首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 30 毫秒
1.
Intensive vegetable crop systems are rapidly developing, with consequences for greenhouse gas (GHGs) emissions, nitrogen leaching and soil carbon. We undertook a field trial to explore the effect of biochar application (0, 10, 20 and 40 t ha−1) on these factors in lettuce, water spinach and ice plant rotation. Our results show that the 20 and 40 t ha−1 soil treatments resulted in the SOC content being 26.3% and 29.8% higher than the control (0 t ha−1), respectively, with significant differences among all treatments (p < .05). Biochar application caused N2O emissions to decrease during the lettuce and water spinach seasons, by 1.5%–33.6% and 12.4%–40.5%, respectively, compared the control, with the 20 t ha−1 application rate resulting in the lowest N2O emissions. Biochar also decreased the dissolved nitrogen (DN) concentration in leachate by 9.8%–36.2%, following a 7.3%–19.9% reduction in dissolved nitrogen in the soil. Similarly, biochar decreased the nitrate (NO3−) concentrations in leachate by 3.9%–30.2%, following a 3.8%–16.7% reduction in the soil nitrate level. Overall, straw biochar applied at rate of 20 t ha−1 produced the lowest N2O emissions and N leaching, while, increasing soil carbon.  相似文献   

2.
Biochar application can reduce global warming via carbon (C) sequestration in soils. However, there are few studies investigating its effects on greenhouse gases in rice (Oryza sativa L.) paddy fields throughout the year. In this study, a year-round field experiment was performed in rice paddy fields to investigate the effects of biochar application on methane (CH4) and nitrous oxide (N2O) emissions and C budget. The study was conducted on three rice paddy fields in Ehime prefecture, Japan, for 2 years. Control (Co) and biochar (B) treatments, in which 2-cm size bamboo biochar (2 Mg ha?1) was applied, were set up in the first year. CH4 and N2O emissions and heterotrophic respiration (Rh) were measured using a closed-chamber method. In the fallow season, the mean N2O emission during the experimental period was significantly lower in B (67 g N ha?1) than Co (147 g N ha?1). However, the mean CH4 emission was slightly higher in B (2.3 kg C ha?1) than Co (1.2 kg C ha?1) in fallow season. The water-filled pore space increased more during the fallow season in B than Co. In B, soil was reduced more than in Co due to increasing soil moisture, which decreased N2O and increased CH4 emissions in the fallow season. In the rice-growing season, the mean N2O emission tended to be lower in B (?104 g N ha?1) than Co (?13 g N ha?1), while mean CH4 emission was similar between B (183 kg C ha?1) and Co (173 kg C ha?1). Due to the C release from applied biochar and soil organic C in the first year, Rh in B was higher than that in Co. The net greenhouse gas emission for 2 years considering biochar C, plant residue C, CH4 and N2O emissions, and Rh was lower in B (5.53 Mg CO2eq ha?1) than Co (11.1 Mg CO2eq ha?1). Biochar application worked for C accumulation, increasing plant residue C input, and mitigating N2O emission by improving soil environmental conditions. This suggests that bamboo biochar application in paddy fields could aid in mitigating global warming.  相似文献   

3.
Purpose

Soil chromium (Cr) pollution has received substantial attention owing to related food chain health risks and possible promotion of greenhouse gas (GHG) emissions. The aim of the present study was to develop a promising remediation technology to alleviate Cr bioavailability and decrease GHG emissions in Cr-polluted paddy soil.

Materials and methods

We investigated the potential role of biochar amendment in decreasing soil CO2, CH4, and N2O emissions, as well in reducing Cr uptake by rice grains at application rates of 0 t ha?1 (CK), 20 t ha?1 (BC20), and 40 t ha?1 (BC40) in Cr-polluted paddy soil in southeastern China. In addition, the soil aggregate size distribution, soil organic carbon (SOC) concentration of soil aggregates, soil available Cr concentration, and rice yield were analyzed after harvesting.

Results and discussion

Biochar amendment significantly reduced CO2, CH4, and N2O emission fluxes. Compared to CK, total C emissions in the BC20 and BC40 treatments decreased by 9.94% and 17.13% for CO2-C, by 30.46% and 37.10% for CH4-C, and by 34.24% and 37.49% for N2O-N, respectively. Biochar amendment increased the proportion of both the 2000–200 μm and 200–20 μm size fractions in the soil aggregate distribution. Accordingly, the organic carbon concentration of these fractions increased, which increased the total SOC. Moreover, biochar amendment significantly decreased soil available Cr concentration and total Cr content of the rice grains by 33.6% and 14.81% in BC20 and 48.1% and 33.33% in BC40, respectively. Rice yield did not differ significantly between biochar amendment treatment and that of CK.

Conclusions

Biochar application reduced GHG emissions in paddy soil, which was attributed to its comprehensive effect on the soil properties, soil microbial community, and soil aggregates, as well as on the mobility of Cr. Overall, the present study demonstrates that biochar has a great potential to enhance soil carbon sequestration while reducing Cr accumulation in rice grains from Cr-polluted rice paddies.

  相似文献   

4.
Changes to soil nutrient availability and increases for crop yield and soil organic C (SOC) concentration on biochar‐amended soil under temperate climate conditions have only been reported in a few publications. The objective of this work was to determine if biochar application rates up to 20 Mg ha?1 affect nutrient availability in soil, SOC stocks and yield of corn (Zea mays L.), soybean (Glycine max L.), and switchgrass (Panicum virgatum L.) on two coarse‐textured soils (loamy sand, sandy clay loam) in S Quebec, Canada. Data were collected from field experiments for a 3‐y period following application of pine wood biochar at rates of 0, 10, and 20 Mg ha?1. For corn plots, at harvest 3 y after biochar application, 20 Mg biochar ha?1 resulted in 41.2% lower soil NH on the loamy sand; the same effect was not present on the sandy clay loam soil. On the loamy sand, 20 Mg biochar ha?1 increased corn yields by 14.2% compared to the control 3 y after application; the same effect was not present on the sandy clay loam soil. Biochar did not alter yield or nutrient availability in soil on soybean or switchgrass plots on either soil type. After 3 y, SOC concentration was 83 and 258% greater after 10 and 20 Mg ha?1 biochar applications, respectively, than the control in sandy clay loam soil under switchgrass production. The same effect was not present on the sandy clay loam soil. A 67% higher SOC concentration was noted with biochar application at 20 Mg ha?1 to sandy clay loam soil under corn.  相似文献   

5.
Biochar application to arable soils could be effective for soil C sequestration and mitigation of greenhouse gas (GHG) emissions. Soil microorganisms and fauna are the major contributors to GHG emissions from soil, but their interactions with biochar are poorly understood. We investigated the effects of biochar and its interaction with earthworms on soil microbial activity, abundance, and community composition in an incubation experiment with an arable soil with and without N-rich litter addition. After 37 days of incubation, biochar significantly reduced CO2 (up to 43 %) and N2O (up to 42 %), as well as NH4 +-N and NO3 ?-N concentrations, compared to the control soils. Concurrently, in the treatments with litter, biochar increased microbial biomass and the soil microbial community composition shifted to higher fungal-to-bacterial ratios. Without litter, all microbial groups were positively affected by biochar × earthworm interactions suggesting better living conditions for soil microorganisms in biochar-containing cast aggregates after the earthworm gut passage. However, assimilation of biochar-C by earthworms was negligible, indicating no direct benefit for the earthworms from biochar uptake. Biochar strongly reduced the metabolic quotient qCO2 and suppressed the degradation of native SOC, resulting in large negative priming effects (up to 68 %). We conclude that the biochar amendment altered microbial activity, abundance, and community composition, inducing a more efficient microbial community with reduced emissions of CO2 and N2O. Earthworms affected soil microorganisms only in the presence of biochar, highlighting the need for further research on the interactions of biochar with soil fauna.  相似文献   

6.
Biochar addition can expand soil organic carbon (SOC) stock and has potential ability in mitigating climate change. Also, some incubation experiments have shown that biochar can increase soil inorganic carbon (SIC) contents. However, there is no direct evidence for this from the field experiment. In order to make up the sparseness of available data resulting from the long‐term effect of biochar amendment on soil carbon fractions, here we detected the contents and stocks of the bulk SIC and SOC fractions based on a 10‐year field experiment of consecutive biochar application in Shandong Province, China. There are three biochar treatments as no‐biochar (control), and biochar application at 4.5 Mg ha?1 year?1 (B4.5) and 9.0 Mg ha?1 year?1 (B9.0), respectively. The results showed that biochar application significantly enhanced SIC content (3.2%–24.3%), >53 μm particulate organic carbon content (POC, 38.2%–166.2%) and total soil organic carbon content (15.8%–82.2%), compared with the no‐biochar control. However, <53 μm silt–clay‐associated organic carbon (SCOC) content was significantly decreased (14%–27%) under the B9.0 treatment. Our study provides the direct field evidence that SIC contributed to carbon sequestration after the biochar application, and indicates that the applied biochar was allocated mainly in POC fraction. Further, the decreased SCOC and increased microbial biomass carbon contents observed in field suggest that the biochar application might exert a positive priming effect on native soil organic carbon.  相似文献   

7.
The application of biochar produced from wood and crop residues, such as sawdust, straw, sugar bagasse and rice hulls, to highly weathered soils under tropical conditions has been shown to influence soil greenhouse gas (GHG) emissions. However, there is a lack of data concerning GHG emissions from soils amended with biochar derived from manure, and from soils outside tropical and subtropical regions. The objective of this study was to quantify the effect on emissions of carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) following the addition, at a rate of 18 t ha−1, of two different types of biochar to an Irish tillage soil. A soil column experiment was designed to compare three treatments (n = 8): (1) non-amended soil (2) soil mixed with biochar derived from the separated solid fraction of anaerobically digested pig manure and (3) soil mixed with biochar derived from Sitka Spruce (Picea sitchensis). The soil columns were incubated at 10 °C and 75% relative humidity, and leached with 80 mL distilled water, twice per week. Following 10 weeks of incubation, pig manure, equivalent to 170 kg nitrogen ha−1 and 36 kg phosphorus ha−1, was applied to half of the columns in each treatment (n = 4). Gaseous emissions were analysed for 28 days following manure application. Biochar addition to the soil increased N2O emissions in the pig manure-amended column, most likely as a result of increased denitrification caused by higher water filled pore space and organic carbon (C) contents. Biochar addition to soil also increased CO2 emissions. This was caused by increased rates of C mineralisation in these columns, either due to mineralisation of the labile C added with the biochar, or through increased mineralisation of the soil organic matter.  相似文献   

8.
To quantify carbon (C) and nitrogen (N) losses in soils of West African urban and peri‐urban agriculture (UPA) we measured fluxes of CO2‐C, N2O‐N, and NH3‐N from irrigated fields in Ouagadougou, Burkina Faso, and Tamale, Ghana, under different fertilization and (waste‐)water regimes. Compared with the unamended control, application of fertilizers increased average cumulative CO2‐C emissions during eight cropping cycles in Ouagadougou by 103% and during seven cropping cycles in Tamale by 42%. Calculated total emissions measured across all cropping cycles reached 14 t C ha?1 in Ouagadougou, accounting for 73% of the C applied as organic fertilizer over a period of two years at this site, and 9 t C ha?1 in Tamale. Compared with unamended control plots, fertilizer application increased N2O‐N emissions in Ouagadougou during different cropping cycles, ranging from 37 to 360%, while average NH3‐N losses increased by 670%. Fertilizer application had no significant effects on N2O‐N losses in Tamale. While wastewater irrigation did not significantly enhance CO2‐C emissions in Ouagadougou, average CO2‐C emissions in Tamale were 71% (1.6 t C ha?1) higher on wastewater plots compared with those of the control (0.9 t C ha?1). However, no significant effects of wastewater on N2O‐N and NH3‐N emissions were observed at either location. Although biochar did not affect N2O‐N and NH3‐N losses, the addition of biochar could contribute to reducing CO2‐C emissions from urban garden soils. When related to crop production, CO2‐C emissions were higher on control than on fertilized plots, but this was not the case for absolute CO2‐C emissions.  相似文献   

9.
The aim of this study was to evaluate the effect of biochar and organic soil amendments on soil physicochemical and microbial load, carbon sequestration potential, nutrient uptake and yield of groundnut in acidic red soil under rainfed condition. Biochar was prepared from red gram, cotton, maize stalk and mesquite wood using pilot scale slow pyrolysis biochar unit. The above sources of biochar at the rate of 2.5 and 5 t ha?1 and enriched farmyard manure 0.75 t ha?1, composted coir pith 10 t ha?1 and arbuscular mycorrhizae 100 kg ha?1 were applied as basal with required nitrogen, phosphorous and potassium fertilizer. Biochar amendment at the rate of 5 t ha?1 reduced the bulk density from 1.41 to 1.36 g cm?3 and increased the soil moisture 2.5%. With respect to soil chemical changes, it raised soil pH from 5.7 to 6.3; increased the cation exchange capacity 1.4 cmol+ kg?1 and enhanced the carbon buildup 4.4 t ha?1. The significant differences in bacteria, fungi and actinomycetes population were observed between biochar and control. The nitrogen, phosphorous and potassium were better utilized under biochar and composted coir pith, which was 21, 5 and 20 kg ha?1 higher than control. The experimental results suggested that application of biochar to acidic red soil favoured good soil physical, chemical and biological environment, and these positive changes influenced growth and yield attributes and enhanced pod yield 29% over control.  相似文献   

10.
ABSTRACT

The interactive effect of biochar, cattle manure and nitrogen (N) fertilizer on the dynamics of carbon (C) mineralization and stabilization was investigated in a sandy soil amended with three sole biochar (0, 20 or 40 t ha?1) or manure (0, 13 or 26 t ha?1) and four combined biochar-manure levels (20 or 40 t ha?1 biochar plus 13 or 26 t ha?1 manure) with or without N fertilizer (0 or 90 kg ha?1) and CO2-C evolution measured over 54-d incubation period. Biochar application, solely or combined with manure resulted in lower applied C mineralized (ACM), indicating C sequestration in the soils. Negative attributable effect (AE) of co-application of biochar and manure on C mineralization was observed relative to the sole treatments. Both ACM and AE were negatively correlated with C/N ratio and mineral N content of the soil-mixtures (r ≥ – 0.573; p ≤ 0.01), indicating microbial N limitation. The double first-order exponential model described CO2-C efflux very well and indicated that ≥94% of C applied was apportioned to stable C pools with slower mineralization rate constant and longer half-life. Cumulative C mineralized and modeled C pools were positively correlated with each other (r ≥ 0.853; p ≤ 0.001) and with readily oxidizable C of soil-amendment mixtures (r ≥ 0.861; p ≤ 0.001). The results suggested that co-application of biochar and manure can promote initial rapid mineralization to release plant nutrients but sequester larger amounts of applied C in refractive C pool, resulting in larger C sequestration in sandy soils.  相似文献   

11.
生物炭和腐殖酸对土壤C、N循环和作物产量均具有深刻影响。该试验以稻麦轮作系统为研究对象,探究生物炭和腐殖酸在经过1 a陈化后对土壤肥力、作物产量和温室气体排放的持续影响。设置了6个处理：B0F0(对照,不添加生物炭和腐殖酸);B0F1(不添加生物炭,腐殖酸添加量为0.6 t/hm2);B0F2(不添加生物炭,腐殖酸添加量为1.2 t/hm2);B1F0(生物炭添加量为20 t/hm2,不添加腐殖酸);B1F1(生物炭添加量为20 t/hm2,腐殖酸添加量为0.6 t/hm2);B1F2(生物炭添加量为20 t/hm2,腐殖酸添加量为1.2 t/hm2)。结果表明：1)试验期内,与B0F0相比,生物炭显著增加了稻麦两季土壤有机碳含量;腐殖酸增加了稻季土壤有机碳含量,对麦季土壤有机碳含量无显著影响;单独施用生物炭或腐殖酸对水稻和小麦产量均没有显著影响,生物炭和腐殖酸混施处理显著提高了小麦产量,增幅为1.0%～5.0%,对水稻产量没有显著影...  相似文献   

12.
Application of crop residues and its biochar produced through slow pyrolysis can potentially increase carbon (C) sequestration in agricultural production systems. The impact of crop residue and its biochar addition on greenhouse gas emission rates and the associated changes of soil gross N transformation rates in agricultural soils are poorly understood. We evaluated the effect of wheat straw and its biochar applied to a Black Chernozemic soil planted to barley, two growing seasons or 15 months (at the full-bloom stage of barley in the second growing season) after their field application, on CO2 and N2O emission rates, soil inorganic N and soil gross N transformation rates in a laboratory incubation experiment. Gross N transformation rates were studied using the 15N isotope pool dilution method. The field experiment included four treatments: control, addition of wheat straw (30 t ha?1), addition of biochar pyrolyzed from wheat straw (20 t ha?1), and addition of wheat straw plus its biochar (30 t ha?1 wheat straw + 20 t ha?1 biochar). Fifteen months after their application, wheat straw and its biochar addition increased soil total organic C concentrations (p?=?0.039 and <0.001, respectively) but did not affect soil dissolved organic C, total N and NH4 +-N concentrations, and soil pH. Biochar addition increased soil NO3 ?-N concentrations (p?=?0.004). Soil CO2 and N2O emission rates were increased by 40 (p?p?=?0.03), respectively, after wheat straw addition, but were not affected by biochar application. Straw and its biochar addition did not affect gross and net N mineralization rates or net nitrification rates. However, biochar addition doubled gross nitrification rates relative to the control (p?2 and N2O emissions and enhance soil C sequestration. However, the implications of the increased soil gross nitrification rate and NO3 ?-N in the biochar addition treatment for long-term NO3 ?-N dynamics and N2O emissions need to be further studied.  相似文献   

13.
Both biochar and compost may improve carbon sequestration and soil fertility; hence, it has been recommended to use a mixture of both for sustainable land management. Here, we evaluated the effects of biochar–compost substrates on soil properties and plant growth in short rotation coppice plantations (SRC). For this purpose, we planted the tree species poplar, willow, and alder in a no‐till field experiment, each of them amended in triplicate with 0 (= control) or 30 Mg ha?1 compost or biochar–compost substrates containing 15% vol. (TPS15) and 30% vol. biochar (TPS30). For three years running, we analyzed plant growth as well as soil pH, potential cation exchange capacity (CEC), stocks of soil organic carbon (SOC), total N, and plant‐available phosphate and potassium oxide.Biochar‐compost substrates affected most soil properties only in the topsoil and for a limited period of time. The CEC and total stocks of SOC were consistently elevated relative to the control. After three years the C gain of up to 6.4 Mg SOC ha?1 in the TPS30 plots was lower than the added C amount. Especially in the case of TPS30 treatment, C input was characterized by the greatest losses after application, although the black carbon of the biochar was not degraded in soil. Additionally, tree growth and woody biomass yield did not respond at all to the treatments. Overall, there were few if any indications that biochar–compost substrates improve the performance of SRC under temperate soil and climate conditions. Therefore, the use of biochar for such systems is not recommended.  相似文献   

14.
Agricultural activities are responsible for greenhouse gases (GHGs) emission in the environment. Strategies are required to enhance the soil organic carbon (SOC) and nitrogen (N) sequestration to adapt and mitigate the climate change. We investigated GHGs emission, SOC and N enhancement under conventional tillage (CT) and zero tillage (ZT) with N management in wheat (Triticum aestivum L.). Seasonal carbon dioxide (CO2) emission and global warming potential (GWP) reduced for ZT treatments over CT without residues and 100% of required N with a blanket split application (CT – R + 100N). The ZT with 5 t ha?1 maize (Zea mays L.) residues retention and 75% of required N and GreenSeekerTM (GS)-aided N management (ZT + R + 75N + GS) reduced yield-scaled GHGs emission and increased total organic carbon (C) stock over CT – R + 100N. However, nitrous oxide (N2O) emission was lower in CT. The GS-based N management saved 26–35 kg N ha?1 in different tillage systems in both years over blanket application with higher N uptake and associated reduction in N2O emission. The study recommends that ZT with residues retention and GS-based N management can minimize the GHGs emission and improve the SOC.  相似文献   

15.
Biochar amendments offer promising potential to improve soil fertility, soil organic carbon (SOC) and crop yields; however, a limited research has explored these benefits of biochar in the arid and semi‐arid regions. This two‐year field study investigated the effects of Acacia tree biomass‐derived biochar, applied at 0 and 10 t ha?1 rates with farmyard manure (FYM) or poultry manure (PM) and mineral phosphorus (P) fertilizer combinations (100 kg P ha‐1), on maize (Zea mays L.) productivity, P use efficiency (PUE) and farm profitability. The application of biochar with organic–inorganic P fertilizers significantly increased soil P and SOC contents than the sole organic or inorganic P fertilizers. Addition of biochar and PM as 100% P source resulted in the highest soil P (104% increase over control) and SOC contents (203% higher than control). However, maize productivity and PUE were significantly higher under balanced P fertilizer (50% organic + 50% mineral fertilizer) with biochar and the increase was 110%, 94% and 170% than 100%‐FYM, 100%‐PM and 100% mineral fertilizer, respectively. Maize productivity and yield correlated significantly positively with soil P and SOC contents These positive effects were possibly due to the ability of biochar to improve soil properties, P availability from organic–inorganic fertilizers and SOC which resulted in higher PUE and maize productivity. Despite the significant positive relationship of PUE with net economic returns, biochar incorporation with PM and mineral fertilizer combination was economically profitable, whereas FYM along biochar was not profitable due to short duration of the field experiments.  相似文献   

16.
Substitution of mineral fertilizers with organic soil amendments is postulated to improve productivity‐relevant soil properties such as aggregation and organic matter (OM) content. However, there is a lack of studies analyzing the effects of biochar and biogas digestate versus mineral fertilizer on soil aggregation and OM dynamics under temperate field conditions. To address this research gap, a field experiment was sampled four years after establishment on a sandy Cambisol in Germany where mineral fertilizer or liquid biogas digestate was applied with or without 3 or 40 Mg biochar ha?1 (produced at 650°C). Soil samples were analyzed for soil organic carbon (SOC) content, pH, cation exchange capacity, bulk density, water‐holding capacity, microbial biomass, aggregate size class distribution, and the SOC content associated with these size classes. 40 Mg biochar ha?1 significantly increased SOC content in all fractions, especially free particulate OM and the 2–0.25 mm fraction. The yield of small macroaggregates (2–0.25 mm) was increased by biochar, but cation exchange capacity, water‐holding capacity, and pH were not consistently improved. Thus, high‐temperature biochar applied to a sandy soil under temperate conditions is primarily recommended to increase SOC content, which could contribute to climate change mitigation if this C remains sequestered over the long‐term. Fertilizer type did not significantly affect SOC content or other measured properties of the sandy Cambisol, suggesting that replacement of mineral fertilizer with digestate has a neutral effect on soil fertility. Co‐application of biochar with digestate provided no advantages for soil properties compared to co‐application with mineral fertilizer. Thus, independent utilization of these organic amendments is equally suitable.  相似文献   

17.
Biochar addition to soils has been frequently proposed as a means to increase soil fertility and carbon (C) sequestration. However, the effect of biochar addition on greenhouse gas emissions from intensively managed soils under vegetable production at the field scale is poorly understood. The effects of wheat straw biochar amendment with mineral fertilizer or an enhanced‐efficiency fertilizer (mixture of urea and nitrapyrin) on N2O efflux and the net ecosystem C budget were investigated for an acidic soil in southeast China over a 1‐yr period. Biochar addition did not affect the annual N2O emissions (26–28 kg N/ha), but reduced seasonal N2O emissions during the cold period. Biochar increased soil organic C and CO2 efflux on average by 61 and 19%, respectively. Biochar addition greatly increased C gain in the acidic soil (average 11.1 Mg C/ha) compared with treatments without biochar addition (average ?2.2 Mg C/ha). Biochar amendment did not increase yield‐scaled N2O emissions after application of mineral fertilizer, but it decreased yield‐scaled N2O by 15% after nitrapyrin addition. Our results suggest that biochar amendment of acidic soil under intensive vegetable cultivation contributes to soil C sequestration, but has only small effects on both plant growth and greenhouse gas emissions.  相似文献   

18.
Management practices can have significant implications for both soil quality and carbon (C) sequestration potential in agricultural soils. Data from two long‐term trials (one at field scale and the other at lysimeter scale), underway in north‐eastern Italy, were used to evaluate the dynamics of soil organic carbon (SOC) and estimate the impact of recommended management practices (RMPs) on soil carbon sequestration. Potential SOC sequestration was calculated as the differences between the change in SOC of treatments differing only for the specified RMP for a period of at least 25 years. The trials compared the following situations: (a) improved crop rotations versus monoculture; (b) grass versus improved crop rotations; (c) residue incorporation versus residue removal; (d) high versus low rates of inorganic fertilizers; (e) integrated nutrient management/organic manures versus inorganic fertilizers. At the lysimeter scale, some of these treatments were evaluated in different soils. A general decrease in SOC (1.1 t C ha?1 year?1) was observed after the introduction of intensive soil tillage, evidencing both the worsening of soil quality and the contribution towards global CO2 emissions. Initial SOC content was maintained only in permanent grassland, complex rotations and/or with the use of large quantities of livestock manure. SOC sequestration reached a maximum rate of 0.4 t C ha?1 year?1 comparing permanent grassland with an improved crop rotation. Crop residue incorporation and rates of inorganic fertilizer had less effect on SOC sequestration (0.10 and 0.038 t C ha?1 year?1, respectively). The lysimeter experiment highlighted also the interaction between RMPs and soil type. Peaty soil tended to be a source of C independent of the amount and quality of C input, whereas a proper choice of tillage practices and organic manures enhanced SOC sequestration in a sandy soil. The most promising RMPs in the Veneto region are, therefore, conversion to grassland and use of organic manures. Although some of these RMPs are already supported by the Veneto Region Rural Development Plan, their more intensive and widespread implementation requires additional incentives to become economically feasible.  相似文献   

19.
Biochar application has the potential to improve soil fertility and increase soil carbon stock, especially in tropical regions. Information on the temperature sensitivity of carbon dioxide(CO_2) evolution from biochar-amended soils at very high temperatures, as observed for tropical surface soils, is limited but urgently needed for the development of region-specific biochar management targeted to optimize biochar effects on soil functions. Here, we investigated the temperature sensitivity of soil respiration to the addition of different rates of Miscanthus biochar(0, 6.25, 12.5, and 25 Mg ha~(-1)) in two types of soils with contrasting textures. Biochar-amended soil treatments and their controls were incubated at constant temperatures of 20, 30, and 40℃. Overall, our results show that: i) considering data from all treatments and temperatures, the addition of biochar decreased soil CO_2 emissions when compared to untreated soils;ii) CO_2 emissions from biochar-amended soils had a higher temperature sensitivity than those from biochar-free soils; iii) the temperature sensitivity of soil respiration in sandy soils was higher than that in clay soils; and iv) for clay soils, relative increases in soil CO_2 emissions from biochar-amended soils were higher when the temperature increased from 30 to 40℃, while for sandy soils, the highest temperature responses of soil respiration were observed when increasing the temperature from 20 to 30℃. Together, these findings suggest a significantly reduced potential to increase soil organic carbon stocks when Miscanthus biochar is applied to tropical soils at high surface temperatures, which could be counteracted by the soil-and weather-specific timing of biochar application.  相似文献   

20.
Biochar addition to soil has been generally associated with crop yield increases observed in some soils, and increased nutrient availability is one of the mechanisms proposed. Any impact of biochar on soil organisms can potentially translate to changes in nutrient availability and crop productivity, possibly explaining some of the beneficial and detrimental yield effects reported in literature. Therefore, the main aim of this study was to assess the medium-term impact of biochar addition on microbial and faunal activities in a temperate soil cropped to corn and the consequences for their main functions, litter decomposition and mineralization. Biochar was added to a corn field at rates of 0, 3, 12, 30 tons ha−1 three years prior to this study, in comparison to an annual application of 1 t ha−1.Biochar application increased microbial abundance, which nearly doubled at the highest addition rate, while mesofauna activity, and litter decomposition facilitated by mesofauna were not increased significantly but were positively influenced by biochar addition when these responses were modeled, and in the last case directly and positively associated to the higher microbial abundance. In addition, in short-term laboratory experiments after the addition of litter, biochar presence increased NO2 + NO3 mineralization, and decreased that of SO4 and Cl. However, those nutrient effects were not shown to be of concern at the field scale, where only some significant increases in SOC, pH, Cl and PO4 were observed.Therefore, no negative impacts in the soil biota activities and functions assessed were observed for the tested alkaline biochar after three years of the application, although this trend needs to be verified for other soil and biochar types.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号