Jongejans, Eelkevan Agtmaal, MaaikeGuo, Yuxivan der Velden, Merit...
10页
查看更多>>摘要：The current focus on intensification and maximizing productivity in agriculture can endanger soil biota and the ecosystem services they provide in such a way that it acts counterproductive and increases the dependence on external inputs. In this study, we aimed to identify the factors that are most limiting for the restoration of soil biota and their ecosystem services on sandy soils. To this end, we assessed microarthropod communities, their relationship with the aboveground food web and their effect on organic matter decomposition, in two land-use types: grasslands with agricultural land use and grasslands with nature land use. The latter are grasslands converted from agricultural land use, for the development of the Dutch National Ecological Network. For these land-use types, we took into account two main factors of disturbance: the number of years since the last tillage (i. e., plowing event), and the current grassland management (mowing or grazing). We found that the diversity of microarthropods was higher in nature grasslands than in agricultural grasslands. The abundance of microarthropods increased with time since last tillage for grasslands that were mown, but not for grasslands that were grazed. An agricultural grassland without tillage since 39 years had a microarthropod abundance similar to reference natural grasslands reported in previous research. The number of predatory beetles increased with a higher microarthropod abundance in mown grasslands, but not so in grazed grasslands. The number of fungivorous and herbofungivorous grazer microarthropods positively influenced the decomposition of soil organic matter as measured with the Tea Bag Index. Furthermore, we found a negative effect of Difenyl and total fungicide concentrations in the soil on (herbo)fungivorous grazers. Contrary to our expectations, we found more pesticide residues in nature grasslands than in agricultural grasslands. In conclusion, to restore the soil microarthropods and the ecosystem services they contribute to, the best practice is to strive for permanent grassland (without tillage) with mowing or low-intensity grazing (without compaction of the topsoil).
查看更多>>摘要：Holistic Management (HM) is claimed to increase production of plants and animals while also increasing soil organic carbon under all conditions in all habitats. Peer-review literature does not support these claims, but several studies report social benefits. Proponents of HM have criticized the small-scale of some studies (less than 2 ha), stating that production and climate benefits only emerge on large working farms (2-66 ha or larger, our size definitions). Here we summarize the conclusions from 22 peer-reviewed studies, focusing on farm-scale studies, and the few social and soil carbon studies from across the globe. Conclusions were synthesized into a diagram showing how grazing pattern (or density), stocking rate and animal type influence biology, climate resilience, and agricultural economics, as well as how HM's management component affects society. This synthesis confirms that HM's intensive grazing approach either has no effect or reduces production, as evidenced by farm-scale studies in United States of America, Argentina and South Africa, thus negating the claim by HM proponents that there is a difference between 'the science and the practice'. Seven peer-reviewed studies show that the potential for increased carbon sequestration with changed grazing management is substantially less (0.13-0.32) than the 2.5-9 t C ha-1 yr-1 estimated by non-peer-review HM literature. Five studies show that HM provides a social support framework for land users. The social cohesion, learning and networking so prevalent on HM farms could be adopted by any farming community without accepting the unfounded HM rhetoric, and governments could allocate funds to train extension agents accordingly. A future focus on collaborative adaptive farm management and other innovations will be more helpful than any further debate about grazing density.
查看更多>>摘要：Cultivation after the converting natural ecosystems to agricultural land is often accompanied by accelerated soil erosion. To better understand how land-use conversion and agricultural erosion separately affect aggregateassociated nitrogen (N) and organic carbon (OC), we examined the responses of aggregate-associated N and OC to both the converting forest to agricultural land and erosion in the agricultural region of Northeast China. Non-erosion sites in forest and agricultural land converted from forestland 60 years ago were selected to address the effects of land-use change. The sites with various erosion intensities in an eroding area of sloping cropland (i. e., non-erosion, light erosion, moderate erosion and heavy erosion) were selected to compare the effects of the erosion intensity. The measured soil metrics included the soil bulk density, water-stable aggregates, and aggregate-associated OC and N along 0-70 cm soil profiles. Converting forest to agricultural land did not significantly influence the OC and N concentrations in each aggregate, while the land-use change significantly reduced the OC and N stocks in macroaggregates but increased them in microaggregates and silt+clay fraction. However, erosion significantly decreased the OC and N concentrations and stocks in each aggregate. The changes in the OC and N stocks in aggregates were mainly due to the depletion of soil aggregates in responding to the conversion of forest to agricultural land but due to decreases in OC and N concentrations in aggregates in responding to soil erosion. Our results indicated that the effects of erosion on aggregate-associated OC and N were greater compared with the effects of converting forest to agricultural land in this Mollisol region.
Pereira, Gislaine SilvaAngnes, GracieleFranchini, Julio CezarDamian, Junior Melo...
11页
查看更多>>摘要：The assessment of impacts of GHG to mitigate emissions in Brazil is a significant challenge for the expansion of integrated cropping systems. In Brazil, most studies on integrated cropping systems were conducted in tropical regions and evaluated N2O fluxes, important GHG due to its global warming potential. However, the dynamics of N2O fluxes of these systems in subtropical climate conditions in Brazil are still unclear. Thus, we investigated N2O emissions under integrated cropping systems and monoculture systems and evaluated N2O fluxes in five consolidated systems: cropland, integrated crop-forest (ICF), pasture, integrated livestock-forest (ILF), and eucalyptus. N2O emissions were monitored weekly using six manual static chambers for each agricultural system. Soil-weather variables were observed consecutively during N2O sampling. We assessed the relation between soil moisture, water-filled porous space (WFPS), rainfall, soil NO3-, and soil NH4+ with N2O. Our results showed that seasonal water availability influenced N2O fluxes in all five systems. Fertilization with N increased N2O daily fluxes in cropland and ICF (N2O maximum from 30 to 50 mu g N m(-2) h(-1)). However, cumulative N2O in the second season was lower than the first season to all evaluated systems. Cropland, ICF, and eucalyptus showed an increase of more than 50% of cumulative N2O emissions compared to the dry to the rainy season, while pasture and ILF presented an increase of more than 200% of cumulative N2O from one season to another. However, the absolute cumulative value was higher for cropland, ICF, and eucalyptus than pasture systems. Thus, the use of annual crops or just monoculture could increase N2O fluxes due to the influence of weather-soil variables. The results showed that N2O emissions were similar between ICF and ILF systems and between cropland, pasture, and eucalyptus. Therefore, integrated cropping systems offer potential for reduced N2O losses to the atmosphere and may support national and international climate change initiatives to reduce GHG emissions in agriculture.
查看更多>>摘要：Foundation species strongly influence other organisms and declines in foundation species due to disturbance can have impacts that extend throughout communities. Spinifex grasses (Triodia spp.) are foundation species of arid Australia that provide resources to many birds, mammals, reptiles and invertebrates. We tested drivers of Triodia scariosa presence and abundance at local and landscape scales using a Bayesian structural equation model and species distribution modelling, based on the mapped distribution of 11,887 spinifex plants in remnant vegetation across a similar to 12,000 km(2) agricultural region. At the local scale (<1 km), there was a negative effect of soil phosphorus on spinifex abundance, particularly when the prevalence of other grasses was high. These results suggest that the combination of other grasses and nutrient enrichment promote hostile conditions for spinifex in small agricultural remnants, possibly through altered competitive interactions. However, at the landscape scale (100 + km), there was a positive effect of phosphorus on spinifex abundance, reinforcing the importance of multi-scale studies. Spinifex presence at the landscape scale was best determined by proximity to nature reserves. Sites closest to reserves were cleared later than more distant sites, which suggests a trajectory of decline consistent with an extinction debt. Our results correspond with a global phenomenon of delayed biodiversity loss and identify key threats to foundation species in human-dominated landscapes. Given that our proposed mechanisms of loss, nutrient enrichment and possible competition are widespread in agricultural regions throughout the world, understanding how to mitigate threats to foundation species should be a priority.
Cabodevilla, XabierWright, Alexander D.Villanua, DiegoArroyo, Beatriz...
8页
查看更多>>摘要：Assessing the effects of agricultural intensification on biodiversity is critical for developing effective management plans for farmland conservation. Among other factors, the direct and indirect impacts of irrigation on wildlife have yet to be thoroughly studied despite significant increases in the surface area of irrigated farmlands since the mid-twentieth century (currently greater than 300 million hectares worldwide). Here, we evaluate the impact of irrigation on bird species occurrence patterns using a BACI (Before-After Control-Impact) design. Our study occurs in a 100 km(2) area with rainfed agriculture in the Mediterranean region of northern Spain. We analysed a 13-year dataset comprised of the 47 most common bird species in the region using a multi-species hierarchical occurrence model. We examined how the implementation of irrigation in a rain-fed farmland area altered the local bird community, identifying which species were negatively or positively impacted by changes to the local ecosystem. The implementation of irrigation had an overall negative impact on the bird community, with occurrence rates of most species (55%) decreasing and only a small fraction (11%) increasing after the onset of irrigation, leading to an overall reduction in site-level species richness. Irrigation had the most detrimental impact on farmland birds (including steppe birds, which are of high conservation concern), but also had negative effects on forest, shrubland, and non-specialist bird species that occur frequently in rainfed agricultural environments. The observed negative impacts on bird occurrences are likely due to the loss of nesting and foraging habitat arising from shifts in crops and/or loss of fallow lands associated with irrigation. The fact that only a few species responded positively to the implementation of irrigation suggests that in the long-term irrigation may lead to substantial negative changes in local bird communities, with less diversity and a lack of ecologically important farmland species. Irrigation schemes should thus be implemented carefully, avoiding areas with high species richness or high densities of endangered species. In cases where irrigation cannot be avoided, promoting diverse agrosystems, avoiding monocultures, and including interspersed rainfed crops and fallow lands may help to mitigate negative effects on local bird communities and their ecosystems.
查看更多>>摘要：In the past two decades, conversion of forests to rubber (Hevea brasiliensis) plantations has spread widely in continental Southeast Asia. In addition to the effect of the establishment of new rubber plantations, the impact of the replanting of rubber trees, i.e., second-rotation plantation establishment, on the soil organic carbon (SOC) pool is unknown because of the short history of land management at such sites. We examined whether the firstrotation rubber plantation (RUB_1st) soils have more of a legacy effect from previous natural forests than the second-rotation plantation soils in Cambodia, so as to improve SOC stock estimates for a series of land use changes in a tropical moist climate zone, e.g., the lowlands of continental Southeast Asia. The total SOC stock, estimated for soil masses equivalent to 0-30 cm depth, was larger in natural forest (FOR) plots (52.7 MgC ha- 1) than in RUB_1st (38.4 MgC ha- 1), early-stage second-rotation plantation (RUB_2nd_A1-6; tree age <= 6 years; 37.2 MgC ha- 1), and middle-stage second-rotation plantation (tree age >6 years; 33.9 MgC ha- 1) plots. Values for factors related to SOC dynamics, such as the mass and carbon/nitrogen (C/N) ratio of leaf litter, soil C/N ratio, soil aluminum content, and bulk density of coarse plant residue (>2 mm), were also higher in FORs than in the rubber plantations. The SOC pools in both high- and low-density fractions of topsoil were lost largely within the first 10 years of forest-rubber plantation conversion. The loss of SOC in the low-density fraction in the RUB_1st might have been compensated to some extent by the remaining plant residue in these former forests. Although weeding resulted in the mixing of temporarily growing C4 grasses with soil in RUB_2nd_A1-6 plots, these grasses might have contributed minimally to the SOC pool in the long term, as reflected by C stable isotope ratios. Accordingly, we presented a conversion factor of SOC stock as 0.66 +/- 0.18 for the 9-year transition period from forests to rubber plantations on a flat topography in a tropical moist climate zone of continental Southeast Asia, and concluded that the replanting of old rubber plantations should take priority over the forest-rubber plantation conversion as possible to reduce the emission of greenhouse gas under the land use change.
Tavakkoli, EhsanFang, YunyingVan Zwieten, LukasRose, Michael T....
14页
查看更多>>摘要：Occasional one-time tillage (strategic tillage, ST) is an effective tool for managing weeds and crop diseases in no-till and conversative farming systems. However, there is limited understanding of the impacts of ST on soil microbiome and their associated soil processes, particularly in dryland agriculture. This study aims to quantify the effect of one-off ST - after three years - on soil microbiomes and functions in a long-term no-till farming system under crop stubble and fertilizer management practices. The results showed that ST had marginal effects on microbial richness and diversity, enzyme activities, and catabolic function, but significantly affected the abundance of some microbial taxa (Actinobacteria, Firmicutes, Verrucomicmbia, Basidiomycota and Ascomycota) that are relevant to carbon (C) degradation. Stubble retention, regardless of tillage and fertilizer management, mainly increased the abundance of copiotrophs such as Proteobacteria (e.g., Rhizobiales) and Actinobacteria (e.g., Streptomyces and Micromonosporaceae), and affected Ascomycota and Basidiomycota. Among the management practices, stubble retention was the main factor that contributed to increased richness and diversity of the soil bacterial and fungal community. Supplementary fertilizer application, regardless of tillage and stubble management had minimal impact on bacterial and fungal richness and diversity, enzyme activity and catabolic function. The variation in bacterial community structure was influenced mainly by soil pH (c.a. 10%), while only a small but significant effect (< 7%; P = 0.001) was attributed to tillage and stubble management. Wheat grain yields ranged between 5 and 5.3 t ha(-1) and were not affected by tillage, stubble, nor fertilizer management practices. Similarly, these management practices did not influence total soil C or nitrogen concentrations. Our findings show that strategic tillage, when used to address specific constraints in no-till systems in dryland agriculture, does not have a significant effect on total soil C, microbial ecology nor catabolic function.
查看更多>>摘要：Agricultural intensification has caused severe declines in ground-dwelling arthropods and associated ecosystem services. The conservation and re-establishment of semi-natural habitats in agricultural landscapes represent widely accepted measures to counter these declines. The effectiveness of these measures nonetheless varies between target taxa and their functional traits, while also being affected by local management. Here, we studied how species richness and abundance of different functional groups of carabid beetles and spiders in apple or-chards were affected by landscape complexity (% semi-natural habitat) and local management intensity (mowing and soil total nitrogen (STN) content). Both abundance and species richness of non-carnivorous carabids and carabids overall were negatively affected by STN, while the abundance of carnivorous carabids and carabids overall was affected by interactive effects of mowing and landscape complexity, showing a positive response to mowing where semi-natural habitats are scarce, but negative responses in landscapes with a higher proportion of semi-natural habitats. The abundance of ground-hunting spiders and spiders overall was generally positively related to % semi-natural habitats, while the abundance of web-building spiders and the species richness of ground-hunting spiders showed a positive correlation with STN at landscapes with a low or medium abundance of semi-natural habitats, but a negative correlation where semi-natural habitats were more abundant. Non-carnivorous carabid diversity benefitted from low nitrogen application, while carnivorous carabid abundance benefitted from mowing intensity especially in simple and structurally homogenous agricultural landscapes. Both web-building and ground-hunting spiders positively responded to low nitrogen applications and intermediate landscape complexity. Overall, a low local management intensity promoted carabid beetles, while spiders were favored by increasing landscape complexity. We conclude that taxon-and functional group-specific, multi-scale conservation strategies are therefore required to conserve invertebrate predators in apple orchards.
Weekers, TimothyMarshall, LeonLeclercq, NicolasWood, Thomas James...
10页
查看更多>>摘要：Commercial apple production relies on managed honey bees (Apis mellifera) for pollination, and on intensive management for pest control. Previous studies have highlighted the potentially detrimental effects of intensive crop management on wild bee diversity in agroecosystems, potentially jeopardizing the pollination services they provide. However, the extent to which honey bee dominance and crop management interact under field-realistic conditions and drive the structure of wild bee assemblages has not been investigated so far. In this study, we measured species richness, as well as the functional and phylogenetic diversity of wild bee assemblages in 36 paired organic and non-organic apple orchards during their flowering season and along a geographic gradient across western Europe. Our results show a strong significant and negative association between honey bee dominance and all wild bee diversity metrics, regardless of local management. Semi-natural habitats had a significant and positive effect on functional diversity, while urbanization and crop cover around the orchards showed no effect on all measured diversity metrics. A greater number of species exhibited less common, or frequent, combinations of functional traits at sites with high honey bee dominance, especially larger bee species with longer tongues. Collectively, we show that wild bee diversity decreases with increasing honey bee dominance, and that this negative association is not buffered by alternative (i.e., organic) management practices in commercial apple orchards. Although organic farming can bring about biodiversity benefits, our study demonstrates that, in the context of commercial apple production, other measures are needed to enhance and harness biodiversity for sustainable and profitable crop production. In particular, a lowered reliance on honey bees and a redesign of orchards through configurational crop heterogeneity and/or the restoration of in-field semi-natural elements are required beyond agricultural input substitution.
NSTL
Elsevier