M. Maljanen, Heli Yli-Moijala, B. Sigurdsson, C. Biasi
{"title":"Stable isotope method reveals the role of abiotic source of carbon dioxide efflux from geothermally warmed soil in southern Iceland","authors":"M. Maljanen, Heli Yli-Moijala, B. Sigurdsson, C. Biasi","doi":"10.16886/ias.2020.05","DOIUrl":"https://doi.org/10.16886/ias.2020.05","url":null,"abstract":"","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"126 1","pages":"41-56"},"PeriodicalIF":0.5,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67597851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this study was to investigate the tree-ring growth of rowan (Sorbus aucuparia L.) and downy birch (Betula pubescens Ehrh.) in Ranaskógur, a forest in East Iceland, and to determine its response to climate factors during the past century. Tree-core samples were collected in September 2018 and from those a tree-ring width (TRW) chronology and a standardized tree-ring index (TRI) chronology were produced. A statistical analysis between the chronologies and monthly mean temperatures and total monthly precipitation was carried out. The study found that both species had similar radial growth during the past century. The growth of birch responded significantly positively to June and July temperatures, while rowan responded significantly positively to July and August temperatures. The growth of neither species was significantly affected by precipitation across the whole period. However, in the 1940s to early 1960s, rowan growth correlated significantly with June precipitation, and birch with April and May precipitation.
{"title":"The long-term effects of climatic factors on radial growth of downy birch (Betula pubescens) and rowan (Sorbus aucuparia) in East Iceland","authors":"Nandini Hannak, Ó. Eggertsson","doi":"10.16886/ias.2020.07","DOIUrl":"https://doi.org/10.16886/ias.2020.07","url":null,"abstract":"The aim of this study was to investigate the tree-ring growth of rowan (Sorbus aucuparia L.) and downy birch (Betula pubescens Ehrh.) in Ranaskógur, a forest in East Iceland, and to determine its response to climate factors during the past century. Tree-core samples were collected in September 2018 and from those a tree-ring width (TRW) chronology and a standardized tree-ring index (TRI) chronology were produced. A statistical analysis between the chronologies and monthly mean temperatures and total monthly precipitation was carried out. The study found that both species had similar radial growth during the past century. The growth of birch responded significantly positively to June and July temperatures, while rowan responded significantly positively to July and August temperatures. The growth of neither species was significantly affected by precipitation across the whole period. However, in the 1940s to early 1960s, rowan growth correlated significantly with June precipitation, and birch with April and May precipitation.","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"33 1","pages":"73-87"},"PeriodicalIF":0.5,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67597914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Baldvinsdottir, Sigþrúður Jónsdóttir, B. Sigurdsson
The present study was the first in Iceland to investigate the effects of different stocking densities of sheep on planted Siberian larch (Larix sibirica) trees. It covered two years and involved four stocking densities in enclosures with 0.1–3.0 m tall trees, as well as a grazed area on treeless commons. The grazing effect was followed for 75 days each summer. A significant grazing effect was found on the vegetation in both years. None of the sheep stocking densities had a measurable effect on the growth or the survival of the larch trees, however, and no damage was observed on their apical shoots. During the second summer, significant visual and measured browsing effects were recorded on side branches in enclosures with medium and high stocking densities. No trees <0.5 m were browsed, however. Siberian larch is generally not sought after by sheep and the results indicated that it may be generally safe to utilize established monoculture Siberian larch stands for sheep grazing during the summer months, if enough other vegetation is present.
{"title":"Impact of different stocking densities of sheep on establishing stands of Larix sibirica in Iceland","authors":"G. Baldvinsdottir, Sigþrúður Jónsdóttir, B. Sigurdsson","doi":"10.16886/ias.2020.08","DOIUrl":"https://doi.org/10.16886/ias.2020.08","url":null,"abstract":"The present study was the first in Iceland to investigate the effects of different stocking densities of sheep on planted Siberian larch (Larix sibirica) trees. It covered two years and involved four stocking densities in enclosures with 0.1–3.0 m tall trees, as well as a grazed area on treeless commons. The grazing effect was followed for 75 days each summer. A significant grazing effect was found on the vegetation in both years. None of the sheep stocking densities had a measurable effect on the growth or the survival of the larch trees, however, and no damage was observed on their apical shoots. During the second summer, significant visual and measured browsing effects were recorded on side branches in enclosures with medium and high stocking densities. No trees <0.5 m were browsed, however. Siberian larch is generally not sought after by sheep and the results indicated that it may be generally safe to utilize established monoculture Siberian larch stands for sheep grazing during the summer months, if enough other vegetation is present.","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"33 1","pages":"89-101"},"PeriodicalIF":0.5,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67598187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abdul-Salam Mahamud Baba, I. Barrio, G. Halldorsson
1CSIR-Savanna Agricultural Research Institute, P.O. Box 52, Tamale-Ghana, West Africa 2United Nations University Land Restoration Training Programme, Árleyni 22, 112 Reykjavík 3Landbunaðarháskóli Íslands, Auðlindaog umhverfisdeild, Keldnaholt, 112 Reykjavík. 4Landgræðsla ríkisins, Gunnarsholt, 851 Hella, Iceland *Corresponding author: isabel@lbhi.is ICEL. AGRIC. SCI. 32 (2019), 17-20 www.ias.is https://doi.org/10.16886/IAS.2019.02
1CSIR Savanna农业研究所，邮政信箱52，西非加纳塔马勒2联合国大学土地恢复培训计划，Árleyni 22112 Reykjavík 3LandbunağarháskóliÍslands，Auğlindog umhverfisdeild，Keldnaholt，112 Reykjawík。4Landgræğsla ríkisins，Gunnarsholt，851 Hella，冰岛*通讯作者：isabel@lbhi.is冰岛。AGRIC。SCI。32（2019），17-20 www.ias.ishttps://doi.org/10.16886/IAS.2019.02
{"title":"Effects of reduced water availability and insecticide on damage caused by cabbage root fly larvae","authors":"Abdul-Salam Mahamud Baba, I. Barrio, G. Halldorsson","doi":"10.16886/IAS.2019.02","DOIUrl":"https://doi.org/10.16886/IAS.2019.02","url":null,"abstract":"1CSIR-Savanna Agricultural Research Institute, P.O. Box 52, Tamale-Ghana, West Africa 2United Nations University Land Restoration Training Programme, Árleyni 22, 112 Reykjavík 3Landbunaðarháskóli Íslands, Auðlindaog umhverfisdeild, Keldnaholt, 112 Reykjavík. 4Landgræðsla ríkisins, Gunnarsholt, 851 Hella, Iceland *Corresponding author: isabel@lbhi.is ICEL. AGRIC. SCI. 32 (2019), 17-20 www.ias.is https://doi.org/10.16886/IAS.2019.02","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67597412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The research described in the paper was financed by Icelandic Forest Research, the research division of the Icelandic Forest Service. Analysis of the 1987-88 data was supported by the Institute of Natural History.
{"title":"Aboveground woody biomass of natural birch woodland in Iceland – Comparison of two inventories 1987-1988 and 2005-2011","authors":"A. Snorrason, T. H. Jónsson, Ó. Eggertsson","doi":"10.16886/ias.2019.03","DOIUrl":"https://doi.org/10.16886/ias.2019.03","url":null,"abstract":"The research described in the paper was financed by Icelandic Forest Research, the research division of the Icelandic Forest Service. Analysis of the 1987-88 data was supported by the Institute of Natural History.","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67597470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Eiríksson, Á. Sigurdsson, Gudmundur H. Johannesson, E. Eythórsdóttir
Predicted genetic progress in production traits was compared using three different models for genetic evaluation of Icelandic dairy cows. The models were: a random regression (RR) test-day model, model using lactation yields until day 305 from calving (LAC1), and the model currently used for the national evaluation, based on lactation yield from calving to the end of lactation regardless of the length of the lactation (LAC2). Additionally, genetic evaluation for somatic cell score with RR and LAC1 were compared. Predicted genetic progress for protein yield was highest when using RR, or 0.170 σa/yr, compared with 0.167 σa/yr and 0.158 σa/yr for LAC1 and LAC2, respectively. Results for other production traits were similar. The main reason could be the shorter generation interval when records can be utilized before the end of lactation and reliable estimated breeding values thus obtained earlier. Application of an RR model will be beneficial for genetic evaluation for production traits and somatic cell score.
{"title":"Comparison of test-day and lactation models for genetic evaluations of Icelandic dairy cows for production traits and somatic cell score","authors":"J. Eiríksson, Á. Sigurdsson, Gudmundur H. Johannesson, E. Eythórsdóttir","doi":"10.16886/ias.2019.04","DOIUrl":"https://doi.org/10.16886/ias.2019.04","url":null,"abstract":"Predicted genetic progress in production traits was compared using three different models for genetic evaluation of Icelandic dairy cows. The models were: a random regression (RR) test-day model, model using lactation yields until day 305 from calving (LAC1), and the model currently used for the national evaluation, based on lactation yield from calving to the end of lactation regardless of the length of the lactation (LAC2). Additionally, genetic evaluation for somatic cell score with RR and LAC1 were compared. Predicted genetic progress for protein yield was highest when using RR, or 0.170 σa/yr, compared with 0.167 σa/yr and 0.158 σa/yr for LAC1 and LAC2, respectively. Results for other production traits were similar. The main reason could be the shorter generation interval when records can be utilized before the end of lactation and reliable estimated breeding values thus obtained earlier. Application of an RR model will be beneficial for genetic evaluation for production traits and somatic cell score.","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"63 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67598004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Björn Thorsteinsson, Gudmundur H. Johannesson, A. Thorlacius, T. Gudmundsson
From May 2001 to June 2002, regular measurements were done on the volume of water runoff from the fields of the Agricultural University of Iceland’s farm at Hvanneyri, western Iceland. Precipitation and other weather factors were continuously monitored. The following components were analysed in the runoff water: total N, ammonia N (NH4-N), oxidized N (TON), phosphate (PO4-P), soluble phosphorus (TSP), K, Ca, Mg, Na, and S. Results show that nutrient runoff varied considerably over the year, highest in winter but low during the summer months. Losses of Ca, Mg, K and Na were relatively high, but N and P runoff was low considering that we are dealing with fertilized organic soils with a high content of soluble P in the top 10 cm and high total N in the whole soil profile. Results showed that major fluctuations and peak runoff events were confined to the winter months. Nutrient losses in relation to field management practices require further studies.
{"title":"Precipitation, runoff and nutrient losses from cultivated Histosols in western Iceland","authors":"Björn Thorsteinsson, Gudmundur H. Johannesson, A. Thorlacius, T. Gudmundsson","doi":"10.16886/ias.2019.06","DOIUrl":"https://doi.org/10.16886/ias.2019.06","url":null,"abstract":"From May 2001 to June 2002, regular measurements were done on the volume of water runoff from the fields of the Agricultural University of Iceland’s farm at Hvanneyri, western Iceland. Precipitation and other weather factors were continuously monitored. The following components were analysed in the runoff water: total N, ammonia N (NH4-N), oxidized N (TON), phosphate (PO4-P), soluble phosphorus (TSP), K, Ca, Mg, Na, and S. Results show that nutrient runoff varied considerably over the year, highest in winter but low during the summer months. Losses of Ca, Mg, K and Na were relatively high, but N and P runoff was low considering that we are dealing with fertilized organic soils with a high content of soluble P in the top 10 cm and high total N in the whole soil profile. Results showed that major fluctuations and peak runoff events were confined to the winter months. Nutrient losses in relation to field management practices require further studies.","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67598099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Eiríksson, Á. Sigurdsson, Gudmundur H. Johannesson, E. Eythórsdóttir
A total of 480,495 test-day yield records of 33,052 cows were used to estimate the genetic parameters for daily milk yield (MY), fat yield (FY), protein yield (PY) and somatic cell score (SCS) of Icelandic dairy cows in the first three lactations with a random regression model. Heritability of all traits was lowest in early lactation in all lactations and highest in midor late lactation. Heritability of lactation yields for the first lactation was 0.43, 0.39 and 0.41 for MY, FY and PY, respectively, but was estimated as lower when using a lactation model. Heritability of SCS in the first lactation was 0.23 using the random regression model but 0.15 using the lactation model. Heritability of persistency of lactation MY, FY and PY were 0.14-0.24 in all lactations and genetic correlations to the whole lactation SCS were -0.08 to -0.13. Heritability of yields had increased from previous estimates for the breed. Genetic variation of persistency in the population makes change of the lactation curve possible through selection.
{"title":"Genetic parameters for Icelandic dairy cows using a random regression test-day model","authors":"J. Eiríksson, Á. Sigurdsson, Gudmundur H. Johannesson, E. Eythórsdóttir","doi":"10.16886/IAS.2019.01","DOIUrl":"https://doi.org/10.16886/IAS.2019.01","url":null,"abstract":"A total of 480,495 test-day yield records of 33,052 cows were used to estimate the genetic parameters for daily milk yield (MY), fat yield (FY), protein yield (PY) and somatic cell score (SCS) of Icelandic dairy cows in the first three lactations with a random regression model. Heritability of all traits was lowest in early lactation in all lactations and highest in midor late lactation. Heritability of lactation yields for the first lactation was 0.43, 0.39 and 0.41 for MY, FY and PY, respectively, but was estimated as lower when using a lactation model. Heritability of SCS in the first lactation was 0.23 using the random regression model but 0.15 using the lactation model. Heritability of persistency of lactation MY, FY and PY were 0.14-0.24 in all lactations and genetic correlations to the whole lactation SCS were -0.08 to -0.13. Heritability of yields had increased from previous estimates for the breed. Genetic variation of persistency in the population makes change of the lactation curve possible through selection.","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67597345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tara A. Mulloy, I. Barrio, Katrín Björnsdóttir, I. Jónsdóttir, D. Hik
Sustainable grazing management in tundra ecosystems is receiving increasing attention. In the Icelandic highlands, past grazing practices have played a major role in the extensive soil erosion, leaving many parts of this tundra rangeland in poor condition. However, the impacts of current grazing practices are not well understood. We measured the short-term effect of grazing by comparing the amount of bare ground and aboveground biomass in grazed and ungrazed plots, with and without fertiliser application, in adjacent dwarfshrub heaths and sparsely vegetated areas, at two sites within and outside the volcanic active zone. Grazing did not affect the amount of bare ground, but in the fertilised plots grazing consistently reduced plant biomass (mainly graminoids). Fertiliser application can increase grazing intensity, which can counteract the additional biomass accumulation. Consequently, the removal of biomass by sheep needs to be considered when fertilisers are used as part of a strategy to combat erosion.
{"title":"Fertilisers mediate the short-term effects of sheep grazing in the Icelandic highlands","authors":"Tara A. Mulloy, I. Barrio, Katrín Björnsdóttir, I. Jónsdóttir, D. Hik","doi":"10.16886/ias.2019.07","DOIUrl":"https://doi.org/10.16886/ias.2019.07","url":null,"abstract":"Sustainable grazing management in tundra ecosystems is receiving increasing attention. In the Icelandic highlands, past grazing practices have played a major role in the extensive soil erosion, leaving many parts of this tundra rangeland in poor condition. However, the impacts of current grazing practices are not well understood. We measured the short-term effect of grazing by comparing the amount of bare ground and aboveground biomass in grazed and ungrazed plots, with and without fertiliser application, in adjacent dwarfshrub heaths and sparsely vegetated areas, at two sites within and outside the volcanic active zone. Grazing did not affect the amount of bare ground, but in the fertilised plots grazing consistently reduced plant biomass (mainly graminoids). Fertiliser application can increase grazing intensity, which can counteract the additional biomass accumulation. Consequently, the removal of biomass by sheep needs to be considered when fertilisers are used as part of a strategy to combat erosion.","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67598167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fungal distribution in a liverwort-based biocrust was examined at different depths (0, 5 and 20 mm) by direct counting using both light and fluorescence microscopy. The DNA-based taxonomic composition of fungi was also determined and differences between depths (above and below 5 mm) were assessed. The fungal biomass was greatest at the surface where large hyphae, sporangia and fungi within plants were more abundant than at 5 mm and 20 mm depth. The texture of the biocrust also differed significantly with depth. Likewise, the analysis of microbial DNA composition revealed a difference between depths, both for the amount of total fungi and of each phylum where the total amount of fungi was highest above 5 mm. Ascomycota fungi were dominant both below 5 mm and near the surface where both their amount and proportion were substantially higher than deeper down. The dark septate Exophiala, Phialocephala and Pseudogymnoascus were the most abundant genera.
{"title":"Fungi in liverwort-based biocrust","authors":"Petra Landmark Gudmundsdottir, Ó. Andrésson","doi":"10.16886/ias.2019.05","DOIUrl":"https://doi.org/10.16886/ias.2019.05","url":null,"abstract":"Fungal distribution in a liverwort-based biocrust was examined at different depths (0, 5 and 20 mm) by direct counting using both light and fluorescence microscopy. The DNA-based taxonomic composition of fungi was also determined and differences between depths (above and below 5 mm) were assessed. The fungal biomass was greatest at the surface where large hyphae, sporangia and fungi within plants were more abundant than at 5 mm and 20 mm depth. The texture of the biocrust also differed significantly with depth. Likewise, the analysis of microbial DNA composition revealed a difference between depths, both for the amount of total fungi and of each phylum where the total amount of fungi was highest above 5 mm. Ascomycota fungi were dominant both below 5 mm and near the surface where both their amount and proportion were substantially higher than deeper down. The dark septate Exophiala, Phialocephala and Pseudogymnoascus were the most abundant genera.","PeriodicalId":50396,"journal":{"name":"Icelandic Agricultural Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67598023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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