生物炭和黄腐酸对滨海滩涂盐碱地土壤性质的提升

为探讨生物炭和黄腐酸对滨海滩涂围垦盐碱地的改良作用,采用田间玉米种植试验法,设置生物炭使用量7.5 t/hm2(BC1)、30 t/hm2(BC2)和黄腐酸用量1.5 t/hm2(FA)及其组合,共6种处理:CK、BC1、BC2、FA、BC1+FA、BC2+FA,研究材料施加对土壤重要盐碱状况表征指标的影响。结果表明,BC2处理降低土壤容重,但低用量BC1处理下土壤容重没有降低,研究区土壤呈逐渐自然板结退化状态;随着生物炭施用量的增加,土壤持水能力呈减小的趋势。生物炭和黄腐酸施用明显提高土壤有机质含量,BC2+FA最高,达到6.31 g/kg;各处理中,周期性脱盐和返盐现象在各处理间的土壤表层呈现一致规律,但BC1+FA和BC2+FA处理的盐分累积明显低于其他处理。结果表明适量生物炭和黄腐酸施用可提高土壤肥力,改善土壤结构,抑制盐分累积,有利于滩涂围垦土地的快速耕地化利用,生物炭使用量为30 t/hm2并黄腐酸用量1.5 t/hm2处理效果最好。     

辣椒秸秆生物炭对酸化土壤交换性能及酶活性的影响

将辣椒秸秆通过高温热解的方法制备成辣椒秸秆生物炭,与酸化土壤共培养,探讨辣椒秸秆生物炭对酸化土壤交换性能及土壤酶活性等的影响。结果表明,添加辣椒秸秆生物炭能显著提高酸化土壤pH,提高幅度与辣椒秸秆生物炭的添加量呈正比;土壤交换性Al~(3+)含量与辣椒秸秆生物炭添加量呈显著负相关;添加辣椒秸秆生物炭能显著影响土壤NO_3~--N和NH_4~+-N。土壤交换性Na~+和交换性K~+与辣椒秸秆生物炭添加量呈显著正相关;交换性K~+的变化与辣椒秸秆生物炭中K元素呈极显著正相关;交换性Ca~(2+)、交换性Mg~(2+)与辣椒秸秆生物炭添加量之间相关性不显著;总盐基离子、土壤阳离子交换量(CEC)与辣椒秸秆生物炭添加量之间呈显著正相关。土壤脲酶、蔗糖酶与辣椒秸秆生物炭添加量呈正相关;土壤酸性磷酸酶、蛋白酶、过氧化氢酶与辣椒秸秆生物炭添加量之间相关性不显著;土壤酶的几何平均数(GMea)表明添加辣椒秸秆生物炭可以显著改善酸化土壤质量。试验为开拓辣椒秸秆利用途径、改善酸化土壤及提高土壤肥力等方面提供提供科学依据。     

施用生物炭对华北平原冬小麦土壤水分和籽粒产量的影响

为探究施用生物炭对华北平原农田土壤水分和冬小麦籽粒产量的影响,于2014—2017年在中国农业大学吴桥实验站设置施用生物炭7 200(BH)、3 600(BM)、1 800(BL)和0kg/hm~2(CK)4个处理。结果表明:与CK处理相比,BH、BM和BL处理3年平均增产分别为1.84%、7.28%和5.03%,并且降低了耗水量,水分利用效率分别提高5.96%～14.86%、9.42%～19.18%和5.96%～13.50%。同时施用生物炭增加了土壤含水量,与CK处理相比,土壤上层0～60cm BM处理增幅最大;中层60～120cm和下层120～200cm均为BL处理增幅最大(P0.05)。综上所述,施用生物炭可以增加土壤含水量和籽粒产量。统计分析表明,当施炭量分别为3 389～3 882和3 500～4 357kg/hm~2,0～60cm土层土壤含水量和籽粒产量均最高,且0～60cm土层土壤含水量与籽粒产量间存在显著的正相关关系(P0.05)。因此,施用生物炭可以增加土壤含水量,降低水分消耗,提高冬小麦籽粒产量和水分利用效率,在本试验条件下以施用3 000～4 500kg/hm~2为宜。     

小麦秸秆生物炭对小白菜中铅累积含量的影响

考察了240℃热解小麦秸秆制备的生物炭对铅离子的吸附性能及对土壤中铅离子的固定效应。结果表明,小麦秸秆生物炭对铅离子以化学吸附为主要过程,298.15K和323.15K下的平衡吸附量分别为45.02 mg/g和51.05 mg/g;通过小白菜种植实验,生物炭在土壤中添加量大于1%时,小白菜含铅量小于0.082mg/kg,且小白菜中铅含量随着生物炭用量的增加而减少,为解决铅离子污染的土壤问题提供了基础数据。     

Straw and biochar strongly affect functional diversity of microbial metabolism in paddy soils

The application of straw and biochar is widely practiced for the improvement of soil fertility. However, its impact on microbial functional profiles, particularly with regard to paddy soils, is not well understood. The aim of this study was to investigate the diversity of microbial carbon use patterns in paddy soils amended with straw or straw-derived biochar in a 3-year field experiment in fallow soil and at various development stages of a rice crop(i.e., tillering and blooming). We applied the community level physiological profiling approach, with 15 substrates(sugars, carboxylic and amino acids, and phenolic acid). In general, straw application resulted in the greatest microbial functional diversity owing to the greater number of available C sources than in control or biochar plots. Biochar amendment promoted the use of α-ketoglutaric acid, the mineralization of which was higher than that of any other substrate. Principal component analyses indicated that microbial functional diversity in the biochar-amended soil was separated from those of the straw-amended and control soils. Redundancy analyses revealed that soil organic carbon content was the most important factor regulating the pattern of microbial carbon utilization. Rhizodeposition and nutrient uptake by rice plants modulated microbial functions in paddy soils and stimulated the microbial use of N-rich substances, such as amino acids. Thus, our results demonstrated that the functional diversity of microorganisms in organic amended paddy soils is affected by both physicochemical properties of amendment and plant growth stage.     

秸秆直接还田与炭化还田对潮土硝化微生物的影响

为比较秸秆直接还田和炭化还田对黄淮海平原小麦/玉米轮作体系典型潮土硝化作用及硝化微生物群落的影响,设置4个处理:全量小麦秸秆还田(S)、全量秸秆炭化还田(B)、半量秸秆半量生物质炭还田(SB)和不进行秸秆或生物质炭还田的对照(CK),连续进行3 a田间试验。对小麦、玉米两个生长季土壤理化性质进行分析,用末端限制性片段长度多态性(Terminal-restriction length polymorphism,T-RFLP)技术和克隆文库技术对氨氧化古菌(Ammonia-oxidizing archaea,AOA)和氨氧化细菌(Ammonia-oxidizing bacteria,AOB)群落结构和多样性进行分析。结果表明,在小麦季,与S处理相比,B处理显著降低了土壤容重,提高了土壤pH、有机碳(SOC)和速效钾(AK)含量(P0.05),但并未显著影响土壤水分、铵态氮(NH_4~+-N)和硝态氮(NO_3~--N)含量;B和SB处理的硝化潜势(Potential nitrification rate,PNR)分别为0.58、0.49μg·h~(-1)·g~(-1)(以NO_2~-计,下同),显著高于CK,与S处理(0.40μg·h~(-1)·g~(-1))差异不显著。玉米季,B处理显著提高了土壤水分、SOC和AK(P0.05),各处理玉米季的PNR整体低于小麦季,B处理最高(0.27μg·h~(-1)·g~(-1)),显著高于CK和S处理(P0.05)。小麦季PNR分别与AK、NH_4~+浓度和土壤容重显著相关(P0.05),与AOA和AOB群落组成均无显著关系;玉米季PNR仅与理化因子SOC显著相关,但该季节PNR与AOB群落结构显著相关。冗余分析(RDA)表明,土壤SOC、容重、pH和AK是显著影响硝化微生物群落结构的主要因子,对AOA和AOB群落结构总变异的解释量分别为76.4%和75.5%。系统发育树分析表明,AOA大部分属于土壤古菌Group1.1b,AOB多属于亚硝化螺菌Nitrosospira簇3。综上,与秸秆直接还田相比,炭化还田提高土壤硝化活性,改善部分土壤理化性质,引起土壤硝化微生物群落结构变化。     

棉纤维生物炭对稻田土壤及水稻Cd含量的影响

为生物炭应用于农田Cd污染的控制及治理提供相关科学依据,研究通过根箱试验,研究棉纤维生物炭对水稻根际和非根际土壤可交换态和不可交换态Cd含量及水稻植株中Cd分配的影响。研究表明:随着棉纤维生物炭的施用量增加,根际和非根际土壤可交换态Cd含量都呈下降趋势,同时不可交换态Cd含量都呈上升趋势。随着棉纤维生物炭的施用量增加,非根际土壤pH值呈逐渐上升趋势。非根际土壤pH值与可交换态Cd含量之间存在显著负相关关系,与不可交换态Cd含量之间存在显著正相关关系。可见,施用棉纤维生物炭可在一定程度上提高非根际土壤pH值,进一步降低了非根际土壤可交换态Cd含量;而根际土壤可交换态Cd含量的下降,主要受棉纤维生物炭的理化性质影响,受土壤pH值影响不大。随着棉纤维生物炭的施用量的增加,水稻各部位Cd含量及累积量都呈现下降趋势,其中籽粒Cd含量的下降幅度最大,为36.57%,根的Cd含量的下降幅度最小,为12.56%。由于茎鞘的生物量和Cd含量都较大,茎鞘中Cd累积量最高,平均为25.44μg plant^-1,是籽粒的2.85倍。因此,在进行农田土壤Cd修复的同时,除了要关注农产品Cd污染,还要考虑如何妥善处理大量的富集Cd的农业废弃物,避免产生二次污染风险。     

Enhancement of Depleted Loam Soil as Well as Cucumber Productivity Utilizing Biochar Under Water Stress

Biochar has recently received increased attention because it improves poor soil fertility. However, its potentiality to enhance soil physical properties under water stress conditions not yet deeply investigated. Hence, extensive field investigations were carried out to study the effects of biochar addition (BA) with deficit irrigation (DI) on soil bulk density (BD), porosity percentage (P%), soil moisture content (SMC%), soil hydraulic conductivity (K), cucumber yield and water use efficiency (WUE) during two consecutive seasons (2016 and 2017). The biochar treatments were B₀ (0 ton ha^?1), B₁ (10 ton ha^?1and B₂ (20 ton ha^?1), while the DI treatments were 1.0 (W₁), 0.60 (W₂) and 0.40 (W₃) of the reference evapotranspiration (ET₀). The parameters were measured at soil depths of 0–10 (d₁), 10–20 (d₂) and 20–30 cm (d₃) for measurement periods of before sowing (P₁), mid-season (P₂) and after harvest (P₃). The results showed that the B₂W₁ combination gave the highest yield (57 and 45.2 t ha^?1), WUE (10.94 and 11.27 kg m^?3), SMC (39.2 and 40.1%) in both seasons, respectively. The B₂W₃ had the highest porosity (47.5 and 46.1%) values at the d₁. Meanwhile, the lowest soil BD values of 1.1 and 1.05 g cm^?3 were obtained by the B₂W₁ at d₁ for 2.16 and 2017, respectively. Statistically, most of the parameters studied under B₂W₂ and B₀W₁ had non-significant differences between them. Hence, the addition of biochar with DI could be an integrated approach to address the drought stress, while enhancing soil and plant properties.     

Challenges in organic component selection and biochar as an opportunity in potting substrates: a review

Plant production in potting substrates provides maximum profit on the applied inputs, and hence, directly improving the socio-economic condition of the grower/nurserymen. The main challenge in this industry is sourcing of materials for their potting substrates. Peat and perlite have been widely preferred materials. However, recently higher prices, more restrictive legislation of many countries and wetland ecosystem destruction through its extraction has limited peat use. Nowadays, producers focus towards peat alternatives that provide good performance, are readily available, inexpensive and environment friendly to attain sustainability in potted plant production. In an effort to grasp sustainability during the last few decades, many industrial and agricultural waste materials were reviewed for their use in potting substrates. In these studies, the major focus remained on material characterization, neglecting their economics, technical aspects and environmental impacts. Thus, switching from peat and perlite to alternatives requires material exploration. In the present review, we summarize a clearer and practical approach for substituting different materials especially biochar to fulfill the need of modern potting substrate industry. Biochar has the potential to sustain the substrate production on a long-term basis.     

生物炭对土壤微生物影响研究进展

近年来,生物炭作为土壤改良剂在国际上引起广泛关注。生物炭施入土壤后可以通过改变土壤的理化性质,直接或间接的影响土壤微生物的生存环境,为微生物提供良好的生长、繁殖空间,从而影响了微生物的丰度、活性以及群落组成,最终提高了作物产量。文章主要针对生物炭对土壤微生物影响的结果,以及不同种类的生物炭对土壤微生物影响的差异进行阐述,并着眼于当前该领域研究上存在的不足及对未来研究的方向进行了展望。