共查询到20条相似文献，搜索用时 31 毫秒
1.
Kang Ni Weixin Ding M. Zaman Zucong Cai Yufeng Wang Xilin Zhang Baoku Zhou 《Biology and Fertility of Soils》2012,48(8):973-979
Nitrous oxide emission (N2O) from applied fertilizer across the different agricultural landscapes especially those of rainfed area is extremely variable (both spatially and temporally), thus posing the greatest challenge to researchers, modelers, and policy makers to accurately predict N2O emissions. Nitrous oxide emissions from a rainfed, maize-planted, black soil (Udic Mollisols) were monitored in the Harbin State Key Agroecological Experimental Station (Harbin, Heilongjiang Province, China). The four treatments were: a bare soil amended with no N (C0) or with 225?kg?N ha?1 (CN), and maize (Zea mays L.)-planted soils fertilized with no N (P0) or with 225?kg?N ha?1 (PN). Nitrous oxide emissions significantly (P?<?0.05) increased from 141?±?5?g N2O-N?ha?1 (C0) to 570?±?33?g N2O-N?ha?1 (CN) in unplanted soil, and from 209?±?29?g N2O-N?ha?1 (P0) to 884?±?45?g N2O-N?ha?1 (PN) in planted soil. Approximately 75?% of N2O emissions were from fertilizer N applied and the emission factor (EF) of applied fertilizer N as N2O in unplanted and planted soils was 0.19 and 0.30?%, respectively. The presence of maize crop significantly (P?<?0.05) increased the N2O emission by 55?% in the N-fertilized soil but not in the N-unfertilized soil. There was a significant (P?<?0.05) interaction effect of fertilization?×?maize on N2O emissions. Nitrous oxide fluxes were significantly affected by soil moisture and soil temperature (P?<?0.05), with the temperature sensitivity of 1.73–2.24, which together explained 62–76?% of seasonal variation in N2O fluxes. Our results demonstrated that N2O emissions from rainfed arable black soils in Northeast China primarily depended on the application of fertilizer N; however, the EF of fertilizer N as N2O was low, probably due to low precipitation and soil moisture. 相似文献
2.
为研究氮肥施用对玉米根际呼吸和土壤基础呼吸温度敏感性的影响,采用动态密闭气室红外CO2分析法,于2010年进行田间试验,该试验设4个处理：裸地不施氮肥（CK）、裸地施氮肥（CK-N）、种植玉米不施加氮肥（M）、种植玉米施加氮肥（M-N）,观测玉米田土壤呼吸各组分的日变化规律,同时观测土壤温度、气温等环境因子。结果表明,不种植玉米处理（CK和CK-N）土壤呼吸速率（土壤基础呼吸）为0.57～1.23μmol·m-2·s-1,施加氮肥对土壤基础呼吸没有显著影响;种植玉米条件下,施氮处理（M-N）的季节平均土壤呼吸速率为3.14μmol·m-2·s-1,显著高于不施氮处理（M）,增幅达31.9%。CK和CK-N处理的土壤基础呼吸温度敏感系数Q10分别为1.20、1.25,而不施氮和施氮条件下玉米根际呼吸的Q10值则分别为1.27、1.49。施加氮肥导致玉米根际呼吸温度敏感性明显增强（Q10值增大）,而土壤基础呼吸的温度敏感性则无明显变化,两种效应的叠加使得种植玉米土壤的总呼吸速率温度敏感性明显增加。 相似文献
3.
Data from a 49-year-long organic–mineral fertilization field experiment with a potato–maize–maize–wheat–wheat crop rotation were used to analyse the impact of different fertilizer variations on yield ability, soil organic carbon content (SOC), N and C balances, as well as on some characteristic energy balance parameters. Among the treatments, the fertilization variant with 87 kg ha?1 year?1 N proved to be economically optimal (94% of the maximum). Approximately 40 years after initiation of the experiment, supposed steady-state SOC content has been reached, with a value of 0.81% in the upper soil layer of the unfertilized control plot. Farmyard manure (FYM) treatments resulted in 10% higher SOC content compared with equivalent NPK fertilizer doses. The best C balances were obtained with exclusive mineral fertilization variants (?3.8 and ?3.7 t ha?1 year?1, respectively). N uptake in the unfertilized control plot suggested an airborne N input of 48 kg ha?1 year?1. The optimum fertilizer variant (70 t ha?1 FYM-equivalent NPK) proved favourable with a view to energy. The energy gain by exclusive FYM treatments was lower than with sole NPK fertilization. Best energy intensity values were obtained with lower mineral fertilization and FYM variants. The order of energy conversion according to the different crops was maize, wheat and potato. 相似文献
4.
Agricultural soils receive large amounts of anthropogenic nitrogen (N), which directly and indirectly affect soil organic matter (SOM) stocks and CO2 fluxes. However, our current understanding of mechanisms on how N fertilization affects SOM pools of various ages and turnover remains poor. The δ13C values of SOM after wheat (C3)-maize (C4) vegetation change were used to calculate the contribution of C4-derived rhizodeposited C (rhizo-C) and C3-derived SOM pools, i.e., rhizo-C and SOM. Soil (Ap from Haplic Luvisol) sampled from maize rhizosphere was incubated over 56 days with increasing N fertilization (four levels up to 300 kg N ha?1), and CO2 efflux and its δ13C were measured. Nitrogen fertilization decreased CO2 efflux by 27–42% as compared to unfertilized soil. This CO2 decrease was mainly caused by the retardation of SOM (C3) mineralization. Microbial availability of rhizo-C (released by maize roots within 4 weeks) was about 10 times higher than that of SOM (older than 4 weeks). Microbial biomass and dissolved organic C remained at the same level with increasing N. However, N fertilization increased the relative contribution of rhizo-C to microbial biomass by two to five times and to CO2 for about two times. This increased contribution of rhizo-C reflects strongly accelerated microbial biomass turnover by N addition. The decomposition rate of rhizo-C was 3.7 times faster than that of SOM, and it increased additionally by 6.5 times under 300 kg N ha?1 N fertilization. This is the first report estimating the turnover and incorporation of very recent rhizo-C (4 weeks old) into soil C pools and shows that the turnover of rhizo-C was much faster than that of SOM. We conclude that the contribution of rhizo-C to CO2 and to microbial biomass is highly dependent on N fertilization. Despite acceleration of rhizo-C turnover, the increased N fertilization facilitates C sequestration by decreasing SOM decomposition. 相似文献
5.
There is a knowledge gap on biochar carbon (C) longevity and its priming effects on soil organic carbon (SOC) and recent root-derived C under field conditions. This knowledge would allow the potential of biochar in long-term soil C sequestration to be established. However, most studies on biochar C longevity and its priming effect have been undertaken in plant-free laboratory incubations.A 388 d field study was carried out in the presence of an annual ryegrass (C3) growing on a rhodic ferralsol with established C3/C4 plant-derived SOC (δ13C: −20.2‰) in a subtropical climate. A 13C-depleted hardwood biochar (δ13C: −35.7‰, produced at 450 °C) was applied at 0 and 30 dry t ha−1 and mixed into the top 100-mm soil profile (equivalent to 3% w/w). We report on the differentiation and quantification of root respiration and mineralisation of soil-C and biochar-C in the field. Periodic 13CO2 pulse labelling was applied to enrich δ13C of root respiration during two separate winter campaigns (δ13C: 151.5–184.6‰) and one summer campaign (δ13C: 19.8–31.5‰). Combined soil plus root respiration was separated from leaf respiration using a novel in-field respiration collar. A two-pool isotope mixing model was applied to partition three C sources (i.e. root, biochar and soil). Three scenarios were used to assess the sensitivity associated with the C source partitioning in the planted systems: 1) extreme positive priming of recent SOC derived from the current ryegrass (C3) pasture; 2) equivalent magnitude of priming of SOC and labile root C; and 3) extreme positive priming of the native C4-dominant SOC.We showed that biochar induced a significant negative priming of SOC in the presence of growing plants but no net priming was observed in the unplanted soil. We also demonstrated the importance of experimental timeframe in capturing the transient nature of biochar-induced priming, from positive (day 0–62) to negative (day 62–388). The presence/absence of plants had no impact on biochar-C mineralisation in this ferralsol during the measurement period. Based on a two-pool exponential model, the mean residence time (MRT) of biochar varied from 351 to 449 years in the intensive pasture system to 415–484 years in the unplanted soils. 相似文献
6.
Carbon Dioxide Emission from Black Soil as Influenced by Land‐Use Change and Long‐Term Fertilization
《Communications in Soil Science and Plant Analysis》2012,43(7-8):1350-1368
Land‐use change and soil management play a vital role in influencing losses of soil carbon (C) by respiration. The aim of this experiment was to examine the impact of natural vegetation restoration and long‐term fertilization on the seasonal pattern of soil respiration and cumulative carbon dioxide (CO2) emission from a black soil of northeast China. Soil respiration rate fluctuated greatly during the growing season in grassland (GL), ranging from 278 to 1030 mg CO2 m?2 h?1 with an average of 606 mg CO2 m?2 h?1. By contrast, soil CO2 emission did not change in bareland (BL) as much as in GL. For cropland (CL), including three treatments [CK (no fertilizer application), nitrogen, phosphorus and potassium application (NPK), and NPK together with organic manure (OM)], soil CO2 emission gradually increased with the growth of maize after seedling with an increasing order of CK < NPM < OM, reaching a maximum on 17 August and declining thereafter. A highly significant exponential correlation was observed between soil temperature and soil CO2 emission for GL during the late growing season (from 3 August to 28 September) with Q10 = 2.46, which accounted for approximately 75% of emission variability. However, no correlation was found between the two parameters for BL and CL. Seasonal CO2 emission from rhizosphere soil changed in line with the overall soil respiration, which averaged 184, 407, and 584 mg CO2 m?2 h?1, with peaks at 614, 1260, and 1770 mg CO2 m?2 h?1 for CK, NPK, and OM, respectively. SOM‐derived CO2 emission of root free‐soil, including basal soil respiration and plant residue–derived microbial decomposition, averaged 132, 132, and 136 mg CO2 m?2 h?1, respectively, showing no difference for the three CL treatments. Cumulative soil CO2 emissions decreased in the order OM > GL > NPK > CK > BL. The cumulative rhizosphere‐derived CO2 emissions during the growing season of maize in cropland accounted for about 67, 74, and 80% of the overall CO2 emissions for CK, NPK, and OM, respectively. Cumulative CO2 emissions were found to significantly correlate with SOC stocks (r = 0.92, n = 5, P < 0.05) as well as with SOC concentration (r = 0.97, n = 5, P < 0.01). We concluded that natural vegetation restoration and long‐term application of organic manure substantially increased C sequestration into soil rather than C losses for the black soil. These results are of great significance to properly manage black soil as a large C pool in northeast China. 相似文献
7.
For a quantitative analysis of SOC dynamics it is necessary to trace the origins of the soil organic compounds and the pathways of their transformations. We used the 13C isotope to determine the incorporation of maize residues into the soil organic carbon (SOC), to trace the origin of the dissolved organic carbon (DOC), and to quantify the fraction of the maize C in the soil respiration. The maize‐derived SOC was quantified in soil samples collected to a depth of 65 cm from two plots, one ’︁continuous maize’ and the other ’︁continuous rye’ (reference site) from the long‐term field experiment ’︁Ewiger Roggen’ in Halle. This field trial was established in 1878 and was partly changed to a continuous maize cropping system in 1961. Production rates and δ13C of DOC and CO2 were determined for the Ap horizon in incubation experiments with undisturbed soil columns. After 37 years of continuous maize cropping, 15% of the total SOC in the topsoil originated from maize C. The fraction of the maize‐derived C below the ploughed horizon was only 5 to 3%. The total amount of maize C stored in the profile was 9080 kg ha−1 which was equal to about 31% of the estimated total C input via maize residues (roots and stubble). Total leaching of DOC during the incubation period of 16 weeks was 1.1 g m−2 and one third of the DOC derived from maize C. The specific DOC production rate from the maize‐derived SOC was 2.5 times higher than that from the older humus formed by C3 plants. The total CO2‐C emission for 16 weeks was 18 g m−2. Fifty‐eight percent of the soil respiration originated from maize C. The specific CO2 formation from maize‐derived SOC was 8 times higher than that from the older SOC formed by C3 plants. The ratio of DOC production to CO2‐C production was three times smaller for the young, maize‐derived SOC than for the older humus formed by C3 plants. 相似文献
8.
利用~(13)C标记和自然丰度三源区分玉米根际CO_2释放 总被引：1，自引：1，他引：0
石灰性土壤中,根际土壤释放的CO_2有三个来源,即根源呼吸、土壤有机碳(SOC)分解和土壤无机碳(SIC)溶解,三源区分土壤释放的CO_2是量化土壤碳平衡的前提。分别在玉米拔节期、抽穗期和灌浆期进行7 h的~(13)O_2脉冲标记,经过27 d示踪期后破坏性取样,测定~(13)标记与自然丰度处理中,玉米地上部、根系、土壤和土壤CO_2的碳含量和δ~(13)值,利用~(13)示踪并结合自然丰度法区分玉米土壤CO_2的来源。研究结果显示,随着玉米生长,根源呼吸对土壤CO_2的贡献呈降低趋势,从拔节期的66.7%降低至灌浆期的25.8%。整个玉米旺盛生育期内(从拔节期到生育期末),根源呼吸和土壤总碳释放对土壤CO_2具有同等贡献,SOC和SIC释放对土壤总碳释放的贡献率分别为30%和20%。玉米生长对土壤的碳输入(根系+根际沉积物)超过土壤总碳(SIC+SOC)的释放,总体表现为土壤碳汇。研究表明,SIC溶解对全球碳库稳定性和调节CO_2浓度的影响非常重要,若忽视石灰性土壤中SIC溶解,则会高估SOC的分解,进而影响SOC激发效应以及土壤碳平衡的评估。 相似文献
9.
Yo Toma Fumiaki Takakai Untung Darung Kanta Kuramochi Suwido H. Limin Salampak Dohong 《Soil Science and Plant Nutrition》2013,59(3):436-451
Our previous research showed large amounts of nitrous oxide (N2O) emission (>200?kg?N?ha?1?year?1) from agricultural peat soil. In this study, we investigated the factors influencing relatively large N2O fluxes and the source of nitrogen (N) substrate for N2O in a tropical peatland in central Kalimantan, Indonesia. Using a static chamber method, N2O and carbon dioxide (CO2) fluxes were measured in three conventionally cultivated croplands (conventional), an unplanted and unfertilized bare treatment (bare) in each cropland, and unfertilized grassland over a three-year period. Based on the difference in N2O emission from two treatments, contribution of the N source for N2O was calculated. Nitrous oxide concentrations at five depths (5–80?cm) were also measured for calculating net N2O production in soil. Annual N fertilizer application rates in the croplands ranged from 472 to 1607?kg?N?ha?1?year?1. There were no significant differences in between N2O fluxes in the two treatments at each site. Annual N2O emission in conventional and bare treatments varied from 10.9 to 698 and 6.55 to 858?kg?N?ha?1?year?1, respectively. However, there was also no significant difference between annual N2O emissions in the two treatments at each site. This suggests most of the emitted N2O was derived from the decomposition of peat. There were significant positive correlations between N2O and CO2 fluxes in bare treatment in two croplands where N2O flux was higher than at another cropland. Nitrous oxide concentration distribution in soil measured in the conventional treatment showed that N2O was mainly produced in the surface soil down to 15?cm in the soil. The logarithmic value of the ratio of N2O flux and nitrate concentration was positively correlated with water filled pore space (WEPS). These results suggest that large N2O emission in agricultural tropical peatland was caused by denitrification with high decomposition of peat. In addition, N2O was mainly produced by denitrification at high range of WFPS in surface soil. 相似文献
10.
Understanding rhizodeposited carbon (C) dynamics of winter wheat (Triticum aestivum L.) is important for improving soil fertility and increasing soil C stocks. However, the effects of nitrogen (N) fertilization on photosynthate C allocation to rhizodeposition of wheat grown in an intensively farmed alkaline soil remain elusive. In this study, pot‐grown winter wheat under N fertilization of 250 kg N ha?1 was pulse‐labeled with 13CO2 at tillering, elongation, anthesis, and grain‐filling stages. The 13C in shoots, roots, soil organic carbon (SOC), and rhizosphere‐respired CO2 was measured 28 d after each 13C labeling. The proportion of net‐photosynthesized 13C recovered (shoots + roots + soil + soil respired CO2) in the shoots increased from 58–64% at the tillering to 86–91% at the grain‐filling stage. Likewise, the proportion in the roots decreased from 21–28% to 2–3%, and that in the SOC pool increased from 1–2% to 6–7%. However, the 13C respired CO2 allocated to soil peaked (17–18%) at the elongation stage and decreased to 6–8% at the grain‐filling stage. Over the entire growth season of wheat, N fertilization decreased the proportion of net photosynthate C translocated to the below‐ground pool by about 20%, but increased the total amount of fixed photosynthate C, and therefore increased the below‐ground photosynthate C input. We found that the chase period of about 4 weeks is sufficient to accurately monitor the recovery of 13C after pulse labeling in a wheat–soil system. We conclude that N fertilization increased the deposition of photoassimilate C into SOC pools over the entire growth season of wheat compared to the control treatment. 相似文献
11.
Effects of biochar application on greenhouse gas emissions,carbon sequestration and crop growth in coastal saline soil 
下载免费PDF全文
下载免费PDF全文 X. W. Lin Z. B. Xie J. Y. Zheng Q. Liu Q. C. Bei J. G. Zhu 《European Journal of Soil Science》2015,66(2):329-338
To evaluate the benefits of application of biochar to coastal saline soil for climate change mitigation, the effects on soil organic carbon (SOC), greenhouse gases (GHGs) and crop yields were investigated. Biochar was applied at 16 t ha?1 to study its effects on crop growth (Experiment I). The effects of biochar (0, 3.2, 16 and 32 t ha?1) and corn stalk (7.8 t ha?1) on SOC and GHGs were studied using 13C stable isotope technology and a static chamber method, respectively (Experiment II). Biochar increased grain mass per plant of the wheat by 27.7% and increased SOC without influencing non‐biochar SOC. On average, 92.3% of the biochar carbon and 16.8% of corn‐stalk carbon were sequestered into the soil within 1 year. The cumulative emissions of CO2, CH4 and N2O were not affected significantly by biochar but cornstalk application increased N2O emissions by 17.5%. The global warming mitigation potential of the biochar treatments (?3.84 to ?3.17 t CO2‐eq. ha?1 t?1 C) was greater than that of the corn stalk treatment (?0.11 t CO2‐eq ha?1 t?1 C). These results suggest that biochar application improves saline soil productivity and soil carbon sequestration without increasing GHG emissions. 相似文献
12.
Xiaoming Kang Yanbin Hao Xiaoyong Cui Huai Chen Changsheng Li Yichao Rui Jianqing Tian Paul Kardol Lei Zhong Jinzhi Wang Yanfen Wang 《Journal of Soils and Sediments》2013,13(6):1012-1023
Purpose
Carbon (C) dynamics in grassland ecosystem contributes to regional and global fluxes in carbon dioxide (CO2) concentrations. Grazing is one of the main structuring factors in grassland, but the impact of grazing on the C budget is still under debate. In this study, in situ net ecosystem CO2 exchange (NEE) observations by the eddy covariance technique were integrated with a modified process-oriented biogeochemistry model (denitrification–decomposition) to investigate the impacts of grazing on the long-term C budget of semiarid grasslands.Materials and methods
NEE measurements were conducted in two adjacent grassland sites, non-grazing (NG) and moderate grazing (MG), during 2006–2007. We then used daily weather data for 1978–2007 in conjunction with soil properties and grazing scenarios as model inputs to simulate grassland productivity and C dynamics. The observed and simulated CO2 fluxes under moderate grazing intensity were compared with those without grazing.Results and discussion
NEE data from 2-year observations showed that moderate grazing significantly decreased grassland ecosystem CO2 release and shifted the ecosystem from a negative CO2 balance (releasing 34.00 g C?m?2) at the NG site to a positive CO2 balance (absorbing ?43.02 g C?m?2) at the MG site. Supporting our experimental findings, the 30-year simulation also showed that moderate grazing significantly enhances the CO2 uptake potential of the targeted grassland, shifting the ecosystem from a negative CO2 balance (57.08?±?16.45 g C?m?2?year?1) without grazing to a positive CO2 balance (?28.58?±?14.60 g C?m?2?year?1) under moderate grazing. The positive effects of grazing on CO2 balance could primarily be attributed to an increase in productivity combined with a significant decrease of soil heterotrophic respiration and total ecosystem respiration.Conclusions
We conclude that moderate grazing prevails over no-management practices in maintaining CO2 balance in semiarid grasslands, moderating and mitigating the negative effects of global climate change on the CO2 balance in grassland ecosystems. 相似文献13.
The aim of this study was to determine the effects of plant absence or presence on microbial properties and enzyme activities at different levels of salinity in a sandy clay soil. The treatments involved five salinity levels—0.5 (control), 2.5, 5, 7.5, and 10 dS m?1 which were prepared using a mixture of chloride salts—and three soil environments (unplanted soil, and soils planted with either wheat or clover) under greenhouse conditions. Each treatment was replicated three times. At the end of the experiment, soil microbial respiration, substrate-induced respiration (SIR), microbial biomass C (MBC), and enzyme activities were determined after plant harvest. Increasing salinity decreased soil microbial properties and enzyme activities, but increased the metabolic quotient (qCO2) in both unplanted and planted soils. Most microbial properties of planted soils were greater than those of unplanted soils at low to moderate salinity levels, depending upon plant species. There was a small or no difference in soil properties between the unplanted and planted treatments at the highest salinity level, indicating that the indirect effects of plant presence might be less important due to significant reduction of plant growth. The lowered microbial activity and biomass, and enzyme activities were due to the reduction of root activity and biomass in salinized soils. The lower values of qCO2 in planted than unplanted soils support the positive influence of plant root and its exudates on soil microbial activity and biomass in saline soils. Nonetheless, the role of plants in alleviating salinity influence on soil microbial activities decreases at high salinity levels and depends on plant type. In conclusion, cultivation and growing plant in abandoned saline environments with moderate salinity would improve soil microbial properties and functions by reducing salinity effect, in particular planting moderately tolerant crops. This helps to maintain or increase the fertility and quality of abandoned saline soils in arid regions. 相似文献
14.
Ieva Jokubauskaite Danute Karčauskienė Alvyra Slepetiene Regina Repsiene Kristina Amaleviciute 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2016,66(8):647-652
ABSTRACTA meta-analysis of 297 treatment data from the Vezaiciai Branch of the Lithuanian Research Centre for Agriculture and Forestry long-term field experiment published from 2006 to 2015 was used to characterize the changes in SOC under different fertilization treatments and residue management practices in Lithuania’s acid soil. A meta-analysis was performed to quantify the relative annual change (RAC) of SOC content and the average RAC rate of SOC under four fertilization modes (farmyard manure (FYM) (40?t?ha?1)); alternative organic fertilizers (in the manure background (40?t?ha?1)); FYM (60?t?ha?1); alternative organic fertilizers (in the manure background (60?t?ha?1)) in two soil backgrounds (naturally acid and limed soil). The average RAC under four fertilization modes was 1.46 g?kg?1?yr?1, indicating that long-term fertilization had considerable SOC sequestration potential. Incorporation of alternative organic fertilizers in unlimed soil showed negative effects (?0.39 and ?0.66 g?kg?1?yr?1) in the observed long-term experiment. The RAC in the limed soil with incorporated organic fertilizers (FYM and alternative organic fertilizers), compared to the control, and varied from 0.25 g?kg?1?yr?1 in the treatment with incorporated alternative organic fertilizers (in the manure background (40?t?ha?1)) to 0.71 g?kg?1?yr?1 in the soil with FYM (60?t?ha?1). In this study, the average RAC rate of SOC under organic fertilization treatments in limed soil (5.07–6.54%) was longer than organic fertilization in unlimed soil (2.11–3.49%), which might be attributed to the application of organic manure that would result in a slow release of fertilizer efficiency. Our results indicate that the application of manure (40 or 60?t?ha?1) showed the greatest potential for C sequestration in agricultural soil and produced the longest SOC sequestration duration. 相似文献
15.
Forested peatlands contain large pools of terrestrial carbon. As well as drainage, forest management such as fertilizer application can affect these pools. We studied the effect of wood ash (application rates 0, 5 and 15 t ha?1) on the heterotrophic soil respiration (CO2 efflux), cellulose decomposition, soil nutrients, biomass production and amount of C accumulated in a tree stand on a pine‐dominated drained mire in central Finland. The ash was spread 13 years before the respiration measurements. The annual CO2 efflux was statistically modelled using soil temperature as the driving variable. Wood ash application increased the amounts of mineral nutrients of peat substantially and increased soil pH in the uppermost 10 cm layer by 1.5–2 pH units. In the surface peat, the decomposition rate of cellulose in the ash plots was roughly double that in control plots. Annual CO2 efflux was least on the unfertilized site, 238 g CO2‐C m?2 year?1. The use of wood ash nearly doubled CO2 efflux to 420–475 g CO2‐Cm?2 year?1 on plots fertilized with 5–15 t ha?1 of ash, respectively. Furthermore, ash treatments resulted also in increased stand growth, and during the measurement year, the growing stand on ash plots accumulated carbon 11–12 times faster than the control plot. The difference between peat C emission and amount of C sequestered by trees on the ash plots was 43–58 g C m?2, while on the control plot it was 204 g C m?2. Our conclusion is that adding wood ash as a fertilizer increases more C sequestration in the tree stand than C efflux from the peat. 相似文献
16.
L. M. Condron D. W. Hopkins E. G. Gregorich A. Black S. A. Wakelin 《European Journal of Soil Science》2014,65(5):741-750
Irrigation of grazed pasture significantly increases plant and animal production, which may in turn increase soil organic carbon (SOC), depending on the balance between primary production and below‐ground allocation of C on the one hand, and the decomposition and export of C from the soil on the other. To evaluate the effect of irrigation on SOC we sampled a grazed pasture field experiment maintained under different irrigation treatments for 62 years. The dry‐land treatment in this experiment only received rainfall at an average of 740 mm year?1. The 10 and 20% irrigation treatments involved application of 100 mm of irrigation when the soil reached 10 and 20% gravimetric moisture content, respectively. The 10 and 20% irrigation treatments received average total annual irrigation inputs of 260 and 770 mm year?1, respectively. The 10 and 20% irrigation treatments increased pasture production by 44 and 74%, respectively, compared with that from the dry‐land. Analysis of soils taken to 1‐m depth revealed that amounts of SOC were not significantly different between the dry‐land (125.5 Mg ha?1) and 10% irrigation (117.8 Mg ha?1) treatments, but these were significantly greater than the 20% irrigation treatment (93.0 Mg ha?1). At 50–100 cm, SOC was also less (34%) for the 20% irrigation treatment than for the 10% irrigation treatment. The relative quantities of carbon (C) and nitrogen (N) in the light fraction (LF) at all soil depths decreased successively from dry‐land to the 20% irrigation treatment, suggesting that wetter soil conditions accelerated decomposition of the LF fraction, a comparatively labile SOC fraction. The C‐to‐N ratio of the bulk soil was also less for the 20% irrigation treatment, indicating more decomposed SOM in the irrigated than in the dry‐land treatment. There were no significant differences in the microbial biomass between the three different irrigation treatments, but the respiration rate (CO2 production) of soil organisms in the 20% irrigation treatment was consistently greater than in the other two treatments. It was concluded that large increases in plant productivity as a result of irrigation had either no effect or significantly reduced SOC stocks under grazed pasture. The reduced SOC content observed in the 20% irrigation treatment was attributed to a combination of increased C losses in animal products and drainage associated with greater stocking, together with accelerated decomposition of organic C resulting from elevated soil moisture maintained throughout the growing season. 相似文献
17.
Contribution of crop residue carbon to soil respiration at a northern Prairie site using stable isotope flux measurements 总被引：1，自引：0，他引：1
A.J. GlennB.D. Amiro M. TenutaC. Wagner-Riddle G. DrewittJ. Warland 《Agricultural and Forest Meteorology》2011,151(8):1045-1054
Heterotrophic respiration from agricultural soils can be differentiated as originating from microbial decomposition of recent litter inputs or crop residue carbon (CRC) and resident soil organic carbon (SOC) pools of varying age and stages of decomposition. Our objective was to determine the relative contributions of these pools to respiration in a northern agroecosystem where the non-growing season is long. A tunable diode laser trace gas analyzer was used to determine atmospheric stable C isotope ratio (δ13C) values and 12CO2 and 13CO2 fluxes over an agricultural field in the Red River Valley of southern Manitoba, Canada. Measurement campaigns were conducted in the fall of 2006 and spring of 2007 following harvest of a maize (C4) crop from soil having SOC derived from previous C3 crops. Stable CO2 isotopologue gradients were measured from the center of four 200 × 200 m experimental plots, and fluxes were calculated using the aerodynamic flux gradient method. The soil in two of the experimental plots underwent intensive tillage, while the other two plots were managed using a form of reduced tillage. Approximately 70% and 20-30% of the total respiration flux originated from the maize C4-CRC during the fall of 2006 and spring of 2007, respectively. At least 25% of the maize residue was lost to respiration during this non-growing period. No difference in the partitioning of heterotrophic respiration into that derived from CRC and SOC was detected between the intensive tillage and recently established reduced tillage treatments at the site. 相似文献
18.
Weiguo Cheng Agnes T. Padre Chizuru Sato Hiroyuki Shiono Satoshi Hattori Akihiko Kajihara 《Soil Science and Plant Nutrition》2016,62(2):212-219
A long-term experiment on combined inorganic fertilizers and organic matter in paddy rice (Oryza sativa L.) cultivation began in May 1982 in Yamagata, northeastern Japan. In 2012, after the 31st harvest, soil samples were collected from five fertilizer treatments [(1) PK, (2) NPK, (3) NPK + 6 Mg ha?1 rice straw (RS), (4) NPK + 10 Mg ha?1 rice straw compost (CM1), and (5) NPK + 30 Mg ha?1 rice straw compost (CM3)], at five soil depths (0–5, 5–10, 10–15, 15–20 and 20–25 cm), to assess the changes in soil organic carbon (SOC) content and carbon (C) decomposition potential, total nitrogen (TN) content and nitrogen (N) mineralization potential resulting from long-term organic matter addition. The C decomposition potential was assessed based on the methane (CH4) and carbon dioxide (CO2) produced, while the N mineralization potential was determined from the potassium chloride (KCl)-extractable ammonium-nitrogen (NH4+-N), after 2, 4, 6 and 8 weeks of anaerobic incubation at 30°C in the laboratory. Compared to NPK treatment, SOC in the total 0–25 cm layer increased by 67.3, 21.0 and10.8%, and TN increased by 64.2, 19.7 and 10.6%, in CM3, RS and CM1, respectively, and SOC and TN showed a slight reduction in the PK treatment by 5.2 and 5.7%, respectively. Applying rice straw compost (10 Mg ha?1) instead of rice straw (6 Mg ha?1) to rice paddies reduced methane production by about 19% after the soils were measured under 8 weeks of anaerobic incubation at 30°C. Soil carbon decomposition potential (Co) and nitrogen mineralization potential (No) were highly correlated with the SOC and TN contents. The mean ratio of Co/No was 4.49, lower than the mean ratio of SOC/TN (13.49) for all treatments, which indicated that the easily decomposed organic matter was from soil microbial biomass and soil proteins. 相似文献
19.
Xinzhang Song Mark O. Kimberley Guomo Zhou Hailong Wang 《Journal of Soils and Sediments》2017,17(9):2250-2256
Purpose
The purpose of this study was to better understand how both the content and flux of soil carbon respond to forest succession and anthropogenic management practices in forests in subtropical China.Materials and methods
We assembled from the literature information on soil organic carbon (SOC) and soil respiration (Rs) covering the forest successional chronosequence from pioneer masson pine (Pinus massoniana) forest (MPF) to medium broadleaf and needleleaf mixed forest (BNMF) and the climax evergreen broadleaf forest (EBF), along with the two major forest plantation types found in subtropical China, Chinese fir (Cunninghamia lanceolata) forest (CFF) and Moso bamboo (Phyllostachys pubescens) forest (MBF).Results and discussion
Both SOC and Rs increased along the forest successional gradient with the climax EBF having both the highest SOC content of 33.1?±?4.9 g C kg?1(mean?±?standard error) and the highest Rs rate of 46.8?±?3.0 t CO2?ha?1 year?1. It can be inferred that when EBF is converted to any of the other forest types, especially to MPF or CFF, both SOC content and Rs are likely to decline. Stand age did not significantly impact the SOC content or Rs rate in either types of plantation.Conclusions
Forest succession generally increases SOC content and Rs, and the conversion of natural forests to plantations decreases SOC content and Rs in subtropical China.20.