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1.
The aim of this study was to assess the changes in soil organic carbon (SOC) stock in relation to the carbon (C) input from nine wheat-based cropping systems and untilled grass. The SOC pool ranged from 32.1 to 49.4 Mg ha?1 at 0–20 cm and from 94 to 171 Mg ha?1 at 0–100 cm for the arable soil, while in untilled grassland, it was higher (54 and 185 Mg C ha?1, respectively). SOC stock was observed to be lower at the unfertilized 2-year rotation and higher at the 4-year rotation with manure and mineral fertilization. The study showed a winter wheat yield decrease of 176.8 kg ha?1 for a 1- Mg ha?1 SOC stock change in the 0–20-cm soil depth. The estimated C input for SOC stock maintenance was from 266 to 340 g C m?2 year?1 for winter wheat and rotations, respectively. Additional C input did not increase the SOC pool, suggesting that arable plots had a limited ability to increase SOC. These results provide guidance for the selection of management practices to improve C sequestration.  相似文献   

2.

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.
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3.
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   

4.
Many studies on soil organic carbon (SOC) sequestration in perennial biomass crops are available for Atlantic and continental environments of North Central Europe, while there is insufficient information for Southern Europe. Therefore, we assessed SOC turnover under Mediterranean climate, after a 9-year-old conversion from two annual crop systems, continuous wheat and maize/wheat rotation, to Miscanthus (Miscanthus sinensis?×?giganteus) and giant reed (Arundo donax), respectively. The naturally occurring 13C signature down to 0.60 m was used to evaluate the total amount of SOC in annual vs perennial species and to determine the portion of SOC derived from perennial species. Soil organic C was significantly higher under perennial (average, 91 Mg C ha?1) than annual species (average, 56 Mg C ha?1), with a stronger accumulation in the topsoil (0–0.15 m). This difference was consistent with reduced soil disturbance associated with perennial crop management. After 9 years of Miscanthus plantation, the amount of C4-derived C was 18.7 Mg ha?1, mostly stored at 0–0.15 m, whereas the amount of C3-derived C under giant reed was 34.7 Mg ha?1 and was more evenly distributed through soil depths, probably due to its deeper root apparatus. It is suggested that both Miscanthus and giant reed have a remarkable potential for SOC sequestration also under Mediterranean conditions, while supporting the growing bioenergy sector with biomass supply.  相似文献   

5.
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   

6.
Abstract

Two Ferralsols (350 and 600 g kg?1 clay) from the Brazilian Cerrado Region were evaluated for long‐term effects (5 and 8 years) of no tillage on carbon (C) stocks in particulate (>53 µm) and mineral‐associated (<53 µm) soil organic matter (SOM) fractions. Carbon stocks in particulate SOM increased under no tillage compared with conventional tillage, and the rate was higher in the clayey soil (0.62 Mg C ha?1 yr?1) than in the sandy clay loam soil (0.31 Mg C ha?1 yr?1). In contrast, the mineral‐associated SOM in the top soil layer (0–20 cm) was not affected by tillage system. Sequestration of atmospheric C in tropical no‐tillage soils seems to be due to accumulation of C in labile SOM fractions, with highest rates in clayey soils probably due to physical protection.  相似文献   

7.
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   

8.
Soil, crop, and fertilizer management practices may affect quality of organic carbon (C) and nitrogen (N) in soil. A long-term field experiment (growing barley, wheat, or canola)was conducted on a Black Chernozem (Albic Argicryoll) loam at Ellerslie, Alberta, Canada, to determine the influence of 19 years (1980 to 1998) of tillage [zero tillage (ZT) and conventional tillage (CT)], straw management [straw removed (SRem) and straw retained (SRet)], and N fertilizer rate (0, 50, and 100 kg N ha?1 in SRet and 0 kg N ha?1 in SRem plots) on macro-organic matter C (MOM-C) and N (MOM-N), microbial biomass C (MB-C), and mineralizable C (Cmin) and N (Nmin) in the 0- to 7.5-cm and 7.5- to 15-cm soil layers. Treatments with N fertilizer and SRet generally had a greater mass of MOM-C (by 201 kg C ha?1 with 100 kg N ha?1 rate and by 254 kg C ha?1 with SRet), MOM-N (by 12.4 kg N ha?1 with 100 kg N ha?1 rate and by 8.0 kg N ha?1 with SRet), Cmin(by 146 kg C ha?1 with 100 kg N ha?1 rate and by 44 kg C ha?1 with SRet), and Nmin(by 7.9 kg N ha?1 with 100 kg N ha?1 rate and by 9.0 kg N ha?1 with SRet)in soil than the corresponding zero-N and SRem treatments. Tillage, straw, and N fertilizer had no consistent effect on MB-C in soil. Correlations between these dynamic soil organic C or N fractions were strong and significant in most cases, except for MB-C, which had no significant correlation with MOM-C and MOM-N. Linear regressions between crop residue C input and mass of MOM-C, MOM-N, Cmin, and Nmin in soil were significant, but it was not significant for MB-C. The effects of management practices on dynamic soil organic C and N fractions were more pronounced in the 0- to 7.5-cm surface soil layer than in the 7.5- to 15-cm subsoil layer. In conclusion, the findings suggest that application of N fertilizer and retention of straw would improve soil quality by increasing macro-organic matter and N-supplying power of soil.  相似文献   

9.
To maximise carbon (C) storage in soils, understanding the fate of C originating from aboveground and belowground residues and their interaction with fertiliser under field conditions is critically important. The use of 13C natural abundance provides unique opportunities to separate both C sources. We investigated the effect of 16 years of C3 straw and C4 root input, with and without nitrogen (N) addition, on SOC stocks and C distribution in soil fractions in the long-term frame trial at Ultuna, Sweden. The straw C input was fixed at 1.77 Mg ha?1 year?1, while the root input depended on maize plant growth, enabling studies on how N fertilisation affected (i) stabilisation of residues and (ii) plant C allocation to belowground organs. Four treatments were investigated: only maize roots (Control), maize roots with N (Control + N), maize roots and straw (Straw) and maize roots, straw and N (Straw + N). After 16 years, 5.6–8.9% of the total SOC stock in the 0–20 cm soil layer was maize-derived. In all four treatments, the relatively labile SOC fractions decreased, while the proportion of more refractory fractions increased. Based on allometric calculation of root inputs, retention of maize roots was 38, 26, 36 and 18% in the Control, Control + N, Straw and Straw + N treatments, respectively. The estimated retention coefficient of C3 straw in the Straw + N treatment was higher than that in the Straw-N treatment. We interpreted these results thus (1) roots were better stabilised in the soil than straw; (2) N fertilisation caused a shift in root to shoot ratio, with relatively more roots being present in N-deficient soil; and (3) N fertilisation caused greater stabilisation of residues, presumably due to increased microbial C use efficiency.  相似文献   

10.
A large proportion of phosphate fertilizer applied to calcareous soils reacts with calcium. Changes in soil phosphorus (P) availability after single application of biochar and phosphate-solubilizing bacteria have been reported. However, interaction of biochar (increasing soil pH) and phosphate-solubilizing bacteria (decreasing soil pH) on P availability in calcareous soil is not well known. An incubation experiment was conducted to study how the interactive effects of biochars (produced from wheat straw and cow manure at 300°C and 500°C with residence time of 1, 3 and 6 h) at different rates (0, 5 and 10 t ha?1) and phosphate-solubilizing Pseudomonas sp. IS8b2 affected on content of soil available P after 0, 60, 120 and 180 days of incubation (DOI) in a calcareous soil. After 60 DOI, the maximum value of available P (50.31 mg kg?1) was observed in the compound treatment of Pseudomonas sp. IS8b2 and wheat straw biochar (10 t ha?1) produced at 500°C with residence time of 3 h. We conclude that the combination use of wheat straw biochar and phosphate-solubilizing bacterium is promising to potentially improve soil P availability in calcareous soil, but further research at field scale is needed to confirm this.  相似文献   

11.
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   

12.
Abstract

Biochar application has been recognized as an effective option for promoting carbon (C) sequestration, but it may also affect the production and consumption of methane (CH4) and nitrous oxide (N2O) in soil. A 1-year field experiment was conducted to investigate the effects of rice husk charcoal application on rice (Oryza sativa L.) productivity and the balance of greenhouse gas exchanges in an Andosol paddy field. The experiment compared the treatments of rice husk charcoal applied at 10, 20 and 40 Mg ha?1 (RC10, RC20 and RC40, respectively), rice husk applied at 20 Mg ha?1 (RH20), and the control (CONT). Rice straw and grain yields did not significantly differ among the treatments. The seasonal cumulative CH4 emissions were 38–47% higher from RC10, RC20 and RC40 than from the CONT. However, the increases were not in proportion to the application rates of rice husk charcoal, and their values did not significantly differ from the CONT. On the contrary, the RH20 treatment significantly increased the cumulative CH4 emission by 227% compared to the CONT. The N2O emissions during the measurement were not affected by the treatments. As a result, the combined global warming potential (GWP) of CH4 and N2O emissions was significantly higher in RH20 than in the other treatments. There was a positive linear correlation between C storage in the top 10 cm of soil and the application rate of rice husk charcoal. The increases in soil C contents compared to the CONT corresponded to 98–149% of the C amounts added as rice husk charcoal and 41% of the C added as rice husk. Carbon dioxide (CO2) fluxes in the off season were not significantly different among RC10, RC20, RC40 and CONT, indicating that C added as rice husk charcoal remained in the soil during the fallow period. The CO2 equivalent balance between soil C sequestration and the combined GWP indicates that the rice husk charcoal treatments stored more C in soil than the CONT, whereas the RH20 emitted more C than the CONT. These results suggest that rice husk charcoal application will contribute to mitigating global warming without sacrificing rice yields.  相似文献   

13.
A 2-year field experiment was conducted to assess system productivity, nutrient use efficiency and apparent balances of phosphorus (P) and potassium (K) in diversified rice-based cropping systems at Gazipur, Bangladesh. Four cropping systems: wheat–fallow–rice, maize–fallow–rice, potato–fallow–rice and mustard–fallow–rice in main plots and four nutrient combinations: NPK, NK, NP and PK in sub-plots were arranged in a split-plot design with three replications. Receiving the NPK treatment, all the component crops gave the highest yield, and omission of N from fertilizer package gave the lowest yield. The maize–rice system removed the highest amount of N (217 kg ha?1), P (41 kg ha?1) and K (227 kg ha?1) followed by wheat–rice, potato–rice and the least in mustard–rice system. The wheat–rice and maize–rice system showed negative K balance of –35.5 and –60.4 kg ha?1 in NPK treatment, while potato–rice system showed a positive K balance of 31.0 kg ha–1 with NPK treatment. The N, P and K uptake and apparent recovery by the test crops may be used for site-specific nutrient management. The K rates for fertilizer recommendation in wheat and maize in Indo-Gangetic plain need to be revised to take account for the negative K balance in soil.  相似文献   

14.
Maintaining soil organic carbon (SOC) in arid ecosystem is important for soil productivity and restoration of deserted sandy soil in western plain of India. There is a need to understand how the cropping systems changes may alter SOC pools including total organic carbon (TOC), particulate organic C (POC), water soluble carbon (WSC), very labile C (VLC), labile C (LC), less labile C (LLC) and non-labile C (NLC) in arid climate. We selected seven major agricultural systems for this study viz., barren, fallow, barley–fallow, mustard–moth bean, chickpea–groundnut, wheat–green gram and wheat–pearl millet. Result revealed that conversion of sandy barren lands to agricultural systems significantly increased available nutrients and SOC pools. Among all studied cropping systems, the highest values of TOC (6.12 g kg?1), POC (1.53 g kg?1) and WSC (0.19 g kg?1) were maintained in pearl millet–wheat system, while the lowest values of carbon pools observed in fallow and barren land. Strong relationships (P < 0.05) were exhibited between VLC and LC with available nutrients. The highest carbon management index (299) indicates that wheat–pearl millet system has greater soil quality for enhancing crop productivity, nutrient availability and carbon sequestration of arid soil.  相似文献   

15.
Specialization within agriculture has been a key factor in increasing farm income. The production systems have become increasingly simple, since farmers only grow a small number of crops which have a favourable market price. However, monocultural systems require increasing use of agrochemicals leading to unsustainable environmental costs. In this work, the soil fertility of two plots in a crop rotation previously grown for 5 years as pasture or maize monoculture was evaluated. In the pasture, the upper 0–20 cm soil layer sequestered 17.4 Mg organic C ha?1 and accumulated 403 kg N ha?1 more than under maize monoculture. Analytical data from pot experiments showed that soil samples from the pasture plot released significantly more mineral N than soil samples from the maize monoculture. Maize dry matter (DM) yields in 2012 and 2013 were 15.3 and 10.0 Mg ha?1 in the pasture plot and 8.8 and 8.4 Mg ha?1 in the maize monoculture plot. Nitrogen recoveries by maize were 175.4 and 68.0 kg ha?1 in the pasture and 78.3 and 50.3 kg ha?1 in the maize monoculture plot. The pool of organic matter accumulated during the pasture phase immobilized important nutrients which benefited the succeeding crop as the organic substrate was mineralized.  相似文献   

16.
We evaluated dryland wheat (Triticum aestivum L.) response to biosolids applications in the inland Pacific Northwest and compared agronomic application rates predicted from yield curves with those predicted from Extension guidance. We applied biosolids rate treatments during the fallow year in 10 on‐farm experiments and determined grain yield, protein, and postharvest soil nitrate. Nitrogen (N) rates were calculated from Extension guidance and compared with biosolids agronomic rate estimates based on yield regressions generated for each site. Eight of the 10 sites had quadratic yield responses. The agronomic biosolids rate at the responsive sites averaged 315 kg ha?1 more grain than the farmer inorganic N rate. At responsive sites, a mean biosolids application rate of 4.7 dry Mg ha?1 (226 kg total N ha?1) was required for 95% of maximum grain yield. Results showed that Extension fertilizer guidance together with calculations for biosolids available N gave reasonable estimates for biosolids application rates.  相似文献   

17.
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   

18.
ABSTRACT

A 6-year field experiment was conducted at Maharashtra, India, from 2011 to 2017 on a silty clay soil, to study the impact of organic manure prepared from common weed Trianthema portulacastrurm Linn. on soybean-fodder maize crop system and soil organic carbon (SOC) sequestration. Organic manures were prepared from Trianthema as compost, vermicompost, dry leaf powder and were compared with application of Farm Yard Manure (FYM), chemical fertilizer treatment (NPK), and control. All treatments were repeated to same earlier treated plots every year for subsequent 6 years. Soil samples were analyzed before experiment and after harvesting of crops at the end of 6 years. All organic manures prepared from Trianthema and FYM increased SOC, nitrogen, phosphorus, and potassium content in the soil as compared to chemical fertilizer treatment and control. The overall increase in SOC content in the 0–60-cm soil depth in vermicompost treatment was 3.51 Mg C ha?1 as compared to control at the end of this 6 years experiment at the carbon sequestration rate of 585 kg ha?1 year?1. Preparation and use of different manures from Trianthema will increase the carbon sequestration in soil, a measure to mitigate global warming.  相似文献   

19.
Abstract

Soil carbon sequestration in agricultural lands has been deemed a sustainable option to mitigate rising atmospheric CO2 levels. In this context, the effects of different tillage and C input management (residue management and manure application) practices on crop yields, residue C and annual changes in total soil organic C (SOC) (0–30 cm depth) were investigated over one cycle of a 4-year crop rotation (2003–2006) on a cropped Andisol in northern Japan. For tillage practices, the effects of reduced tillage (no deep plowing, a single shallow harrowing for seedbed preparation [RT]) and conventional deep moldboard plow tillage (CT) were compared. The combination of RT, residue return and manure application (20 Mg ha?1 in each year) increased spring wheat and potato yields significantly; however, soybean and sugar beet yields were not influenced by tillage practices. For all crops studied, manure application enhanced the production of above-ground residue C. Thus, manure application served not only as a direct input of C to the soil, but the greater crop biomass production engendered enhanced subsequent C inputs to the soil from residues. The SOC contents in both the 0–5 cm and 5–10 cm layers of the soil profile were greater under RT than under CT treatments because the crop residue and manure were densely incorporated into the shallow soil layers. Comparatively, neither tillage nor C input management practices had significant effects on annual changes in SOC content in either the 10–20 cm or 20–30 cm layers of the soil profile. When soil C sequestration rates, as represented by annual changes in total SOC (0–30 cm), were assessed on a total soil mass basis, an anova showed that tillage practices had no significant effect on total C sequestration, but C input management practices had significant positive effects (P ≤ 0.05). These results indicate that continuous C input to the soil through crop residue return and manure application is a crucial practice for enhancing crop yields and soil C sequestration in the Andisol region of northern Japan.  相似文献   

20.
ABSTRACT

Crop production in arid regions is characterized with high temperature, drought and salinity which decrease water and nutrient use efficiency. This study was conducted to investigate the effect of wheat residue mulch in relation to N fertilizer application rates for cotton productivity under dryland condition of Uzbekistan. Main plots were control of no mulch addition and a 5 t ha?1 mulch treatment. These plots were split into 5 N rate plots of 0, 70, 140, 210 or 280 kg of N ha?1. The results showed that mulching pattern decreased soil temperature by 0.7–1.5°C as compared to conventional treatment (CT), regardless of N fertilization rates. The soil water storage increased by 41.8, 17.3, 48.0 mm in the flowering, boll formation and ripening stages of cotton, respectively under mulching treatment. Soil available N concentration and nutrients uptake by plants consistently increased with the increase of N fertilization rates with positive correlations. At flowering period, the plant height, chlorophyll content, stem diameter, and a number of fruit branches in plants were higher by 32.3%, 46.8%, 26.7% and 55.3%, respectively at 210 kg N ha?1 under mulching treatment as compared to the non-fertilized control. The highest cotton yield was obtained at 210 kg N ha?1 application under mulching treatment. The correlation difference between mulch and N application rates was higher (R2 = 0.97) than the difference in CTs and N application rates (R2 = 0.89). This study showed that mulching had a greater impact to preserve nutrients and water resources in the soil, thereby improved cotton growth and yield.  相似文献   

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