A Comparative Study of Nitrogen Loss after Application of Biochar Coated Urea and Common Urea in Vegetable Soil at Chaihe Catchment of Dianchi Lake

[Objective] This study aimed to provide the basis for scientific and rea- sonable application of nitrogen fertilizer and control Of agricultural non-point source pollution in vegetable-growing area at Chaihe catchment of Dianchi Lake. [Method] A pot experiment was carried out to compare the loss of nitrogen via ammonia volatilization and nitrogen leaching after application of biochar coated urea （BCU） and common urea （Urea） with different nitrogen rates （0 mg N/kg soil, 400 mg N/kg soil, 320 mg N/kg soil and 280 mg N/kg soil）. [Result] The results indicated that the amount of nitrogen loss was proportional to nitrogen applied rate. Leaching nitrogen was higher than ammonia volatilization. Compare with Urea treatments, ammonia volatilization and nitrogen leaching losses were significantly lower in BCU treatments at the same nitrogen application rate. At the nitrogen application rate of 320 and 280 mg N/kg soil, nitrogen loss, ammonia volatilization and leaching nitrogen was 43.5%-45.5%, 3.7%-21.7% and 49.8%-52.1% lower in BCU treatments than in Ure- a treatments, respectively. [Conclusion] The application of BCU could minimize nitro- gen loss by reducing nitrate leaching loss. It can be concluded that the low nitrogen application rate combined with BCU have a practical influence on controlling the risk of nitrogen pollution in Dianchi Lake.

Effects of Reduced Nitrogen Fertilization and Biochar Application on CO_2 and N_2O Emissions from a Summer Maize-Winter Wheat Rotation Field in North China

This experiment was conducted in Xinxiang, Henan from June 2013 to June 2014. Total four treatments were designed including farmers ’ common practice （F, 250 kg/hm^2）, 80% F （LF, 200 kg/hm^2）, 80% F＋biochar （LFC） and no fertilizer （CK） to measure the dynamic emissions of CO2 and N2O from a summer maize-winter wheat field by static chamber-gas chromatography method. The results showed that the soil CO2 emission was 21.8-1 022.7 mg/（m^2·h）, and was mainly influenced by soil temperature and moisture content. During the growth of summer maize, the soil CO2 emission was more significantly affected by soil moisture con-tent; and in winter wheat growing season, it was more significantly affected by soil temperature in the top 5 cm. The LF and LFC treatments significantly reduced the soil cumulative CO2 emission, especial y during the growth of winter wheat. Fertiliza-tion and irrigation were the main factors influencing the soil N2O emission. The soil N2O emission during the fertilization period accounted for 73.9%-74.5% and 40.5%-43.6% of the soil cumulative N2O emission during the summer maize-and winter wheat-growing season, respectively. The peak of emission fluxes was determined by fertilization amount, while the occurrence time of emission peak and emission re-duction effect were influenced by irrigation. The LF treatment reduced the soil cu-mulative N2O emission by 15.7%-16.8% and 18.1%-18.5% during the growth period of summer maize and winter wheat, respectively. Reduced nitrogen fertilization is an effective way for reducing N2O emission in intensive high-yielding farmland. Under a suitable nitrogen level （200 kg/hm^2）, the application of biochar showed no significant effect on the soil N2O emission in a short term. The N2O emission factors of the L and LF treatments were 0.60% and 0.56%, respectively. ln the intensive high-yield-ing farmland of North China, reducing the nitrogen application amount is an appro-priate measure to mitigate greenhouse gas emissions without crop yield loss.

Effects of straw and biochar addition on soil nitrogen,carbon,and super rice yield in cold waterlogged paddy soils of North China

The additions of straw and biochar have been suggested to increase soil fertility, carbon sequestration, and crop produc- tivity of agricultural lands. To our knowledge, there is little information on the effects of straw and biochar addition on soil nitrogen form, carbon storage, and super rice yield in cold waterlogged paddy soils. We performed field trials with four treatments including conventional fertilization system （CK）, straw amendment 6 t ha^-1 （S）, biochar amendment 2 t ha^-1 （C1）, and biochar amendment 40 t ha^-1 （C2）. The super japonica rice variety, Shennong 265, was selected as the test Crop. The results showed that the straw and biochar amendments improved total nitrogen and organic carbon content of the soil, reduced N2O emissions, and had little influence on nitrogen retention, nitrogen density, and CO2 emissions. The S and C1 increased NH4^＋-N content, and C2 increased NO3^--N content. Both S and C1 had little influence on soil organic carbon density （SOCD） and C/N ratio. However, C2 greatly increased SOCD and C/N ratio. C1 and C2 significantly improved the soil carbon sequestration （SCS） by 62.9 and 214.0% （P〈0.05）, respectively, while S had no influence on SCS. C1 and C2 maintained the stability of super rice yield, and significantly reduced CH4 emissions, global warming potential （GWP）, and greenhouse gas intensity （GHGI）, whereas S had the opposite and negative effects. In summary, the biochar amendments in cold waterlogged paddy soils of North China increased soil nitrogen and carbon content, improved soil carbon sequestration, and reduced GHG emission without affecting the yield of super rice.

A high-performance biochar produced from bamboo pyrolysis with in-situ nitrogen doping and activation for adsorption of phenol and methylene blue

Nitrogen doping is a promising method for the preparation of functional carbon materials.In this study,a nitrogen-doped porous coral biochar was prepared by using bamboo as raw material,urea as nitrogen source,and KHCO3 as green activator through in-situ pyrolysis.The structure of the obtained biochar was characterized by various techniques including nitrogen adsorption and desorption,Raman spectroscopy,X-ray photoelectron spectrometer,and etc.The adsorption properties of nitrogen-doped biochar were evaluated with phenol and methylene blue probes.The results showed that the nitrogen source ratio had a significant effect on the evolution of pore structure of biochar.Low urea addition ratio was beneficial to the development of pore structures.The optimum specific surface area of nitrogen-doped biochar could be up to 1693 m^2·g^-1.Nitrogen doping can effectively improve the adsorption capacity of biochar to phenol and methylene blue.Biochar prepared at 973.15 K with low urea addition ratio exhibited the highest adsorption capacity for phenol and methylene blue,and the equilibrium adsorption capacity was 169.0 mg·g^-1 and 499.3 mg·g^-1,respectively.By comparing the adsorption capacity of various adsorbents in related fields,it is proved that the nitrogen-doped biochar prepared in this study has a good adsorption effect.

Preparation of Clay/Biochar Composite Adsorption Particle and Performance for Ammonia Nitrogen Removal from Aqueous Solution

This study aimed to present a novel clay/biochar composite adsorption particle, which made from abandoned reed straw and clay to remove ammonia nitrogen(NH4^+-N) from micro-contaminated water. The removal performance of NH4^+-N by composite adsorption particle was monitored under different raw material proportions and initial NH4^+-N concentration. Besides, adsorption kinetics and adsorption isotherms were investigated to reveal the adsorption mechanisms. The results showed that NH4^+-N was effectively removed under optimal proportion of biochar, foaming agent and crosslinker with 20%, 3%, and 3%, respectively. The optimal contact time was 150 min and the best removal efficiency was 88.6% at initial NH4^+-N concentration of 20 mg L^-1. The adsorption performance was well described by the second order kinetic model and Freundlich model. The novel clay/biochar composite adsorption particle in this study demonstrated a high potential for NH4^+-N removal from surface water.

Biochar Effectively Reduces Ammonia Volatilization From Nitrogen-Applied Soils in Tea and Bamboo Plantations

Intensive practices in forest soils result in dramatic nitrogen(N)losses,particularly ammonia(NH_(3))volatilization,to adjacent environmental areas.A soil column experiment was conducted to evaluate the effect of bamboo biochar on NH_(3) volatilization from tea garden and bamboo forest soils.The results showed that biochar amendment effectively reduced NH_(3) volatilization from tea garden and bamboo forest soil by 79.2%and 75.5%,respectively.The soil pH values increased by 0.53-0.61 units after biochar application.The NH_(4)^(+)-N and total N of both soils were 13.8-29.7%and 34.0-41.9%higher under the biochar treatments than under the control treatment,respectively.In addition,the soil water contents of the two biochar-amended soils were significantly higher(P<0.05),by 10.7-12.5%,than that of the soils without biochar amendment.Therefore,biochar mitigates NH_(3) volatilization from the tested forest soils,which was due to the increases in soil NH_(4)^(+)-N,total N and water contents after biochar amendment.Our main findings suggest that biochar addition is an effective management option for sustainable forest management.

Influence of Biochar on Nitrogen Use Efficiency and Root Morphology of Rice-Seedling in Two Contrasting Paddy Soils

Biochar may affect the root morphology and nitrogen(N)use efficiency(NUE)of rice at seedling stage,which has not been clearly verified until now.To clarify it,we conducted a pot experiment regarding to two soil types(Hydragric Anthrosol and Haplic Acrisol),two biochar application rates(0.5 wt%and 1.5 wt%)and two rice varieties(common rice var.Xiushui134 and hybrid super rice var.Zhongkejiayou12-6)meanwhile.Seedling NUE of common rice Xiuhui134 was significantly increased(p<0.05)by 78.2%in Hydragric Anthrosol and by 91.4%in Haplic Acrisol following biochar addition with 1.5 wt%.However,biochar addition exerted no influence on seedling NUE of super rice Zhongkejiayou12-6 in both soils.Overall,0.09–0.10 units higher soil pH and 105–116%higher soil NH_(4)^(+)-N were observed in Xiushui134 growing two soils with 1.5 wt%biochar.In addition,improved root morphology(including longer root length,larger root surface area,bigger root volume,and more root tips)contributed to the higher seedling NUE of Xiushui134 in two soils.The soil pH and NH_(4)^(+)-N content,also the root morphology were influenced by biochar,which though could not thoroughly explained the NUE of Zhongkejiayou12-6.In conclusion,biochar application to paddy soil changed soil pH and NH_(4)^(+)-N content,root growth,and the consequent seedling NUE of rice,which effects are relative with rice cultivar,biochar addition rate,and soil type.

Carbon Sequestration and Nitrogen Transformation in Soil Cooperated with Organic Composts and Biochar during Corn (<i>Zea mays</i>) Cultivation

Background: Objectives of this study were to investigate changes of soil carbon contents and to evaluate N mineralization and nitrification rates in soils cooperated with organic composts and biochar during the 2nd year corn cultivation. Methods and Results: For the experiment, the soil texture used in this study was clay loam. Application rates of chemical fertilizer were 480-150- 260 kg/ha (N-P2O5-K2O) as recommended amount after soil test. Biochar application was 0.2% to soil weight. The soil samples were periodically taken at every 15-day interval during corn cultivation periods. The treatments were consisted of cow compost (CC), pig compost (PC), swine digestate from aerobic digestion system (AD), and their biochar cooperation. TC contents in treatments cooperated with biochar at harvesting stages were ranged from 0.96% to 1.24%, and its CC applied plot was highest at 1.24%. It was observed that TC contents with biochar treatments were higher than the compost treatment only. Therefore, it was observed to be carbon sequestration into corn field cooperated with biochar. For nitrogen transformation in soil cooperated with organic composts and biochar, net mineralization rates were dramatically decreased at 44 days after sowing, but nitrification rates were abruptly increased at 73 days after sowing. For N mineralization and nitrification rates, it was shown that they were generally low in the soil cooperated with biochar as compared to the only application plots of different organic composts. Also, it was observed to be highest in the application plot of pig compost manure. Conclusion: Overall, application of biochar in the cropland could be an important role for mitigation of greenhouse gas as well as carbon sequestration.

Effects of Biochar,Arbuscular Mycorrhizal Fungi and Nitrogen Application on Crop(Cichorium intybus L.)Growth and Soil Properties in Cadmium Contaminated Soil

The effects of biochar(BC),arbuscular mycorrhizal fungi(AM),nitrogen(N)and their composite treatments(BC+N,AM+N,BC+AM and BC+AM+N)application on Cichorium intybus L.(C.intybus L.)nutrient uptake,soil properties and cadmium(Cd)accumulation were investigated in Cd contaminated soil(0.11 mg·kg^(-1)).The results showed that the addition of BC increased the rate of mycorrhizal infection.However,the addition of N slightly inhibited mycorrhizal colonization,and the shoot and root bioaccumulation of chicory was positively influenced by BC and N when inoculated with AM fungi.Compared with the single component treatment(AM,BC or N)or two-component treatment(BC+N,AM+N or BC+AM),the three-component composite treatment(BC+AM+N)had the highest shoot bioaccumulation,whereas BC+AM treatment was considered the best for root biomass bioaccumulation.Compared with the control treatment,the single component treatment(AM,BC or N)and the composite treatment resulted in an overall improvement of the chicory shoot,root related nutrient uptake(N,P,K,Mg,Ca,Mn and Fe)and some soil physicochemical properties;in addition,these treatments showed better results than BC+AM+N and BC+AM treatments.Among the Cd-related indexes,Cd concentrations in the shoot,root and soil of C.intybus L.were reduced through treatment with AM and BC.However,a lower bioconcentration coefficient(BCF)and a higher transfer coefficient(TF)were observed in both treatments,and the most desirable effect was observed following the combination treatment(BC+AM).Compared with other single management,the shoot and root Cd concentrations of C.intybus L.after the management of N alone were higher,and the value of BCF(2.63%)was higher,but the value of TF(1.05%)was lower.Indexes related to Cd improved concurrently following the application of N in combination with BC or AM.Therefore,in Cd contaminated soils,single or combined application of BC,AM and N could promote chicory growth and nutrient uptake and improve some soil physicochemical properties.However,N should not be applied alone and needed to be combined with AM and BC;furthermore,it was evident that the treatment with the three composites(BC+AM+N)was optimal from an application point of view.

减氮配施生物炭对北疆小麦产量品质及固碳减排的影响

为研究生物炭在北疆灌区农田应用的稳产增产及固碳减排综合潜力,探索农田氮肥优化施用途径,该研究于2021年4月—2022年7月在新疆奇台设置常规施氮(N1:300 kg/hm^(2))、氮肥减量15%(N2:255 kg/hm^(2))、氮肥减量30%(N3:210 kg/hm^(2))、单施生物炭(B:20 t/hm^(2))、常规施氮+生物炭(N1B)、氮肥减量15%+生物炭(N2B)、氮肥减量30%+生物炭(N3B)7个处理,分析两季小麦(春小麦、冬小麦)种植期间不同处理下麦田土壤有机碳含量、土壤呼吸速率、小麦品质及产量变化。结果表明,与单施常规氮肥相比,施用生物炭后土壤总有机碳(soil total organic carbon,SOC)、活性有机碳(active organic carbon,AOC)、碳库管理指数(carbon pool management index,CPMI)和小麦产量、籽粒水分及蛋白(干基)含量均呈提高趋势。综合表现以氮肥减量15%配施生物炭(N2B)处理最优,较氮肥常规单施(N1)相比,AOC、SOC均有显著提高,2 a产量分别显著提高22.12%、36.17%(P<0.05)。与常规施氮相比,氮肥减量15%配施生物炭(N2B)处理下,2022年冬小麦蛋白(干基)、面筋(湿基)、Zeleny沉降值均有提高,而2021年各处理间差异不显著(P>0.05)。同时,除单施生物炭(B)处理(2021年)和除单施生物炭(B)及减氮15%(N2)处理外(2022年),其他处理下土壤CO_(2)累积排放量较单施常规氮肥均有所升高。综上,氮肥减量15%(255 kg/hm^(2))配施20 t/hm^(2)生物炭时其农田土壤固碳减排效果及小麦产量品质综合表现较好,建议作为北疆灌区麦田氮肥优化配施生物炭的理想施肥方案。

棉秆和油页岩共热解生物炭的氨氮吸附性能研究

使用棉秆(CS)和油页岩(OS)为原料,采用共热解的方式制备了共热解生物炭,探究了对氨氮的吸附性能。考察了不同热解时间、CS和OS比例、热解温度、CS的粒径对共热解生物炭的氨氮吸附量的影响规律,确定了最佳制备条件,并研究了吸附动力学和吸附等温线模型。研究表明,棉秆和油页岩共热解后生物炭的结构特性和表面形貌有较大改善,对氨氮的吸附能力有明显的提高。最佳的制备条件是热解温度为500℃、m(棉秆)∶m(油页岩)=3∶1、热解时间为30 min和CS的粒径为0.20~0.30 mm。在投加量为10.0 g/L、pH 9.0时,最佳条件所制备炭的吸附量为4.89 mg/g,是棉秆生物炭的2.2倍。吸附过程以准二级动力学和Langmuir等温吸附模型描述。吸附机制主要包括为离子交换、静电吸附和配位作用。

Effect of Biochar and Inorganic Fertilizer on Soil Biochemical Properties in Njoro Sub-County, Nakuru County, Kenya

Declining soil fertility is a major constraint to potato farming, the second most important food crop in Kenya. The objective of the study was to determine the effect of different rates of biochar and inorganic fertilizer on some soil properties;soil pH, soil phosphomonoesterases, inorganic nitrogen and extractable phosphorus. The study was conducted for two seasons (short and long rains) at two locations (Egerton University agricultural field and farmer’s field in Mau Narok) using a split-plot design in a randomized complete block (RCBD) arrangement with variety as the main plot and soil amendments as the subplot. Biochar and Diammonium Phosphate (DAP) at 0, 5, and 10 t⋅ha−1 and 0, 250, and 500 kg⋅ha−1 respectively, were applied, resulting in nine treatment combinations. Two potato varieties (Shangi and Destiny) were used in the study. A combination of 5 t⋅ha−1 biochar and 500 kg⋅ha−1 DAP and sole application of biochar at 5 t⋅ha−1 resulted in an increase of 1.25, 2.54 units in soil pH in two seasons, respectively. Similarly, a combination of 5 t⋅ha−1 biochar and 250 kg⋅ha−1 DAP increased soil available phosphorus by 105 units from 30.7 mg⋅kg−1 to 136 mg⋅kg−1. The application rate of 5 t⋅ha−1 biochar with 250 or 500 kg⋅ha−1 DAP significantly increased soil nitrate by 102.11 and 116.14 units, respectively. Soils amended with biochar at 5 t⋅ha−1 combined with 500 kg⋅ha−1 DAP, 10 t⋅ha−1 of biochar combined with either 250 kg or 500 kg of DAP gave the highest alkaline enzymes (mM pNP × kg−1 × h−1). However, the highest acid soil phosphomonoesterases were obtained under the sole application of DAP at 500 ha−1. Thus, using biochar with chemical fertilizer seems a plausible option to ameliorate the declining nutrient base of farmland in Kenya, which could sustainably support potato growth.

生物炭配施氮素对Cd胁迫下泡桐幼苗生理生态的影响

【目的】探究生物配施氮素对Cd胁迫下泡桐幼苗形态特征、根系形态、抗氧化性、光合特性及Cd积累、富集及转运的影响。【方法】以‘泡桐1201’幼苗为试验材料,设置组培和水培结合试验,通过生物炭和氮素单一处理,生物炭配施氮素处理,测定幼苗的生长指标、根系参数、光合气体参数、抗氧氧化酶活性、MDA含量及Cd积累量、富集系数与转运系数。【结果】①Cd胁迫下,施加生物炭和氮素可以显著增加泡桐‘幼苗株高、生物量及根系参数,两者交互处理效果最佳;②泡桐幼苗叶片和根系SOD、CAT活性增加,MDA活性降低。POD活性在两者单施处理下随浓度的升高而降低,在两者交互处理下随浓度的增大略有回升;③生物炭和氮素单施或配施,泡桐幼苗叶片Chla、Chlb、Chl(a+b)显著增加,Chl(a/b)无显著变化;泡桐幼苗叶片光合气体参数(P_(n)、T_(r)、C_(i)、G_(s))升高,单一生物炭处理下WUE最高,Ls值显著降低,叶片光合作用增强;④泡桐幼苗Cd含量减小,富集系数降低,转运系数及Cd积累量增大;⑤对泡桐幼苗叶片幼苗各指标进行相关性及PCA分析,发现各指标之间存在相关性,整体促进效果为生物炭配施氮素>生物炭>氮素。【结论】施加生物炭和氮素可提高泡桐幼苗光合能力,减少对Cd的吸收,缓解Cd毒害,进而增大生物量,促进各器官Cd积累量,以生物炭配施氮素处理效果最佳。

生物炭与氮肥共施对甘蔗产量和糖分质量的影响

【目的】探求生物炭对大田新植甘蔗生长的效应,从而为甘蔗生产上应用生物炭和制定氮肥高效管理提供理论基础。【方法】试验以甘蔗品种‘GT11’和‘B8’为材料,设置低氮N 120 kg/hm^(2)和高氮N 600 kg/hm^(2)2个氮水平,生物炭C0、C10和C20 t/hm^(2)3个水平,调查测定炭氮配施对甘蔗农艺生长、氮积累量和氮利用率及产量构成因素的影响。【结果】生物炭可适当增加甘蔗出苗率、分蘖率和株高,生物炭虽对产量增加无明显效应,但能够提高甘蔗糖分0.19%~0.82%,从而使产糖量增加了1.93%~10.77%。高炭处理下甘蔗氮累积量增加了0.41%~4.74%,但对氮利用率未起到显著提高作用。【结论】生物炭对新植甘蔗的分蘖、氮累积量及糖度累积起到了一定的促进作用,但这种效应因品种而异,氮在其中的作用大于生物炭的作用。

秸秆和生物炭对紫色土坡耕地产流产沙与氮素流失的影响

[目的]探究不同添加量的秸秆和生物炭对紫色土坡耕地的具体改良效果,从而为合理防治三峡库区水土流失提供理论参考。[方法]采用人工模拟降雨的方法,以裸坡为对照,研究了紫色土中添加水稻秸秆(施用量4,7,10 t/hm^(2))和生物炭(含量13,39,65 t/hm^(2))对紫色土坡耕地产流产沙与氮素流失的影响。[结果](1)高强度降雨条件下,紫色土混掺生物炭加快了坡面产流进程,而施加碎混秸秆能延长起始产流时间、削减产流速率;(2)紫色土添加生物炭后累积产沙量较对照增加了0.64%~66.29%,而施加碎混秸秆后减少了42.58%~70.27%,且施加碎混秸秆对坡面产沙的抑制效应远强于对坡面产流的控制作用;(3)地表径流中氮素流失过程以NO-3-N为主,且TN,NO-3-N和NH+4-N的流失量和养分流失模数整体表现为生物炭处理最大,碎混秸秆处理最小。[结论]紫色土坡耕地施加碎混秸秆能促渗阻流、有效控制水土及养分流失,而短期施加生物炭可能会产生负面影响。

生物炭辅配硫酸铵对土壤氮素淋溶的影响

为探究添加生物炭对硫酸铵肥料中氮素释放性能的影响。通过土柱淋溶模拟试验研究不同炭肥比(1∶3、1∶4、1∶5)下制备的生物炭-硫酸铵肥料(BC-AS_(1/3)、BC-AS_(1/4)、BC-AS_(1/5))的氮素淋失特征。结果表明:1)添加生物炭能够有效吸附硫酸铵肥料,减缓硫酸铵的氮素释放速率。3种不同炭肥比下,BC-AS1/4处理的生物炭-硫酸铵颗粒表面最为光滑紧密,成型性最好;2)与常规硫酸铵处理AS相比,不同炭肥处理均显著改善了土壤保水保肥性能,减少了土壤无机氮淋失。其中BC-AS(1/4)处理的铵、硝态氮累积淋出量相较于AS处理分别降低80.83%、11.56%,表现出最小的淋出速率和累积淋失量,缓释效果最好;3)相较于常规硫酸铵处理AS,不同炭肥处理均提高了土柱土壤氮素累积。其中BC-AS1/4处理表现出最好的养分固持效果;4)各土层土壤有机碳含量与土壤全氮呈正相关关系,生物炭-硫酸铵肥料中碳的投入能够有效提高土壤养分的持有能力。综上,生物炭-硫酸铵肥料能够有效减缓氮素释放速率,减少氮素养分淋失,提高土壤养分持有能力,有利于提高肥料利用效率。其中炭肥比为1∶4时生物炭与硫酸铵结合效果最好,表现出最佳的缓释效果及培肥特征。

田间老化生物质炭对茶园土壤氮素形态和细菌群落的影响

【目的】研究田间老化生物质炭对酸性茶园土壤氮素形态和细菌群落结构的影响,探讨土壤氮素形态与微生物群落结构及多样性之间的关系,从而为评估生物质炭在茶园生态系统的长期效应提供科学数据。【方法】2010年在福建省农业科学院茶叶研究所试验基地,试验设置5个生物质炭施用量:0、8、16、32和64 t·hm^(-2),依次记为CK、B1、B2、B3和B4处理。2022年(第12 a)春茶采收后,采集0~20 cm土层土壤,探究不同生物质炭用量对土壤氮素形态及细菌群落结构的影响,并分析其影响因素。【结果】与CK相比,施用生物质炭处理12a后土壤有机碳、全氮、硝态氮、铵态氮、有效钾、pH、砂粒含量分别增加了7.95%~21.40%、11.69%~25.54%、53.45%~115.84%、1.13%~38.86%、28.49%~114.13%、5.51%~12.46%和21.11%~67.88%;碱解氮、有效磷、黏粒和粉粒含量分别下降了11.97%~17.25%(B1处理除外)、15.18%~50.36%、15.64%~38.21%和8.57%~30.63%。生物质炭处理可提高土壤细菌Alpha多样性,增加了变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、芽单胞菌门(Gemmatimonadota)和粘球菌门(Myxococcota)的丰度,减少绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)和浮霉菌门(Planctomycetes)的丰度。非度量多维尺度和线性判别分析结果显示,B0和B4之间有比较明显的分离,B4处理下产生了19种显著差异的微生物类群。相关分析和冗余分析结果表明,土壤有效磷、速效钾、硝态氮、黏粒是驱动土壤细菌群落结构变化的关键环境因子。【结论】生物质炭施用12a后,仍然能够增加土壤碳氮和速效养分养分含量,改善土壤质地结构,从而提高了土壤细菌群落多样性,64 t·hm~(-2)生物质炭用量可长期提高土壤供氮能力。

生物炭包膜尿素的制备及其固氮潜力的研究

为了探究生物炭包膜尿素的缓释性能及对土壤固氮的影响,以300、500和700℃下制备的杨木生物炭为包膜材料制备了3种生物炭包膜尿素,采用间歇土柱淋溶试验对氮素的释放特征进行分析。结果表明,杨木生物炭对铵态氮和硝态氮具有较好的吸附性能,低温下制备的生物炭对铵态氮吸附效果更好;与尿素相比,施用生物炭包膜尿素土壤的总氮淋溶量减少了9.73%~14.67%,铵态氮淋溶量减少了25.28%~30.36%,硝态氮淋溶量减少了10.34%~18.38%;在同等施氮水平下,生物炭包膜尿素相较于尿素可以显著增加土壤铵态氮和硝态氮的含量。其中,土壤中铵态氮含量增加了66.4%~200.1%,土壤硝态氮的含量增加了477.9%~537.6%。因此,生物炭用作肥料的包膜材料具有广阔的应用前景。

减氮配施生物炭对土壤肥力和水稻产量的补偿效应与机制

氮素是水稻生长所必需的营养元素。为了提高产量往往过量施加氮肥,这不仅导致氮肥利用率低,还破坏了土壤质量,减少氮肥施用则会导致水稻减产。为探究土壤改良剂(生物炭)能否补偿减氮带来的负面影响,本研究采用盆栽试验,设置常规施氮(氮肥施用量110 kg/hm^(2),CK)、减氮10%(C1)及减氮10%条件下配施2.5%生物炭(C2)和5%生物炭(C3)4个处理,探讨在减少氮肥使用条件下生物炭对土壤肥力及水稻产量的补偿效应及机制。结果表明:减氮10%对土壤综合肥力无显著影响,施加生物炭可有效地提高土壤肥力,且添加5%生物炭对土壤肥力的提升效果优于添加2.5%生物炭。减氮10%导致水稻产量显著降低,而生物炭施加可一定程度补偿减氮造成的减产,其中添加2.5%生物炭对水稻产量的补偿效果优于添加5%生物炭,但仍未恢复到常规施氮水平。采用结构方程探究减氮和施加生物炭条件下水稻产量的驱动因素,结果表明,减氮配施生物炭通过改变土壤pH值、全钾含量、铵态氮含量和硝态氮含量,进而直接或间接影响水稻产量,其中铵态氮含量和硝态氮含量是主要的调控因子,其不仅直接影响水稻产量,还可通过调控每穗粒数、有效穗数和千粒质量间接影响水稻产量的形成;pH值和全钾含量对水稻产量有负面效应。本研究可为东北黑土区水稻种植业化肥减量和生物炭的高效利用提供科学依据。

生物炭和氮肥联合施用对水稻生产中土壤细菌群落的影响

生物炭作为一种土壤改良剂可以有效地改善土壤污染问题。探讨生物炭和氮肥配施对土壤细菌群落的影响,对科学施肥具有重要意义。以往的研究发现,生物炭和氮肥配施可以改变土壤的理化性质,但对土壤微生物影响的研究较少。为探讨生物炭和氮肥配施对土壤细菌群落的影响,对水稻进行盆栽试验,结果表明:生物炭与氮肥的施加使细菌群落的多样性降低,改良后的土壤中细菌的优势门为Proteobacteria、Acidobacteria、Gemmatimonadetes和Actinobacteria,生物炭和氮肥配施提高了Acidobacteria和Actinobacteria的相对丰度,降低了Proteobacteria和Gemmatimonadetes相对丰度。冗余分析结果表明,土壤p H值、硝态氮、全磷和全氮是影响土壤微生物群落标志物种丰度的主要驱动因素。生物炭与氮肥配施会改变土壤细菌群落和土壤养分的代谢过程。研究结果为探索适合我国东北黑土区土壤微环境调控的最佳碳、氮模型提供了科学依据。