| 1. |
- Aronsson, Helena, et al.
(författare)
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Effects of pig and dairy slurry application on N and P leaching from crop rotations with spring cereals and forage leys
- 2014
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Ingår i: Nutrient cycling in agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 98, s. 281-293
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Tidskriftsartikel (refereegranskat)abstract
- Two crop rotations dominated by spring cereals and grass/clover leys on a clay soil were studied over 2 years with respect to nitrogen (N) and phosphorus (P) leaching associated with pig or dairy slurry application in April, June and October. Leaching losses of total N (TN), total P (TP), nitrate-N and dissolved reactive P (DRP) were determined in separately tile-drained field plots (four replicates). Mean annual DRP leaching after October application of dairy slurry (17 kg P ha(-1)) to growing grass/clover was 0.37 kg ha(-1). It was significantly higher than after October application of pig slurry (13 kg ha(-1)) following spring cereals (0.16 kg ha(-1)) and than in the unfertilised control (0.07 kg P ha(-1)). The proportion of DRP in TP in drainage water from the grass/clover crop rotation (35 %) was higher than from the spring cereal rotation (25 %) and the control (14 %). The grass/clover rotation proved to be very robust with respect to N leaching, with mean TN leaching of 10.5 kg ha(-1) year(-1) compared with 19.2 kg ha(-1) year(-1) from the cereal crop rotation. Pig slurry application after cereals in October resulted in TN leaching of 25.7 kg ha(-1) compared with 7.0 kg ha(-1) year(-1) after application to grass/clover in October and 19.1 kg ha(-1) year(-1) after application to spring cereals in April. In conclusion, these results show that crop rotations dominated by forage leys need special attention with respect to DRP leaching and that slurry application should be avoided during wet conditions or combined with methods to increase adsorption of P to soil particles.
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| 2. |
- Dahlin, Sigrun, et al.
(författare)
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Mulch N recycling in green manure leys under Scandinavian conditions
- 2011
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Ingår i: Nutrient cycling in agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 91, s. 119-129
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) recycling to the regrowth of mulched red clover (Trifolium pratense L.) and mulched mixed red clover/perennial ryegrass (Lolium perenne L.) leys was determined in field experiments during three consecutive years using (15)N-labelled shoot material. Nitrogen recycling was greater in the pure clover stands than in the mixed stands in the beginning of the growing season, but increased successively in the mixed stands so that it was similar (14-15.5%) in both stands at the end of the season. This recycling of N from the mulch led to increased biomass accumulation but did not alter stand composition in the mixed stands. Mulch-derived N was incorporated into the soil organic N in both pure clover and mixed stands which thus contributed to building up soil fertility. An approximately similar proportion of N remained unaccounted for in mulched pure clover and mixed stand leys and presumably represented gaseous losses. To exploit the benefits of green manure leys in the humid temperate zone while minimising the negative environmental impact, these should be harvested rather than mulched.
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| 3. |
- Liu, Jian, et al.
(författare)
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Freezing-thawing effects on phosphorus leaching from catch crops
- 2014
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Ingår i: Nutrient cycling in agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 99, s. 17-30
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Tidskriftsartikel (refereegranskat)abstract
- It is suggested that catch crops can be grown to reduce phosphorus (P) losses. However, after exposure to freezing-thawing cycles (FTCs), catch crop material can become a source of P losses to waters in moderately cold climates. This study screened potential P leaching from intact plant material of eight catch crop species: chicory (Chichorium intybus L.), cocksfoot (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), red clover (Trifolium pratense L.), phacelia (Phacelia tanacetifolia L.), white mustard (Sinapis alba L.), oilseed radish (Raphanus sativus L. oleiformis), and white radish (R. longipinnatus). The catch crops were grown in six field experiments on clay soils, where soil lysimeters (0.25 m deep) with intact crops were extracted in autumn and after used for leaching experiments before and after seven FTCs in the laboratory. The eight catch crops did not reduce P leaching before FTCs. After FTCs, leachate total-P concentration from ryegrass, oilseed radish and red clover lysimeters were significantly (p=0.0022) higher than those from the other species and the control without a catch crop. FTCS significantly (p= 0.0064) altered total-P concentration and the proportions of different forms of P. There was a significant increase in total-P concentration in leachate from ryegrass (p=0.0008) and oilseed radish (p= 0.02). Thus, the potential risk of P leaching from ryegrass and oilseed radish material after FTCs must ne considered, since they are commonly grown as nitrogen catch crops in the Nordic countries. Morever, the roots of the tested catch crops contained 7-86 % total-P, which is important when ealuating O leaching risks.
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| 4. |
- Mattsson, Lennart
(författare)
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Estimating the crop response to fertilizer nitrogen residues in long-continued field experiments
- 2012
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Ingår i: Nutrient cycling in agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 93, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the cumulated effect of long-continued nitrogen (N) inputs is important for both agronomic and environmental reasons. However, only little attention has been paid to estimate the crop response to mineral fertilizer N residues. Before interpreting estimates for the crop response to previous N input rates, the experimental design for testing needs to be examined. Experimental designs that suspend the customary N inputs, leaving the test crop unfertilized, ignore any interaction between the rate of N applied in the past and the rate applied in the test year. We estimated the interaction using data from five long-continued field experiments on mineral and organic N input rates where the main plots were subdivided for incremental rates of mineral N fertilizer in the test year. The interaction between N applied in the past and in the test year significantly affected grain yield and N offtake when the residual effect originated from organic applications, but the interaction was not significant when mineral N fertilizer had been used in the past, making the residual effect of N applied in the past additive to the effect of N applied in the test year. The dry matter (DM) grain yield of spring barley decreased by an average of 5 kg DM/ha and the grain N offtake by 46 g N/ha for a decrease in the annual mineral N rate of 1 kg N/ha applied for more than three decades. Although statistically significant, the crop response to mineral fertilizer N residues was of minor importance when compared with the residual effect of organic inputs.
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| 5. |
- Svanbäck, Annika, et al.
(författare)
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Influence of soil phosphorus and manure on phosphorus leaching in Swedish topsoils
- 2013
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Ingår i: Nutrient cycling in agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 96, s. 133-147
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, subsurface transport of phosphorus (P) from agricultural soils represents the primary pathway of concern for surface water quality. However, there are mixed findings linking P in leachate with soil P and limited understanding of the interactive effects of applied P sources and soil test P on P leaching potential. Identifying soils that are susceptible to P leaching when manure is applied is critical to management strategies that reduce P loadings to water bodies. Intact soil columns (20 cm deep) from five long-term fertilization trials across Sweden were used in leaching experiments with simulated rainfall to explore the interactive effects of dairy cow (Bos taurus L.) manure application, soil test P and cropping system. Strong relationships were observed between ammonium-lactate extractable P in soil and dissolved reactive P (DRP) concentrations in leachate, although regression slopes varied across soils. For three soils, application of manure (equal to 21-30 kg P ha-1) to the soil columns significantly increased DRP leaching losses. The increase in DRP concentration was correlated to soil test P, but with wide variations between the three soils. For two soils leachate P concentrations after manure addition were independent of soil P status. Despite variable trends in P leaching across the different soils, P concentrations in leachate were always moderate from soils at fertilization rates equivalent to P removal with harvest. Results clearly stress the importance of long-term P balance to limit P leaching losses from Swedish agricultural soils.
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| 6. |
- Weslien, Per, 1963, et al.
(författare)
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Carrot cropping on organic soil is a hotspot for nitrous oxide emissions
- 2012
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Ingår i: Nutrient Cycling in Agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 94:2-3, s. 249-253
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Tidskriftsartikel (refereegranskat)abstract
- The emissions of the greenhouse gas nitrous oxide (N2O) were measured from a non nitrogen fertilized carrot (Daucus carota ssp. sativa) field on an organic soil in Sweden during one cropping and post-harvest season. The cumulative emission during the measuring period of 149 days was 41 (±2.8) kg N2O ha−1. Dividing the measuring period into a cropping and a post-harvest period revealed that the presence of carrots strongly stimulated N2O emissions, as the emission during the cropping period was one order of magnitude higher compared to the post-harvest period. The N2O emission from the carrot field were higher than fluxes reported from cereal crop and grass production, but in the same order as reported fluxes from vegetable cropping on organic soils. In conclusion, our results indicate that the cultivation of root vegetable, such as carrots, on organic soil can be a high point source for N2O emissions.
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