Rice husk biochar application to paddy soil and its effects on soil physical properties,plant growth,and methane emission

The objective of this study was to investigate the effects of the application of rice husk biochar on selected soil physical properties, rice growth, including root extension, and methane (CH₄) emissions from paddy field soil. Three replication experiments were conducted using outdoor pot experiments utilizing commercial rice husk biochar mixed with paddy soil at a rate of 0 (control), 2, and 4 % (weight biochar/weight soil) in which the rice was cultivated for 100 days under a continuously flooded condition. The physical properties of soils were analyzed before and after the growing periods. Some parameters of rice growth and CH₄ emissions of paddy soils were monitored weekly during the experiment. Root extension was also analyzed after harvesting. The experiments showed that the application of rice husk biochar improved the physical properties of paddy soils. It led to a decrease in bulk density and an increase in saturated hydraulic conductivity, including the total pore volume as well as the available soil water content. The shoot height of rice plants was significantly higher in soil amended with 4 % biochar than that in the control soil. However, other plant growth parameters and root extension were only slightly affected by the application. It was also found that amending soil with biochar led to a reduction of the total CH₄ emissions by 45.2 and 54.9 % for an application rate of 2 and 4 %, respectively, compared with the control. Our results showed that the higher the application rate, the stronger the effect of biochar was observed. More research is still necessary for a better understanding of the underlying mechanisms.     

Soil organic carbon sequestration as affected by tillage, crop residue, and nitrogen application in rice–wheat rotation system

Despite being a major domain of global food supply, rice?Cwheat cropping system is questioned for its contribution to carbon flux. Enhancing the organic carbon pool in this system is therefore necessary to reduce environmental degradation and maintain agricultural productivity. A field experiment (November 2002?CMarch 2006) evaluated the effects of soil management practices such as tillage, crop residue, and timing of nitrogen (N) application on soil organic carbon (SOC) sequestration in the lowland of Chitwan Valley of Nepal. Rice (Oryza sativa L.) and wheat (Triticum aestivum L.) were grown in rotation adding 12?Mg?ha^?1?y^?1 of field-dried residue. Mung-bean (Vigna radiata L.) was grown as a cover crop between the wheat and the rice. Timing of N application based on leaf color chart method was compared with recommended method of N application. At the end of the experiment SOC sequestration was quantified for five depths within 50?cm of soil profile. The difference in SOC sequestration between methods of N application was not apparent. However, soils sequestered significantly higher amount of SOC in the whole profile (0?C50?cm soil depth) with more pronounced effect seen at 0?C15?cm soil depth under no-tillage as compared with the SOC under conventional tillage. Crop residues added to no-tillage soils outperformed other treatment interactions. It is concluded that a rice?Cwheat system would serve as a greater sink of organic carbon with residue application under no-tillage system than with or without residue application when compared to the conventional tillage system in this condition.     

生物炭对双季水稻产量、养分吸收和土壤性状的残留效应

生物炭对改良酸性土壤质量和提高作物产量具有重要作用。本研究以常规稻中嘉早17(早稻)和杂交稻五优308(晚稻)为供试品种,于2015年开始设置不施生物炭(C0)和一次性施用生物炭20 t/hm^2(C20)处理,以阐明施用生物炭3年后对双季稻产量、养分吸收和土壤性状的残留效应。结果表明,与C0处理相比,C20处理显著提高双季早稻产量,但对晚稻产量无显著影响;C20处理显著提高早、晚稻钾素吸收,对早稻氮素和磷素吸收有增加的趋势,但未达显著水平。试验进行4年后,C20处理显著提高土壤有机质含量和pH值。因此,在本试验中的酸性红壤上一次性施用生物炭后的第4年,生物炭仍然对双季水稻产量和土壤肥力具有提升效应。     

Influence of Oil Palm Empty Fruit Bunch Biochar on Floodwater pH and Yield Components of Rice Cultivated on Acid Sulphate Soil under Rice Intensification Practices

Abstract

Rice has a vital role in food security but the production is limited in infertile and degraded soils. Rice is cultivated on acid sulphate soil in the coastal area of Peninsular Malaysia. Soil amendment using biological charcoal (biochar) increases the soil fertility. Thus, empty fruit bunch biochar (EFBB) was applied in a pot experiment under a controlled environment using an organic system of rice intensification (SRI) practice and its effects on the floodwater pH, acid sulphate soil properties and growth performance of rice and yield of rice MR219 were preliminarily investigated. EFBB increased grain yield by 141 to 472%. Plant growth and yield parameters in EFBB amended soils were significantly higher than in soil without biochar. The number of tillers increased significantly with the increase in biochar applied; 28 tillers were produced in the control, while up to 80 tillers were produced in the plots applied 40 t ha^–1 EFBB. Moreover, the decline of Al³⁺ in flood water indicated that EFBB mitigated Al³⁺ toxicity. Soil water pH increased from 3.5 to 6 with increasing EFBB application rates. The grain yield was linearly correlated to the application rate of EFBB. This pot study demonstrates that the application of EFBB combined with organic fertilization and intermittent irrigation has the potential to improve rice yield on acid sulphate soil. Further study in the field is warranted to determine the effect of EFBB on large scale rice production.     

水稻低碳生产研究进展

 稻田是甲烷(methane,CH4)和氧化亚氮(nitrous oxide,N2O)的重要发生源。稻田中CH4和N2O的产生、消耗以及传输过程受稻田土壤类型、水分条件、肥料种类、施肥量及方法、耕作模式和制度、水稻品种等多种因素影响。CH4和N2O具有不同的排放特性,很多研究结果表明,水稻生长期间的中期排水烤田、后期干湿交替能显著降低CH4排放量,但同时也可能促进N2O的排放,因此,如何同时减少CH4和N2O的排放量是实现稻田低碳生产的关键要素;另一方面,稻田土壤的碳固定也是使稻田系统从源转变成汇的关键技术。从水稻生产过程中CH4排放、N2O排放、稻田土壤有机碳动态、减排措施四个方面综述了近年来水稻低碳生产相关研究状况,重点总结了国内外有关影响稻田CH4和N2O排放的关键影响因素、增加稻田土壤有机质含量的主要措施以及各种减排措施的全球增温潜势评价研究,并对水稻低碳生产研究作了展望。     

土壤施用生物质炭对取食水稻的灰飞虱生活史特征的影响

【目的】为评价土壤施用生物质炭在防治农作物害虫中的潜力,观察了土壤施用生物质炭对取食水稻的灰飞虱(Laodelphaxstriatellus)发育和生殖的影响。【方法】开展室内盆栽试验,采用生物质炭种类(玉米、水稻和小麦秸秆)与添加量（0、30和50g/kg）的2因素×3水平组合处理土壤,种植水稻苗、接种灰飞虱,观察灰飞虱的发育和生殖表现。【结果】1)生物质炭种类与添加量互作影响灰飞虱若虫历期,当施用玉米或水稻生物质炭时,不同添加量之间的若虫历期无显著差异;当施用小麦生物质炭时,添加30g/kg生物质炭处理下的若虫历期比对照(18.70±0.30 d)延长1.54 d。2)生物质炭种类与添加量没有显著互作影响雌成虫寿命。添加量不影响,但生物质炭种类具有显著影响,施用玉米或小麦生物质炭处理雌成虫寿命比水稻生物质炭处理雌成虫寿命(23.70±0.48d)分别延长2.13 d或3.10 d。3)生物质炭种类与添加量互作影响灰飞虱雌虫终身产卵量,施用生物质炭使生殖力下降,但下降幅度随生物质炭处理不同而异,当添加30g/kg生物质炭时,施用玉米生物质炭处理下的雌虫终身产卵量(176.40±6.84粒)比施用水稻或小麦生物质炭处理分别多22.80粒或18.95粒;当添加50g/kg生物质炭时,施用玉米生物质炭处理的雌虫终身产卵量(140.30±3.26粒)比施用水稻或小麦生物质炭处理分别少16.90粒或21.60粒。【结论】施用生物质炭可减弱灰飞虱的生殖力,减幅随生物质炭种类与添加量的不同而异。     

施用生物质炭对酸性茶园土壤氨挥发的影响

氨挥发是土壤氮素损失的主要因素之一。通过田间试验,研究了施用生物质炭对酸性茶园土壤理化性质及氨挥发的影响,以期为评价生物质炭在茶园土壤中的应用提供科学数据。试验设不施氮肥(对照CK)、单施氮肥(B0N1,225 kg·hm-2)、施8 t·hm-2生物质炭基础上增施氮肥(B1N1)、施16 t·hm-2生物质炭基础上增施氮肥(B2N1)4个处理,施氮量春季追肥、秋季追肥和冬季基肥比例为3︰3︰4,进行了为期1年的观测。结果表明,与B0N1处理相比,B1N1和B2N1处理显著提高了土壤p H值和有机碳含量(P0.05),显著降低了土壤容重(P0.05),全氮量变化不显著(P0.05);与B0N1处理相比,B1N1和B2N1处理土壤铵态氮平均含量降低了5.34%~12.59%,硝态氮平均含量增加了11.02%~36.54%,促进硝化作用。酸性茶园土壤氨挥发量为13.01~40.95 kg·hm-2,氨挥发损失率为7.29%~12.42%,冬季基肥期氨挥发损失量最大;施氮显著增加土壤氨挥发量(P0.05),增施生物质炭则显著降低了氨挥发量(P0.05),降幅为26.25%~28.21%。土壤铵态氮浓度是影响氨挥发的最主要因素,施用生物质炭降低了土壤铵态氮浓度,从而抑制了氨挥发。     

Rice yield and soil carbon dynamics over three years of applying rice husk charcoal to an Andosol paddy field

Rice husk charcoal (RC) produced from the pyrolysis of rice husk (RH) can be one of the cost-effective biochars for use in rice-based farming systems. This study investigated changes in rice yield and soil carbon sequestration over three years of RC application to an Andosol paddy field. The treatments were RC application at 0.02, 0.2, and 2 kg m^?2 (RC0.02, RC0.2, and RC2, respectively), RH application at 0.2 kg m^?2 (RH0.2), and a control with no RC or RH application (CONT). The results showed that RC2 increased culm length by 4% and straw weight by 14% on average over the three years. These increases in plant growth coincided with a higher level of silicon uptake by the rice plants, although they did not significantly affect grain yield. The soil carbon content was progressively increased by RC2 over the three years, whereas it was not significantly affected by RC0.02 or RC0.2. A considerable amount (>72%) of the applied carbon with RC2 remained in the soil by taking account of its downward movement below the 10 cm layer of the paddy field after three consecutive years of RC application. We conclude that rice husk charcoal application to Andosol paddy fields is an effective option for increasing carbon sequestration. Furthermore, the increase in silicon uptake by rice plants suggests that rice husk charcoal can also be functioning as a silicon fertilizer.     

土壤施用生物质炭对取食水稻的灰飞虱生活史特征的影响

【目的】为评价土壤施用生物质炭在防治农作物害虫中的潜力,观察了土壤施用生物质炭对取食水稻的灰飞虱(Laodelphax striatellus)发育和生殖的影响。【方法】开展室内盆栽试验,采用生物质炭种类(玉米、水稻和小麦秸秆)与添加量(0、30和50 g/kg)的2因素×3水平组合处理土壤,种植水稻苗、接种灰飞虱,观察灰飞虱的发育和生殖表现。【结果】1)生物质炭种类与添加量互作影响灰飞虱若虫历期,当施用玉米或水稻生物质炭时,不同添加量之间的若虫历期无显著差异;当施用小麦生物质炭时,添加30 g/kg生物质炭处理下的若虫历期比对照(18.70±0.30 d)延长1.54 d。2)生物质炭种类与添加量没有显著互作影响雌成虫寿命。添加量不影响,但生物质炭种类具有显著影响,施用玉米或小麦生物质炭处理雌成虫寿命比水稻生物质炭处理雌成虫寿命(23.70±0.48 d)分别延长2.13 d或3.10 d。3)生物质炭种类与添加量互作影响灰飞虱雌虫终身产卵量,施用生物质炭使生殖力下降,但下降幅度随生物质炭处理不同而异,当添加30 g/kg生物质炭时,施用玉米生物质炭处理下的雌虫终身产卵量(176.40±6.84粒)比施用水稻或小麦生物质炭处理分别多22.80粒或18.95粒;当添加50 g/kg生物质炭时,施用玉米生物质炭处理的雌虫终身产卵量(140.30±3.26粒)比施用水稻或小麦生物质炭处理分别少16.90粒或21.60粒。【结论】施用生物质炭可减弱灰飞虱的生殖力,减幅随生物质炭种类与添加量的不同而异。     

生物炭与氮肥施用对双季稻田温室气体排放的影响

以我国南方双季稻田为研究对象,旨在探究生物炭与氮肥施用对稻田温室气体排放的影响.试验共设置5个处理,分别为不施氮肥不施生物炭(N0B0)、单施40 t/hm2生物炭(N0B2)、单施氮肥(N1B0)、氮肥配施20 t/hm2生物炭(N1B1)、氮肥配施40 t/hm2生物炭(N1B2).采用静态暗箱-气象色谱法连续监测...     

Long-term effect of no-tillage on soil organic carbon and nitrogen in an irrigated rice-based cropping system

A 10-year field experiment was conducted to determine the effect of no-tillage (NT) on soil organic carbon (SOC) and nitrogen (N) in an irrigated rice-based cropping system. The results showed that concentrations of SOC, soil total N (STN), and soil organic N (SON) were higher at 0–5 cm depth but lower at 5–10 cm depth under NT than conventional tillage (CT), while at 10–20 cm depth the differences were not significant. Consequently, stocks of SOC, STN, and SON under NT were higher at 0–5 cm depth but lower at 5–10 cm depth than those under CT. However, no significant differences were observed in stocks of SOC, STN, and SON at 0–20 cm depth between NT and CT, indicating that the lower st ocks of SOC, STN, and SON at 5–10 cm depth could offset the greater stocks of them at 0–5 cm depth under NT. In addition, there were no significant differences in soil inorganic N concentration and soil C:N ratio between NT and CT at all the three depths. Our study suggests that (1) NT farming does not necessarily store SOC and N more than CT soils for the upper soil layer and (2) converting from CT to NT farming may not cause a significant change in soil N mineralization in the irrigated rice-based cropping systems.     

Toposequential Variation in Soil Fertility and Rice Productivity of Rainfed Lowland Paddy Fields in Mini-Watershed (Nong)in Northeast Thailand

Abstract

Mini-watersheds called Nongin Thai are geographical components of rainfed lowland rice culture in Northeast Thailand, and constitute distinct units in understanding environmental constraints for low and unstable rainfed rice production there. The toposequential variation of soil fertility and its relation to rice productivity within mini-watersheds, was examined by phytometry of sampled soils and field measurements of rice growth and yield. The phytometry experiment with irrigated potted rice using soils sampled from various rice fields within each mini-watershed, revealed that soil fertility as evaluated by rice dry matter production showed a 5 times difference among the fields at most. The difference in the soil fertility was ascribed primarily to that in nitrogen (N) supply capacity, which itself had a strong correlation with soil organic carbon (SOC) content. Accordingly, the biomass production of pot-grown rice was proportional to SOC. content, which suggested the usefulness of SOC as an index for soil fertility evaluation. The effect of clay on the soil fertility was much less than that of SOC. The actual rice yield in each field also showed quite large field-to-field variation, most of which was explained by the SOC content, rice growth duration and fertilizer application rate even though water availability also affected the yield. The yield positively correlated with growth duration and hence with earlier transplanting. Both SOC and clay contents of fields showed steep gradients with ascending field elevation within mini-watersheds, resulting in a marked toposequential distribution of rice yield. The toposequential distributions of SOC and clay contents imply that rice culture after deforestation accelerated soil erosion from upper to lower fields. The large toposequential gradient in soil fertility requires different resource and crop management for each toposequential position, in order to improve rice productivity of the mini-watershed as a whole.     

施用石灰与生物炭对酸性土壤花生氮素吸收及产量的影响

为明确石灰与生物炭对酸化土壤改良及花生氮营养的作用效果,通过田间小区试验,研究了石灰、生物炭单施与配施对酸化土壤性质、花生氮素吸收利用及生长发育的影响。结果表明,与CK相比,单施石灰显著提高了土壤pH值、有机质、碱解氮和交换性钙含量,花生植株氮吸收量和收获指数显著增加13.1%和4.6%,花生生物量和产量显著提高11.7%和16.1%;单施生物炭显著增加了土壤pH值、有机质、碱解氮含量和土壤碳氮比,但对花生氮吸收量、生物量和产量无显著影响;表明酸性土壤明显抑制了花生生长,单施石灰促进花生生长及氮高效利用效果优于生物炭。石灰与生物炭配施后,土壤pH值、有机质、碱解氮、交换性钙含量及碳氮比更协调,花生植株氮吸收量、氮利用率、生物量和产量均得到进一步提高。所有处理中,4500 kg/hm²生物炭配施450 kg/hm²石灰处理的花生植株氮吸收量、氮收获指数、氮利用率、生物量及产量最高,分别比CK增加30.7%、8.7%、5.7%、27.6%和35.8%。因此,4500 kg/hm²石灰和450 kg/hm²生物炭配施是酸性土壤改良、氮素高效及花生高产栽培的有效手段。     

Long-term effects of mulch,fertilization and tillage on cassava grown in sandy soils in northern Colombia

Cassava (Manihot esculenta Crantz) is often cultivated in sandy soils that are very low in nutrients and organic matter. Under such conditions, yields often decline when the crop is grown successively without fertilizer application. An 8-year on-farm trial was conducted on sandy soils in northern Colombia to study effects of (1) surface mulching with residues of the grass Panicum maximum, (2) moderate applications of N, P and K fertilizer and (3) tillage on crop productivity, root quality and soil properties. Mulch applications significantly increased root and top biomass, increased root dry matter content while reducing its yearly variation, and decreased root HCN, particularly in the absence of fertilizer. Mulch applications also significantly reduced soil temperatures within the top 20 cm and increased soil organic carbon, K, P, Ca and Mg. Without mulch, soil pH decreased over the years. Annual applications of 21 kg ha⁻¹ P resulted in a build-up of soil P, whereas no build-up of soil K was observed with applications of 41 kg K ha⁻¹. The application of N, P and K fertilizer significantly increased root and top biomass and reduced root HCN, especially if no mulch was applied. Where both mulch and fertilizer applications were absent, root yield and top biomass declined over the years. Tillage, except when combined with fertilizer application, had no effect on root yield, top biomass, root dry matter or HCN contents. Neither were effects of tillage observed in any of the studied soil parameters. The trial indicated that, to sustain cassava productivity in poor sandy soils, applications of plant mulch and/or chemical fertilizer are highly desirable.     

不同生物炭类型及添加量对土壤碳氮转化的影响

通过室内培养试验,研究不同生物炭类型(椰壳炭、稻壳炭、柠条炭)以及生物炭添加水平对不同土壤(砖红壤和水稻土)碳素转化的影响。结果表明,在施用等量尿素的情况下,随着生物炭添加量的增加土壤的有机碳含量显著提高。对土壤氮素转化的影响总体表现一致,土壤铵态氮含量逐渐减少,而硝态氮含量逐渐增加;添加1%、2%、5%生物炭的处理土壤NH_4~+-N含量分别比对照降低了13.3%~16.0%、18.6%~28.5%、51.1%~68.8%,NO_3~--N含量比对照提高了6.4%~13.3%、12.9%~19.7%、18.4%~22.7%,这可能与添加生物炭后土壤pH升高引起的氨挥发增加有关,然而其影响程度与土壤类型、生物炭类型和生物炭添加量密切相关。     

Effects of Crop Residue and Nitrogen Rates on Yield and Yield Components of Two Dryland Wheat (Triticum aestivum L.) Cultivars

Abstract

In most southern parts of Iran, wheat (Triticum aestivum L.) residues have been traditionally burned or removed; that is often criticized for soil organic and nutrient losses, reducing soil microbial activity and increasing CO₂ emission. A 2-years (2005?2007) field study was carried out at the College of Agriculture, Shiraz University, Shiraz, Iran, to evaluate the influence of crop residues management and nitrogen (N) rates on dryland wheat. The experiment was conducted as strip split plot with four replications. Horizontal plots were three crop residues rates (0, 500 and 1000 kg ha-¹), vertical plots consisted of two dryland current wheat cultivars (CVs) (Azar 2 and Nicknejad), and sub-plots were three N rates (0, 35, and 70 kg N ha-¹). Increasing crop residue rates increased soil organic carbon. Number of spike per plant, grains per spike, grains per plant and 1000-grain weight of both CVs significantly increased with increased N and residue rates in both years. The lowest grain yield was obtained from 1000 kg ha-¹ residue incorporation without N application showing the soil N imbalance. The optimum crop growth and the highest grain yield was achieved from the highest crop residues and N rates, indicating that the most reliable system for dryland wheat production in the region is complete residues incorporation into the soil following disking, seeding with chisel seeder and application of 70 kg N ha-¹.     

Modeling the impacts of contrasting nutrient and residue management practices on grain yield of sorghum (Sorghum bicolor (L.) Moench) in a semi-arid region of Ghana using APSIM

The cropping systems model APSIM (Agricultural Production Systems sIMulator) was applied to assess the response of sorghum grain yield to inorganic fertilizers applications and residue retention in diverse farmers’ management systems (homestead fields and bush farms). The model was parameterized using data collected from experiments under optimum growth conditions (limited water or nutrient stress). Independent data from field experiments with three levels of P and four levels of N fertilizers conducted at two different locations and soils were used to evaluate the model. Soil water and fertility parameters measured were used for simulations while same starting conditions were assumed for unmeasured parameters for all trials. APSIM predicted the grain yield response of sorghum to both N and P applications with an overall modified internal coefficient of efficiency of 0.64. Following model parameterization, a long-term simulation study was conducted using a stochastic weather data derived from historical weather data to assess the effects of crop residue management on grain production. A gradual decline in sorghum grain yield was simulated over the 30-year simulation period in both the homestead fields and the bush farms, with yields being much lower in the latter under farmers’ management practices. Half the amount of mineral N fertilizer used in the bush farms was needed in the homestead fields to produce the average grain yields produced on the bush farm with full fertilization, if crop residues were returned to the fields in the homestead. Year-to-year variability in grain yield was consistently higher with the removal of crop residues, irrespective of management systems. APSIM was responsive to both organic and inorganic fertilizer applications in the study area and also highlighted the essential role of crop residues and inorganic fertilizer in influencing the temporal sorghum grain production and hence the impact of farmers’ management practices on food security. This was evident in the rapid decline in soil organic carbon (SOC) accompanied by a decline in grain yield over the 30 years of cropping. The use of inorganic fertilizer and retention of crop residues (SOC) are critical for attaining food security in the study area.     

The cost of uncertainty for nitrogen fertilizer management: A sensitivity analysis

Uncertainties in soil nitrogen (N) supply and crop N demand present a challenge to farmers deciding on N fertilizer rates. While field studies have documented the improvements in N use efficiency possible with site-specific N management approaches that address these uncertainties, a general understanding of the importance of uncertainty across a wide range of cropping systems is yet to emerge. Here a general model of N rate decision-making is presented which computes the optimal N rate that maximizes expected profit given uncertainties in N supply and demand. The cost of uncertainty is measured as the difference in N rate when soil N supply and crop N demand are unknown versus known perfectly. Eliminating uncertainty in soil N supply (but not crop demand) would reduce average N rates by 5–15% in typical irrigated rice systems, 10–30% in wheat, and 20–40% in maize. Perfect knowledge of potential crop N demand (but not soil supply) would reduce rates by 3–10% in all systems. Simultaneous knowledge of both factors reduced N rates by significantly more than the sum of their individual effects, reflecting important interactions between supply and demand uncertainties. This indicates that the value of information for one factor is inversely related to the level of uncertainty in the other. Studies that separately consider information on soil N supply or crop N demand may therefore underestimate the total benefit of management approaches that address both these uncertainties. Site-specific N management could lead to substantial reductions of N rates without yield loss in a wide range of cropping systems, thereby improving profitability and environmental quality.     

头季稻氮肥运筹对再生稻根际机能及产量的影响

[目的]再生稻是头季稻生长的延续.本研究尝试从根际微生态系统的变化来阐明机械化栽培下头季稻氮肥管理对头季-再生季水稻产量形成的影响,为再生稻高产高效栽培提供参考.[方法]以"甬优1540"为材料,通过2年的田间试验,在头季总施氮量(225.00 kg/hm2)不变的前提下,设置头季不同氮肥运筹处理,分析了机械化栽培下再...     

秸秆还田对玉米产量和土壤团聚体组成及有机碳分布的影响

研究秸秆还田对土壤团聚体组成、有机碳分布及玉米产量的影响,为秸秆合理利用与土壤培肥提供科学依据。采用田间定位试验的方法,研究秸秆还田(SNPK)和生物炭还田(BNPK)处理对玉米产量,土壤团聚体组成及其有机碳分布的影响。结果表明,与常规施肥相比,SNPK和BNPK处理4年后玉米产量分别提高6.95%和4.83%;SNPK和BNPK处理均提高了0~20 cm土层2 mm团聚体含量,降低0.25 mm团聚体含量,均降低21~40 cm土层中2 mm团聚体含量;SNPK处理提高0~20 cm土层有机碳含量14.11%,BNPK处理对土壤有机碳提高不明显,二者均提高0~20 cm土层中0.25~1 mm和0.25 mm粒级中的有机碳含量;SNPK处理明显提高0~20 cm土层2 mm粒级团聚体对有机碳的贡献率,BNPK处理对各粒级团聚体对有机碳的贡献率影响不明显。长期秸秆还田和生物炭还田能够改变土壤团聚体的分布,有利于土壤结构的形成,提高土壤固碳能力,增加玉米产量。