辣椒穴盘育苗中椰糠替代草炭的效果分析

草炭是短期内不可再生资源,而椰糠作为栽培基质可实现园林废弃物的资源化再利用,为探索椰糠替代草炭用于辣椒穴盘育苗的可能性,采用草炭、蛭石、珍珠岩和椰糠作为育苗基质原料,复合基质中保持20%珍珠岩和20%蛭石（体积比）不变的条件下,以草炭∶蛭石∶珍珠岩为3∶1∶1常用复合基质作为对照组,设计7种育苗基质组合,研究不同比例椰糠替代草炭对辣椒穴盘苗生长和生理的影响。结果表明：复合基质中椰糠替代草炭的处理对辣椒苗期生长指标、干鲜质量和SPAD值影响不尽相同,其中与对照相比,以椰糠∶蛭石∶珍珠岩=3∶1∶1（体积比）处理效果最佳,不但促进了辣椒幼苗的生长,显著增加了株高、茎粗,而且能显著提高辣椒全株干、鲜质量,辣椒的壮苗指数高于对照,但壮苗指数、SPAD值均与对照无显著差异。综上所述,育苗基质中椰糠替代草炭能够有效改善辣椒幼苗质量,且椰糠∶蛭石∶珍珠岩=3∶1∶1（体积比）为最佳辣椒育苗基质组合,说明椰糠可以全部代替草炭用于辣椒穴盘育苗。     

Aerobic and anaerobic burning alter trace metal availability in peat soils: evidence from laboratory experiments

As global warming becomes more pronounced, climate change and human activities are leading to frequent peat fire incidents. Fire plays an important role in the environmental distribution of trace metals in peat soils. In the current study, we collected peat soils from six peatlands of the Great Khingan Mountains in Northeast China, where wildfires have often occurred in recent decades. To investigate the transformation of trace metals in peat soils by fire, burning experiments at 250°C (light) or 600°C (severe) and under aerobic (AE, flaming) and anaerobic (AN, smouldering) conditions (AE250, AE600, AN250, AN600) were carried out in the laboratory to investigate the effect of different burning intensities on the distribution of Cu, As, Pb, and Cd in peat soils. The European Community Bureau of Reference (BCR) sequential extraction method for metal fractions was applied for partitioning four fractions (exchangeable, reducible, oxidizable, and residual). The results showed that AE600 significantly decreased the percentages of oxidizable Cu, As, Cd and Pb (Cu_oxi, As_oxi Cd_oxi and Pb_oxi) compared with those of the original samples, e.g., Cu_oxi decreased from 68.84% ± 12.76% to 15.82% ± 8.02% in peat under moss, which might result from organic matter decrease. Under AN250 conditions, the exchangeable As (As_exc) and Pb (Pb_exc) significantly increased by more than twice. Different burning intensities significantly changed the various fractions of Cu, e.g., more than 20% Cu_oxi transferred to exchangeable and reducible fractions as the temperature increased. Most of the available fractions of As transformed to residual As after burning. Our study suggests that the AE600 treatment increased the ecotoxicity and bioavailability of Cu, Pb and Cd in peat soils, while AN250 burning decreased the potential ecotoxicity of Cu, As, and Pb. Compared with lower temperature flaming burning (AE250), the ecotoxicity and bioavailability of Cu and Pb were greater in high temperature (AE600) conditions. Smouldering fires at both temperatures (AN250 and AN600) maintained a high potential ecotoxicity and bioavailability of Cu and Pb in peat soils.     

有机物料施用对潮土活性有机碳及微生物群落组成的影响

土壤活性有机碳是土壤中周转较快,对管理措施反应较为敏感的碳组分,但不同有机物料的影响效应及其微生物机制尚不清楚.比较小麦-玉米轮作条件下,麦季秸秆还田(R)和木本泥炭(MT)连续施用2年对玉米收获期潮土可矿化有机碳(PCM)、微生物生物量碳(MBC)、可溶性有机碳(DOC)、易氧化有机碳(ROC)、颗粒有机碳(POC)...     

小麦内根圈中几类微生物群体数量比较的研究

报道了２种土壤和２种土壤里小麦内根圈中几类微生物群体数量的测定结果,提出了以“好气性细菌总数”为参考系的比较方法分析小麦内根圈的根圈效应。小麦内根圈对芽胞杆菌有强烈的抑制效应。相对于“好气性细菌总数”而言,２种土壤中的贫营养细菌数和固氮菌数的相对数量相差很大,而小麦内根圈的根圈效应起一定的“中和”作用。荧光假单胞菌群不论在总数上还是在与“好气性细菌总数”的相对数量上优势都很低,与前人的一些报道相距甚远。在南温带冬季作物生长期,耐寒细菌群的代谢作用不可忽视。     

调节草炭pH值对其有效养分和番茄、辣椒幼苗生长的影响

为了解不同调节剂对酸性草炭pH值调节作用,同时对草炭养分有效性的影响,评价调节后草炭的育苗特性,以碳酸钾、氧化钙为调节剂,设计不同的添加水平,分析不同投入量条件下草炭pH值、养分有效性变化规律及投入量与有效养分相关性,比较调节后草炭对番茄、辣椒幼苗生长的影响。结果表明,草炭pH值、速效磷、速效钾随着碳酸钾投入量增加而不断增加,草炭交换性钙、镁、锰和有效铁随着碳酸钾投入量的增加而不断减少;草炭pH值、交换性钙随着氧化钙投入量增加而不断增加,草炭交换性镁随着氧化钙投入增加先增加后减少,草炭交换性锰和有效铁随着氧化钙投入急剧减少。草炭添加不同水平的碳酸钾和氧化钙后,对番茄、辣椒幼苗生长发育皆表现为先改善后抑制的影响规律;同等条件下,碳酸钾对番茄、辣椒幼苗生长的改善效果强于氧化钙;每千克草炭添加碳酸钾2、4、6 g和氧化钙0.8、1.6 g改善效果显著,其对应的草炭pH 5.05、5.93、6.28、5.29、6.08;利用pH值与CI指标建立了碳酸钾-番茄模型、氧化钙-番茄模型、碳酸钾-辣椒模型和氧化钙-辣椒模型,其对应的最优pH 5.64、5.84、5.61、5.76。     

添加外源有机物和黏粒材料对沙黄土有机碳和菠菜生长的影响

快速提升贫瘠土壤的有机碳含量是改良土壤、增加土地生产力的重要途径。本研究通过温室盆栽试验，设置了沙黄土对照(CK)、沙黄土+木本泥炭(LW)、沙黄土+褐煤1(LC1)、沙黄土+褐煤2(LC2)、沙黄土+木本泥炭+红黏土黏粒(LWR)、沙黄土+木本泥炭+砒砂岩黏粒(LWS)和沙黄土+木本泥炭+膨润土(LWB)共7个处理，每个处理5次重复，研究了不同处理下菠菜生育期内(35d)生长、生理指标差异及各处理对土壤有机碳含量提升效果。结果表明：与CK相比，各处理收获期菠菜产量和土壤有机碳含量均显著增加(P<0.05),LW、LC2、LC1、LWS、LWR和LWB处理下收获期菠菜产量分别增加了18.6%、51.3%、80.8%、127.6%、148.1%和203.8%，对应处理土壤有机碳含量分别增加了92.4%、84.3%、66.8%、84.0%、116.3%和98.3%，土壤pH均有一定程度降低。与LW处理相比，补充黏粒材料后，LWS、LWR和LWB处理下收获期菠菜叶面积分别显著增加了55.0%、86.5%和98.3%(P<0.05)，各处理土壤pH、电导率、有机碳和全氮含量有一定程...