胶冻样芽孢杆菌与生物质炭复配及对番茄产量和品质的影响

以提高胶冻样芽孢杆菌在土壤中的存活率、减缓其衰亡速率,延长存活时间,提高其对土壤难溶性钾的解钾效率为目的,利用不同种类的秸秆生物质炭与胶冻样芽孢杆菌进行复配筛选。通过室内培养试验发现,中性小麦秸秆炭可作为胶冻样芽孢杆菌较理想的载体。当土壤培养35天后,土壤速效钾含量在施用炭基解钾菌肥条件下较空白提高了28.53%,较小麦秸秆炭和纯菌液处理分别提高了20.75%、13.41%。纯菌液处理土壤中胶冻样芽孢杆菌的菌落数从1.1×10~9个/g土降为9.0×10~5个/g土,而炭基解钾菌肥处理则为1.4×10~7个/g土。田间施用炭基解钾菌肥能够提高番茄植株和果实中的全钾含量;提高番茄产量和品质,显著提高番茄Vc含量,降低硝酸盐含量。因此,中性小麦秸秆炭与胶冻样芽孢杆菌的复配能够提高菌剂的存活率,有效促进土壤中矿物态钾的释放。     

Carbon and trace element fluxes in the pore water of an urban soil following greenwaste compost, woody and biochar amendments, inoculated with the earthworm Lumbricus terrestris

The benefits of adding composted organic materials to soils to enhance carbon storage could be countered by the mobilisation of some harmful pollutants commonly found in frequently degraded urban soils. Therefore non-composted materials could be a safer option. In the present study, carbon and trace element fluxes in soil pore water were studied in response to the surface mulch addition and the incorporation into an urban soil of greenwaste compost versus two non-composted amendments; a woody oversize material and biochar following inoculation with the vertical burrowing earthworm Lumbricus terrestris. The aim was to establish (i) to what extent the non-composted amendments impacted on mobility of soluble trace elements in the soil, compared to the composted amendment, and (ii) if/how this was regulated by earthworm activity.Both composted and non-composted amendments enhanced dissolved organic carbon (DOC) in soil pore water to ∼100-300 mg l⁻¹ in the upper depth of the soil profile above which they were applied as a mulch and similarly within the mesocosms in which they were mixed. Dissolved organic carbon, dissolved nitrogen (DTN) and trace metals, especially Cu and Pb, where enhanced to the greatest extent by greenwaste compost, because of strong co-mobilisation of metals by DOC. Biochar enhanced As and Cu mobility in the field profile and, additionally Pb in the mesocosms, with no effect on Cd. The woody, oversize amendment neither greatly increased DOC nor As, Cu, Pb or Zn mobility although, unlike the other amendments, earthworms increased DOC and Cd mobility when soils were amended with this material.This study concludes that non-composted amendments had a lower impact on DOC and thus trace element co-mobility than the composted greenwaste in this urban soil, whilst the general influence of earthworms was to reduce DOC and hence associated trace element mobility. In wider environmental terms the addition of non-composted materials to some urban soils, versus composted greenwaste could reduce the risk of mobilising potentially harmful elements, whilst usefully improving soil quality.     

Degradability of black carbon and its impact on trace gas fluxes and carbon turnover in paddy soils

Rice paddy soils are characterized by anoxic conditions, anaerobic carbon turnover, and significant emissions of the greenhouse gas methane. A main source for soil organic matter in paddy fields is the rice crop residue that is returned to fields if not burned. We investigated as an alternative treatment the amendment of rice paddies with rice residues that have been charred to black carbon. This treatment might avoid various negative side effects of traditional rice residue treatments. Although charred biomass is seen as almost recalcitrant, its impact on trace gas (CO₂, CH₄) production and emissions in paddy fields has not been studied. We quantified the degradation of black carbon produced from rice husks in four wetland soils in laboratory incubations. In two of the studied soils the addition of carbonised rice husks resulted in a transient increase in carbon mineralisation rates in comparison to control soils without organic matter addition. After almost three years, between 4.4% and 8.5% of the black carbon added was mineralised to CO₂ under aerobic and anaerobic conditions, respectively. The addition of untreated rice husks resulted in a strong increase in carbon mineralisation rates and in the same time period 77%-100% of the added rice husks were mineralised aerobically and 31%-54% anaerobically. The ¹³C-signatures of respired CO₂ gave a direct indication of black carbon mineralisation to CO_2. In field trials we quantified the impact of rice husk black carbon or untreated rice husks on soil respiration and methane emissions. The application of black carbon had no significant effect on soil respiration but significantly enhanced methane emissions in the first rice crop season. The additional methane released accounted for only 0.14% of black carbon added. If the same amount of organic carbon was added as untreated rice husks, 34% of the applied carbon was released as CO₂ and methane in the first season. Furthermore, the addition of fresh harvest residues to paddy fields resulted in a disproportionally high increase in methane emissions. Estimating the carbon budget of the different rice crop residue treatments indicated that charring of rice residues and adding the obtained black carbon to paddy fields instead of incorporating untreated harvest residues may reduce field methane emissions by as much as 80%. Hence, the production of black carbon from rice harvest residues could be a powerful strategy for mitigating greenhouse gas emissions from rice fields.     

不同改良剂对皖南烟田土壤性状及烤烟产量和品质的影响

通过布置田间小区试验,研究了不同农林废弃物制成的5种改良剂对烟稻轮作土壤性状和烤烟生长发育、产量和烟叶品质的影响。不同改良剂施入土壤后,土壤体积质量较不施改良剂的对照处理显著下降,而田间持水量明显提高,表明烟田土壤物理性状得到明显改善。改良剂能明显促进不同生育期烟株的生长:烟株团棵期,改良剂X1处理叶片宽显著高于对照;旺长期,X1、X2、X5处理叶长显著大于对照,且X5处理叶面积显著大于对照;成熟期,X1、X2、X5处理上部叶和下部叶长显著高于对照。改良剂能增加烟叶产量,尤其是改良剂X3、X5,明显增加了上等烟和中等烟的产量。改良剂X1、X2、X3处理上等烟总分显著高于对照,即改良剂处理烤出的上等烟综合品质更优。     

生物炭降解有机污染物的研究进展

生物炭是指生物质在无氧或低氧条件下高温裂解炭化而产生的一种富碳产物.由于其精致的孔隙结构和独特的表面化学性质,对土壤环境中的有机污染物有超强的吸附和降解能力,进而影响有机污染物的迁移和转化.近年来生物炭对有机污染物的吸附降解特性及机理研究已成为环境科学领域的研究热点之一.主要从生物炭的典型特征、降解有机污染物的机理、影响因素以及今后研究方向等方面进行了综述,以期为国内生物炭的研究提供参考.     

滇池柴河流域蔬菜地土壤施用生物炭包膜尿素与普通尿素的氮损失研究

[目的]为滇池柴河流域蔬菜种植区更科学、合理使用氮肥以及当地农业面源污染控制提供依据。[方法]通过盆栽试验,比较施用炭基包膜尿素与普通尿素对柴河周边蔬菜地土壤氨挥发和氮淋失的影响。[结果]氮损失量与施氮量呈正比,氮素淋失量均高于氨挥发量;同一施肥水平的两种肥料氨挥发、氮素淋失和氮素损失量间差异在0.05水平显著(普通尿素生物炭包膜尿素);在施氮量为320和280 mg/kg的水平下,生物炭包膜尿素处理比普通尿素处理氮损失低43.5%~45.5%,其中氨挥发低3.7%~21.7%,氮淋溶低49.8%~52.1%,而硝态氮是氮素淋溶的主要形式占总氮淋出的76.0%~95.7%(普通尿素处理)和51.6%~53.5%(生物炭包膜尿素处理)。[结论]生物炭包膜尿素主要通过减少硝氮淋失来控制氮损失。减量施氮并结合生物炭包膜尿素的施用,对控制该地区氮肥施用带来的水体污染具有现实指导作用。     

生物黑炭输入对果园土壤性状及活性有机碳的影响

为了解生物黑炭施用对果园土壤质量的改良效果,采用田间试验研究了不同生物黑炭施入量对果园土壤性状及活性有机碳的影响。结果表明:施用生物黑炭提高了果园土壤含水量、总氮含量及pH值,降低了土壤容重,提高了土壤微生物生物量碳含量。与对照相比,生物黑炭处理的土壤含水量及总氮含量分别提高3.26%～25.61%和61.22%～87.76%,pH值提高0.03～0.30个单位,土壤容重降低13.13%～19.38%,土壤微生物生物量碳含量提高84.34%～107.55%。     

重金属-有机物复合污染农田土壤修复策略研究

介绍了我国农田土壤重金属-有机物复合污染现状,重点分析了重金属-有机物土壤复合污染的相互作用及过程,对适用于复合污染农田土壤联合修复技术进行了总结.在此基础上,结合生物碳用于土壤修复的机理与实践情况,提出了“不同种类生物炭改良＋耐性植物”这一针对重金属-有机物复合污染农用土壤有效的修复策略.     

生物质炭与化肥氮配施对植烟土壤微生物功能多样性的影响

采用盆栽试验研究了生物质炭配施不同用量化肥氮对烤烟根区土壤微生物群落功能多样性的影响。研究结果显示,添加生物质炭提高了土壤有机碳和微生物生物量碳含量;减少15%化肥氮配施生物质炭处理(T3)显著提高了土壤过氧化氢酶活性,提升了土壤新陈代谢水平。不同处理土壤微生物的碳源利用率不同,以T3处理的AWCD(平均颜色变化率)值最高,且微生物丰富度和优势度均为较高水平。主成分和热图分析表明,不同处理微生物功能差异性和优势碳源不同,其中T3处理的微生物群落功能差异性较小,优势碳源羧酸类中包含的碳源种最多。添加生物质炭可提高烟株根冠比23.06%～42.36%。因此,添加生物质炭可增强植烟土壤微生物活性,提高土壤微生物功能多样性,以减少15%化肥氮配施生物质炭效果最好。     

生物质炭对贵州黄壤朝天椒减氮的生物效应及氮肥利用率的影响

为探究生物质炭对贵州黄壤朝天椒减氮的施用效果,采用大田试验,研究了生物质炭与氮肥减量配施(CF_(100)B_0(化肥氮100%)、CF_(90)B_(10)(化肥氮90%+生物质炭氮10%)、CF_(85)B_(15)(化肥氮85%+生物质炭氮15%)、CF_(80)B_(20)(化肥氮80%+生物质炭氮20%))对贵州黄壤朝天椒产量、品质、养分积累和氮肥利用率的影响。结果表明:与常规施肥(CF_(100)B_0)处理相比,CF_(90)B_(10)处理可提高朝天椒产量,其中鲜椒增产7.3%、干椒增产2.5%,但是增产效果并不显著,而CF_(85)B_(15)和CF_(80)B_(20)处理的产量略有降低;生物质炭与氮肥减量配施处理可显著影响朝天椒果实中的硝酸盐和Vc含量,其中,CF_(90)B_(10)、CF_(85)B_(15)和CF_(80)B_(20)处理的硝酸盐含量降低了4.8%～8.9%,而CF_(90)B_(10)处理的Vc含量则较CF_(100)B_0处理提高了9.6%,但还原糖和游离氨基酸含量在各处理间无差异;此外,与CF_(100)B_0处理相比,生物质炭与氮肥减量配施可使氮肥偏生产力(PFP_N)提高2.08～2.62 kg·kg~(-1),以CF_(90)B_(10)处理最高,而氮肥农学效率(AE_N)和氮肥表观利用率(RE_N)则随着生物质炭替代化学氮肥比例的增加呈降低趋势,以CF_(90)B_(10)处理的AE_N和RE_N最高,分别为7.70 kg·kg~(-1)和40.3%。综上,生物质炭与氮肥减量配施可有效保证贵州朝天椒稳产增效,因此,短期条件下推荐生物质炭替代化学氮肥10%作为贵州黄壤朝天椒氮肥减施替代的最适比例。