SOIL EROSION IN THREE GRAZED PLANT COMMUNITIES IN NORTHEASTERN PATAGONIA

Grazing has been identified as the main cause of land degradation in Patagonia. However, land degradation is highly variable among areas, even within the same paddock. This strongly suggests that different plant communities differ in their resistance to land degradation. In this study, we have evaluated soil erosion at both microsite and community scales in coexisting plant communities subject to sheep grazing in northeastern Patagonia. Three plant communities coexist in the area: two shrub steppes dominated by Chuquiraga avellanedae Lorentz and Nassauvia ulicina (Hook. f.) Macloskie, and a grass steppe dominated by Nassella tenuis (Phil.) Barkworth. At a community scale, our results indicate that shrub steppes generally experienced soil erosion, whereas the grass steppe commonly did not show signs of soil erosion/deposition. At a microsite scale, non‐vegetated soil surface types and degraded mounds never accumulated sediments, regardless of plant community. In contrast, we found that in some sites, the intact mounds and grasses entrapped sediments, but in other sites, soil erosion prevailed. Our results highlight the fact that soil erosion measurements are scale dependent, because results at microsite and community scales often differ. When comparing among communities, grass steppe is more intensely grazed, but at the same time, it shows less evidence of past and present erosion. In contrast, the N. ulicina community showed a direct relationship between grazing and soil erosion. Finally, soil erosion was not related to grazing in the C. avellanedae community. Our results demonstrate that the grass steppe is more resistant to land degradation than shrub steppes. Copyright © 2014 John Wiley & Sons, Ltd.     

Post-Soviet agricultural change predicts future declines after recent recovery in Eurasian steppe bird populations

The socioeconomic impacts of the break-up of the Soviet Union after 1991 have resulted in massive changes in agriculture on the Eurasian (Pontian) steppe, most of which is now confined to Kazakhstan. Recent trends in agriculture are well documented but their impacts on the characteristic bird community of this vast region, which contains over 10% of the world’s remaining grasslands, are poorly understood. We modelled bird population density in a representative region in central Kazakhstan along a land-use gradient ranging from pristine steppe to arable fields and heavily grazed pastures. Long-abandoned arable fields and ungrazed pristine steppe were the most important habitats for most species, and post-1991 abandonment of arable agriculture suggests that many species have enjoyed a period of significant population growth. Livestock concentration effects, leading to high grazing pressure in small areas, are also likely to have benefitted several species of high conservation concern. However, analysis of land-use statistics and socioeconomic surveys among land managers suggest that recent and predicted future trends in agriculture in the steppe zone, particularly the reclamation of abandoned cereal fields and reduced grazing pressure, may cause populations of most species, including a number of biome-restricted species, to decline in the near future. We discuss possible conservation solutions, including improvements in the protected area system and land-sparing options.     

Historical influences on the vegetation and soils of the Martha’s Vineyard, Massachusetts coastal sandplain: Implications for conservation and restoration

Both disturbance history and previous land use influence present-day vegetation and soils. These influences can have important implications for conservation of plant communities if former disturbance and land use change species abundances, increase colonization of nonnative plant species or if they alter soil characteristics in ways that make them less suitable for species of conservation interest. We compared the plant species composition, the proportion of native and nonnative plant species, and soil biogeochemical characteristics across seven dominant land use and vegetation cover types on the outwash sandplain of Martha’s Vineyard that differed in previous soil tillage, dominant overstory vegetation and history of recent prescribed fire. The outwash sandplain supports many native plant species adapted to dry, low nutrient conditions and maintenance of native species is a management concern. There was broad overlap in the plant species composition among pine (Pinus resinosa, P. strobus) plantations on untilled soils, pine plantations on formerly tilled soils, scrub oak (Quercus ilicifolia) shrublands, tree oak (Q. velutina, Q. alba) woodlands, burned tree oak woodlands, and sandplain grasslands. All of these land cover categories contained few nonnative species. In contrast, agricultural grasslands had high richness and cover of nonnative plants. Soil characteristics were also similar among all of the woodland, shrubland and grassland land cover categories, but soils in agricultural grasslands had higher pH, extractable Ca²⁺ and Mg²⁺ in mineral soils and higher rates of net nitrification. The similarity of soils and significant overlap in vegetation across pine plantations, scrub oak shrublands, oak woodlands and sandplain grasslands suggests that the history of land use, current vegetation and soil characteristics do not pose a major barrier to management strategies that would involve conversion among any of these vegetation types. The current presence of high cover of nonnative species and nutrient-enriched soils in agricultural grasslands, however, may pose a barrier to expansion of sandplain grasslands or shrublands on these former agricultural lands if native species are not able to outcompete nonnative species in these anthropogenically-enriched sites.     

Human land use and patterns of parasitism in tropical amphibian hosts

Landscape alterations by humans can change patterns of parasite transmission. Depending on the type alteration and the life histories of parasites and hosts, parasitism may increase or decrease. To investigate whether parasitism in tropical amphibians was associated with land use change, I studied three species of amphibians, Rana vaillanti, Eleutherodactylus fitzingeri, and Smilisca puma from the Province of Heredia, Costa Rica, in the Atlantic lowlands. Frogs were collected and examined for parasites during the rainy seasons of 2001-2003 from sites in forest or clear-cut cattle pastures. The abundances of five species of parasites and parasite species richness of R. vaillanti were significantly higher in pasture habitat. A single parasite species shared by E. fitzingeri and S. puma showed a trend of increased abundance in pasture habitats. Overall, the abundances of six parasite species (three trematodes, an intestinal nematode, an encysted nematode, and a filarial nematode) were higher in pastures, while two species (trematodes) were higher in forest. This study suggests that land use activities in tropical regions affects the abundance and richness of amphibian parasites. Converting forest to pasture may impact the abundance of amphibian parasites because subsequent water quality changes (e.g. eutrophication, higher pH) often enhance habitat and resources for intermediate hosts (e.g. snails, mosquitoes) involved in parasite life cycles. Aquatic amphibians (e.g. R. vaillanti) may be particularly prone to experiencing increases in parasitism in agricultural habitats due to the positive relationship between many aquatic intermediate hosts and water quality changes associated with agricultural land use.     

Conservation management for Orthoptera in the Dadia reserve, Greece

The diversity patterns, the ecological structure and the typical species of the orthopteran assemblage in the Dadia reserve are investigated. The reserve was designed to protect the black vulture (Aegypius monachus) and other raptors. A total of 39 orthopteran species were found, including Paranocarodes chopardi, a pamphagid species with very restricted distribution. All species can be represented in a network of six complementary habitats, including open oak woodlands, agricultural fields separated with hedges, humid grasslands, as well as serpentine grasslands. The buffer zone of the reserve is far more important for Orthoptera conservation than the core areas, which host most of the black vulture nests. Management focusing on raptors is in general compatible with conservation of Orthoptera. We suggest the maintenance of forest openings in the buffer zone, the maintenance of forest heterogeneity, the enhancement of periodical livestock grazing, and the use of nine indicator species and Paranocarodes chopardi in the reserve monitoring program.     

Protected areas do not fulfil the wintering habitat needs of the trans-Saharan migratory Montagu’s harrier

Populations of migratory birds can be affected by events happening at both breeding and wintering grounds. The Sahel is a vast region holding a large number of wintering trans-Saharan migratory European birds, and current land-use changes there may represent a threat for these species. We used satellite tracking data from the migratory Montagu’s harrier to evaluate habitat use of the species during the wintering season, and whether the current network of protected areas is effective to provide their habitat needs during that season. We also developed an ecological niche model for the species in Western-Central Sahel to check if the most suitable sites are included within current protected areas. Tracked harriers occupied a large region encompassing a total of eight countries. The most preferred habitats during winter were croplands and some natural vegetation habitats, especially grasslands. Protected areas only covered a small proportion of the overall wintering grounds of tracked harriers and the most suitable areas for the species in Western-Central Sahel. Increasing the extent of preferred natural habitats within protected areas should benefit the conservation of this and probably other insect-eating raptors. However, substantial increases in extent and number of protected areas in sub-Saharan Africa are very unlike to occur. Conservation actions in the region should therefore be mostly focused on improving land use planning and management outside protected areas, specially enhancing agricultural practices to make biodiversity conservation compatible with poverty alleviation. These can be chiefly targeted at an area of <20,000 km² of very suitable habitat for these species.     

Assessment of fungal communities in soil and tomato roots subjected to diverse land and crop management systems

Effects of diverse agricultural land management practices on soil and on root colonizing fungal communities were determined through a PCR-based molecular method and a culture-dependent method, respectively, in a field location with uniform soil type. Initiated in July 2000, the management systems were: conventional tomato production, frequent tillage (disk fallow), undisturbed weed fallow, bahiagrass pasture (Paspalum notatum var. notatum ‘Argentine’), and an organically managed system including cover crops and annual applications of poultry manure and urban plant debris. Culture-dependent colony counting was used to identify and enumerate communities of root colonizing fungi and length heterogeneity polymerase chain reaction (LH-PCR) analysis of internal transcribed spacer-1 (ITS-1) profiles to characterize phylotypes in soil fungal communities. Three years after initiation of land management treatments and midway through tomato cultivation, both methods detected a high degree of similarity in fungal community composition between weed fallow and bahiagrass plots. Soil fungal communities in organically managed plots were similar to each other and distinct from communities in other land management systems while the composition of root colonizing fungal communities in organic plots was divergent. The results demonstrate that the soil fungal communities and root colonizing fungal communities were affected differently depending on land and crop management practices. Fusarium oxysporum was a dominant species in all soil and root colonizing fungal communities except those subjected to organic management practices.     

The raptor community of Central Sulawesi: habitat selection and conservation status

Diurnal raptors were surveyed in Central Sulawesi on foot in 16 sample areas, and by car along 2700 km road transects in August-September 2000. All 23 resident species were recorded and their frequency of occurrence assessed in broad habitat categories. Farmlands were unusually poor in raptors. Of their six associated species, the formerly common black kite (Milvus migrans) may be almost extirpated. Indiscriminate pesticide use is suspected to be a major factor. Wetlands and sea-coasts are limited in area and are also the most heavily disturbed natural habitats. All four piscivorous eagles were found to be rare or very local. Among them, only the grey-headed fishing-eagle (Ichthyophaga ichthyaetus) was found to be more frequent than was previously known. Excessive human fishing pressure may be the main threat, together with extensive wetland conversion into ricefields or fishponds. Forest raptors (13 species), including all Sulawesi endemic Falconiformes, were the most numerous and widespread birds of prey. Although they exhibited a fairly high tolerance to forest degradation and fragmentation (insular syndrome), their main threat is the high deforestation rate, especially the loss of the presumably more productive lowland forests.     

Changes in agricultural management drive the diversity of Burkholderia species isolated from soil on PCAT medium

In order to assess the diversity of culturable Burkholderia populations in rhizosphere and bulk soil and to evaluate how different agricultural management regimes and land use history affect this diversity, four treatments were evaluated: permanent grassland; grassland converted into maize monoculture; arable land and arable land converted into grassland. Burkholderia isolates obtained on PCAT medium were grouped in 47 clusters using 16S ribosomal RNA gene based PCR-DGGE combined with BOX genomic fingerprinting (DGGE-BOX). The distribution of the isolates in the DGGE-BOX clusters was used to calculate the Shannon diversity index per treatment. Interestingly, we observed that the Burkholderia diversity was affected by changes in the agricultural management, since the highest diversity was observed in permanent grassland and in continuous arable land. In addition, the diversity tended to be higher in the rhizosphere than in the corresponding bulk soil. The use of species abundance models indicated that rhizosphere communities had more even distributions than communities collected from the bulk soil. Identification of isolates revealed that only 2% of these belonged to the B. cepacia complex and that the majority was assigned to either (1) new Burkholderia species or (2) Burkholderia species that had originally been isolated from soil. Isolates classified as B. hospita, B. caledonica and Burkholderia sp. ‘LMG 22934’ and ‘LMG 22936’ were found mainly in the arable land, while isolates belonging to Burkholderia sp. ‘LMG 22929’ and B. phytofirmans were associated with the grassland area. Another potentially new Burkholderia species, ‘LMG 22932’, was found in both areas, in close association with the maize rhizosphere.     

Growth and competitiveness of the New Zealand tree species Podocarpus cunninghamii is reduced by ex-agricultural AMF but enhanced by forest AMF

The composition of arbuscular mycorrhizal fungi (AMF) communities found in agricultural systems has been found to be very different to that of forest. The implications of this, if any, for the restoration of indigenous forest on ex-agricultural land is poorly understood. This study investigated the effect that AMF communities isolated from ex-agricultural and forest soils have on the growth of an indigenous New Zealand tree species (Podocarpus cunninghamii). The forest AMF community was isolated from a remnant stand of P. cunninghamii forest and the ex-agricultural AMF from a retired grazing grassland. In addition, the study examined how the two AMF communities affected the competitiveness of P. cunninghamii when grown in competition with an invasive grass species (Agrostis capillaris), which is frequently dominant on ex-agricultural land in New Zealand. P. cunninghamii growth was significantly decreased by inoculation with ex-agricultural AMF compared to forest AMF. Furthermore, the forest AMF community was able to significantly increase P. cunninghamii root production when in competition with A. capillaris. The findings suggest that when attempting to restore indigenous forest on ex-agricultural land, inoculation of tree seedlings with appropriate forest AMF may improve their growth and survival.     

Birds and mammals of salt marshes and salt steppes in Southern Slovakia (CSSR)

Saline marshes and steppes along the Danube in southern Slovakia lie on the northernmost border of the complex of Central European saline soils. The ecology of the saline localities studied is outlined on the basis of 48 bird and 18 mammal species. Some birds are confined to the saline localities studied because these are relatively well conserved and extensive rather than because they are saline. The root vole (Microtus oeconomus (Pallas)), known only from the area studied, and the lizard Lacerta vivipara Jacquin, living in isolated populations in mountainous areas, are the only known vertebrate relics. Some functional aspects of the animals studied are stressed. The saline localities are threatened by reclamation for agricultural use, by fire, drainage and lowering the underground water table, but primarily by pollution from both oily water and the dumping of refuse. In order to conserve these unique communities, total protection is needed except, perhaps, from cattle-grazing on the steppes.     

Effect of agricultural land use change on community composition of bacteria and ammonia oxidizers

Purpose

Soil microbial communities can be strongly influenced by agricultural practices, but little is known about bacterial community successions as land use changes. The objective of this study was to determine microbial community shifts following major land use changes in order to improve our understanding of land use impacts on microbial community composition and functions.

Materials and methods

Four agricultural land use patterns were selected for the study, including old rice paddy fields (ORP), Magnolia nursery planting (MNP), short-term vegetable (STV), and long-term vegetable (LTV) cultivation. All four systems are located in the same region with same soil parent material (alluvium), and the MNP, STV, and LTV systems had been converted from ORP for 10, 3, and 30 years, respectively. Soil bacteria and ammonia oxidizer community compositions were analyzed by 454 pyrosequencing and terminal restriction fragment length polymorphism, respectively. Quantitative PCR was used to determine 16S rRNA and amoA gene copy numbers.

Results and discussion

The results showed that when land use was changed from rice paddy to upland systems, the relative abundance of Chloroflexi increased whereas Acidobacteria decreased significantly. While LTV induced significant shifts of bacterial composition, MNP had the highest relative abundance of genera GP1, GP2, and GP3, which were mainly related to the development of soil acidity. The community composition of ammonia-oxidizing bacteria (AOB) but not ammonia-oxidizing archaea was strongly impacted by the agricultural land use patterns, with LTV inducing the growth of a single super predominant AOB group. The land use changes also induced significant shifts in the abundance of 16S rRNA and bacterial amoA genes, but no significant differences in the abundance of archaea amoA was detected among the four land use patterns. Soil total phosphorous, available phosphorous, NO₃ ^?, and soil organic carbon contents and pH were the main determinants in driving the composition of both bacteria and AOB communities.

Conclusions

These results clearly show the significant impact of land use change on soil microbial community composition and abundance and this will have major implications on the microbial ecology and nutrient cycling in these systems, some of which is unknown. Further research should be directed to studying the impacts of these microbial community shifts on nutrient dynamics in these agroecosystems so that improved nutrient management systems can be developed.     

Microbial function in adjacent subtropical forest and agricultural soil

Soil microbial communities and their activities are altered by land use change; however impacts and extent of these alterations are often unclear. We investigated the functional responses of soil microbes in agricultural soil under sugarcane and corresponding native soil under Eucalyptus forest to additions of contrasting plant litter derived from soybean, sugarcane and Eucalyptus in a microcosm system, using a suite of complimentary techniques including enzyme assays and community level physiological profiles (CLPP). Initially agricultural soil had 50% less microbial biomass and lower enzyme activities than forest soil, but significantly higher nitrification rates. In response to litter addition, microbial biomass increased up to 11-fold in agricultural soil, but only 1.8-fold in forest soil, suggesting a prevalence of rapidly proliferating ‘r’ and slower growing ‘K’ strategists in the respective soils. Litter-driven change in microbial biomass and activities were short lived, largely returning to pre-litter addition levels by day 150. Decomposition rates of sugarcane and soybean litter as estimated via CO₂ production were lower in agricultural than in forest soil, but decomposition of more recalcitrant Eucalyptus litter was similar in both soils, contradicting the notion that microbial communities specialise in decomposing litter of the dominant local plant species. Enzyme activities and community level physiological profiles (CLPP) were closely correlated to microbial biomass and overall CO₂ production in the agricultural soil but not the forest soil, suggesting contrasting relationships between microbial population dynamics and activity in the two soils. Activities of enzymes that break down complex biopolymers, such as protease, cellulase and phenol oxidase were similar or higher in the agricultural soil, which suggests that the production of extracellular biopolymer-degrading enzymes was not a factor limiting litter decomposition. Enzyme and CLPP analyses produced contrasting profiles of microbial activity in the two soils; however the combination of both analyses offers additional insights into the changes in microbial function and community dynamics that occur after conversion of forest to agricultural land.     

Supporting wild pollinators in a temperate agricultural landscape: Maintaining mosaics of natural features and production

Pollination has received attention recently due to reported sharp declines of Apis mellifera in several locations, and it has been proposed that diverse native bee communities may be key for continued pollination of economically important crops. However, there is some inconsistency in the literature as to how these communities should best be managed. To address this issue, we collected bees from an intensively managed agricultural region in eastern Australia using blue vane traps. Both linear remnants of vegetation, which form part of a larger corridor network, and adjacent fields of native and exotic pastures, wheat, canola, and lucerne were sampled. A total of 3249 individual bees, representing four families and 36 species were collected. Highly modified environments of nectar-bearing crop supported the most species-rich bee assemblages, and the highest abundance of individual bee species. Distance from the remnants did not limit the body size of species occupying fields (up to 400 m). However, richness of bee assemblages also responded positively to the presence of conservation land in nearby areas, or the number of remnant native trees surrounding traps. Linear remnants of native vegetation contributed to assemblage heterogeneity by adding unique species to the regional pool. Our findings indicate that agricultural industries that currently rely on pollination by A. mellifera should ensure that intensive land use is complemented by untilled areas in the form of conservation land, or farm dams and scattered trees in fields, to support wild pollinators that may act as insurance against further future losses of managed hives.     

Large-scale habitat associations of birds in lowland Iceland: Implications for conservation

Iceland is responsible for many internationally important populations of breeding bird species, yet very little is currently known about how these species use the habitats available to them. Lowland areas of Iceland, in particular, have undergone significant landscape changes over the last century, such as widespread drainage of wetlands and conversion to agriculture, changes in grazing pressure and recently, extensive afforestation. The impact of these changes on breeding bird species will depend on the relative importance of different habitats for each species, and the threats facing those habitats. Here we report the results of a large-scale survey of the factors influencing patterns of habitat selection of eight populations of Charadriiform bird species throughout lowland Iceland; oystercatcher Haematopus ostralegus, golden plover Pluvialis apricaria, dunlin Calidris alpina, snipe Gallinago gallinago, whimbrel Numenius phaeopus, black-tailed godwit Limosa limosa, redshank Tringa totanus and arctic skua Stercorarius parasiticus. Ordination analyses and multiple logistic regression models are constructed to explore the components of habitats that influence the distribution of these species. Five of the eight species analysed showed significant preferences for lowland wetland habitats and four significantly selected areas containing wet features such as pools and high water tables. These results allow us to identify future conflicts in land use that are likely to result from government-supported large-scale afforestation of lowland areas and hydro-electric developments.     

Arbuscular mycorrhizal fungi in degraded typical steppe of inner Mongolia

Arbuscular mycorrhizal (AM) fungi may have some potential use in the restoration of degraded grassland through beneficial effects on plant growth and soil quality. A field investigation was conducted in three grassland sites of typical steppe in Inner Mongolia. The three plant communities, one of which was undegraded, one moderately degraded and the third severely degraded, were studied by collecting soil samples and samples of four plant species that occurred in all three sites. The percentage of root length colonized by AM fungi was estimated and the species composition and diversity of AM fungus spores recovered from the soil were determined using spore morphological characteristics. Although differences between the sites may have been due partly to other factors, it is likely that the degree of degradation was an important factor. No decline was found in the AM colonization of the roots of the indicator plant species in the moderately or severely degraded plant communities, and two plant species showed higher colonization status in the two degraded areas. Glomus geosporum and Scutellospora calospora were the dominant AM fungi in the undegraded steppe, while G. geosporum and Glomus aggregatum dominated the two degraded sites which also had low spore densities, species richness and diversity indices. However, different AM species showed different distributions among the three plant communities and the results indicate that both biotic and abiotic factors were important in determining the AMF communities, with biotic factors possibly the more important. Copyright © 2008 John Wiley & Sons, Ltd.     

Transformation of the salt structure of soils of the stony steppe during agricultural use

The salt structure and structure of salt profiles of automorphic and hydromorphic soils of stony steppes on fallow land and arable land are studied. It is shown that during agricultural use of these soils the general maintenance of salts in a profile, including that in the root-inhabited layer, increases and the type of salt changes. In cation structures the quantity of Na⁺ and, to a lesser degree, of Ca²⁺, increase, and in the anion structure CO₃²⁻ increases. It is shown that the most significant transformation of the salt mode of soils during agricultural use is observed in soils with low humidity.     

Application of the soil-ecological multiplicative index to assess suitability of Cis-Ural chernozems for cultivation with due account for economic parameters

The evolution of Russian concepts concerning the assessment of soil suitability for cultivation in relation to several campaigns on large-scale plowing of virgin steppe soils is examined. The major problems of agricultural land use in steppe areas—preservation of rainfed farming in the regions with increasing climatic risks, underestimation of the potential of arable lands in land cadaster assessments, and much lower factual yields in comparison with potential yields—are considered. It is suggested that the assessments of arable lands should be performed on the basis of the soil–ecological index (SEI) developed by I. Karmanov with further conversion of SEI values into nominal monetary values. Under conditions of land reforms and economic reforms, it is important to determine suitability of steppe chernozems for plowing and economic feasibility of their use for crop growing in dependence on macroeconomic parameters. This should support decisions on optimization of land use in the steppe zone on the basis of the principles suggested by V. Dokuchaev. The developed approach for assessing soil suitability for cultivation was tested in the subzone of herbaceous–fescue–feather grass steppes in the Cis-Ural part of Orenburg oblast and used for the assessment of soil suitability for cultivation in the southern and southeastern regions of Orenburg oblast.     

Modelling the foraging habitat selection of lesser kestrels: conservation implications of European Agricultural Policies

Cereal steppe habitat is a low intensive system that is rapidly disappearing as a result of changes in agricultural practices, and has the highest number of bird species with an Unfavourable Conservation Status of any habitat in Europe. A logistic regression model showed that the lesser kestrel, a globally threatened species, prefers to forage close to colonies, selects fields with livestock and avoids tree plantations. The conservation of this species is dependent on maintenance of extensive agriculture characterised by a rotation of cereal and grazed fallow. Abandonment of traditional agriculture and recent changes in agri-environmental programme support, which favour afforestation, are jeopardising the future of cereal steppes. Agri-environment measures are likely to be the most effective means of retaining the specific characteristics of cereal steppe habitat.     

黄土丘陵区不同土地利用方式对土壤微生物量碳氮磷的影响

为探讨植被区与土地利用方式对土壤微生物量的影响,在陕西省延河流域森林区、森林草原区和草原区采集5种土地利用方式下的土壤剖面样品(0-10cm,10-30cm),并对其微生物量碳(SMBC)、微生物量氮(SMBN)和微生物量磷(SMBP)及土壤理化性质进行了分析。结果表明,微生物量磷的含量在3个植被区中均是在农地、撂荒地中相对较高,微生物量碳、氮在森林区表现为:乔木林地>农地在森林草原区表现为:灌木林地>天然草地>乔木林地>农地>撂荒地在草原区表现为:天然草地>乔木林地>灌木林地>农地>撂荒地。相同土地利用方式下,土壤养分和微生物量在森林区最高,森林草原区次之,草原区最低。相关分析表明,微生物量碳、氮、磷、代谢熵、微生物量碳氮比与土壤养分相关性极为密切。因此,土壤微生物量能够作为评价土壤质量的生物学指标。不同植被区不同土地利用方式对土壤质量的改善作用不同,林地和天然草地作用效果好,对土壤微生物量的提高有明显的促进作用。