Potter, Teal S.Vereecke, LeaLankau, Richard A.Sanford, Gregg R....
9页
查看更多>>摘要：Long-term, systems-based experiments have previously demonstrated how different cropping systems change soil physiochemical properties and, less commonly, soil microbial communities. These long-term experiments allow for isolating the effects of management on soil microbial communities by minimizing variability in soil type, climate, and short-term effects of management intra-annual variability, and thus are able to inform best practices for regional cropping systems. In this study we address whether soil microbial communities are uniquely affected by upper Midwest US cropping systems' management in a 26-year-old trial and examined how well microbial community responses to management track observed changes in soil physiochemical properties. We found that microbial biomass was highest in continuous pasture, lowest in continuous corn, and intermediate in alfalfabased dairy forage rotations for both fungi and bacteria. Fungal taxonomic richness exhibited the same trend, but bacterial richness did not differ among cropping systems. Microbial community composition differed significantly among the cropping systems but could not be further explained by physical or chemical differences linked to particular management practices. We conclude that upper Midwest U.S. cropping systems cultivate distinct soil microbial communities, justifying further research on proximate drivers that cause the observed patterns and the consequences of altered microbial communities.
查看更多>>摘要：The application of nitrogen (N) fertilizer and straw (S) is a common practice in rice cultivation. However, the dynamic changes in the long-term effects on methane (CH4) and nitrous oxide (N2O) emissions and soil organic carbon (SOC) and total nitrogen (STN) sequestration rates are poorly documented. A field experiment was performed in the years of 1-2, 6-7 and 12-13 in China with three treatments: no N or S (-N-S), 300 kg N ha(-1) without S (+N-S), and 300 kg N ha(-1) combined with 4.8 t ha(-1) S (+N+S). Compared with -N-S, CH4 emissions in +N-S varied from a negative effect in years 1-2 (-11.3%) to a positive effect in years 12-13 (7.6%). However, a constant increase was found in +N+S by 3.7, 15.8 and 7.6 times in years 1-2, 6-7 and 12-13, respectively. For N2O emissions, +N-S relative to -N-S increased by 5.4-8.9 times, and +N+S increased the emissions by from 3.0 to 5.2, and to 17.3 times, respectively. Therefore, the global warming potential (GWP) of CH4 and N2O emissions in +N+S was 3.3-3.7, 7.7-14.3 and 5.8-7.8 times higher than that in +N-S and -N-S, respectively. The grain yield of +N+S ranged from 5.6 to 10.0 t ha(-1), 30-56% and 42-71% higher than that in +N-S and -N-S. Moreover, the SOC sequestration rates of +N+S decreased from the values of 2.7 to1.6 and to 0.4 t C ha(-1) yr(-1), respectively, which were 15-80% and 17-73% higher than those of +N-S and -N-S. Compared to -N-S, the +N-S and +N+S increased STN sequestration rates by 0.01-0.06 and 0.03-0.05 t N ha(-1) yr(-1), respectively. The findings suggest that the positive effects of N and S on the GWP and STN sequestration showed an upward and then downward trend, while the SOC sequestration exhibited a continuous decline.
查看更多>>摘要：Many insects have a crucial role as pollinators in both natural ecosystems and agricultural systems. Reports of declining pollinator populations highlight the question how we can support them. Next to semi-natural habitat, different land use types can provide resources for pollinators. However, whether and how different cultivars of pollinator-dependent crops support pollinator populations has not been studied to date. This preliminary study investigated how the abundance of Osmia cornuta and the richness, abundance and community composition of wild pollinators (i.e. wild bees and hover flies) fluctuates throughout the bloom period of three sequentially flowering sweet cherry (Prunus avium) cultivars. Total pollinator richness and abundance increased throughout the bloom period of the different cherry cultivars. This increase was driven by an increase of wild bee richness and abundance, coupled with a decrease of nest-searching bees. The abundance of O. cornuta was found to in-crease throughout the bloom period. Furthermore, the composition of the pollinator community was significantly different across the different cultivars. Results of this preliminary study reflect the dynamics of wild bee emergence, mating and nest construction, which results in an increase in pollinator diversity and abundance in spring. This study also provides the first evidence that sequentially flowering cultivars of a pollinator-dependent crop can provide complementary floral resources that support complementary pollinator communities. Given the importance of wild pollinators for crop pollination, these results have implications for crop production and pollinator persistence in agricultural landscapes.
Image, MikeGardner, EmmaClough, YannSmith, Henrik G....
15页
查看更多>>摘要：Agri-environment schemes are programmes where landholders enter into voluntary agreements (typically with governments) to manage agricultural land for environmental protection and nature conservation objectives. Previous work at local scale has shown that these features can provide additional floral and nesting resources to support wild pollinators, which may indirectly increase floral visitation to nearby crops. However, the effect of entire schemes on this important ecosystem service has never previously been studied at national scale. Focusing on four wild pollinator guilds (ground-nesting bumblebees, tree-nesting bumblebees, ground-nesting solitary bees, and cavity-nesting solitary bees), we used a state-of-the-art, process-based spatial model to examine the relationship between participation in agri-environment schemes across England during 2016 and the predicted abundances of these guilds and their visitation rates to four pollinator dependent crops (oilseed rape, field beans, orchard fruit and strawberries). Our modelling predicts that significant increases in national populations of ground-nesting bumblebees and ground-nesting solitary bees have occurred in response to the schemes. Lack of significant population increases for other guilds likely reflects specialist nesting resource requirements not wellcatered for in schemes. We do not predict statistically significant increases in visitation to pollinator-dependent crops at national level as a result of scheme interventions but do predict some localised areas of significant increase in bumblebee visitation to crops flowering in late spring. Lack of any significant change in visitation to crops which flower outside this season is likely due to a combination of low provision of nesting resource relative to floral resource by scheme interventions and low overall participation in more intensively farmed landscapes. We recommend future schemes place greater importance on nesting resource provision alongside floral resource provision, better cater for the needs of specialised species and promote more contiguous patches of semi-natural habitat to better support solitary bee visitation.
查看更多>>摘要：Haitian watersheds suffer from a lack of environmental management and the absence of conservation practices, which impairs natural resources and agricultural productivity. This is aggravated by harvesting trees to compensate for reduced crop production and income. Deforestation can further deteriorate the natural and agricultural systems by increasing the temporal variability of water availability, often realized in the forms of floods and droughts. The goal of this study was to determine the effects of both deforestation and afforestation on water resources and agricultural productivity. We selected the Courjolle River watershed and its downstream irrigation districts because they represent the linkage between the upstream forest and downstream agricultural areas. Watershed hydrology and dry bean growth were simulated with the Soil and Water Assessment Tool (SWAT) model and the CSM-CROPGRO-Dry bean model of the Decision Support System for Agrotechnology Transfer (DSSAT). The parameters for both models were calibrated to streamflow and dry bean growth measurements that were made in the study areas. Deforestation and afforestation scenarios were developed based on an understanding of the local landscape. The modeling experiment showed that deforestation could decrease water availability and stability, causing a decrease in dry bean production, while afforestation had the opposite effect. An increase of the afforested areas from 25% to 100% of the watershed increased the streamflow by 2-7%, compared to the current land cover, during dry periods. On the other hand, an increase in deforested areas decreased the amount of available water for downstream agricultural areas by 6-24%. Potential changes in the water availability due to the land cover changes then affected the yield of dry bean grown in the downstream irrigation areas, from - 42-24% under the deforestation and afforestation scenarios. The study demonstrated how improved hydrologic stability due to an increase in tree cover could promote agricultural production. It also showed that afforestation could be an effective way to manage both the natural and agricultural resources in Haiti, improving the environmental sustainability of the watershed and the economic sustainability of local smallholder farmers.
Berman, Manuel CastroO' Farrell, InesHuber, PaulaMarino, Damian...
21页
查看更多>>摘要：Modern agricultural practices heavily rely on the use of agrochemicals. Glyphosate based herbicides are among the most widespread agricultural supplies. The massive application of glyphosate in conventional farming, provides continuous inputs of the herbicide into the environment, unintentionally placing non-target organisms at risk. Shallow lakes immersed in agroecosystems serve as integrators of human interventions in their watersheds. Autotrophic plankton, which are key components of biogeochemical cycles and food-webs, respond quickly to anthropogenic disturbances. Here, we assessed the environmental implications and ecological consequences of agricultural land use and glyphosate contamination on phytoplankton from 52 shallow lakes scattered over 180,000 km2 across the central pampas in Argentina, which lay on areas differentially impacted by glyphosate. Indicators of glyphosate usage positively correlated with lake turbidity and Cyanobacteria abundance, and were negatively associated with Chlorophyceae diversity. Glyphosate impact indicators were also associated with higher abundance of the small-sized representatives within each major algal class, which are assumed to be better adapted to poor light conditions. Detection of the presence of GLY-transporter genes (phnD) in seston samples was associated with higher picocyanobacteria biomass and lower pico-eukaryotic algae. Our results illustrate that the observed distribution patterns of phytoplankton can be explained by the combination of the watershed's agricultural profile, conductivity, and light quality.
查看更多>>摘要：Irrigation in traditional oases in the Mena region was possible in the past via traditional techniques (foggaras, tabia) and a relative availability of water resources. To promote the development of sustainable oases, in the context of global changes and water resources scarcity and degradation, an assessment of an innovative subsurface irrigation system (Chahbani) was conducted in Saharan Jemna oasis (South of Tunisia). Irrigation water salinity (ECw) was classified brackish (ECw ranged between 3.2 dSm(-1) and 4.5 dSm(-)(1)). Field investigations were conducted during two crop years (2018, 2019) for palm trees. Capacitance sensors (Decagon 5TE) were installed at six soil depths (0.15 m, 0.40 m, 0.60 m, 0.80, 1 m and 1.20 m) for real time monitoring of soil water moisture (theta) and pore electrical conductivity (ECp). A numerical model (HYDRUS (2D/3D)) was calibrated then applied to investigate the effect of different filed irrigation amounts ((T1(F) (73% crop evapotranspiration (ETc); T2(F) (120% ETc)) and different buried diffuser optimization (opt) positions from the trunk of the palm tree (X) and soil depths (Z): (T1(opt) (X = 1.5 m and Z 0.3 m); T2(O)(pt) (X = 0.5 m and Z = 0.3 m); T3(opt) (X = 1.5 m and Z = 0.6 m); T4(opt) (X = 0.5 m and Z = 0.6 m)) on mot water uptake, yield production and soil salinity distribution. Simulation results for both field treatments T1(F) and T2(F) showed that the amount of root water uptake was always lower than 100%(ETc) with observed yield equal to 45% and 50% for T1(F) and T2(F), respectively. According to buried diffuser position scenarios, installation of the buried diffuser at the canopy of the date palm T1(opt) (X = 1.5 m) as used in Jemna oasis, showed the least calculated relative yield (37%). However, for lateral distance, X = 0.5 m, root water uptake was equal to 649 mm for T2(Opt) (Z = 0.3 m) and 855 mm for T4(Opt) (Z = 0.6 m) with relative yield equal to 54% and 71%, respectively. According to simulation results, all position scenarios showed salt accumulation on the top soil layers and leaching requirement fraction (LR) application failed to decrease salinity for 0-0.4 m soil depth. Supplemental leaching using surface irrigation is thus recommended. Further studies for irrigation with buried diffuser under arid climate and brackish water need to focus on its impact on oasis sustainability especially when used for traditional oases as irrigation system.
Chen, KeKleijn, DavidScheper, JeroenFijen, Thijs P. M....
8页
查看更多>>摘要：Managing ecosystem services might reduce the dependence of modern agriculture on external inputs and increase the sustainability of agricultural production. Insect pollinators and arbuscular mycorrhizal fungi (AMF) provide vital ecosystem services for crop production, but it has not been tested whether their effects on crop yield interact and how their effects are influenced by nutrient availability. Here we manipulated insect pollination, AMF inoculation and fertilizer application (four levels) in a randomized complete block design with potted raspberry (Rubus idaeus L.) to assess the interacting effects of these variables on crop yield. AMF inoculation increased the per-plant flower number by 33% and the fruit number by 35%, independently from insect pollination and fertilizer application. Single berry weight furthermore increased more strongly with fertilizer application rates in AMF inoculated plants than in non-inoculated plants. As a consequence, AMF inoculation boosted raspberry yield by 43% compared to non-inoculated plants. AMF inoculation increased pollinator visitation rate per plant under intermediate fertilizer levels, suggesting additional indirect effects of AMF inoculation on yield. Fruit yield of pollinated plants increased more strongly with fertilizer application rate than the yield of plants from which pollinators had been excluded. At maximum nutrient availability, the combined benefits of both ecosystem services resulted in a 135% higher yield than that of fertilizer-only treatments. Our results suggest that the benefits of ecosystem services on yield can be additive or synergistic to the effects of conventional management practices. Intensive, high-input farming systems that do not consider the potential adverse effects of management on ecosystem service providing species might risk becoming limited by delivery of ecosystem services. Proactively managing ecosystem services, on the other hand, has the potential to increase crop yield at the same level of external inputs.
Ye, GuipingFan, JianboHu, Hang-WeiZhong, Xiaojian...
12页
查看更多>>摘要：Cellulose is an essential component of plant cell walls, and one of the major constituents of soil organic matter. Decomposition of cellulose, mediated by microorganisms, is critical to the sustainable development of arable soils. However, how exogenous cellulose addition, as a surrogate for organic material amendment, influences the diversity and community compositions of soil microorganisms and their network complexity remains largely unknown. To bridge this knowledge gap, we conducted a microcosm experiment incubated with soils that had been subjected to long-term mineral or organic fertilization. Cellulose addition increased the cumulative CO2 emission in all treatments, with the highest value found in the pig manure amended soils. Cellulose addition significantly reduced the alpha diversity of bacteria and fungi across all fertilization treatments, with a more pronounced effect observed for fungi. Moreover, cellulose addition strongly altered bacterial community structure by increasing the relative abundance of copiotrophic bacteria such as Actinobacteria and Proteobacteria while reducing that of oligotrophic bacteria (e.g., Chloroflexi). Compared with no-fertilizer treatment, the influence of cellulose addition on bacterial and fungal community structure was stronger in long-term mineral or organic fertilized soils. Cellulose addition altered the relative abundance of bacterial and fungal functional groups by generally enriching microbes involved in chemoheterotrophy and suppressing those involved in methylotrophy, pathotroph, saprotroph-symbiotroph, and saprotroph-pathotroph. In addition, cellulose addition decreased soil microbial complexity and the number of potential keystone species, but did not change the key role of Chloroflexi in soil microbial network. Overall, our results demonstrated that cellulose addition decreased soil microbial diversity and network complexity, with possible short-term negative consequences for ecosystem functioning in Ultisols.
查看更多>>摘要：Grain crops are an important part of the human diet, accounting for a third of the consumed calories. Throughout human history, annual grain crops with high yields have been obtained through domestication. However, the "annual" characteristic brings associated a series of economic and environmental disadvantages, such as soil erosion or low soil resources use, that can be solved if the agriculture of annual varieties evolves towards perenniality. For this reason, there are numerous research groups dedicated to study and obtain perennial varieties of the most cultivated grain crops. In this review article, we have summarized the most important advances related to the subject, focusing on the domestication and hybridization of the most productive grains globally: wheat, rice, maize, rye and sorghum. We highlight their benefits for sustainable agriculture worldwide due to perennial grains may contribute to reducing erosion, acting avoiding carbon losses, reducing nutrient losses to waters or capturing nutrients deeper in soil when they are scarce, reducing farm costs and thus, increasing the effectiveness of agricultural grain crops. Despite perennial grain crops having disadvantages, they possess outstanding characteristics which make them resilient crops to deal with the imminent climate change. However, maintaining the perenniality trait without reducing genetic biodiversity is a great challenge of current scientific importance that must be deeply considered.
NSTL
Elsevier