加拿大一枝黄花入侵对杭州湾湿地围垦区土壤养分及活性有机碳组分的影响

加拿大一枝黄花(Solidago canadenis)是我国危害最严重的外来入侵植物之一,为了阐明其对入侵地生态系统的影响,以浙江省慈溪市杭州湾湿地围垦区内自然分布的加拿大一枝黄花群落和3种土著植物群落:束尾草(Phacelurus Griseb)群落、白茅(Imperata cylindrica)群落和芦苇(Phragmites australis)群落为研究对象,采用野外样地实验的方法,研究了加拿大一枝黄花入侵对土壤氮、磷和钾含量以及有效性和活性有机碳组分含量的影响。结果表明加拿大一枝黄花的入侵显著降低了土壤的p H(P0.05),对土壤全氮、全磷、全钾、有效磷、速效钾和钾含量没有显著影响(P0.01),但显著提高了碱解氮、铵态氮和硝态氮的含量(P0.01),其中加拿大一枝黄花0~10 cm土层碱解氮含量分别是束尾草、白茅和芦苇的1.72倍、2.35倍和2.00倍。加拿大一枝黄花入侵对土壤总有机质含量无显著影响(P0.01),但是却改变了活性有机碳组分,与束尾草、白茅和芦苇相比,加拿大一枝黄花群落0~10 cm表层土壤中微生物生物量碳的含量分别提高了196.72%、180.21%和41.47%;可溶性碳0~10 cm土层分别降低了27.27%、40.78%和4.00%,10~20 cm土层分别降低了41.36%、39.49%和29.63%;易氧化碳含量在两个土层中均显著降低(P0.01)。上述结果表明加拿大一枝黄花的入侵降低了土壤p H,提高了土壤氮素的有效性,改变了活性有机碳组分。     

氨氧化基因丰度和潜在氨氧化速率对加拿大一枝黄花入侵和土壤类型的响应

  【目的】  土壤类型和植物入侵影响土壤微生物群落结构和功能,基于此,我们研究加拿大一枝黄花 (Solidago canadensis) 入侵两种类型土壤后,土壤中氨氧化古细菌 (AOA) 和氨氧化细菌 (AOB) 的基因丰度和潜在氨氧化速率 (PAOR) 的变化规律及影响机理。  【方法】  云南和浙江是加拿大一枝黄花入侵的重点地区,本研究在云南省滇池周边的海东湿地公园、捞鱼河湿地公园和安乐村 (土壤类型均为冲积土) 以及浙江省东部的杭州湾湿地公园、临海上盘镇和路桥镇峰江村 (土壤类型均为黄泥田土),分别选择一块采样地,面积为100～150 m2。在每块采样地加拿大一枝黄花入侵 (Mono) 和未入侵 (Nat) 之处,划出0.5 m × 0.5 m,采集土壤和植物样品。Mono和Nat地块相距10～20 m,每个地块重复3次。采用qPCR和室内培养技术分析土壤中AOA、AOB基因丰度和PAOR,用植物生态和土壤化学方法分析植物生物量和土壤化学性状。  【结果】  加拿大一枝黄花入侵后,冲积土中AOA丰度和PAOR显著下降,黄泥田土中AOA丰度和PAOR却显著提高,而AOB丰度在两种类型土壤中均显著提高。Nat冲积土中AOA丰度和PAOR大于黄泥田土,而Mono条件下冲积土中AOA丰度和PAOR小于黄泥田土,AOB丰度在两种土壤类型中均变化较小。Mono样地植被地上部分和地下部分生物量、土壤有机质含量和pH是影响冲积土和黄泥田土AOA丰度和PAOR的重要因素。与AOA不同,冲积土AOB丰度仅受植物地下部分生物量的影响,而黄泥田土AOB丰度同时受植物地下部分生物量、土壤总磷含量和pH影响。  【结论】  加拿大一枝黄花入侵大大增加了植被地上部和地下部生物量,进而为微生物提供了大量的碳源,同时提高了土壤pH,因此,氨氧化细菌AOB的丰度显著增加。土壤类型仅影响AOA的丰度,对AOB和氨氧化潜力没有显著影响,而加拿大一枝黄花入侵显著影响两类土壤中的AOA、AOB丰度以及氨氧化潜力。     

珠穆朗玛峰北坡土壤脲酶和中性磷酸酶活性初步研究

研究了珠穆朗玛峰北坡地区沿绒布河谷海拔4400～5550m的夏季土壤中水解酶类脲酶、中性磷酸酶活性,并探讨了这两种土壤酶与土壤有机质和海拔高度的相互关系。结果表明:(1)随着海拔升高,土壤脲酶、中性磷酸酶活性呈高低波动变化,在研究区域出现多个峰值,总的趋势是上升的,其最大值分别出现在海拔5500m和5450m处。(2)偏相关分析表明,土壤脲酶活性与有机质含量呈正相关,土壤中性磷酸酶活性与有机质含量呈显著正相关;土壤脲酶活性与海拔的相关性不具显著性意义,中性磷酸酶活性与海拔呈极显著正相关。     

黄土高原刺槐人工林根际和非根际土壤磷酸酶活性对模拟降水变化的响应

利用野外控制穿透雨试验,分析了7个降水梯度处理(增水20%,60%,80%,减水20%,60%,80%和对照)对黄土高原刺槐人工林根际和非根际土碱性磷酸酶活性的影响。结果表明:0—20 cm和20—40 cm土层增水处理的根际土磷酸酶活性分别比对照处理高55.9%和88.3%,非根际土磷酸酶活性分别高109%和121%。减水处理的土壤磷酸酶活性没有明显低于对照,但是显著低于增水处理。0—20 cm的土壤磷酸酶活性在3个增水梯度上根际间差异不显著,但在3个减水梯度上差异显著。磷酸酶活性与土壤含水量和土壤有机磷含量均呈显著正相关关系。上述结果说明在半干旱地区短期降水增加对土壤磷酸酶活性的影响比短期干旱的影响大,降水变化可以通过影响土壤含水量、土壤有机磷和生物量改变土壤磷酸酶活性。研究降水对土壤酶活性的影响对气候变化下黄土高原植被恢复具有重要意义。     

中药材龙胆GAP基地土壤酶活性的研究

分别采用硫代硫酸钠滴定法、高锰酸钾滴定法、TTC-脱氢酶活性测定法和磷酸苯二钠比色法测定龙胆GAP基地土壤中转化酶、过氧化氢酶、脱氢酶和磷酸酶的活性。对不同月份、种植不同年生龙胆根际土及非根际土中酶活性的测定结果进行分析表明:土壤过氧化氢酶活性在6月份出现一较高值,脱氢酶活性较高时期在7月份,土壤转化酶活性较大值出现在7、8月份,磷酸酶活性则逐月增高至9月份达到最大值,土壤总体酶活指标极大值出现在8月份;随着龙胆种植年限的增加,土壤过氧化氢酶和脱氢酶活性有所提高,而磷酸酶和转化酶活性没有明显变化,种植不同年生龙胆土壤中酶的活性随季节波动不尽相同。比较GAP基地龙胆根际土与非根际土中酶活性,土壤转化酶和过氧化氢酶的活性均表现为根际土非根际土,而土壤磷酸酶和脱氢酶的活性则为非根际土根际土;相关分析结果显示,过氧化氢酶活性与酸性及中性磷酸酶活性显著负相关;酸性、中性及碱性三种磷酸酶活性之间存在极显著正相关;总体酶活指标与转化酶、酸性磷酸酶、中性磷酸酶活性呈显著正相关。本研究完善了中药材龙胆GAP种植基地土壤酶的信息,为综合评价基地土壤肥力提供了科学数据,为药用植物龙胆的合理施肥、品质的提高提供了科学依据。     

不同施肥措施对春玉米农田土壤酶活性的影响

为研究肥料配比对春玉米农田土壤酶活性的影响,连续4年采用田间定位种植春玉米,分析各生育期各土层酶活性,利用聚类分析和主成分分析揭示酶活性的动态变化差异。结果表明,各种施肥措施显著增加蔗糖酶、脲酶和磷酸酶活性,主要影响10~20 cm土层酶活性。施用有机肥土壤酶活性最大值出现在散粉期,施用无机肥土壤酶活性最大值出现在大喇叭口期。随着土层深度的增加,蔗糖酶、脲酶、磷酸酶活性呈下降趋势;过氧化氢酶活性10~20 cm土层最低。配合施肥中增施氮肥降低过氧化氢酶活性,增加蔗糖酶、脲酶活性;增施磷肥增加脲酶、磷酸酶活性;增施有机肥增加过氧化氢酶活性,降低蔗糖酶、脲酶活性。单施氮肥降低土壤脲酶和磷酸酶活性。有机无机肥配施能够延长春玉米生育期土壤酶活性的高值期。土壤蔗糖酶、脲酶、过氧化氢酶和磷酸酶活性分别受全钾、全氮、有机质和全氮、全磷和有机质含量的影响,施肥通过改变土壤元素含量及供给能力影响土壤酶活性。     

参与碳氮磷转化的水解酶对不同施肥响应的差异

本文旨在研究土壤水解酶对不同施肥的响应差异以及影响因素。通过在红壤中添加牛粪有机肥、化肥进行90d的室内土壤培养试验,采用微孔板荧光法动态分析5、30和90d参与碳氮磷转化的土壤水解酶(α-1,4-葡萄糖苷酶、β-1,4-葡萄糖苷酶、纤维素酶、木聚糖酶、亮氨酸氨基肽酶、β-1,4-N-乙酰氨基葡萄糖苷酶、磷酸酶)活性。与不施肥(对照)相比,在30 d后,化肥处理的总酶活性显著下降,对应的参与碳氮磷转化酶活性均有不同程度下降;而有机肥处理的总酶活性在培养期内均未发生显著变化,但是其α-1,4-葡萄糖苷酶显著增加,而磷酸酶活性显著降低。参与碳转化的4种水解酶中,只有α-1,4-葡萄糖苷酶活性对施肥的响应较强,且施加有机肥增加其活性而无机肥则降低其活性;对于参与氮转化的水解酶而言,化肥明显抑制了亮氨酸氨基肽酶活性,而有机肥增加了β-1,4-N-乙酰氨基葡萄糖苷酶活性;磷酸酶活性明显受到有机肥的抑制作用,而对化肥的响应总体不明显。不同水解酶对不同施肥的响应有明显差异,NMDS分析表明,α-1,4-葡萄糖苷酶和亮氨酸氨基肽酶响应最明显,其次为磷酸酶与木聚糖酶;相关和冗余分析显示,土壤p H、可溶性有机碳对酶活性的影响最大,一定程度说明了不同肥料通过影响土壤理化性质进而影响水解酶活性。     

刺萼龙葵入侵对不同类型土壤特性的影响

外来入侵植物对土壤生态系统的影响已成为入侵生态学研究的热点。本文选取河北宣化和吉林白城2个刺萼龙葵(Solanum rostratum Dunal.)入侵典型地区,研究刺萼龙葵入侵对不同类型土壤养分及酶活性的影响。每个地区分别选择4个生境作为样地,宣化地区生境包括荒地、路边、农田和林地,白城地区生境包括荒地、路边、农田和草原,其中宣化的林地和白城的草原为每个地区特有的生境。采用滴定法和比色法测定土壤养分和酶活性。结果表明,与未入侵样地(CK)相比,刺萼龙葵入侵显著提高了农田、林地和草原的土壤全氮含量(P0.05),其中宣化(灌淤土)农田和林地全氮含量比CK增加102.49%、79.02%,白城(淡黑钙土)农田和草原比CK增加44.04%、21.81%;刺萼龙葵入侵显著提高了农田和林地的土壤铵态氮含量(P0.05),其中宣化农田、林地中土壤铵态氮含量比CK增加137.59%、50.32%,白城农田中增加140.18%;刺萼龙葵入侵也提高了路边、林地、农田(白城)和荒地(宣化)的土壤硝态氮含量(P0.05),其中,宣化荒地、路边和林地土壤硝态氮含量较CK增加65.52%、32.96%和22.68%,白城路边和农田分别增加132.59%、153.96%。刺萼龙葵入侵显著提高了宣化地区及白城荒地和农田的土壤有机质含量(P0.05);降低了宣化荒地、农田和林地的土壤全磷含量(P0.05),土壤全磷分别比CK降低54.63%、70.81%和29.68%,白城路边和草原的土壤全磷含量分别较CK下降17.40%、14.69%(P0.05);刺萼龙葵入侵对2个地区土壤全钾和速效钾则无显著影响。刺萼龙葵入侵显著提高了荒地、农田、林地、草原和路边(宣化)的土壤脲酶活性(P0.05);宣化路边和白城荒地、草原的中性磷酸酶的活性,宣化荒地和林地土壤过氧化氢酶活性均显著提高(P0.05),对白城过氧化氢酶则无显著影响。刺萼龙葵入侵对某些生境的土壤养分和酶活性无显著影响可能与入侵生境的小气候、入侵时间长短等因素相关,需进一步深入研究。总之,刺萼龙葵入侵改变了2个地区土壤理化性质和酶活性,其可能通过改变土壤养分及土壤酶活性,以创造对自身有利的土壤环境,从而进一步扩散蔓延。     

不同施肥处理下灌耕灰钙土水解酶活性的剖面分布及其相关性

在不同施肥处理下,对西北半干旱区灌耕灰钙土,土壤转化酶、脲酶和碱性磷酸酶活性的剖面分布以及土壤酶与土壤全量养分、土壤酶之间相关性进行研究。结果表明,各处理在小麦的各个生育期土壤转化酶、脲酶和碱性磷酸酶的活性均为:0～10 cm土层10～20 cm土层20～40 cm土层,且绝大多数处理各土层之间酶活性差异都达到显著水平。土壤转化酶、脲酶和碱性磷酸酶与土壤有机质、全氮、全磷含量基本呈正相关,有的达到显著和极显著水平,三种酶与全钾含量均为负相关,基本未达显著。土壤转化酶、脲酶和碱性磷酸酶活性三者之间的相关性呈极显著和显著正相关,酶的总体活性大小可以用来衡量土壤肥力水平的高低。     

植烟沙泥田土掺混紫色土对土壤酶活性及理化性质的影响

为了探讨南雄烟区植烟沙泥田土壤改良新途径,采用盆栽方法研究了沙泥田土掺不同比例紫色土后土壤的理化性质和相关酶活性的变化规律。结果表明:当沙泥田土掺混10%~50%的紫色土后,土壤的砂粒含量逐渐下降到11.57%,粉粒含量逐渐上升到62.19%,土壤质地由壤土逐渐变为粉砂壤土,pH值从微酸性逐渐变成弱碱性;氧化还原酶类酶的活性逐渐增强,水解酶类酶活性则逐渐减弱,微量元素含量(钼除外)逐渐降低,中量元素交换性钙和交换性镁含量分别比对照(A1)增加了313%和37.1%;当沙泥田土掺混30%紫色土时,全钾和缓效钾含量分别比对照(A1)高出50%和69.2%,但其它养分含量有不同程度下降;相关分析结果表明,土壤酶活性受到土壤养分和中微量元素含量的影响,过氧化氢酶、多酚氧化酶、酸性磷酸酶和中性磷酸酶活性与pH值、有机质、全氮、碱解氮、有效磷、全钾和速效钾等养分含量均达到显著或极显著相关水平;有效铜、有效锌、有效硼、交换性钙和交换性镁含量与过氧化氢酶、过氧化物酶、多酚氧化酶和中性磷酸酶活性均达到显著或极显著相关水平;通过主成分分析得出沙泥田土掺混10%紫色土后的土壤因子综合主成分分值最高,掺混效果最好。     

Response of Soil Microbial Biomass and Enzyme Activity to Soil Fertilization in an Eroded Farmland of Chinese Mollisols

The aims of this study were to examine interrelationships between microbial biomass and enzyme activities of soil quality and to determine their suitability for differentiating areas. The study included five simulated erosion soil depths (0, 5, 10, 20, and 30 cm), which had received contrasting fertilizer treatments over a 5-year period in an eroded black soil of northeastern China. Our results indicated that soil microbial carbon, nitrogen, urease, phosphatase, and invertase activities declined as the erosion depth increased. On the five erosion depths, soil microbial carbon, phosphatase, and invertase variation ranged as follows: 35.4–53.3, 39.8–45.2, and 55.9–67.1%, respectively. In the fertilizer + manure treatment, soil microbial carbon, nitrogen, urease, phosphatase, and invertase activities were significantly greater (P < 0.05) than those of fertilizer treatment in all five different erosion depths. Overall, this study may be considered as the foundation for soil quality evaluation and fertility restoration in northeastern China and similar regions.     

Microbial populations,enzyme activities and nitrogen-phosphorus-potassium enrichment in earthworm casts and in the surrounding soil of a pineapple plantation

Summary Total populations of bacteria and fungi, dehydrogenase activity (as a measure of total potential microbial activity), and urease and phosphatase activities were determined in earthworm casts and surrounding laterite soils planted to pineapple. The casts contained higher microbial populations and enzyme activities than the soil. Except for fungal populations, statistically significant (P = 0.05) increases were found in all other parameters. Microbial populations and enzyme activities showed similar temporal trends with higher values in spring and summer and lower values in winter. The earthworm casts contained higher amounts of N, P, K and organic C than the soil (P = 0.05). Selective feeding by earthworms on organically rich substrates, which break down during passage through the gut, is likely to be responsible for the higher microbial populations and greater enzyme activity in the casts.     

祁连山青海云杉林土壤理化性质和酶活性海拔分布特征

选取祁连山排露沟流域海拔2 900～3 300 m的青海云杉林为研究对象,通过野外采样和室内分析,研究了不同海拔梯度青海云杉林土壤理化性质和酶活性的分布特征,并探讨二者之间的关系。结果表明:(1)随着海拔的升高,土壤含水量、有机质、全氮、速效钾含量逐渐增大;而土壤容重、pH、全钾含量逐渐减小;土壤全磷含量先减小后增大,速效磷含量没有明显的变化规律。(2)随着海拔的升高,土壤蔗糖酶活性和碱性磷酸酶活性总体上呈增强趋势;脲酶活性总体上呈先减弱后增强趋势,蛋白酶活性变化幅度较小且差异不显著(P0.05)。(3)土壤酶活性和土壤有机质、氮、磷、钾等密切相关,其中蔗糖酶、脲酶、蛋白酶与土壤全氮、全钾、速效钾具有显著相关性(P0.05)。(4)4种土壤酶活性间呈显著或极显著相关,酶促反应具专一性和共同性特点。     

Response of soil enzymes and microbial communities to root extracts of the alien Alternanthera philoxeroides

Alternanthera philoxeroides is an alien invasive species, which can cause substantial damage to the local ecosystem by secreting allelochemicals. The objective of the present study was to appraise the effects of root extracts of the invasive plant Alternanthera philoxeroides on soil enzyme and native microbial community. Urease activity was measured using the phenol sodium hypochlorite colorimetric method, sucrase activity was determined by 3, 5-dinitrosalicylic acid colorimetric method, catalase activity was determined using the KMnO₄ titration method and alkaline phosphatase activity was determined by the disodium phenyl phosphate colorimetric method. The soil microbial community was investigated by pyrosequencing of the 16S rRNA gene. Results showed that the alkaline phosphatase, sucrase and urease activities were all significantly lower than that of the control treatment. The structure of the soil microbial community in the treatments with root extracts addition clearly differed from that of the control treatment. The result showed that the relative abundance of microorganism decreased including Burkhholderia, Gp6, Gp1 and Gp4 in the applied treatments at genus level as compared to control treatment. Hence, we inferred that A. philoxeroides could inhibit the growth of native plant species through toxic effects on soil enzyme activities and the microbial community.     

转双价（Bt＋CpTI）棉种植对土壤速效养分和酶活性的影响

本研究利用三室根箱对棉花根部土壤进行分区采集,以转双价棉SGK321及其亲本常规棉石远321为研究对象,对3个生长时期（播种后40、50 d和60 d）不同根区（S1、S2和S3）土壤速效养分（硝态氮、铵态氮和速效磷）含量及酶（脲酶、碱性磷酸酶和过氧化氢酶）活性变化进行了对比分析。研究结果表明,与常规棉相比,转双价棉的种植促进了S2根区土壤中磷素向有效态的转化,使S2和S3根区土壤硝态氮含量下降,而对各根区土壤脲酶、碱性磷酸酶和过氧化氢酶活性及土壤铵态氮无显著影响。主成分分析结果表明,土壤速效养分和酶活性变化主要受生长时期的影响,转双价棉种植对其影响是非常有限的。     

蚯蚓活动对生态滤池土壤酶活性的影响

通过构建蚯蚓生态滤池和无蚯蚓对照生态滤池的实验,研究了蚯蚓活动对生态滤池土壤酶活性(蔗糖酶、脲酶、碱性磷酸酶)的影响以及酶活性的季节动态变化特征。研究结果表明,在0~20 cm的基质层,三种土壤酶活性随土壤深度的增加而减少;蚯蚓活动对生态滤池的基质酶活性有促进作,蔗糖酶和脲酶活性在蚯蚓作用下得到显著的提高,而碱性磷酸酶对蚯蚓活动的响应仅限于5~10 cm基质层;在试验期内,生态滤池内的蚯蚓数量及生物量受温度及土壤湿度的影响表现出较大的季节波动:夏季最高,春季冬季相对较高,秋季最低;三种土壤酶活性表现为相似的季节变化规律:秋季活性最高,而秋季和夏季的酶活性高于春季和冬季。蚯蚓活动对生态滤池基质土壤蔗糖酶活性和脲酶显著的促进作用,并间接影响了其对生活污水污染物去除效果。     

Assessing air-drying and rewetting pre-treatment effect on some soil enzyme activities under Mediterranean conditions

Soil enzyme activities are useful indicators of soil quality as they are very sensitive to disturbance. Sample storage or pre-treatments could affect the results in these assays, which are normally determined in fresh samples, kept cold or frozen. The objectives of this study were to (i) evaluate the effect of air-drying or air-drying and rewetting on β-glucosidase, acid phosphatase and urease activities in soils from different locations, degradation status and sampling seasons, and (ii) assess if air-drying or air-drying and rewetting is an accurate sample storage and pre-treatment procedure for enzyme activities in soil quality evaluations under semiarid Mediterranean conditions. Our results showed that urease, phosphatase and β-glucosidase activities were hardly affected by air-drying of degraded and non-degraded soils from the two locations studied in all seasons. Short incubations (4, 8 and 12 d at 23 °C) of rewetted air-dried soil at 55% of water-holding capacity showed different patterns depending on the enzyme studied. Urease and β-glucosidase activities were relatively stable during incubation, with several significant (P<0.05) shifts up and down in some soils and samplings. However, acid phosphatase showed an increase in activity with incubation, of between 5% and 50% relative to air-dried samples. These increases followed no pattern and were unrelated to soil characteristics or sampling date. Hence, urease, phosphatase and β-glucosidase activities determined in air-dried soil samples seem to be representative of those obtained under field-moist conditions. In contrast, short incubations of rewetted soil samples can produce fluctuations in these enzyme activities, mainly of acid phosphatase, and estimations in these conditions are not so representative of field-moist soil values.