Response of soil respiration to addition of different forms of nitrogen and mowing in a saline-alkali grassland in the northern agro-pastoral ecotone
Shu-Ya HU1,2, Hua-Jie DIAO1,3, Hui-Ling WANG3, Yuan-Chao BO3, Yan SHEN1, Wei SUN4, Kuan-Hu DONG3, Jian-Hui HUANG1,2, Chang-Hui WANG,1,*1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China 2University of Chinese Academy of Sciences, Beijing 100049, China 3College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Jinzhong, Shanxi 030801, China 4Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun 130024, China
National Natural Science Foundation of China(31770526) National Natural Science Foundation of China(31872406) National Key R&D Program of China(2017YFA0604802) National Key R&D Program of China(2016YFC0500703)
Abstract Aims The agro-pastoral ecotone is considered as fragile ecosystems which are strongly affected by agriculture and animal husbandry. The saline-alkali grassland is a unique grassland type in the agro-pastoral ecotone. A large amount of fertilizers are used to increase productivity in this area, which also promotes the emission of reactive nitrogen (N) gases and leads to the changes in soil carbon and N cycles. Mowing is a primary management practice in the agro-pastoral grassland in northern China. In order to explore the impact of N addition and mowing on carbon dynamic in this saline-alkali grassland located in the agro-pastoral ecotone, we determined the response of soil respiration to N addition and mowing. Methods This study area is located in Youyu County, an agro-pastoral grassland ecosystem in northern China. The field experiment was set up in May, 2017. The treatments included: control (without mowing and mowing), addition of urea, addition of slow release urea, addition of urea + mowing, addition of slow release urea + mowing. Each treatment included 6 replicates. Therefore, there were totally 36 plots in this experiment. Soil respiration rate, soil temperature, soil moisture content, microbial biomass, inorganic N content, above-ground and below-ground biomass were measured under different treatments, and the cumulative carbon emissions and CO2 fluxes were calculated. Important findings Our results showed that: (1) Short-term (2017-2018) N addition significantly increased soil respiration rates and soil cumulative carbon emissions. Meanwhile, soil respiration rates and cumulative carbon emissions were significantly higher under urea treatment than those under slow release urea addition. (2) Mowing significantly reduced soil respiration rates and cumulative carbon emissions. (3) The interaction of short-term N addition and mowing had no significant effect on soil respiration rate. Therefore, short-term N addition can promote soil carbon release from the saline-alkali grassland in the agro-pastoral ecotone of northern China. Mowing can reduce soil respiration and decrease cumulative of carbon emissions. This may be because that mowing reduced the input of litter and further reduced soil substrate for microbes, which led to a decrease in soil microbial activity. However, long-term effect of N addition and mowing on soil carbon dynamics in saline-alkaline grasslands in the agro-pastoral ecotone still needs to be further explored. Keywords:mowing;nitrogen forms;soil respiration;agro-pastoral ecotone;saline-alkali grassland
PDF (1240KB)元数据多维度评价相关文章导出EndNote|Ris|Bibtex收藏本文 引用本文 胡姝娅, 刁华杰, 王惠玲, 薄元超, 申颜, 孙伟, 董宽虎, 黄建辉, 王常慧. 北方农牧交错带温性盐碱化草地土壤呼吸对不同形态氮添加和刈割的响应. 植物生态学报, 2020, 44(1): 70-79. DOI: 10.17521/cjpe.2019.0270 HU Shu-Ya, DIAO Hua-Jie, WANG Hui-Ling, BO Yuan-Chao, SHEN Yan, SUN Wei, DONG Kuan-Hu, HUANG Jian-Hui, WANG Chang-Hui. Response of soil respiration to addition of different forms of nitrogen and mowing in a saline-alkali grassland in the northern agro-pastoral ecotone. Chinese Journal of Plant Ecology, 2020, 44(1): 70-79. DOI: 10.17521/cjpe.2019.0270
新窗口打开|下载原图ZIP|生成PPT 图12017和2018年各处理间土壤含水量及土壤温度的季节动态(平均值+标准误差)。CK, 对照处理; M, 刈割处理; SUN, 添加缓释尿素处理; SUN + M, 添加缓释尿素+刈割处理; UN, 添加尿素处理; UN + M, 添加尿素+刈割处理。不同小写字母表示差异显著(p < 0.05)。
Fig. 1Seasonal dynamics of soil water content and soil temperature in 2017 and 2018 (mean + SE). CK, control treatment; M, mowing treatment; SUN, slow release urea treatment; SUN + M, slow release urea and mowing treatment; UN, urea treatment; UN + M, urea and mowing treatment. Different lowercase letters indicate significant differences (p < 0.05).
新窗口打开|下载原图ZIP|生成PPT 图2北方农牧交错带温性盐碱化草地不同处理的土壤呼吸速率季节动态(平均值+标准误差)。CK, 对照处理; M, 刈割处理; SUN, 添加缓释尿素处理; SUN + M, 添加缓释尿素+刈割处理; UN, 添加尿素处理; UN + M, 添加尿素+刈割处理。不同小写字母表示差异显著(p < 0.05)。
Fig. 2Seasonal dynamics of soil respiration rates under different treatments of saline-alkali grassland in the northern agricultural-pastoral ecotone (mean + SE). CK, control treatment; M, mowing treatment; SUN, slow release urea treatment; SUN + M, slow release urea and mowing treatment; UN, urea treatment; UN + M, urea and mowing treatment. Different lowercase letters indicate significant differences (p < 0.05).
Table 1 表1 表1氮添加、刈割及其交互作用对北方农牧交错带温性盐碱化草地土壤呼吸的影响 Table 1Effects of N addition, mowing and their interactions on soil respiration in saline-alkali grassland in the northern agricultural-pastoral ecotone
因素 Factor
df
F
P
测定时间 Measuring time (Time)
16
35.947
0.000
氮添加 Nitrogen addition (N)
2
3.955
0.020
刈割 Mowing
1
55.789
0.000
测定时间×氮添加 (Time × N)
32
0.547
0.981
测定时间×刈割 (Time × Mowing)
16
11.760
0.000
施氮处理×刈割 (N × Mowing)
2
0.150
0.481
测定时间×氮添加×刈割 (Time × N × Mowing)
32
0.579
0.977
*, correlation is significant at the 0.05 level; **, correlation is significant at the 0.01 level. *, 相关性在0.05水平上显著; **, 相关性在0.01水平上显著。
新窗口打开|下载原图ZIP|生成PPT 图3土壤呼吸对不同处理的响应(平均值+标准误差)。M, 刈割处理; SUN, 添加缓释尿素处理; SUN + M, 添加缓释尿素+刈割处理; UN, 添加尿素处理; UN + M, 添加尿素+刈割处理。不同小写字母表示差异显著(p < 0.05)。
Fig. 3Response of soil respiration to different treatments (mean + SE). M, mowing treatment; SUN, slow release urea treatment; SUN + M, slow release urea and mowing treatment; UN, urea treatment; UN + M, urea and mowing treatment. Different lowercase letters indicate significant differences (p < 0.05).
图4
新窗口打开|下载原图ZIP|生成PPT 图4北方农牧交错带温性盐碱化草地不同处理的生长季土壤CO2排放量(平均值+标准误差)。CK, 对照处理; M, 刈割处理; SUN, 添加缓释尿素处理; SUN + M, 添加缓释尿素+刈割处理; UN, 添加尿素处理; UN + M, 添加尿素+刈割处理。*, 差异性在0.05水平上显著。
Fig. 4CO2 cumulative emissions during the growing season under different treatments of saline-alkali grassland in the northern agricultural-pastoral ecotone (mean + SE). CK, control treatment; M, mowing treatment; SUN, slow release urea treatment; SUN + M, slow release urea and mowing treatment; UN, urea treatment; UN + M, urea and mowing treatment. *, difference is significant at the 0.05 level.
新窗口打开|下载原图ZIP|生成PPT 图5北方农牧交错带温性盐碱化草地不同处理的土壤呼吸速率与土壤温度和土壤水分的相关性。CK, 对照处理; M, 刈割处理; SUN, 添加缓释尿素处理; SUN + M, 添加缓释尿素+刈割处理; UN, 添加尿素处理; UN + M, 添加尿素+刈割处理。**, 相关性在0.01水平上显著。
Fig. 5Correlation between soil respiration rates and soil temperature and moisture under different treatments of saline-alkali grassland in the northern agricultural-pastoral ecotone. CK, control treatment; M, mowing treatment; SUN, slow release urea treatment; SUN + M, slow release urea and mowing treatment; UN, urea treatment; UN + M, urea and mowing treatment. **, correlation is significant at the 0.01 level.
3 讨论
3.1 土壤呼吸对短期氮添加的响应
短期不同形态氮添加提高了北方农牧交错带盐碱草地的土壤呼吸速率, 与其他****在紫花苜蓿(Medicago sativa)草地以及羊草草地中不同水平氮添加的研究结果(孙海燕等, 2018; 胡伟等, 2019)一致。2018年土壤呼吸速率对氮添加的响应大于2017年, 这可能是由于氮添加对土壤呼吸的影响存在累积效应(Du et al., 2018), 土壤呼吸对氮添加的响应依赖于氮添加的持续时间, 会随处理持续时间的增加而增强(Li et al., 2018b)。也有研究结果发现氮添加会降低荒漠草原土壤呼吸速率, 这是由于土壤中氮浓度的增加引起土壤酸化, 降低微生物生物量(Ye et al., 2018)、微生物活性和酶活性, 抑制了土壤微生物的呼吸(康静等, 2019)。我们研究地点的土壤类型属于盐碱化草地, 氮添加两年后土壤pH并未显著降低(p > 0.05), 这表明盐碱草地短期氮添加不会导致土壤呼吸速率受土壤酸化的影响而降低。施氮会增加土壤中有效氮含量(Kang et al., 2016), 有效氮含量的增加促进了植被生长, 使地下生物量增加(Li et al., 2018b), 提高土壤自养呼吸(Chen et al., 2016; Li et al., 2018b); 土壤有效氮含量的增加还会改变土壤微生物群落结构(Zhou et al., 2017), 增加土壤微生物生物量和微生物活性(Zhang et al., 2017a), 提高土壤异养呼吸。本研究结果发现氮添加显著提高土壤有效氮含量; 2018年氮添加处理下土壤无机氮(NH4-N、NO3-N)含量比2017年氮添加处理下增加25% (p < 0.01), 土壤呼吸速率与微生物生物量碳显著正相关(表3)。土壤有效氮的增加促进土壤微生物生长, 提高微生物代谢效率, 从而提高土壤呼吸速率。土壤呼吸速率与无机氮呈负相关关系可能是由于氮添加导致土壤氮有效性增加, 地上地下生物量比值显著增加(p < 0.01), 植物对地下部分分配比例降低, 自养呼吸速率降低而产生的。
Table 3 表3 表3北方农牧交错带温性盐碱化草地土壤呼吸与土壤微生物, 土壤理化性质的相关性 Table 3Pearson’s correlation between soil respiration and soil microorganisms, and soil physical and chemical properties of saline-alkaline grasslands in the northern agricultural-pastoral ecotone
SR
NH4+
NO3-
BNPP
AGB
BGB
Litter
MBC
MBN
MBC/MBN
DOC
SR
1.000
NH4+
-0.412**
1.000
NO3-
-0.321**
0.450**
1.000
BNPP
0.072
0.108
0.295*
1.000
AGB
-0.013
0.468**
0.433**
0.233*
1.000
BGB
0.005
-0.139
-0.358**
-0.102
-0.032
1.000
Litter
-0.189
0.622**
0.536**
0.180
0.489**
-0.193
1.000
MBC
0.253*
-0.363**
-0.372**
-0.029
-0.138
0.380**
-0.337**
1.000
MBN
0.191
-0.314**
-0.248*
-0.231
-0.219
0.316**
-0.281*
0.561**
1.000
MBC/MBN
0.026
0.166
-0.066
0.215
0.043
0.162
0.026
0.185
-0.306**
1.000
DOC
0.194
-0.190
-0.410**
-0.180
-0.134
0.187
-0.341**
0.327**
0.096
0.064
1.000
*, correlation is significant at the 0.05 level; **, correlation is significant at the 0.01 level. BNPP, net below-ground biomass; AGB, above-ground biomass; BGB, below-ground biomass; Litter, litter biomass; MBC, microbial biomass carbon; MBN, microbial biomass nitrogen; DOC, dissolved organic carbon; SR, soil respiration rates. *, 相关性在0.05水平上显著; **, 相关性在0.01水平上显著。AGB, 地上生物量; BGB, 地下生物量; BNPP, 净地下生物量; DOC, 可溶性有机碳; Litter, 凋落物生物量; MBC, 微生物生物量碳; MBN, 微生物生物量氮; SR, 土壤呼吸速率。
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Soil acidification exerts a greater control on soil respiration than soil nitrogen availability in grasslands subjected to long-term nitrogen enrichment 1 2016
... 短期不同形态氮添加提高了北方农牧交错带盐碱草地的土壤呼吸速率, 与其他****在紫花苜蓿(Medicago sativa)草地以及羊草草地中不同水平氮添加的研究结果(孙海燕等, 2018; 胡伟等, 2019)一致.2018年土壤呼吸速率对氮添加的响应大于2017年, 这可能是由于氮添加对土壤呼吸的影响存在累积效应(Du et al., 2018), 土壤呼吸对氮添加的响应依赖于氮添加的持续时间, 会随处理持续时间的增加而增强(Li et al., 2018b).也有研究结果发现氮添加会降低荒漠草原土壤呼吸速率, 这是由于土壤中氮浓度的增加引起土壤酸化, 降低微生物生物量(Ye et al., 2018)、微生物活性和酶活性, 抑制了土壤微生物的呼吸(康静等, 2019).我们研究地点的土壤类型属于盐碱化草地, 氮添加两年后土壤pH并未显著降低(p > 0.05), 这表明盐碱草地短期氮添加不会导致土壤呼吸速率受土壤酸化的影响而降低.施氮会增加土壤中有效氮含量(Kang et al., 2016), 有效氮含量的增加促进了植被生长, 使地下生物量增加(Li et al., 2018b), 提高土壤自养呼吸(Chen et al., 2016; Li et al., 2018b); 土壤有效氮含量的增加还会改变土壤微生物群落结构(Zhou et al., 2017), 增加土壤微生物生物量和微生物活性(Zhang et al., 2017a), 提高土壤异养呼吸.本研究结果发现氮添加显著提高土壤有效氮含量; 2018年氮添加处理下土壤无机氮(NH4-N、NO3-N)含量比2017年氮添加处理下增加25% (p < 0.01), 土壤呼吸速率与微生物生物量碳显著正相关(表3).土壤有效氮的增加促进土壤微生物生长, 提高微生物代谢效率, 从而提高土壤呼吸速率.土壤呼吸速率与无机氮呈负相关关系可能是由于氮添加导致土壤氮有效性增加, 地上地下生物量比值显著增加(p < 0.01), 植物对地下部分分配比例降低, 自养呼吸速率降低而产生的. ...
Differential responses of short-term soil respiration dynamics to the experimental addition of nitrogen and water in the temperate semi-arid steppe of Inner Mongolia, China 1 2014
... 草地外源氮(N)输入不仅会直接影响土壤呼吸速率的大小, 还会通过改变植被组成、根系生长、土壤微生物活性(Peng et al., 2017)以及土壤微环境等因子直接或间接影响土壤呼吸和土壤碳排放(贺云龙等, 2018).研究发现土壤呼吸受草地类型、施氮水平、施氮年限、施氮频次等方面的影响(王丹和陈永金, 2015; Peng et al., 2017; 胡伟等, 2019; 康静等, 2019).但是由于氮添加时间、氮添加年限、氮的形态以及添加氮的水平在不同的控制实验存在差异, 因此草地土壤呼吸速率对氮添加的响应尚无定论, 基于上述处理的不同, 现有的研究发现氮添加对土壤呼吸的影响有促进(Peng et al., 2011; 张蔷等, 2017), 无影响(Liu & Greaver, 2010; Qi et al., 2014)和抑制(Li et al., 2018a; Wei et al., 2018)作用等.对于草地利用方式而言, 刈割对不同类型草地以及相同类型下不同利用方式草地的土壤呼吸都会产生差异性影响(孙振中等, 2012; 马俐等, 2016). ...
Soil respiration and the global carbon cycle 1 2000
Reconciling multiple impacts of nitrogen enrichment on soil carbon: Plant, microbial and geochemical controls 1 2018
... 短期不同形态氮添加提高了北方农牧交错带盐碱草地的土壤呼吸速率, 与其他****在紫花苜蓿(Medicago sativa)草地以及羊草草地中不同水平氮添加的研究结果(孙海燕等, 2018; 胡伟等, 2019)一致.2018年土壤呼吸速率对氮添加的响应大于2017年, 这可能是由于氮添加对土壤呼吸的影响存在累积效应(Du et al., 2018), 土壤呼吸对氮添加的响应依赖于氮添加的持续时间, 会随处理持续时间的增加而增强(Li et al., 2018b).也有研究结果发现氮添加会降低荒漠草原土壤呼吸速率, 这是由于土壤中氮浓度的增加引起土壤酸化, 降低微生物生物量(Ye et al., 2018)、微生物活性和酶活性, 抑制了土壤微生物的呼吸(康静等, 2019).我们研究地点的土壤类型属于盐碱化草地, 氮添加两年后土壤pH并未显著降低(p > 0.05), 这表明盐碱草地短期氮添加不会导致土壤呼吸速率受土壤酸化的影响而降低.施氮会增加土壤中有效氮含量(Kang et al., 2016), 有效氮含量的增加促进了植被生长, 使地下生物量增加(Li et al., 2018b), 提高土壤自养呼吸(Chen et al., 2016; Li et al., 2018b); 土壤有效氮含量的增加还会改变土壤微生物群落结构(Zhou et al., 2017), 增加土壤微生物生物量和微生物活性(Zhang et al., 2017a), 提高土壤异养呼吸.本研究结果发现氮添加显著提高土壤有效氮含量; 2018年氮添加处理下土壤无机氮(NH4-N、NO3-N)含量比2017年氮添加处理下增加25% (p < 0.01), 土壤呼吸速率与微生物生物量碳显著正相关(表3).土壤有效氮的增加促进土壤微生物生长, 提高微生物代谢效率, 从而提高土壤呼吸速率.土壤呼吸速率与无机氮呈负相关关系可能是由于氮添加导致土壤氮有效性增加, 地上地下生物量比值显著增加(p < 0.01), 植物对地下部分分配比例降低, 自养呼吸速率降低而产生的. ...
Association of white clover ( Trifolium repens L.) with rhizobia of sv. trifolii belonging to three genomic species in alkaline soils in North and East China 1 2016