| 1. |
- Hoffmann, M., et al.
(författare)
-
Leaching of nitrogen in Swedish agriculture - A historical perspective
- 2000
-
Ingår i: Agriculture, Ecosystems & Environment. - 0167-8809 .- 1873-2305. ; 80:3, s. 277-290
-
Tidskriftsartikel (refereegranskat)abstract
- There is a need to examine long-term changes in nitrogen leaching from arable soils. The purpose of this study was to analyse variations in specific leaching rates (kg ha-1 per year) and gross load (Mg per year) of N from arable land to watercourses in Sweden from a historical perspective. The start of the study was set to 1865 because information on crop distribution, yield and livestock has been compiled yearly since then. The SOIL/SOILN model was used to calculate nitrogen leaching. Calculations were done for cereals, grass and bare fallow for three different soil types in nine agricultural regions covering a range of climatic conditions. Results indicate that both specific leaching rates and gross load of nitrogen in the middle of 19th century were approximately the same as they are today for the whole of south and central Sweden. Three main explanations for this were (1) large areas of bare fallow typical for the farming practice at the time, (2) enhanced mineralisation from newly cultivated land, and (3) low yield. From 1865, i.e. the start of the calculations, N leaching rates decreased and were at their lowest around 1930. During the same period, gross load was also at its lowest despite the fact that the acreage of arable land was at its most extensive. After 1930, average leaching increased by 60% and gross load by 30%, both reaching a peak in the mid-1970s to be followed by a declining trend. The greatest increase in leaching was in regions where the increase in animal density was largest and these regions were also those where the natural conditions for leaching such as mild winters and coarse-textured soils were found. Extensive draining projects occurred during the period of investigation, in particular an intensive exploitation of lakes and wetlands. This caused a substantial drop in nitrogen retention and the probable increase in net load to the sea might thus have been more affected by this decrease in retention than the actual increase in gross load. (C) 2000 Elsevier Science B.V.
|
|
| 2. |
- Alexandridis, Nikolaos, et al.
(författare)
-
Climate change and ecological intensification of agriculture in sub-Saharan Africa : A systems approach to predict maize yield under push-pull technology
- 2023
-
Ingår i: Agriculture, Ecosystems and Environment. - 0167-8809 .- 1873-2305. ; 352
-
Tidskriftsartikel (refereegranskat)abstract
- Assessing effects of climate change on agricultural systems and the potential for ecological intensification to increase food security in developing countries is essential to guide management, policy-making and future research. ‘Push-pull’ technology (PPT) is a poly-cropping design developed in eastern Africa that utilizes plant chemicals to mediate plant–insect interactions. PPT application yields significant increases in crop productivity, by reducing pest load and damage caused by arthropods and parasitic weeds, while also bolstering soil fertility. As climate change effects may be species- and/or context-specific, there is need to elucidate how, in interaction with biotic factors, projected climate conditions are likely to influence future functioning of PPT. Here, we first reviewed how changes in temperature, precipitation and atmospheric CO2 concentration can influence PPT components (i.e., land use, soils, crops, weeds, diseases, pests and their natural enemies) across sub-Saharan Africa (SSA). We then imposed these anticipated responses on a landscape-scale qualitative mathematical model of maize production under PPT in eastern Africa, to predict cumulative, structure-mediated impacts of climate change on maize yield. Our review suggests variable impacts of climate change on PPT components in SSA by the end of the 21st century, including reduced soil fertility, increased weed and arthropod pest pressure and increased prevalence of crop diseases, but also increased biological control by pests’ natural enemies. Extrapolating empirical evidence of climate effects to predict responses to projected climate conditions is mainly limited by a lack of mechanistic understanding regarding single and interactive effects of climate variables on PPT components. Model predictions of maize yield responses to anticipated impacts of climate change in eastern Africa suggest predominantly negative future trends. Nevertheless, maize yields can be sustained or increased by favourable changes in system components with less certain future behaviour, including higher PPT adoption, preservation of field edge density and agricultural diversification beyond cereal crops.
|
|
| 3. |
- Alexandridis, Nikolaos, et al.
(författare)
-
Climate change and ecological intensification of agriculture in sub-Saharan Africa – A systems approach to predict maize yield under push-pull technology
- 2023
-
Ingår i: Agriculture, Ecosystems & Environment. - 0167-8809 .- 1873-2305. ; 352
-
Tidskriftsartikel (refereegranskat)abstract
- Assessing effects of climate change on agricultural systems and the potential for ecological intensification to increase food security in developing countries is essential to guide management, policy-making and future research. ‘Push-pull’ technology (PPT) is a poly-cropping design developed in eastern Africa that utilizes plant chemicals to mediate plant–insect interactions. PPT application yields significant increases in crop productivity, by reducing pest load and damage caused by arthropods and parasitic weeds, while also bolstering soil fertility. As climate change effects may be species- and/or context-specific, there is need to elucidate how, in interaction with biotic factors, projected climate conditions are likely to influence future functioning of PPT. Here, we first reviewed how changes in temperature, precipitation and atmospheric CO2 concentration can influence PPT components (i.e., land use, soils, crops, weeds, diseases, pests and their natural enemies) across sub-Saharan Africa (SSA). We then imposed these anticipated responses on a landscape-scale qualitative mathematical model of maize production under PPT in eastern Africa, to predict cumulative, structure-mediated impacts of climate change on maize yield. Our review suggests variable impacts of climate change on PPT components in SSA by the end of the 21st century, including reduced soil fertility, increased weed and arthropod pest pressure and increased prevalence of crop diseases, but also increased biological control by pests’ natural enemies. Extrapolating empirical evidence of climate effects to predict responses to projected climate conditions is mainly limited by a lack of mechanistic understanding regarding single and interactive effects of climate variables on PPT components. Model predictions of maize yield responses to anticipated impacts of climate change in eastern Africa suggest predominantly negative future trends. Nevertheless, maize yields can be sustained or increased by favourable changes in system components with less certain future behaviour, including higher PPT adoption, preservation of field edge density and agricultural diversification beyond cereal crops.
|
|
| 4. |
- Andersson, Georg, et al.
(författare)
-
Effects of farming intensity, crop rotation and landscape heterogeneity on field bean pollination
- 2014
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 1873-2305 .- 0167-8809. ; 184, s. 145-148
-
Tidskriftsartikel (refereegranskat)abstract
- Organic farming has the potential to enhance ecosystem services such as crop pollination. However, it is not known if a similar effect can be generated on conventional farms, without reducing external inputs such as inorganic fertilizers and pesticides, by using more complex crop rotations including ley for animal fodder production. In two separate designs, both located in southern Sweden, we tested if local organic farming and the landscape proportion of conventionally managed leys, along a landscape heterogeneity gradient, affected the pollination success of field bean. The number of developed pods was higher on organic farms compared to conventional ones. Development of beans, which demands high pollination efficiency, increased with increasing landscape heterogeneity, but only on organic farms. Increasing proportion of ley on conventional farms did not significantly influence the development of beans. The number of developed pods was not affected by the proportion of ley in the landscape. Our results demonstrate that in order to maximize pollination success it is important to improve both field management and preserve semi-natural habitats in the agricultural landscape. Reducing farming intensity with conventionally managed leys does not seem to be as effective as organic farming for delivering crop pollination services. (C) 2013 Elsevier B.V. All rights reserved.
|
|
| 5. |
- Audet, Joachim, et al.
(författare)
-
Nitrous oxide emissions from streams in a Swedish agricultural catchment
- 2017
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 236, s. 295-303
-
Tidskriftsartikel (refereegranskat)abstract
- Excess nitrogen fertiliser in agricultural soils might be leached to streams and converted to the greenhouse gas nitrous oxide (N2O). To assess the importance of N2O emissions from agricultural streams, concentration dynamics and emissions N2O emissions in streams were investigated in a 32 km2 lowland agricultural catchment located in Sweden. Dissolved N2O concentration was measured at nine occasions between December 2014 and August 2015 at nine stream stations. The stream stations represented sub-catchments with different land use characteristics with agricultural land use ranging from 0 to 63% of the area. Stream N2O percentage saturation ranged 40-2701% and showed large spatial and temporal variations. Statistical analysis using mixed models revealed that N2O concentration was significantly linked to nitrate concentration in the stream water, to the percentage arable land in the sub catchments as well as to the stream water discharge. Using two empirical equations to estimate the N2O emissions showed that streams were generally a source of N2O to the atmosphere (mean 108 and 175 mu g N m(-2) h(-1) with first and second equation). The catchment scale estimate of N2O stream emissions was compared to the estimate obtained using IPCC guidelines linking N fertilisation inputs and leaching to N2O emissions. The comparison suggested that N2O stream emission calculated using the IPCC methodology might be underestimated. A coarse estimate suggests that N2O stream emissions represent about 4% of the total N2O emissions from N-fertiliser at the catchment scale. Hence while streams covered only 0.1% of the catchment area they were of disproportionate importance as a source of N2O to the atmosphere.
|
|
| 6. |
- Bahram, Mohammad
(författare)
-
Cropping systems with higher organic carbon promote soil microbial diversity
- 2021
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 319
-
Tidskriftsartikel (refereegranskat)abstract
- Food systems need to become more sustainable. There is a need to investigate the agricultural management components that address the sustainability better. Long crop rotations are suggested to be environmentally friendly, yet, little is known how soil microbial communities may be affected by long-term rotation under organic cropping with cover crops and manure and conventional cropping with different nitrogen rates. We examined the composition and diversity of soil bacterial and fungal communities in a five-field crop rotation at the beginning and end, respectively in 2013 and 2018. Our analysis revealed that bacterial and to a lesser extent fungal diversity increased by the end of the rotation in all organic treatments and in conventional treatments with low to medium nitrogen rate (20‐100 kg of nitrogen per hectare). Conventional treatment with no added nitrogen decreased bacterial and fungal diversity. Nitrogen rate of 150 kg/ha decreased only bacterial diversity, while the impact on fungal diversity was neutral. Crop rotation significantly increased the relative abundance of bacterial taxa involved in nitrification and denitrification. Of fungal functional groups, the relative abundance of pathogenic functional groups decreased and mycorrhizal groups increased during crop rotation and especially with added cover crops. Our results suggest that crop rotation may outperform cropping systems in structuring soil microbial communities.
|
|
| 7. |
- Benegas, Laura, et al.
(författare)
-
Effects of trees on infiltrability and preferential flow in two contrasting agroecosystems in Central America
- 2014
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 183, s. 185-196
-
Tidskriftsartikel (refereegranskat)abstract
- We tested the hypothesis that trees have measurable effects on infiltrability, macroporosity, and preferential flows in agrosilvopastoral systems. Managing agricultural systems for water conservation is a critical component of sustainable systems. We investigated the relationship between infiltrability and the distance to the nearest tree, and whether differences in macroporosity can account for differences in infiltrability.In both systems, preferential soil water flows were dominant compared to matrix flow. Trees in the pasture landscape improved infiltrability and preferential flow but had no significant effect in the coffee agroforestry system. After comparing rainfall intensity and frequency data to the measured infiltrability values, we conclude that trees in the pasture system reduce surface runoff at the highest observed rainfall intensities (>50 mm h(-1)). The volcanic soils of the coffee plantation are less degraded and their high natural permeability has been maintained. Since the coffee plants at this site are established (40 years) perennial vegetation with substantial residues and extensive root systems like trees, they improve soil physical properties similarly to trees.Trees increase hydrologic services in pasture lands, a rapidly expanding land use type across Latin America, and therefore may be a viable land management option for mitigating some of the negative environmental impacts associated with land clearing and animal husbandry. However, in land management practices where understorey perennial vegetation makes up a large proportion of the cover, such as for coffee agroforestry systems, the effect of trees on infiltration-related ecosystem services could be less pronounced (C) 2013 Elsevier B.V. All rights reserved.
|
|
| 8. |
- Berg, Åke, et al.
(författare)
-
Linking occurrence and changes in local abundance of farmland bird species to landscape composition and land-use changes
- 2015
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 204, s. 1-7
-
Tidskriftsartikel (refereegranskat)abstract
- Changes in agricultural policies have caused dramatic changes in land-use in agricultural landscapes. To investigate whether such changes in land-use relate to temporal changes in bird communities a repeated inventory (1994 and 2004) of farmland birds was made in 212 point-count sites in south-central Sweden.Distinct changes in abundance of several species over the study period were recorded, abundance of the 16 studied species decreased by 23%. The decline was significant for eight species, while two species increased significantly. Persistence and colonisation models suggested similar species-habitat relationships as the snapshot models, i.e. eight of the 12 associations were in line with what could be expected from the snapshot models. Occurrence of nine species was linked to land-use whereas six species displayed links between changes in occurrence and changes in land-use. In line with previous studies positive effects of short rotation coppice and negative effects of autumn-sown crops were found, while set-asides showed fewer effects than expected. In the snapshot models several species showed links to landscape characteristics such as amount of forest (negative for five species) and landscape heterogeneity (positive for six species). The evidence for effects of the landscape variables on persistence/colonisation was more restricted.The results suggest that both land-use changes and the landscape setting may cause local changes in abundance of farmland birds, even for species displaying a general decline in numbers between years, the effects of land-use changes being, however, strongly species specific. (C) 2014 Elsevier B.V. All rights reserved.
|
|
| 9. |
- Berndes, Göran, 1966, et al.
(författare)
-
Cadmium accumulation and Salix-based phytoextraction on arable land in Sweden
- 2004
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 103:1, s. 207-223
-
Tidskriftsartikel (refereegranskat)abstract
- Cadmium accumulation in arable soils causes concern due to possible direct environmental effects and health risks associated with exposure of humans to cadmium through agricultural products. This paper discusses the problem of cadmium accumulation in Swedish arable land, and evaluates Salix (Salix vinimalis) cultivation as a tool for addressing the problem. It is found that Salix cultivation offers an effective option for addressing the cadmium accumulation, especially when the topsoil has high cadmium content due to anthropogenic inflows, and the subsoil naturally contains little cadmium. The estimated practical potential for Salix-based cadmium management (ca. 490 000 ha) is very large compared to the present Salix plantation area in Sweden (ca. 15 000 ha). However, the estimates of the net economic value of cadmium removal from arable land indicate that the economics of Salix production will not improve dramatically due to an induced cadmium removal. Salix-based cadmium management will therefore most likely take place in counties where Salix cultivation can be expected to expand as a response to an unfilled biomass demand in the energy sector. © 2003 Elsevier B.V. All rights reserved.
|
|
| 10. |
- Blanchet, Guillaume, et al.
(författare)
-
Responses of soil properties and crop yields to different inorganic and organic amendments in a Swiss conventional farming system
- 2016
-
Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 230, s. 116-126
-
Tidskriftsartikel (refereegranskat)abstract
- In agro-ecosystems, fertilization practices are crucial for sustaining crop productivity. Here, based on a 50-year long-term experiment, we studied the influence of fertilization practices (inorganic and/or organic) and nitrogen (N) application rates on (i) soil physicochemical properties, (ii) microbial and earthworm communities and (iii) crop production. Our results showed that soil organic carbon content was increased by incorporation of crop residues (+2.45%) and farmyard manure application (+6.40%) in comparison to the use of mineral fertilizer alone. In contrast, soil carbon stock was not significantly affected by these fertilization practices. Overall, only farmyard manure application improved soil physicochemical properties compared to mineral fertilization alone. Soil microbial population was enhanced by the application of organic amendments as indicated by microbial biomass and phospholipid-derived fatty acids contents. The fertilization practices and the N application rates affected significantly both the biomass and composition of earthworm populations, especially the epigeic and endogeic species. Finally, farmyard manure application significantly increased crop yield (+3.5%) in comparison to mineral fertilization alone. Crop residue incorporation rendered variable but similar crop yields over the 50-year period. The results of this long-term experiment indicate that the use of organic amendments not only reduces the need for higher amount of mineral N fertilizer but also improves the soil biological properties with direct effects on crop yield.
|
|
