Increased Soil Microbial Biomass Research Articles

Urbanization effects on soil nitrogen transformations and microbial biomass in the subtropics

As urbanization can involve multiple alterations to the soil environment, it is uncertain how urbanization effects soil nitrogen cycling. We established 22–0.04 ha plots in six different land cover types—rural slash pine (Pinus elliottii) plantations (n = 3), rural natural pine forests (n = 3), rural natural oak forests (n = 4), urban pine forests (n = 3), urban oak forests (n = 4) and urban lawns (n = 5) to investigate how net soil nitrogen mineralization rates and soil microbial biomass differed between urban forests and rural forests and between urban forests and urban lawns in the Florida panhandle. Urban forest sites have 2.5 times as much net total nitrogen mineralized than rural forest sites based on the mean daily rates averaged over the 2 years study (2010–2012). Urbanization may increase soil microbial biomass and activity (potential carbon mineralization rates) and this may be influencing the soil nitrogen mineralization rates in the forest sites. To include an urban lawn (turfgrass) component in the study, one time measurements of soils from the aforementioned forest sites and from urban lawn sites (no fertilization, no irrigation) were collected in 2012. Urban forest sites and urban lawns sites do not differ in their potential carbon mineralization rates, potential net total nitrogen mineralization rates or microbial biomass carbon and nitrogen contents. However, lawns have a higher potential net nitrification rate compared to urban forests.

Earthworms increase soil microbial biomass carrying capacity and nitrogen retention in northern hardwood forests

Earthworms have been shown to produce contrasting effects on soil carbon (C) and nitrogen (N) pools and dynamics. We measured soil C and N pools and processes and traced the flow of 13C and 15N from sugar maple (Acer saccharum Marsh.) litter into soil microbial biomass and respirable C and mineralizable and inorganic N pools in mature northern hardwood forest plots with variable earthworm communities. Previous studies have shown that plots dominated by either Lumbricus rubellus or Lumbricus terrestris have markedly lower total soil C than uncolonized plots. Here we show that total soil N pools in earthworm colonized plots were reduced much less than C, but significantly so in plots dominated by contain L. rubellus. Pools of microbial biomass C and N were higher in earthworm-colonized (especially those dominated by L. rubellus) plots and more 13C and 15N were recovered in microbial biomass and less was recovered in mineralizable and inorganic N pools in these plots. These plots also had lower rates of potential net N mineralization and nitrification than uncolonized reference plots. These results suggest that earthworm stimulation of microbial biomass and activity underlie depletion of soil C and retention and maintenance of soil N pools, at least in northern hardwood forests. Earthworms increase the carrying capacity of soil for microbial biomass and facilitate the flow of N from litter into stable soil organic matter. However, declines in soil C and C:N ratio may increase the potential for hydrologic and gaseous losses in earthworm-colonized sites under changing environmental conditions.

Soil Enzymes and Microbial Activity as Influenced by Tillage and Fertilization in Wheat Production

to investigate the influence of five fertilization treatments and three tillage systems on wheat productivity, soil microbial biomass and some enzymes activity. Fertilization treatments were control (without treatment) (F1), Farmyard manure (F2), Compost (F3), Mineral fertilizers (F4) and a mixture of farmyard manure + compost + chemical fertilizers (F5). Tillage systems were no-tillage (NT), minimum tillage (MT) and conventional tillage (CT). Experiments were designed in a split plot based on randomized complete block design (RCBD) with three replications in 2010-11 and 2011-12 growing seasons. Main plots were the tillage systems while the fertilization treatments were arranged in sub plots. The highest rate of grain yield was produced in MT system under F5 treatment. CT system showed the average reduction in grain yield of about 17% than MT; while CT showed average increasing of about 4% than NT in wheat grain yield. MT and NT systems increased soil microbial biomass compared to CT. Farm yard manure or compost applications increased soil microbial biomass significantly compared with mineral fertilizer. The urease, dehydrogenase and phosphatase activities in the F4 treatment were significantly lower than in the other fertilizer treatments F2, F3, and F5. The highest value of urease activity was under NT + F2 treatment in the two years of this study.

Effect of early dry season induced by the Three Gorges Dam on the soil microbial biomass and bacterial community structure in the Dongting Lake wetland

In this study, we used the soil microbial biomass (SMB) and the bacterial community structure as indicators to determine the potential ecological responses of the Dongting Lake wetland (China) to the early dry season that has been induced by the Three Gorges Dam (TGD), the largest hydroelectric project in the world. We measured the soil properties, SMB and bacterial community structure for samples E0, E20 and E40 (for which the dry season arrived early by 0, 20 and 40 days, respectively). The results indicated a significant increase in SMB as the dry season occurred increasingly earlier. The microbial biomass carbon (MBC) was used as a representative for the SMB and increased for the samples in the following order: E0<E20<E40. The bacterial 16S rDNA gene copy number changed similarly to the MBC. Significant changes were also observed in the soil bacterial community structure. The bacterial community structure of E40 was more diverse than that of E20, which was similar to that of E0. The relationship between the bacterial community composition and the soil properties was evaluated by redundancy analysis (RDA). The results indicated that the lead time of the dry season was the controlling influence on the soil bacterial community structure.

CO2 enrichment and N addition increase nutrient loss from decomposing leaf litter in subtropical model forest ecosystems.

As atmospheric CO2 concentration increases, many experiments have been carried out to study effects of CO2 enrichment on litter decomposition and nutrient release. However, the result is still uncertain. Meanwhile, the impact of CO2 enrichment on nutrients other than N and P are far less studied. Using open-top chambers, we examined effects of elevated CO2 and N addition on leaf litter decomposition and nutrient release in subtropical model forest ecosystems. We found that both elevated CO2 and N addition increased nutrient (C, N, P, K, Ca, Mg and Zn) loss from the decomposing litter. The N, P, Ca and Zn loss was more than tripled in the chambers exposed to both elevated CO2 and N addition than those in the control chambers after 21 months of treatment. The stimulation of nutrient loss under elevated CO2 was associated with the increased soil moisture, the higher leaf litter quality and the greater soil acidity. Accelerated nutrient release under N addition was related to the higher leaf litter quality, the increased soil microbial biomass and the greater soil acidity. Our results imply that elevated CO2 and N addition will increase nutrient cycling in subtropical China under the future global change.

Interaction matters: Synergy between vermicompost and PGPR agents improves soil quality, crop quality and crop yield in the field

Organic amendments not only promote soil quality and plant performance directly but also facilitate the establishment of introduced microbial agents. A field experiment with a fully factorial design was conducted using three levels of vermicompost (without vermicompost, low dose of 15Mgha−1 and high dose of 30Mgha−1), with and without plant growth-promoting rhizobacteria (PGPR) to investigate their effects in a tomato – by spinach rotation system. Our results demonstrated that applying PGPR alone had no effect on soil properties and crop performance. Vermicompost enhanced the beneficial effects of PGPR on both soil and crop, with the extent of promotion depending on the dose of vermicompost and crop types. In the presence of vermicompost, PGPR significantly (P<0.05) reduced soil carbon and nitrogen but increased soil microbial biomass carbon and nitrogen. PGPR also significantly increased the yield of tomato and spinach under the low dose of vermicompost, but only significantly increased tomato yield under the high dose of vermicompost. There were strongly synergistic effects between vermicompost and PGPR on crop quality, with crop nitrate concentration being significantly decreased, while the vitamin C in tomato and soluble protein in spinach was significantly increased. Our results revealed the high potential of integrating vermicompost and microbial agents to substitute for regular chemical fertilization practices.

26年长期施肥对土壤微生物量碳、氮及土壤呼吸的影响研究

Soil microbial properties play important roles in soil quality changes and nutrition cycling. The relationship between soil microbial properties and soil quality changes as a result of climate conditions,soil types,tillage and fertilizer.Lots of studies had been done; however,there are not too many reports on loessial soil. Loessial soil is one of the main types of soil on loess plateau. The study about loessial soil plays an important role in getting better soil environment and increasing productivity of dryland on loess plateau. In this paper,the relationship between soil quality and soil microbial properties such as soil microbial biomass carbon,soil microbial biomass nitrogen and soil basal respiration was studied in order to illustrate the function of soil microbial properties as bio-indicators of soil health. The long-term experiment was set up in1984 in Changwu county,Shaanxi province,China. We collected samples from the 0—20 cm soil zone of the long-term wheat cultivation and fertilization system. Nine treatments were carried out in this study: 1) fallow( F); 2) no fertilization as control( CK); 3) nitrogen( N); 4) phosphorus( P); 5) manure( M); 6) nitrogen + phosphorus( NP); 7)phosphorus + manure( PM); 8) nitrogen + manure( NM); 9) nitrogen + phosphorus + manure( NPM). The chemical properties such as p H,organic matter,total nitrogen,and total phosphorus content were analyzed in order to determine to the effects of long-term wheat cultivation and fertilization on soil nutrients. The soil microbial biomass carbon,soil microbial biomass nitrogen,basal respiration and the derivative indices of the arable soil in different long-term fertilization systems were also analyzed. The results showed that different fertilization on loessial soil in 26 years significantly affected soil chemical and microbial properties. Long-time combined application of organic and mineral fertilizers had more effect on soil organic matter,total nitrogen and total phosphorus content than mineral fertilizers alone. All these properties in treatment with fertilizers input NPM were the highest. In different fertilization treatments,the contents of soil microbial biomass carbon changed between 254.65 mg / kg and 745.26 mg / kg,and the contents of soil microbial biomass nitrogen changed from 31.70 mg / kg to 120.54 mg / kg. Long-term fertilization and planting increased the content of soil microbial biomass carbon and soil microbial biomass nitrogen. Especially, organic fertilizers can significantly enhance soil microbial biomass content.Compared with CK,the treatments with organic fertilizers input increased soil microbial biomass carbon,soil microbial biomass nitrogen and soil basal respiration. The soil basal respiration of treatments with organic fertilizer was increased by15.91% to 75.73%. In the meantime chemical fertilizer had no promotion on the soil basal respiration,and decreased the metabolic quotient. Some of soil microbial properties( Soil microbial biomass carbon,Soil microbial biomass nitrogen,Soil basal respiration) were significantly correlated with soil organic matter and soil total nitrogen contents. Soil basal respiration was also significantly correlated with soil total phosphorus content. The correlations between microbial quotient and soil nutrients,metabolic quotient and soil nutrients were not obvious. These results indicate that soil microbial properties reflect the changes of soil quality and thus can be used as biological indices in the evaluation of soil fertility.

Effects of biochar amendments on soil microbial biomass and activity.

Environmental benefits reported in the literature of using biochar as a soil amendment are generally increased microbial activity and reduced greenhouse gas (GHG) emissions. This study determined the effects of amendment with biomass feedstocks (spent coffee grounds, wood pellets, and horse bedding compost) and that of biochars (700°C) produced from these feedstocks on soil microbial biomass (C and N) and activity. Soils were amended with these substrates at 0.75% by weight and incubated for up to 175 d under laboratory conditions. Biochar residual effects on soil microbial activity were also studied by amending these soils with either ammonium nitrate (NHNO, 35 mg N kg) or with glucose (864 mg C kg) plus NHNO. Soil microbial biomass C and N, net N mineralization, and CO, NO, and CH emissions were measured. Amendment with biomass feedstocks significantly increased soil microbial biomass and activity, whereas amendment with the biochars had no significant effect. Also, biochar amendment had no significant effect on either net N mineralization or NO and CH emissions from soil. These results indicate that production of biochars at this high temperature eliminated potential substrates. Microbial biomass C in biochar-amended and unamended soils was not significantly different following additions of NHNO or glucose plus NHNO, suggesting that microbial access to otherwise labile C and N was not affected. This study shows that biochars produced at 700°C, regardless of feedstock source, do not enhance soil microbial biomass or activity.

Soil microbial responses to winter legume cover crop management during organic transition

Legume cover cropping has been widely used as an efficient strategy to improve soil fertility. Although this management practice is important to resolve N deficiency for the transition from conventional to organic production systems, optimization is necessary to determine legume cover crop species and termination methods. This study used soil microbial properties and processes to evaluate the suitability of several legume cover crops and termination methods for organic transition in southeastern USA. Soil samples were taken from two newly-established study sites, each containing 12 treatments of three termination methods (disk, flail, and spray) and four cover types (no cover crop, Austrian winter pea, hairy vetch, and crimson clover). Compared to disking and spraying, flail mowing significantly increased soil microbial biomass C by ∼17%, C mineralization by ∼25%, N mineralization by ∼16%, and nitrification potential by ∼36%, 12 weeks after cover crop termination. However, cover cropping only stimulated nitrification potential, but not C and N mineralization. Furthermore, the activities of soil enzymes (exoglucanase, β-glucosidase, and β-glucosaminidase) appeared to be more responsive to cover types than to termination methods. Among three cover crops, Austrian winter pea showed the greatest positive effects on nitrification potential, β-glucosidase, and β-glucosaminidase. The ratio of C mineralization to microbial biomass C also differed with cover types, being lowest in Austrian winter pea. Our results indicated that legume species even with small differences in C-to-N ratio and lignin and cellulose contents could have varied effects on soil microbial properties and processes. Nitrification potential, representing the function of a small group of soil microbial community, was proved to be sensitive to both legume species and termination methods.

Short-term effects of nitrogen deposition on soil microbial biomass in Calluna heathlands NW Spain: critical loads

We evaluate the short-term effects of different N deposition loads on nutrient dynamic of soil microbial biomass in Cantabrian heathlands. A surplus of 10 kg N ha-1 yr-1 above N background deposition was required to increase soil microbial biomass N content in old Calluna heathlands, while a surplus of 20 kg N ha-1 yr-1 was required in young ones. The increase of atmospheric N deposition showed no change in soil microbial biomass C content. This caused a decrease in C:N ratio with the highest N deposition loads, being linked to a bacterial biomass dominance against fungal dominance.

Increase of fast nutrient cycling in grassland microcosms through insect herbivory depends on plant functional composition and species diversity

Nutrient cycling in terrestrial ecosystems is affected by various factors such as plant diversity and insect herbivory. While several studies suggest insect herbivory to depend on plant diversity, their interacting effect on nutrient cycling is unclear.In a greenhouse experiment with grassland microcosms of one to six plant species of two functional groups (grasses and legumes), we tested the influence of plant species richness (diversity) and functional composition on plant community biomass production, insect foliar herbivory, soil microbial biomass, and nutrient concentrations in throughfall. To manipulate herbivory, zero, three or six generalist grasshoppers (Chorthippus parallelus) were added to the plant communities.Increasing plant species richness increased shoot biomass and grasshopper performance, without significantly affecting root biomass or insect herbivory. Plant functional composition affected all of these parameters, e.g. legume communities showed the highest shoot biomass, the lowest grasshopper performance and suffered the least herbivory. Nutrient concentrations (dissolved mineral N, PO4‐P, SO4‐S) and pH in throughfall increased with herbivory. PO4‐P and pH increases were positively affected by plant diversity, especially under high herbivore pressure. Plant functional composition affected several throughfall variables, sometimes fully explaining diversity effects. Increasing plant diversity tended to increase soil microbial biomass, but only under high herbivore pressure. Faeces quantities strongly correlated with changes in pH and PO4‐P; frass may therefore be an important driver of throughfall pH and a main source of PO4‐P released from living plants. Our results indicate that insect herbivory may significantly influence fast nutrient cycling processes in natural communities, particularly so in managed grasslands.

Influence of long-term fertilization on soil microbial biomass, dehydrogenase activity, and bacterial and fungal community structure in a brown soil of northeast China.

In this study, the effect of mineral fertilizer and organic manure were evaluated on soil microbial biomass, dehydrogenase activity, bacterial and fungal community structure in a long-term (33 years) field experiment. Except for the mineral nitrogen fertilizer (N) treatment, long-term fertilization greatly increased soil microbial biomass carbon (SMBC) and dehydrogenase activity. Organic manure had a significantly greater impact on SMBC and dehydrogenase activity, compared with mineral fertilizers. Bacterial and fungal community structure was analyzed by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). Long-term fertilization increased bacterial and fungal ribotype diversity. Total soil nitrogen (TN) and phosphorus (TP), soil organic carbon (SOC) and available phosphorus (AP) had a similar level of influence on bacterial ribotypes while TN, SOC and AP had a larger influence than alkali-hydrolyzable nitrogen (AHN) on fungal ribotypes. Our results suggested that long-term P-deficiency fertilization can significantly decrease soil microbial biomass, dehydrogenase activity and bacterial diversity. N-fertilizer and SOC have an important influence on bacterial and fungal communities.Electronic supplementary materialThe online version of this article (doi:10.1007/s13213-014-0889-9) contains supplementary material, which is available to authorized users.

Long‐term outcome of nitrogen immobilization to restore endemic sand grassland in Hungary

Summary Soil nitrogen immobilization by carbon amendment is a management technique used for conservation purposes to increase the competitive ability of late‐seral plant species over early‐seral species based on their different tolerance of low soil nitrogen content. We immobilized nitrogen over six growing seasons on three ex‐arable fields with poor sandy soils in the Hungarian lowland in order to restore endemic sandy grassland. Sucrose and sawdust were applied at rates based on previous laboratory experiments using local soils. We tested the efficacy of long‐term carbon amendment for lowering soil nitrogen availability and favouring late‐seral native species over early‐seral weed species. Carbon amendments resulted in significant increase in soil microbial biomass C and reduced soil nitrogen availability after 2 years. Total vegetation cover was reduced by reducing soil nitrogen availability, but total species richness was not impacted. Cover of early‐seral species decreased, and species richness and cover of late‐seral species increased irrespective of nitrogen immobilization. However, after 4–6 years reducing soil nitrogen availability hampered the spread of moss under vascular vegetation. Synthesis and applications. This study supports the efficacy of carbon amendment as a tool to immobilize available soil nitrogen in the upper soil layers. However, the desired impact on vegetation was not fully achieved despite application over several years. Nitrogen immobilization was most relevant to bryophytes, lacking deep root systems, which may explain the responsiveness of this group to N limitation. The different impact of N availability on the complex of early‐seral, late‐seral vascular species and that of the bryophyte layer provides opportunity for directing state transformations in arid grasslands. Bryophyte cover can be suppressed through carbon amendments in order to enhance the germination and establishment of grassland species. The advantage of the method is that it opens bryophyte cover gradually without disturbing the soil surface, possibly avoiding the establishment of invasive species. However, further studies are required for deeper insight.

Biodiesel Co-Product (BCP) Decreases Soil Nitrogen (N) Losses to Groundwater

This study compares a traditional agricultural approach to minimise N pollution of groundwater (incorporation of crop residues) with applications of small amounts of biodiesel co-product (BCP) to arable soils. Loss of N from soil to the aqueous phase was shown to be greatly reduced in the laboratory, mainly by decreasing concentrations of dissolved nitrate-N. Increases in soil microbial biomass occurred within 4 days of BCP application—indicating rapid adaptation of the soil microbial community. Increases in biomass-N suggest that microbes were partly mechanistic in the immobilisation of N in soil. Straw, meadow-grass and BCP were subsequently incorporated into experimental soil mesocosms of depth equal to plough layer (23 cm), and placed in an exposed netted tunnel to simulate field conditions. Leachate was collected after rainfall between the autumn of 2009 and spring of 2010. Treatment with BCP resulted in less total-N transferred from soil to water over the entire period, with 32.1, 18.9, 13.2 and 4.2 mg N kg−1 soil leached cumulatively from the control, grass, straw and BCP treatments, respectively. More than 99 % of nitrate leaching was prevented using BCP. Accordingly, soils provided with crop residues or BCP showed statistically significant increases in soil N and C compared to the control (no incorporation). Microbial biomass, indicated by soil ATP concentration, was also highest for soils given BCP (p < 0.05). These results indicate that field-scale incorporation of BCP may be an effective method to reduce nitrogen loss from agricultural soils, prevent nitrate pollution of groundwater and augment the soil microbial biomass.

不同灌水施肥策略对土壤微生物量碳氮和酶活性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 不同灌水施肥策略对土壤微生物量碳氮和酶活性的影响 DOI: 10.5846/stxb201405090925 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金重点项目（U1033004）；国家863计划（2011AA100504）；中国科学院战略性先导科技专项子课题（XDA05070403） Effect of different irrigation and fertilization strategies on soil microbial biomass carbon and nitrogen and enzyme activity Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:根区局部灌溉形成一个土壤水分分布不均匀的环境，影响了土壤微生物量和酶活性。为探明这种影响，在2种灌水水平（正常灌水和轻度缺水）和2种有机无机N肥配施（单施无机N肥和有机无机N肥配施）下，以常规灌溉（CI）为对照，研究分根区交替灌溉（AI）和固定部分根区灌溉（FI）对土壤微生物量C（MBC）、微生物量N（MBN）和酶活性的影响。与CI相比，AI提高拔节期土壤MBC和抽雄期土壤脲酶活性，但是降低大喇叭口期土壤MBC以及拔节期和抽雄期土壤MBN和拔节期土壤脲酶活性；FI增加抽雄期土壤转化酶活性，但是降低大喇叭口期土壤MBC和可溶性碳（DOC）以及3个时期土壤MBN。与正常灌水相比，AI下轻度亏水增加拔节期和抽雄期土壤DOC，但是降低大喇叭口期土壤MBC和拔节期土壤MBN。与单施无机N肥相比，AI下有机无机N肥配施增加拔节期土壤DOC、MBN和过氧化氢酶活性，而FI下则降低大喇叭口期土壤MBC和转化酶活性。因此，在轻度缺水和有机无机氮配施条件下，分根区交替灌溉可以提高玉米拔节期土壤微生物量碳和可溶性碳。 Abstract:Partial root-zone irrigation creates a heterogeneous soil moisture distribution that may affect soil microbial biomass and enzyme activity. In order to understand such effect, a pot experiment was conducted to investigate the effects of alternate partial root-zone irrigation (AI) and fixed partial root-zone irrigation (FI) on soil microbial biomass C (MBC), microbial biomass N (MBN) and enzyme activity when conventional irrigation (CI) as the control, under two irrigation levels (normal irrigation and mild water deficit) and two ratios of inorganic to organic N (only inorganic N and combined application of inorganic and organic N fertilizers). Compared to CI, AI increased soil MBC at the jointing stages and urease activity at the tasselling stage, but reduced soil MBC at the bell-mouthed stage, MBN at the jointing and tasselling stages and urease activity at the jointing stage. FI enhanced soil invertase activity at the tasselling stage, but reduced soil MBC and dissolved oxidized C (DOC) at the bell-mouthed stage and MBN at the three stages. Compared to normal irrigation, mild water deficit increased soil DOC at the jointing and tasselling stages, but reduced soil MBC at the bell-mouthed stage and MBN at the jointing stages under AI. Compared to only inorganic N, combined application of inorganic and organic N fertilizers increased soil DOC, MBN and catalase activity at the jointing stage under AI, but it reduced soil MBC and invertase activity at the bell-mouthed stage under FI. Therefore, alternate partial root-zone irrigation increased soil microbial biomass C and dissolved C at the jointing stage under mild water deficit and combined application of inorganic and organic N fertilizers. 参考文献 相似文献 引证文献

Soil characteristic comparison of fenced and grazed riparian floodplain wetlands in the typical steppe region of the Inner Mongolian Plateau, China.

In recent decades, degradation of ecosystem in the steppe region of the Inner Mongolia Plateau, especially in riparian floodplain wetlands, has become a significant ecological crisis. Not uncommonly, with the increasing of livestock in the Inner Mongolian steppe region, a riparian floodplain wetland is becoming a hotspot area of grazing for local herdsmen. Hence, it is essential to understand degradation mechanisms of riparian floodplain wetland ecosystems caused by extensive grazing. In this study, the spatial distribution of soil compaction, salinity, total nitrogen, total phosphorus, organic carbon, and microbial biomass C and N were investigated. The results showed that grazing led to an increase in soil compaction and soil surface salinity, which significantly lowered levels of total N, P, and TOC in the soil surface. Grazing decreased soil microbial biomass C and N concentration in the lower riparian floodplain wetland, whereas it significantly increased soil microbial biomass C and N concentration in the higher riparian floodplain wetland. Elevation differences in the riparian floodplain wetland increased spatial heterogeneity in the soil and thus resulted in different influence of grazing on wetland soils and ecosystem. Therefore, elevation differences and grazing intensity were the main factors controlling soil characteristics in the riparian floodplain wetland of this region.

生草栽培对山核桃林地土壤养分及微生物多样性影响

PDF HTML阅读 XML下载 导出引用 引用提醒 生草栽培对山核桃林地土壤养分及微生物多样性的影响 DOI: 10.5846/stxb201212171814 作者: 作者单位: 浙江农林大学 亚热带森林培育国家重点实验室培育基地;浙江省淳安县林业局,浙江农林大学 亚热带森林培育国家重点实验室培育基地,浙江农林大学 亚热带森林培育国家重点实验室培育基地 作者简介: 通讯作者: 中图分类号: 基金项目: 浙江省重点科技创新团队果品产业创新团队（2009R50033）；浙江特色干果产业提质增效关键技术集成与示范（2012GA700001）；浙江农林大学“研究生科研创新基金项目”（3122013240134） Effects of sod-cultural practices on soil nutrients and microbial diversity in the Carya cathayensis forest Author: Affiliation: The Nurturing Station for the State Key Laboratory of Subtropical Silviculture,Zhejiang A&F University,Lin’an 311300; Chun'an Forestry Bureau of Zhejiang Province, Chun'an 311700,The Nurturing Station for the State Key Laboratory of Subtropical Silviculture,Zhejiang A F University,Lin’an 311300,The Nurturing Station for the State Key Laboratory of Subtropical Silviculture,Zhejiang A F University,Lin’an 311300 Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:高强度经营导致山核桃林地土壤性质改变，设置了白三叶、黑麦草、油菜、紫云英、自然杂草和清耕（对照）6个处理，以3次重复，随机排列的2年田间试验，研究了不同生草栽培对山核桃林地土壤养分和微生物多样性的影响。结果表明：与清耕相比，生草栽培均能改善土壤养分状况，除全钾外，白三叶和紫云英处理较其他处理能显著提高土壤养分含量，其余几个处理间差异不明显；生草栽培显著提高了土壤微生物生物量碳（MBC）含量，白三叶、黑麦草、紫云英、油菜和自然杂草处理分别较清耕提高了169.6%、159.7%、144.1%、138.6% 和58.6%，差异达显著水平（P < 0.05）。6种不同处理的土壤微生物活性（AWCD）、微生物Shannon指数和均匀度指数均存在明显差异。不同处理的土壤AWCD为白三叶 > 紫云英 > 油菜 > 自然杂草 > 黑麦草 > 清耕；白三叶处理的土壤微生物Shannon指数高于其他处理；白三叶、紫云英和油菜处理的土壤微生物均匀度指数显著高于其他处理。相关性分析表明，土壤微生物活性、微生物Shannon指数和均匀度指数两两之间均达到极显著差异（P < 0.01），三者与土壤各养分指标之间未达显著差异，但表现为正相关关系。白三叶、紫云英和油菜对改善土壤微生物特性效果较好。 Abstract:Rapid development of the hickory (Carya cathayensis Sarg.) industry and excessive use of herbicides as well as other intensive management practices have resulted in serious damage to soil properties and forest vegetation. A decline in soil nutrients and a reduction in soil microbial biodiversity are often observed. To evaluate the potential of sod-culture to improve soil fertility and microbial activities of C. cathayensis forest soil, a 2-year field trial was initiated in 2010. In this study, six treatments (white clover, rye grass, oil rape seed, milk vetch, natural weeds and clean tillage (as CK)) each with three replicates were assessed in a randomized design. The effects of sod-culture treatments on soil nutrients and soil microbial biomass carbon in the C. cathayensis forest soil were measured. Changes in soil microbial diversity were also evaluated using Biolog. The results showed that there are various degrees of change in soil organic matter, available N, available K, available P, total N, total K and total P in C. cathayensis forest soil due to the different sod-culture treatments. Data indicated that except for soil total K, sod-culture treatments enhanced soil nutrient content significantly in the C. cathayensis forest soil as compared with the CK treatment. White clover and milk vetch treatments increased soil nutrient content to a greater extent than the other treatments. There was no significant difference in soil nutrient content between the remaining treatments. Sod-culture treatments increased soil microbial biomass carbon (MBC) in C. cathayensis forest soil as compared with the CK treatment. White clover, rye grass, oil rape seed, milk vetch and natural weed treatments significantly (P < 0.05) increased MBC by 169.6%, 159.7%, 144.1%, 138.6% and 58.6%, respectively. There were differences in soil microbial activity, Shannon diversity and uniformity indices between the six treatments. The Average Well Color Development sequence is as follows: white clover > milk vetch > oil rape seed > natural weeds > rye grass > CK. The Shannon index sequence is as follows: white clover > natural weeds > oil rape seed > milk vetch > rye grass > CK. The uniformity index sequence is as follows: white clover > milk vetch > oil rape seed > natural weeds > rye grass > CK. The Shannon index and uniformity index results were relatively uniform among different treatments. Using the Biolog 96 h absorbance values, principal component analysis was performed using Data Processing System software. The front nine principal components were extracted from the principal component analysis and their cumulative contribution accounted for 86.98% of the total variance. The variance contribution rates of PC1 and PC2 were 33.20% and 11.51%, respectively. The first two principal components (PC1 and PC2) were used for the analysis of soil microbial community functional diversity. The results showed that there is an obvious differentiation in the PC axis of different treatments. The PC1 axis distinguishes the white clover treatment and CK treatment from the other treatments. The white clover treatment sits on the most positive side of the PC1 axis, while the CK treatment sits on the negative side of the PC1 axis. Correlation analysis showed that there were significant differences (P < 0.01) among microbial activity, the Shannon diversity index and the uniformity index in any paired comparison, although there was no significant difference between these three indices and the soil nutrient indices, despite the fact that they were positively correlated. In conclusion, this study showed that planting white clover, milk vetch or oil rape seed will provide the best results for improving soil nutrients and microbial properties under C. cathayensis forest. 参考文献 相似文献 引证文献

Effects of relay intercropping maize on rhizosphere soil microbial ecological characteristics in capsicum fields

采用常规稀释平板法、氯仿熏蒸法、BIOLOG GN微平板反应系统及种间根系分隔技术, 以线辣椒单作(SC)为试验对照, 研究了间套作处理[玉米/线辣椒套作+根部塑料膜分隔(ICP)、玉米/线辣椒套作+根部尼龙网分隔(ICM)、玉米/线辣椒套作根部无分隔(ICN)]对线辣椒根际土壤微生物生态特征的影响。结果表明: 整个线辣椒生育期内, 各套作处理线辣椒根际土壤微生物总数与细菌总数具有相同的变化趋势, ICN和ICM处理的真菌、细菌、放线菌数量和细菌/真菌(B/F)、放线菌/真菌(A/F)比值均大于ICP与SC处理。盛果期, ICN处理根际土壤微生物量碳和微生物量氮比同处理其他生育期增加14.2%~54.0%和10.6%~54.7%。各处理土壤微生物群落<i>AWCD</i>的变化随培养时间呈现明显的"S"型曲线。间套作玉米显著提高了线辣椒根际土壤微生物群落的Shannon-Wiener指数(<i>P</i><0.05)、Simpson指数、种间相遇几率和McIntosh指数(<i>P</i><0.05), 并改变了土壤微生物对单一碳源的利用能力。线辣椒根际土壤微生物的不同多样性指数分别与其生物学产量之间存在显著或极显著正相关。说明间套作改善了土壤微生态环境。

Soil carbon dynamics as affected by long-term contrasting cropping systems and tillages under semiarid Mediterranean climate

In a dryland Mediterranean agrosystem (Sicily, Italy) a comparative study was carried out among two crop systems (wheat/wheat and wheat/bean) after 19 years under three most used tillage managements (conventional, dual layer and no-tillage), in order to ascertain the effects of those experimental factors, single and combined, on various soil organic C pools (total and extractable organic C, microbial biomass C, basal respiration). Field CO2 fluxes from soil, throughout a year, were also determined. Moreover, C input and output were assessed, as well as microbial and metabolic quotients. Tillage management more than cropping system affected the soil organic C stored in the first 15cm of soil. After 19 years, no-tillage caused a 3.6Mgha−1 increase of C content in wheat/faba rotation while of 5.6Mgha−1 in wheat monoculture. The higher soil total organic C content in wheat monoculture was ascribed to a lower quality of residues supplied (higher both C/N ratio and acid detergent fibre (ADF) content). Moreover, wheat/bean rotation increased soil microbial biomass C, basal respiration and microbial quotient, thus suggesting that crop rotation more than tillage management was the driving factor in improving soil biochemical indicators.

Conventional tillage increases soil microbial biomass and activity in the Loess Plateau, China

Land-use change can affect the quantity and quality of soil organic matter (SOM) as well as soil microbial biomass and activity. Land use in the Loess Plateau has undergone great changes in the past five decades. To understand the effects of these changes on soil chemical and biological properties in the Loess Plateau, we determined soil organic carbon (SOC), total nitrogen (TN), soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN), and basal respiration in millet cropland (MC), grazed grassland (GG) and enclosed grassland (EG). Grazing exclusion led to an increase of SOC and TN. Compared with the MC, the two grasslands had higher SOC and TN values in the 0–10 cm layer, but lower values in the 20–30 cm layer. SMBC and SMBN values in the EG were intermediate between the MC and GG. Conversion of cropland to grassland increased soil basal respiration (SR) and metabolic quotient (qCO2), while grazing exclusion resulted in higher SR but lower qCO2. The study suggests that grassland enclosure could increase SOM as well as soil microbial biomass and activity, and conventional cropland might be the optimal land-use type to maintain soil chemical and biological properties in the Loess Plateau, China.