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1.
Reducing ammonia (NH3) volatilization is a practical way to increase nitrogen (N) fertilizer use efficiency (NUE). In this field study, soil was amended once with either cotton (Gossypium hirsutum L.) straw (6 t ha?1) or its biochar (3.7 t ha?1) unfertilized (0 kg N ha?1) or fertilized (450 kg N ha?1), and then soil inorganic N concentration and distribution, NH3 volatilization, cotton yield and NUE were measured during the next two growing seasons. In unfertilized plots, NH3 volatilization losses in the straw-amended and biochar-amended treatments were 38–40% and 42–46%, respectively, less than that in control (i.e., unamended soil) during the two growing seasons. In the fertilized plots, NH3 volatilization losses in the straw-amended and biochar-amended treatments were 30–39% and 43–54%, respectively, less than that in the control. Straw amendment increased inorganic N concentrations, cotton yield, cotton N uptake and NUE during the first cropping season after application, but not during the second. In contrast, biochar increased cotton N uptake and NUE during both the first and the second cropping seasons after application. Furthermore, the effects of biochar on cotton N uptake and NUE were greater in the second year than in the first year. These results indicate that cotton straw and cotton straw biochar can both reduce NH3 volatilization and also increase cotton yield, N uptake and NUE. In addition, the positive effects of one application of cotton straw biochar were more long-lasting than those of cotton straw.  相似文献   

2.
Use of nitrogen (N) fertilizer is underway to increase in Sub-Saharan Africa (SSA). The effect of increasing N rates on ammonia (NH3) volatilization—a main pathway of applied-N loss in cropping systems—has not been evaluated in this region. In two soils (Alfisols, ALF; and Andisols, AND) with maize crop in the East African highlands, we measured NH3 volatilization following urea broadcast at six rates (0–150 kg N ha?1) for 17 days, using a semi-open static chamber method. Immediate irrigation and urea deep placement were tested as mitigation treatments. The underlying mechanism was assessed by monitoring soil pH and mineral N (NH4+ and NO3?) concentrations. More cumulative NH3-N was volatilized in ALF than in AND at the same urea-N rate. Generally, higher urea-N rates increased proportional NH3-N loss (percent of applied N loss as NH3-N). Based on well-fitted sigmoid models, simple surface urea application is not recommended for ALF, while up to 60 kg N ha?1 could be adopted for AND soils. The susceptibility of ALF to NH3 loss mainly resulted from its low pH buffering capacity, low cation exchange capacity, and high urease activity. Both mitigation treatments were effective. The inhibited rise of soil pH but not NH4+ concentration was the main reason for the mitigated NH3-N losses, although nitrification in the irrigation treatment might also have contributed. Our results showed that in acidic soils common to SSA croplands, proportional NH3-N loss can be substantial even at a low urea-N rate; and that the design of mitigation treatments should consider the soil’s inherent capacity to buffer NH3 loss.  相似文献   

3.
Biochar added to agricultural soils may sequester carbon and improve physico-chemical conditions for crop growth, due to effects such as increased water and nutrient retention in the root zone. The effects of biochar on soil microbiological properties are less certain. We addressed the effects of wood-based biochar on soil respiration, water contents, potential ammonia oxidation (PAO), arylsulfatase activity (ASA), and crop yields at two temperate sandy loam soils under realistic field conditions. In situ soil respiration, PAO, and ASA were not significantly different in quadruplicate field plots with or without biochar (20 Mg ha?1); however, in the same plots, volumetric water contents increased by 7.5 % due to biochar (P?=?0.007). Crop yields (oat) were not significantly different in the first year after biochar application, but in the second year, total yields of spring barley increased by 11 % (P??1, applied during two consecutive years, substantiated that biochar was not inhibitory to PAO and ASA as reference plots consistently showed lowest activities. For PAO, it was found that soil pH, rather than biochar rates, was a driving environmental variable. For ASA, the methodological approach was challenged by product sorption, but results did not suggest that biochar significantly stimulated the enzyme activity. Crop yields of maize in field experiments with 10–100 Mg biochar ha?1 were unaffected by biochar except for a negative effect of the highest annual rates of 50 Mg ha?1 in the first year after application. In conclusion, the present wood-based biochar poorly affected the measured microbial processes and generally resulted in similar crop yields in reference and biochar-amended soil plots.  相似文献   

4.
Application of urea in lowland rice fields leads to ammonia (NH3) volatilization and environmental pollution, and diminishes nitrogen recovery by rice (Oryza sativa L.). Amending urea with biochar could reduce NH3 loss from urea as well as improve chemical properties of acid soils. An incubation study was conducted using a closed-dynamic air flow system to determine NH3 volatilization from urea and chemical properties of an acid soil (Typic Paleudults). The soil was mixed with three rates of chicken litter biochar (20, 40, and 60 g pot?1) and 1.31 g urea. Mixing an acid soil with biochar (60 g pot?1) in waterlogged to stimulate conditions in paddy condition significantly reduced NH3 loss and total titratable acidity. Biochar application also increased soil pH, total nitrogen, available nitrate, organic matter, total organic carbon, total carbon, available phosphorus, and exchangeable cations. Thus, chicken litter biochar can be used to reduce urea-N loss and ameliorate chemical properties of acid soils. This aspect is being embarked on in our on-going field experiments.  相似文献   

5.
The continuous airflow enclosures with an acid trap method was widely used to investigate ammonia (NH3) volatilization in field; however, it could be time-consuming for the estimation of NH3 volatilization in field with the application of controlled-release urea (CRU) because NH3 volatilization with CRU application could occur during the entire crop growth period. An NH3 volatilization estimation method based on the modified Jayaweera–Mikkelsen (J-M) model combined with the Sherlock–Goh model was used to simulate NH3 volatilization in a paddy field after 255 kg N ha?1 as CRU (polymer-coated urea with the concentration of 43% nitrogen, 100% for basal) and urea (70% for basal, 30% for topdressing) during the rice growth period including flooded and non-flooded periods in Wuxi, China. Results indicated that NH3 volatilization can be modeled with the proposed measure because no significant difference (P< 0.001) was observed between the simulated values and the observed values; the correlation coefficient (r2) was 0.615 for CRU and 0.840 for urea during the flooded period, and 0.991 for CRU and 0.946 for urea during the non-flooded period. Compared with urea, NH3 volatilization was minimized by 43.2% with the application of CRU based on simulated value within the rice growth period, which was 40.40 kg N ha?1 for CRU and 78.62 kg N ha?1 for urea during the flooded period, and 5.52 kg N ha?1 for CRU and 2.33 kg N ha?1 for urea during the non-flooded period. Therefore, CRU could be a promising nitrogen fertilizer to prevent NH3 losses in the rice paddies at the investigated area.  相似文献   

6.

Purpose

The objective of this study was to determine the changes in the main soil chemical properties including pH, electrical conductivity (EC), available phosphorus (P), soil organic carbon (SOC) and total nitrogen (TN) stocks after long-term (31 years) additions of two types of organic matters—rice straw and rice straw compost, combined with NPK fertilizers in single rice paddy in a cold temperate region of Japan.

Materials and methods

A long-term experiment on combined inorganic fertilizers and organic matters in paddy rice cultivation began in May 1982 in Yamagata, northeastern Japan. After the 31st harvest, soil samples were collected from five 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). Soil chemical properties of pH, EC, available P, SOC, and TN were analyzed.

Results and discussion

The pH decreased significantly only at the higher compost rate of 30 Mg ha?1, while EC increased in all the organic matter treatments. Available P significantly increased in the CM1 and CM3 treatments by 55.1 and 86.4 %. The amounts of SOC stock increased by 67.2, 21.4, and 8.6 %, and soil TN stock by 64.1, 20.2, and 8.5 % in CM3, RS, and CM1, respectively, compared to NPK treatment.

Conclusions

Significant changes in soil properties were observed after 31 years of organic matter applications with reference to PK- and NPK-fertilized rice paddy soils. A significant decrease in pH was observed with the application of a high rate (30 Mg ha?1) of rice straw compost but not with the conventional rate of 10 Mg ha?1. However, EC increased significantly relative to that of the PK- and NPK-fertilized plots in all the organic matter treatments. Available P significantly increased in the CM1 and CM3 treatments by 55.1 and 86.4 %. The amounts of SOC stock expressed as a percentage of total C applied to the soil were higher from 10 Mg ha?1 compost (28.7 %) than that from 6 Mg ha?1 rice straw (17.4 %), indicating a more effective soil organic C accumulation from rice straw compost than that from original rice straw.
  相似文献   

7.
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   

8.
Abstract

Both nitrogen (N) deposition and biochar can affect the emissions of nitrous oxide (N2O), carbon dioxide (CO2) and ammonia (NH3) from different soils. Here, we have established a simulated wet N deposition experiment to investigate the effects of N deposition and biochar addition on N2O and CO2 emissions and NH3 volatilization from agricultural and forest soils. Repacked soil columns were subjected to six N deposition events over a 1-year period. N was applied at rates of 0 (N0), 60 (N60), and 120 (N120) kg Nh a?1 yr?1 without or with biochar (0 and 30 t ha?1 yr?1). For agricultural soil, adding N increased cumulative N2O emissions by 29.8% and 99.1% (p < 0.05) from the N60 and N120 treatments, respectively as compared to without N treatments, and N120 emitted 53.4% more (p < 0.05) N2O than the N60 treatment; NH3 volatilization increased by 33.6% and 91.9% (p < 0.05) from the N60 and N120 treatments, respectively, as compared to without N treatments, and N120 emitted 43.6% more (p < 0.05) NH3 than N60; cumulative CO2 emissions were not influenced by N addition. For forest soil, adding N significantly increased cumulative N2O emissions by 141.2% (p < 0.05) and 323.0% (p < 0.05) from N60 and N120 treatments, respectively, as compared to without N treatments, and N120 emitted 75.4% more (p < 0.05) N2O than N60; NH3 volatilization increased by 39.0% (p < 0.05) and 56.1% (p < 0.05) from the N60 and N120 treatments, respectively, as compared to without N treatments, and there was no obvious difference between N120 and N60 treatments; cumulative CO2 emissions were not influenced by N addition. Biochar amendment significantly (p < 0.05) decreased cumulative N2O emissions by 20.2% and 25.5% from agricultural and forest soils, respectively, and increased CO2 emissions slightly by 7.2% and NH3 volatilization obviously by 21.0% in the agricultural soil, while significantly decreasing CO2 emissions by 31.5% and NH3 volatilization by 22.5% in the forest soil. These results suggest that N deposition would strengthen N2O and NH3 emissions and have no effect on CO2 emissions in both soils, and treatments receiving the higher N rate at N120 emitted obviously more N2O and NH3 than the lower rate at N60. Under the simulated N deposition circumstances, biochar incorporation suppressed N2O emissions in both soils, and produced contrasting effects on CO2 and NH3 emissions, being enhanced in the agricultural soil while suppressed in the forest soil.  相似文献   

9.
Impacts of crop residue biochar on soil C and N dynamics have been found to be subtly inconsistent in diverse soils. In the present study, three soils differing in texture (loamy sand, sandy clay loam and clay) were amended with different rates (0%, 0.5%, 1%, 2% and 4%) of rice-residue biochar and incubated at 25°C for 60 days. Soil respiration was measured throughout the incubation period whereas, microbial biomass C (MBC), dissolved organic C (DOC), NH4+-N and NO3–N were analysed after 2, 7, 14, 28 and 60 days of incubation. Carbon mineralization differed significantly between the soils with loamy sand evolving the greatest CO2 followed by sandy clay loam and clay. Likewise, irrespective of the sampling period, MBC, DOC, NH4+-N and NO3–N increased significantly with increasing rate of biochar addition, with consistently higher values in loamy sand than the other two soils. Furthermore, regardless of the biochar rates, NO3–-N concentration increased significantly with increasing period of incubation, but in contrast, NH4+-N temporarily increased and thereafter, decreased until day 60 in all soils. It is concluded that C and N mineralization in the biochar amended soils varied with the texture and native organic C status of the soils.  相似文献   

10.
To clarify nitrogen (N) sources, the overall N budget in a forested watershed in Kanagawa Prefecture, Central Japan was estimated by measuring dissolved inorganic N (DIN; NH4 + + NO3 – + NO2 –) from Nov 2004 through Oct 2005. The estimated N budget (–1.43 kg N ha–1 year–1) showed that the N output rate (stream water N) was higher than the N input rate (bulk deposition N) in the watershed. The annual NO2 – and NO3 – input rates were 0.02 and 1.99 kg N ha–1 year–1, respectively. NH4 + was the predominant source in this forested watershed, accounting for 71% (4.99 kg N ha–1 year–1) of DIN input rate. In addition, this study estimated rainfall pH, air temperature, and wind direction, which were considered as controlling factors related to the atmospheric deposition rate of NH4 +. This study showed that the rainfall NH4 + was inversely proportional to the initial pH of the rainfall, which was calculated by adding the amount of H+ consumed by the dissociation process of NH3(aq) to the measured rainfall pH. This result implies that acid rain can elevate the solubility of NH3(g) and the dissociation capacity of NH4 + throughout the process of precipitation. Also, this study provides strong evidence that the high NH4 + deposition rate is mainly derived from NH3(g) emitted from livestock wastes under the NH3 transport condition of warm summer and favorable wind direction.  相似文献   

11.
The need for bioenergy is increasing with increase in global energy demand, and sustainable soil and fertilizer management practices for bioenergy feedstock production are gaining importance. In this greenhouse study, we evaluated the effects of biochar and fertilizer nitrogen on soil and energy crop sunflower (Helianthus annuus L. var. Giganteus). Sunflower plants were treated with three rates of biochar, control (0 Mg ha?1), low (25 Mg ha?1) and high (50 Mg ha?1), and three rates of fertilizers, 0% (control), 50% (low) and 100% (high) of the recommended nitrogen dose. Plant height, quality (chlorophyll content), biomass yield, feedstock energy, ash content and tissue nutrients were measured along with soil moisture and pH. Results showed an 11% increase in mean plant height under low biochar compared to control biochar-treated plants. High nitrogen treatment produced 26% and 18% more stalk and total above-ground plant (whole plant) biomass, respectively, compared to the control nitrogen treatment. High biochar treatment resulted in higher soil moisture holding, but lower soil pH than the control biochar treatment. Plant quality, energy and ash contents were not affected by either biochar or nitrogen. The plant tissue analysis provides a complete tissue macro- and micronutrient information on sunflower cultivar Giganteus, which was not done previously.  相似文献   

12.
Applications of dairy farm effluents to land may lead to ammonia (NH3) volatilization and nitrous oxide (N2O) emissions. Nitrogen (N) transformation process inhibitors, such as urease inhibitors (UIs) and nitrification inhibitors (NIs), have been used to reduce NH3 and N2O losses derived from agricultural N sources. The objective of this study was to examine the effects of amending dairy effluents with UI (N-(n-butyl) thiophosphoric triamide (NBTPT)) and NI (dicyandiamide (DCD)) on NH3 and N2O emissions. Treatments included either fresh or stored manure and either fresh or stored farm dairy effluent (FDE), with and without NBTPT (0.25 g kg?1 N) or DCD (10 kg ha?1), applied to a pasture on a free-draining volcanic parent material soil. The nutrient loading rate of FDE and manure, which had different dry matter contents (about 2 and 11 %, respectively) was 100 kg N ha?1. Application of manure and FDE led to NH3 volatilization (15, 1, 17 and 0.4 % of applied N in fresh manure, fresh FDE, stored manure and stored FDE, respectively). With UI (NBTPT), NH3 volatilization from fresh manure was significantly (P?<?0.05) decreased to 8 % from 15 % of applied N, but the UI did not significantly reduce NH3 volatilization from fresh FDE. The N2O emission factors (amount of N2O–N emitted as a percentage of applied N) for fresh manure, fresh FDE and stored FDE were 0.13?±?0.02, 0.14?±?0.03 and 0.03?±?0.01 %, respectively. The NI (DCD) was effective in decreasing N2O emissions from stored FDE, fresh FDE and fresh manure by 90, 51 and 46 % (P?<?0.05), respectively. All types of effluent increased pasture production over the first 21 days after application (P?<?0.05). The addition of DCD resulted in an increase in pasture production at first harvest on day 21 (P?<?0.05). This study illustrates that UIs and NIs can be effective in mitigating NH3 and N2O emissions from land-applied dairy effluents.  相似文献   

13.
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   

14.
Abstract

To assess their impacts on net global warming, total greenhouse gas emissions (mainly CO2, N2O and CH4) from agricultural production in arable land cropping systems in the Tokachi region of Hokkaido, Japan, were estimated using life cycle inventory (LCI) analysis. The LCI data included CO2 emissions from on-farm and off-farm fossil fuel consumption, soil CO2 emissions induced by the decomposition of soil organic matter, direct and indirect N2O emissions from arable lands and CH4 uptake by soils, which were then aggregated in CO2-equivalents. Under plow-based conventional tillage (CT) cropping systems for winter wheat, sugar beet, adzuki bean, potato and cabbage, on-farm CO2 emissions from fuel-consuming operations such as tractor-based field operations, truck transportation and mechanical grain drying ranged from 0.424 Mg CO2 ha?1 year?1 for adzuki bean to 0.826 Mg CO2 ha?1 year?1 for winter wheat. Off-farm CO2 emissions resulting from the use of agricultural materials such as chemical fertilizers, biocides (pesticides and herbicides) and agricultural machines were estimated by input–output tables to range from 0.800 Mg CO2 ha?1 year?1 for winter wheat to 1.724 Mg CO2 ha?1 year?1 for sugar beet. Direct N2O emissions previously measured in an Andosol field of this region showed a positive correlation with N fertilizer application rates. These emissions, expressed in CO2-equivalents, ranged from 0.041 Mg CO2 ha?1 year?1 for potato to 0.382 Mg CO2 ha?1 year?1 for cabbage. Indirect N2O emissions resulting from N leaching and surface runoff were estimated to range from 0.069 Mg CO2 ha?1 year?1 for adzuki bean to 0.381 Mg CO2 ha?1 year?1 for cabbage. The rates of CH4 removal from the atmosphere by soil uptake were equivalent to only 0.020–0.042 Mg CO2 ha?1 year?1. From the difference in the total soil C pools (0–20 cm depth) between 1981 and 2001, annual CO2 emissions from the CT and reduced tillage (RT) soils were estimated to be 4.91 and 3.81 Mg CO2 ha?1 year?1, respectively. In total, CO2-equivalent greenhouse gas emissions under CT cropping systems in the Tokachi region of Hokkaido amounted to 6.97, 7.62, 6.44, 6.64 and 7.49 Mg CO2 ha?1 year?1 for winter wheat, sugar beet, adzuki bean, potato and cabbage production, respectively. Overall, soil-derived CO2 emissions accounted for a large proportion (64–76%) of the total greenhouse gas emissions. This illustrates that soil management practices that enhance C sequestration in soil may be an effective means to mitigate large greenhouse gas emissions from arable land cropping systems such as those in the Tokachi region of northern Japan. Under RT cropping systems, plowing after harvesting was omitted, and total greenhouse gas emissions from winter wheat, sugar beet and adzuki bean could be reduced by 18%, 4% and 18%, respectively, mainly as a result of a lower soil organic matter decomposition rate in the RT soil and a saving on the fuels used for plowing.  相似文献   

15.
A field experiment was conducted to evaluate the combined or individual effects of biochar and nitrapyrin (a nitrification inhibitor) on N2O and NO emissions from a sandy loam soil cropped to maize. The study included nine treatments: addition of urea alone or combined with nitrapyrin to soils that had been amended with biochar at 0, 3, 6, and 12 t ha?1 in the preceding year, and a control without the addition of N fertilizer. Peaks in N2O and NO flux occurred simultaneously following fertilizer application and intense rainfall events, and the peak of NO flux was much higher than that of N2O following application of basal fertilizer. Mean emission ratios of NO/N2O ranged from 1.11 to 1.72, suggesting that N2O was primarily derived from nitrification. Cumulative N2O and NO emissions were 1.00 kg N2O-N ha?1 and 1.39 kg NO-N ha?1 in the N treatment, respectively, decreasing to 0.81–0.85 kg N2O-N ha?1 and 1.31–1.35 kg NO-N ha?1 in the biochar amended soils, respectively, while there was no significant difference among the treatments. NO emissions were significantly lower in the nitrapyrin treatments than in the N fertilization-alone treatments (P?<?0.05), but there was no effect on N2O emissions. Neither biochar nor nitrapyrin amendment affected maize yield or N uptake. Overall, our results showed that biochar amendment in the preceding year had little effect on N2O and NO emissions in the following year, while the nitrapyrin decreased NO, but not N2O emissions, probably due to suppression of denitrification caused by the low soil moisture content.  相似文献   

16.
Reclamation of sodic soils is proving increasingly vital as greater land area becomes salt-affected in the northern Great Plains of the United States. Flue gas desulfurization gypsum (FGDG) can be an agriculturally important resource for increasing land productivity through the amelioration of sodic soils. Biochar is also considered as an aid in reclaiming degraded soils. In this incubation study, two rates of FGDG (33.6 Mg ha?1 and 66.2 Mg ha?1), two rates of biochar made from sugar beet (Beta vulgaris L.) pulp (16.8 Mg ha?1), and one rate of FGDG combined with one rate of biochar (33.6 Mg ha?1 ea.) were applied to a sodic soil. Soil physicochemical properties, including cationic exchange, pH, electrical conductivity (ECe), sodium adsorption ratio (SARe), total organic carbon (TOC), water retention, and soil respiration rate, were assessed during and at the end of the incubation period. Addition of FGDG to sodic soil increased ECe from 3.5 to 8.4 dS m?1 and decreased SARe from 16 to 9. Biochar addition to sodic soil increased TOC from 62.2 to 99.5 μg g?1 and increased soil respiration rate (mg C kg?1 soil day?1) on every measurement period. When FGDG and biochar were both added to the sodic soil, TOC did not significantly improve; however, ECe increased from 3.5 to 7.7 dS m?1, SARe decreased from 16 to 9, and soil respiration rate increased for all measurements. The results confirm there is potential for FGDG and biochar to reclaim sodic soils alone, and applied in combination.  相似文献   

17.
Combining amendments to the soil made by biochar or hydrochar with nitrogen (N) fertilizer can modify soil N dynamics and availability. Such a response suggests that these amendments would affect ammonia (NH3) emissions from slurry similarly, and potentially reduce volatilization of NH3. This study measured the potential emissions of NH3 following application of pig slurry to the surface of silt‐loam and loam soils amended with biochar and hydrochar (both derived from Miscanthus × giganteus (Greef et Deu)) at a rate of 3% soil dry weight (16 t ha?1 soil area, on average) and 60% water‐filled pore space (WFPS). The experiment was carried out in a dynamic chamber connected to a photo‐acoustic trace gas analyser in a controlled climate (20°C) for 48 hours. Statistically significant differences (P < 0.05) in total emissions were observed between both treatment and soil types. Surprisingly, both amendments increased emissions of NH3 compared with the control; cumulative NH3 emissions averaged 38.7 and 23.5% of applied total ammonium nitrogen (TAN) for hydrochar and biochar, respectively, whereas it was 18.2% for the control. The larger emissions in hydrochar‐amended soil were attributed to the reduced ability to absorb NH4+ associated with greater hydrophobicity and strong pH buffering of the slurry. Furthermore, final soil analyses with deionised water extracts showed significant differences (P < 0.05) in mineral N concentration between treatments. The smaller ammonium concentrations in biochar‐amended soil suggest that some NH4+‐N was immobilized by adsorption on to biochar surfaces. This study observed that biochar and hydrochar properties, as well as soil characteristics, play important roles in controlling NH3 emissions from surface slurry applications. The results obtained identified circumstances where these amendments even enhance volatilization, which provides new information on and insight into the extent and limitations of the potential of biochar and hydrochar for the mitigation of emissions.  相似文献   

18.
Little information is available regarding the effect of sewage sludge biochar on soil properties and crop yield. Thus, our objective was to evaluate the effect of sewage sludge (S) and its biochar (B) on maize shoot yield, nutrients and heavy metals uptake in two calcareous soils. The amendments were applied at the rates of 0, 10, 20 and 40 Mg ha?1. Moreover, NK treatment was included to compare the effects of S and B with conventional fertilization. At harvest time, plant shoots and soil samples were collected for yield, nutrients uptake and chemical analyses. The highest shoot dry matter was obtained in the S treatment. The B application in the clay loam and loam soils resulted in 5.2% increment and 17.7% decrement of shoot dry matter relative to the control, respectively. Shoot dry matter in the NK treatment was significantly higher than in the control. B application decreased Fe, Zn, Mn, Cu and Pb uptake by maize shoot. DTPA-extractable Pb in B-amended soils was lower than in control, while an inverse trend was obtained for available Fe, Zn, Mn and Cu. Biochar application at the rate of 7.3 Mg ha?1 might be suggested for maize cultivation in clay loam soils.  相似文献   

19.
A laboratory column experiment was conducted to investigate the effects of 400°C biochar at application rate of 15 g kg?1 (21.9 t ha?1) with different particle sizes (<0.5 mm (S1), 0.5–1 mm (S2) and 1–2 mm (S3)) and application depths (0–2 cm depth (D0), 4–6 cm depth (D5) and 8–10 cm depth (D10)) on hydro-physical properties of sandy loam soil. The results indicated that applying biochar decreased the waterfront and saturated hydraulic conductivity of sandy loam soil. The cumulative evaporation was the highest and amounted to 40.9 mm in the non-treated soil, but it recorded the lowest amount of 32.2–35.5 mm in the biochar-treated soil. Applying biochar caused significant increases in the amount of conserved and retained water with the highest amount of water conserved in soil treated with S2 biochar at D5. Moreover, the cumulative water infiltration through the soil was significantly reduced by S1 and S2 biochars at D0. The values of saturated hydraulic conductivity for biochar treatments were significantly lower than those for the control, with the lowest values for S1 at D0 and D5. These results suggest positive improvement for the hydro-properties of coarse-textured soils following biochar addition, especially with finer particles of biochar.  相似文献   

20.
Abstract

Many countries have reported that green revolution (GR) technology caused some adverse effects on agricultural lands, but there is no research on the effects of GR in Indonesia. To evaluate the effect of GR technology on sawah soil in Indonesia, a comparative study between seedfarms, where GR technology has been continuously applied, and non-seedfarms was conducted in Java as a pioneer place of GR technology in Indonesia and, in particular, on the carbon and nitrogen status in sawah soils. The term sawah refers to a leveled and bounded rice field with an inlet and outlet for irrigation and drainage. Soil samples collected by Kawaguchi and Kyuma in 1970 and new samples taken in 2003 from the same sites or sites close to the 1970 sampling sites were analyzed and compared. During the period 1970–2003 the land-use pattern of sawah in seedfarms and non-seedfarms did not change, but cultivation intensity increased. The results showed that total carbon (TC) and total nitrogen (TN) contents significantly increased from 31.90 to 40.42 Mg ha?1 and from 3.04 to 3.97 Mg ha?1, respectively, and TC and TN were mostly found accumulated in the surface soil layer. The difference in land management practices between seedfarms and non-seedfarms affected the change in TC and TN content in the 0–20 cm soil layer from 1970 to 2003. In seedfarms, where rice had been planted in a monoculture system, TC and TN contents in the 0–20 cm soil layer increased from 34.50 to 39.24 Mg ha?1 and from 3.16 to 3.95 Mg ha?1, respectively. In non-seedfarms, TC and TN increased more than in seedfarms from 29.77 to 41.37 Mg ha?1 and from 2.94 to 3.98 Mg ha?1, respectively. Within the 0–100 cm soil layer, TC and TN increased from 92.68 to 112.83 Mg ha?1 and from 9.34 to 12.03 Mg ha?1 and from 79.60 to 114.86 Mg ha?1 and from 8.93 to 11.44 Mg ha?1 for seedfarms and non-seedfarms, respectively. No significant difference was observed between the two main soil types, Inceptisols and Vertisols, in Java. Intensive use of sawah over a long time may eliminate the original difference in the properties of these two soil types.  相似文献   

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