Restoration of pasture after topsoil removal: Effects on soil carbon and nitrogen mineralization,microbial biomass and enzyme activities

The restoration of soil biochemical activities after topsoil removal to depths 0 (S₀), 10 (S₁₀) or 20 (S₂₀)cm, and re-establishment of a grass-clover pasture, was studied with Judgeford silt loam, a Typic Dystrochrept, in the Wellington area. Organic matter contents of the S₁₀ and S₂₀ samples were initially 58 and 40%, and biochemical activities, on average, 32 and 20%, respectively of S₀ values. Organic matter content increased only slowly in the stripped plots. Yields of pasture herbage, soil CO₂ and mineral-N production, three indices of microbial biomass, and invertase, amylase, cellulase, xylanase, urease, phosphatase, and sulphatase activities increased more rapidly, but had not reached S₀ levels after 3 yr. The ratios of biomass indices varied with depth of topsoil removed; over the trial, biomass-C to ATP ratios averaged 236, 205, and 168 in the S₀, S₁₀, and S₂₀ samples respectively. Biochemical activities were generally correlated significantly with herbage yields in the S₁₀ or S₂₀, but not in the S₀ plots; organic C or total N contents were not generally correlated significantly with yields over the first 2 yr. Overall, invertase, and then sulphatase, activity appeared to be the best indicators of soil fertility status in this stripped soil.     

长期施用化肥对黑垆土酶活性影响

对设在黄土高原旱地土壤上的长期化学肥料定位试验经16年连续施肥后收获期土壤的5种酶活性进行了测定,结果表明,土壤过氧化氢酶活性随施磷量的增加而降低,脲酶活性随施氮肥量增加而增加。相关分析表明碱性磷酸酶活性与有机C相关达显著水平,过氧化氢酶活性与有效磷达极显著负相关。通径分析表明蔗糖酶、脲酶、碱性磷酸酶活性对产量的影响作用达到显著或极显著水平,土壤酶活性是土壤物理化学性质等的综合作用结果,用它们可以对长期施用化肥的土壤肥力进行评价。     

The response of properties of soil cropped with shell beans and treated with disinfectant and fertiliser during the plant growing season

Disinfectants and fertilisers exert strong impact on soil processes by affecting the structure and the activity of the soil microbial community. Most relevant studies examined these impacts independently, under laboratory conditions and without crop cover. In this study, we have monitored the response of soil chemical, microbial, and biochemical properties to disinfectant and fertiliser treatments in field plots cultivated with beans. The measured properties comprised microbial C and N, asparaginase, gultaminase, urease, and acid phosphomonoesterase activities and contents of organic N, organic C, inorganic N, and inorganic P. We ran four different treatments using different combinations of chemical (metham sodium) and biological disinfectant (a mixture of neem cake and essential oils) and fertilisers (NPK 8-16-24 and cow manure) in plots cultivated with shell beans, while the control soil was neither treated nor cropped with beans. The data were expressed as percentage (%RC) in relation to the control values. The disinfectant and fertiliser treatments had less impact on soil properties compared to bean crop growth (except for microbial C and N, and content of organic C). In comparison to the control, higher activities of urease and asparaginase and content of inorganic N were recorded in bean cropped plots at the stage of seedlings (June), while higher activities of acid phosphomonoesterase and glutaminase and content of organic N were recorded at the stage of plant flowering (August). In October, the values of all properties were higher in the control plots compared to the treated plots. The joint effect of disinfectants x fertilisers affected the response of content of organic C and N and extractable P and glutaminase activity. The %RC of the properties exhibited more negative values in plots treated with chemical disinfectant and chemical fertiliser than in the other treatments. We suggested that the response of soil properties to disinfectants and fertilisers were influenced by the growth of P. vulgaris.     

长期施氮肥对黄棕壤微生物生物性状的影响及其调控因素

基于黄棕壤小麦-甘薯轮作的长期定位试验,探究不同施氮处理土壤微生物生物量碳(MBC)、氮(MBN)含量和酶活性的变化及其潜在调控因子,为科学施氮提高土壤质量和改善土壤生态功能提供依据。试验选取始于2011年4个施氮处理:不施肥(CK)、不施氮肥(PK)、施化学氮肥(NPK)和化学氮肥配施有机肥(NPKM),调查两季作物收获后土壤MBC和MBN含量、酶活性及微生物碳氮利用效率的变化,并通过冗余分析(RDA)和结构方程模型(SEM)明确调控弱酸性黄棕壤中MBC和MBN变化的潜在因素。小麦和甘薯两季的结果表明:施氮肥降低了土壤MBC、MBN含量和蔗糖酶(SSC)、脲酶(SUE)活性,与NPK处理相比, NPKM处理增加了MBC、MBN含量和SSC、SUE活性。长期施用氮肥提高了土壤有机碳(SOC)和土壤养分[全氮(TN)和矿质态氮(MN)]含量,但施氮肥显著降低土壤p H以及微生物的碳氮利用效率。与小麦季相比,甘薯季土壤SOC和MN含量有所下降,而MBN含量和SSC活性有所升高。RDA和SEM结果表明,氮肥的施用强化了MBC与MBN、SSC与MBC以及SUE与MBC之间的关联性;不同施氮处理下土壤p H、有机碳、氮含量以及微生物的碳氮利用效率的变化直接或间接地影响土壤MBC、MBN含量和SSC、SUE活性,其中p H是调控土壤MBC变化的直接因素,而土壤SSC和SUE活性与MBC、MBN含量相互影响。长期施用氮肥降低了黄棕壤MBC、MBN含量和酶活性,化学氮肥配施有机肥有利于缓解生物性状的下降,土壤p H是影响MBC变化的主要因素,小麦-甘薯轮作中土壤微生物强烈的碳代谢过程利于增加MBN。     

Microbial biomass activities in urban soils in two consecutive years

Ecological soil functions are protected in Germany. Thus, for the sustainable use of urban soil resources data on the function of soils to serve as a habitat are required. Soil microbial biomass and activities were studied in two surface horizons in two consecutive years at nine sites in Stuttgart, Germany, differing in land use. Microbial biomass (chloroform‐fumigation extraction, substrate‐induced respiration) and microbial activities (potential N mineralization, potential ammonium oxidation, and enzyme activities of dehydrogenase, urease, arylsulfatase, and phosphatase) were determined in 2001 and 2002. DIN/ISO standard methods were applied as far as they were available. Furthermore, soil chemical properties were determined in the 2001‐samples. Large differences in chemical and microbiological properties among surface horizons were found. Concentrations of microbial biomass and microbial activities were, however, often comparable to agricultural or forest surface soils. The lowest microbial biomass and activities were observed at a highly disturbed railway area where vegetation was missing and total organic C (TOC) had been altered by anthropogenic organic particles. In contrast, microorganisms were promoted at vegetated sites and where organic impurities were negligible. As TOC was altered by obscure organic matter, total N (TN) and not TOC closely correlated with soil microbiological properties. Biomass and activity generally decreased with depth, but mixing of organic matter resulted in more uniform depth distribution of microbial properties in one garden soil. In 2002, microbial biomass and activity were often lower compared to 2001, but interpretation of this difference hampered as the number of samples taken was probably not sufficient to address the spatial variability in soil properties. Additional studies are needed to develop simple and cost‐effective procedures for the evaluation of ecological quality of urban soils by combined efforts of city planners and soil scientists.     

土壤紧实程度对其某些相关理化性状和土壤酶活性的影响

利用外力夯实、向土壤中加入蛭石等方法造成土壤容重不同,以研究土壤紧实程度对其理化性状的影响。结果表明,紧实土壤水分的散失较快,晴天地温高,且变化幅度大,阴天和夜间紧实土壤地温低,变化幅度小。紧实土壤可降低植株对土壤养分的吸收,致使土壤余留的有效态养分较多。土壤的转化酶、脲酶、过氧化氢酶、多酚氧化酶、磷酸酶活性的变化也受土壤紧实度的影响。总之,土壤疏松有助于保水、蓄热和提高多种土壤酶活性。     

陕西土壤脲酶活性与土壤肥力关系分析

根据陕西７种主要土壤１９个土样的脲酶活必及理化性质的测定结果，经相关、通径和主成分分析表明：土壤脲酶活性可明显反映出土壤肥力水平差异，脲酶活性大小受到土壤理化性质直接和间接的影响。用主成分组成的土壤肥力信息系统分析统计和用土壤的脲酶活性及理化性质分别评价土壤肥力得到的结果相似。     

长期有机无机肥配施对土壤水稳性团聚体酶活性的影响

The activities of invertase, protease, urease, acid phosphomonoesterase, dehydrogenase, and catalase in different fractions of waterstable aggregates (WSA) were examined in long-term (26 years) fertilised soils. The long-term application of organic manure (OM) with chemical fertiliser (CF) significantly increased macroaggregate and decreased microaggregate percentages, enhanced the mean weight diameter, and significantly increased soil total carbon (TC) and total nitrogen (TN) contents of WSA in different size fractions. Combined fertilisation with OM and CF also increased invertase, protease, urease, acid phosphomonoesterase, dehydrogenase, and catalase activities of WSA in different size fractions. Enzyme activities were higher in macroaggregates than in microaggregates. The distribution of enzyme activities generally followed the distribution of TC and TN in WSA. The geometric mean of the enzyme activities in different WSA of OM-treated soils was significantly higher than that in soils treated with 100% CF or no fertiliser. The results indicated that the long-term combined application of OM with CF increased the aggregate stability and enzyme activity of different WSA sizes, and consequently, improved soil physical structure and increased soil microbial activity.     

长期施用畜禽粪便对土壤生物化学质量指标的影响

采用两种母质发育的,长期施用畜禽粪便和化肥的稻麦轮作土壤作为供试土壤,探讨了施用畜禽粪便对土壤微生物组成、微生物生物量及活性、土壤酶活性等生物化学质量指标的影响。研究结果显示,与施用化肥比较,长期施用畜禽粪便显著提高了土壤细菌和放线菌数量(+72%和+132%)、土壤微生物生物量碳、氮(+89%和+74%)、土壤基础呼吸速率和微生物商(+49%和+45%),但降低了土壤真菌的数量(-38%)。土壤脲酶和转化酶活性也表现为长期施用畜禽粪便土壤高于施用化肥土壤。由于受土壤pH值强烈影响,土壤微生物代谢商(qCO2)和土壤磷酸酶活性没有表现出明显的变化规律。回归分析结果显示,长期施用畜禽粪便改变土壤活性有机碳含量和理化性质是导致土壤生物化学质量指标变化的主要原因。     

不同施肥处理对黄泥土微生物生物量碳氮和酶活性的影响

通过室内培育实验,研究了不同施肥处理对黄泥土微生物生物量C、N和脲酶、酸性磷酸酶、蔗糖酶活性的影响。培养过程中,单施化肥处理土壤微生物生物量C、N均呈下降趋势,施用有机肥处理的土壤微生物量C前期升高至一定水平后或保持稳定、或呈下降趋势,而微生物生物量N总体均呈下降趋势;不同施肥处理的脲酶活性呈前期上升后期下降趋势,而酸性磷酸酶和蔗糖酶则单施化肥处理呈上升趋势、配施有机肥处理呈下降趋势。与对照处理相比,单施化肥处理显著降低土壤微生物生物量C、N,高量施用化肥处理还显著降低土壤脲酶活性,但对酸性磷酸酶和蔗糖酶活性的影响并不明显。秸秆施用可显著提高土壤微生物生物量C、N和酶活性,特别是高量施用秸秆的效果更明显。施用猪粪由于同时带入了大量的活性养分,对土壤微生物生物量C、 N和酶活性的影响尚难评价。在高度集约农业利用下,继续保持较高的化肥施用量并不利于土壤生物质量的维护和提高,而秸秆直接还田才是保持土壤健康状态的有效措施。     

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。     

三峡库区不同林龄柑橘土壤酶活性的演变

土壤酶驱动土壤生态系统养分的循环和控制生态系统的功能。本研究以生长年限为10、20年和30年的柑橘林0~20 cm和20~40 cm土层土壤为研究对象,主要探讨了土壤脲酶、转化酶和过氧化氢酶活性随着柑橘林龄的延长和土壤深度的增加的变化规律。结果表明,随着柑橘林龄的延长,0~20 cm土层土壤过氧化氢酶活性10年和20年样地之间无显著性差异,但都显著大于30年的样地;而0~20 cm土层土壤转化酶和脲酶活性逐渐提高,20年时达到最大值,其后又降低。随着土壤深度的增加,过氧化氢酶、转化酶和脲酶活性在3个林龄的柑橘林中都呈现显著的下降趋势。相关性分析的结果表明,土壤转化酶活性、脲酶活性都与土壤有机碳和微生物量碳氮之间都具有显著的正相关性,而过氧化酶氢活性与土壤理化特性及其微生物量之间都无显著的相关性。主成分分析结果进一步显示,土壤转化酶活性、脲酶活性、有机碳和微生物生物量碳氮均在第一主成分中具有较大的载荷,对第一主成分的贡献最大。以上结果表明脲酶和转化酶活性能够做为柑橘土壤质量变化的敏感指标。     

Long-term effects of farmyard manure and sewage sludge on some soil biochemical characteristics

 Changes in some soil biochemical properties were investigated following repeated applications of aerobically digested sewage sludge (SS) under field conditions over 12 years, and compared with those of an adjacent soil cultivated and amended with 5 t ha^–1 year^–1 (dry weight) farmyard manure (FYM) for at least 40 years, as well as with those of an adjacent uncultivated soil, in order to ascertain changes in soil quality. A short-term aerobic incubation was used to determine the potential of the samples to mineralize the organic C supplied. Results indicated that cultivation caused a reduction in total, humified and potentially mineralizable organic C, total N, light-fraction (LF) C, total and water-soluble carbohydrates, phenolic compounds, cation-exchange capacity (CEC), microbial biomass C, specific respiration, hydrolytic and urease activities, and an increase in the heavy metal content. Total and water-soluble carbohydrates and phenolic compounds expressed as a percentage of total organic C (TOC) were similar in the differently managed plots. Of the two amendments, FYM treatments showed higher amounts of TOC and N, LF-C, total and water-soluble carbohydrates, phenolic substances, CEC, specific respiration of biomass, hydrolytic and urease activities, similar amounts and characteristics of humified organic matter and lower concentrations of Cu, Zn and Cr. Both FYM and SS were inadequate treatments for the restoration of soil organic matter lost as a consequence of cultivation. Received: 20 October 1998     

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。     

土地开发对农田土壤养分和盐分变异特征的影响

利用地统计学方法研究了新疆库尔勒市包头湖农场土地开发后土壤空间变异特征。结果表明:土地开发后种植区的土壤有机质和盐分降低,有效磷含量增加,碱解氮含量变化不大;尤其是土地开发后撂荒地土壤有机质含量下降明显。土壤盐分与有机质、碱解氮及速效钾的含量均呈显著正相关,与有效磷呈显著负相关。因此,土地开发后需增施有机肥,补充钾肥,并尽可能不撂荒。     

A STUDY OF ACTIVITIES OF ENZYMES HYDROLYSING SUCROSE AND STARCH AND OF OXYGEN UPTAKE IN A SEQUENCE OF SOILS UNDER TUSSOCK GRASSLAND

Biochemical activities were studied at three sampling dates in a sequence of four soils, ranging in altitude from 275 to 1,520 m, on schist parent material in a tussock-grassland association on the Old Man Range, Central Otago. Activities were similar under different tussock species. The uppermost part of the soil appeared to be most affected by seasonal changes because fluctuations at different sampling dates were greater in samples of topsoil from depth 1 to 7.5 cm than in samples of A, AB, and B horizons at depths approximately 4, 13, and 28 cm. Activities of enzymes without added substrate and of enzymes hydrolysing sucrose or starch generally increased with increasing altitude of the soils and were strongly correlated with organic C content and, to a lesser extent, with soil moisture content. In previous pasture surveys, enzymes hydrolysing sucrose had not been significantly correlated with organic C. Although oxygen uptakes were also positively correlated with these factors, and with numbers of viable bacteria, consistent differences between soils were not found. Differences between A and AB horizons were usually greatest in the soil at the highest altitude but, otherwise, rates of regression of biochemical activities with depth of soil were generally similar in all soils. Results may be indicative of biochemical activities in other mountain-soil sequences.     

黄土高原旱地轮作与施肥长期定位试验研究 Ⅱ.土壤酶活性与土壤肥力

本文分析了长期试验土壤酶活性与土壤有机C、全N、有效P含量、主要微生物类群之间的关系。相关分析表明,土壤脲酶、碱性磷酸酶、蛋白酶活性随土壤有机C含量的增加而增加,蔗糖酶、过氧化氢酶活性与有机C之间的关系因施肥种类及种植方式的不同而不同;微生物数量仅真菌与脲酶、蛋白酶活性之间的相关性达到显著水平。除过氧化氢酶外,其它4种酶的活性均与当年种植冬小麦处理的产量存在显著相关关系。利用主成分分析与通径分析揭示了土壤酶活性与养分之间的内在关系及酶活性对土壤养分的影响。根据主成分分析结果,旱地土壤肥力状况用脲酶、碱性磷酸酶、蛋白酶活性作为综合评价指标优于过氧化氢酶与蔗糖酶。     

红壤水稻土累积酶活性及养分对长期不同施肥处理的响应

本研究基于鹰潭农田生态系统国家野外科学观测研究站24年的长期定位试验,揭示对照(不施肥,CK)、有机肥(C)、化学氮磷钾肥(NPK)、化学氮磷钾肥+有机肥(NPKC)等不同施肥处理对红壤水稻土酶活性及土壤养分的影响。于晚稻收获后采集各小区耕层土壤,测定红壤水稻土中转化酶、脲酶活性(测定时并设加0.5 ml甲苯与不加甲苯处理)及转化酶动力学特征,同时测定土壤养分含量及微生物生物量碳,分析酶活性与养分含量及微生物生物量碳间的关系,明确土壤中累积酶活性及土壤养分对长期不同施肥处理的响应。结果发现,与对照相比,施肥处理下土壤转化酶活性显著提高了31.3%~131.7%,微生物生物量碳显著提高了84.9%~125.1%;在没有甲苯抑制微生物活性下,施肥处理的转化酶底物蔗糖转化速率增加量提高了89.5%~153.7%,脲酶底物尿素转化增加量提高了59.2%~98.9%,表明微生物显著影响两种累积酶表观酶活性;转化酶活性、脲酶活性与微生物生物量碳呈显著正相关。与对照处理相比,施肥处理显著增加了土壤有机碳(30.1%~36.3%)、全磷(28.6%~102.9%)、速效磷(62.2%~445.0%)、碱解氮(35.9%~56.4%)含量;统计分析显示,转化酶活性、脲酶活性均与碱解氮、有机碳含量显著正相关。与对照相比,各施肥处理土壤的转化酶米氏常数(Km)差异并不显著,而转化酶表观活性(Vmax)及转化系数(Vmax/Km)均显著增加。长期施肥处理增加了土壤养分含量和微生物生物量碳,提高了土壤中累积酶的活性。     

Soil biochemical and microbial indices in wet tropical forests: Effects of deforestation and cultivation

Little information is available about the long‐term effects of deforestation and cultivation on biochemical and microbial properties in wet tropical forest soils. In this study, we evaluated the general and specific biochemical properties of soils under evergreen, semi‐evergreen, and moist deciduous forests and adjacent plantations of coconut, arecanut, and rubber, established by clear felling portions of these forests. We also examined the effects of change in land use on microbial indices and their interrelationships in soils. Significant differences between the sites occurred for the biochemical properties reflecting soil microbial activity. Microbial biomass C, biomass N, soil respiration, N mineralization capacity, ergosterol, levels of adenylates (ATP, AMP, ADP), and activities of dehydrogenase and catalase were, in general, significantly higher under the forests than under the plantations. Likewise, the activities of various hydrolytic enzymes such as acid phosphomonoesterase, phosphodiesterase, casein‐protease, BAA‐protease, β‐glucosidase, CM‐cellulase, invertase, urease, and arylsulfatase were significantly higher in the forest soils which suggested that deforestation and cultivation markedly reduced microbial activity, enzyme synthesis and accumulation due to decreased C turnover and nutrient availability. While the ratios of microbial biomass C : N and microbial biomass C : organic C did not vary significantly between the sites, the ratios of ergosterol : biomass C and ATP : biomass C, qCO2 and AEC (Adenylate Energy Charge) levels were significantly higher in the forest sites indicating high energy requirements of soil microbes at these sites.     

长期施肥对城市边缘区不同作物土壤酶活性的影响

以开封市为例,探讨了长期施肥条件下城市边缘区不同作物土壤酶活性的变化及其与土壤养分的关系。结果表明,土壤酶活性受施肥处理影响明显,其中蛋白酶、过氧化氢酶、转化酶和脲酶活性在化肥处理中均受到抑制,在有机肥中却得到大幅提升,碱性磷酸酶活性变化与之正好相反;在混施处理中各酶活性均有不同程度的增强,其中以脲酶活性增强尤为突出。土壤酶活性在各作物之间表现出一定的差异,但总的来说差异不显著。土壤各酶之间及酶与土壤肥力因素之间存在显著或极显著相关关系,因此土壤酶活性可以作为城市边缘区土壤环境质量评价的生物肥力指标之一。