.19Cc	2.56±0.05Bb	2.35±0.03Ac	4.91±0.03Bc

土层 Soil layer	处理Treatment	大团聚体Macro-aggregate			微团聚体Micro-aggregate
土层 Soil layer	处理Treatment	>2 mm	0.25~2 mm	总和Sum	0.053~0.25 mm	< 0.053 mm	总和Sum
0~20 cm	CK	28.7±0.9Ba	57.0±0.4Ba	85.7±0.5Aa	7.7±0.3Bc	7.8±2.2Bb	15.5±2.3Ba
	N	26.7±4.1Ba	61.4±1.9Aa	88.1±2.2Aa	6.7±1.5Bb	5.2±0.9Bb	11.9±2.2Bb
	P	39.3±2.2Aa	46.8±3.8Ba	86.1±5.8Aa	8.4±0.4Bc	6.0±0.6Bc	14.2±0.8Bb
	NP	17.8±1.1Cab	50.2±2.9Ba	68.0±1.8Ba	16.7±1.6Ab	15.3±0.3Ab	32.0±1.8Aa
20~40 cm	CK	28.8±1.6Ab	42.9±1.6ABa	71.7±0.2Bb	12.8±0.9Cb	15.4±0.9Aa	29.0±0.2Ba
	N	28.7±0.6Aa	46.4±0.2Aa	75.1±0.7Ab	14.6±0.4BCa	10.3±0.4Ba	25.4±0.7Cab
	P	30.6±2.0Ab	39.4±2.0Ba	70.0±1.3Cb	16.9±1.4ABb	13.1±1.5ABa	32.1±1.3Ab
	NP	30.3±1.5Ab	37.4±0.4Ba	67.7±1.1Ca	17.9±0.8Aab	14.5±0.5Ab	35.2±1.1Ab
40~60 cm	CK	20.4±0.8Bb	43.1±1.1Ab	63.5±0.7Ac	21.6±1.0Aa	15.0±0.3Aa	36.6±0.7Ba
	N	27.0±0.3Aa	37.9±1.0Bb	60.6±0.7Ac	21.4±0.2Aa	13.7±0.5Aa	39.4±0.7Ba
	P	20.1±1.0Bb	36.9±1.6Bb	57.0±1.9Bc	24.8±1.5Aa	18.2±1.0Aa	43.0±2.0Aa
	NP	21.2±0.8ABa	36.4±0.3Bb	57.6±0.7Bb	22.1±0.6Aa	20.3±0.2Aa	42.4±0.7Aa