The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
C. Pfister - One of the best experts on this subject based on the ideXlab platform.
-
Spring-summer temperatures reconstructed for northern Switzerland and southwestern Germany from Winter rye harvest dates, 1454–1970
Climate of the Past, 2011Co-Authors: O. Wetter, C. PfisterAbstract:Abstract. This paper presents a unique 517-yr long documentary data-based reconstruction of spring-summer (MAMJJ) temperatures for northern Switzerland and south-western Germany from 1454 to 1970. It is composed of 25 partial series of Winter Grain (secale cereale) harvest starting dates (WGHD) that are partly based on harvest related bookkeeping of institutions (hospitals, municipalities), partly on (early) phenological observations. The resulting main Basel WGHD series was homogenised with regard to dating style, data type and altitude. The calibration and verification approach was applied using the homogenous HISTALP temperature series from 1774–1824 for calibration (r = 0.78) and from 1920–1970 for verification (r = 0.75). The latter result even suffers from the weak data base available for 1870–1950. Temperature reconstructions based on WGHD are more influenced by spring temperatures than those based on grape harvest dates (GHD), because rye in contrast to vines already begins to grow as soon as sunlight brings the plant to above freezing. The earliest and latest harvest dates were checked for consistency with narrative documentary weather reports. Comparisons with other European documentary-based GHD and WGHD temperature reconstructions generally reveal significant correlations decreasing with the distance from Switzerland. The new Basel WGHD series shows better skills in representing highly climate change sensitive variations of Swiss Alpine glaciers than available GHD series.
-
Spring-summer temperatures reconstructed for northern Switzerland and south-western Germany from Winter rye harvest dates, 1454–1970
2011Co-Authors: O. Wetter, C. PfisterAbstract:Abstract. This paper presents a unique 517 yr long documentary data – based reconstruction of spring-summer (MAMJJ) temperatures for northern Switzerland and south western Germany from 1454 to 1970. It is composed of 25 partial series of Winter Grain (secale cereale) harvest starting dates (WGHD) that are in one part based on harvest related bookkeeping of institutions (hospitals, municipalities), in the other part to (early) phenological observations. The resulting main Basel WGHD series was homogenised with regard to dating style, data type and altitude. The calibration and verification approach was applied using the homogenous HISTALP temperature series from 1774–1824 for calibration (r = 0,78) and from 1920–1970 for verification (r = 0.75). The latter result even suffer from the weak data basis available for 1870–1950. Temperature reconstructions based on WGHD are more influenced by spring temperatures than those based on grape harvest dates (GHD), because rye in contrast to vines already begins to grow as soon as sunlight brings the plant to above freezing. The earliest and latest harvest dates were checked for consistency with narrative documentary weather reports. Comparisons with other European documentary-based GHD and WGHD temperature reconstructions generally reveal significant correlations decreasing with the distance from Switzerland. The new Basel WGHD series shows better skills in representing highly climate change sensitive variations of Swiss Alpine glaciers than available GHD series.
Paul A. Umina - One of the best experts on this subject based on the ideXlab platform.
-
Insecticide Responses in the Collembola Pest, Sminthurus viridis (Collembola: Sminthuridae), in Australia.
Journal of economic entomology, 2020Co-Authors: Aston L. Arthur, Marielle Babineau, Paul A. UminaAbstract:Lucerne flea (Sminthurus viridis Linnaeus) is an important establishment pest of Winter Grain crops and pastures in Australia. Control of S. viridis largely relies on the application of insecticides through foliar sprays or seed treatments; however, in recent years, farmers have faced increasing difficulties managing this pest. This is likely due to their high inherent tolerance to certain chemicals, although there are increasing concerns around emerging resistance. Despite this, there have been no studies worldwide investigating insecticide sensitivity shifts on S. viridis. Further, there is currently no established method to test the response of S. viridis to neonicotinoids, which are now widely used to protect many crops attacked by this species. Here, we established a robust and sensitive bioassay methodology to test neonicotinoids against S. viridis. We also generated important sensitivity data for the first time across multiple S. viridis populations from geographically distinct regions in Australia to two commonly used insecticides, omethoate, and imidacloprid. While there was variation in responses between populations for both chemicals, there is no evidence to suggest insecticide resistance has evolved in the field. This study is an important step for future monitoring of insecticide resistance in S. viridis, particularly given the considerable selection pressure imposed on this pest in Australia and its purported high-risk of evolving resistance.
-
Predicting the timing of first generation egg hatch for the pest redlegged earth mite Halotydeus destructor (Acari: Penthaleidae)
Experimental and Applied Acarology, 2015Co-Authors: Garrick Mcdonald, Paul A. Umina, Sarina Macfadyen, Peter Mangano, Ary A. HoffmannAbstract:Integrated pest management in Australian Winter Grain crops is challenging, partly because the timing and severity of pest outbreaks cannot currently be predicted, and this often results in prophylactic applications of broad spectrum pesticides. We developed a simple model to predict the median emergence in autumn of pest populations of the redlegged earth mite, Halotydeus destructor , a major field crop and pasture pest in southern Australia. Previous data and observations suggest that rainfall and temperature are critical for post-diapause egg hatch. We evaluated seven models that combined rainfall and temperature thresholds derived using three approaches against previously recorded hatch dates and 2013 field records. The performance of the models varied between Western Australia and south-eastern Australian States. In Western Australia, the key attributes of the best fitting model were more than 5 mm rain followed by mean day temperatures of below 20.5 °C for 10 days. In south-eastern Australia, the most effective model involved a temperature threshold reduced to 16 °C. These regional differences may reflect adaptation of H. destructor in south-eastern Australia to varied and uncertain temperature and rainfall regimes of late summer and autumn, relative to the hot and dry Mediterranean-type climate in Western Australia. Field sampling in 2013 revealed a spread of early hatch dates in isolated patches of habitat, ahead of predicted paddock scale hatchings. These regional models should assist in monitoring and subsequent management of H. destructor at the paddock scale.
-
Does Bdellodes lapidaria (Acari: Bdellidae) have a role in biological control of the springtail pest, Sminthurus viridis (Collembola: Sminthuridae) in south-eastern Australia?
Biological Control, 2011Co-Authors: John M. K. Roberts, Andrew R. Weeks, Ary A. Hoffmann, Paul A. UminaAbstract:Abstract Throughout southern Australia, the lucerne flea, Sminthurus viridis (Collembola: Sminthuridae), is an important pest of a variety of Winter Grain crops and pastures. The predatory mite, Bdellodes lapidaria (Acari: Bdellidae), co-occurs with S. viridis and is reported to be a biological control agent of this pest. Using laboratory bioassays and field experiments, we assessed the susceptibility of B. lapidaria to several pesticides and investigated its impact in controlling S. viridis. In the laboratory, B. lapidaria was found to be susceptible to the synthetic pyrethroids, α-cypermethrin and bifenthrin, but relatively tolerant to the avermectin, abamectin, and organophosphorous chemicals, omethoate and chlorpyrifos. In field experiments, B. lapidaria was not adversely affected by applications of either bifenthrin or omethoate. Despite strong intraspecific interactions, we found no detectable impact of B. lapidaria on S. viridis numbers in the field. These results indicate that B. lapidaria has a relatively high tolerance to several pesticides, perhaps partly through behavioural avoidance, but little impact as a biological control agent on S. viridis in south-eastern Australia.
-
Survival and reproduction of the pest mites Balaustium medicagoense and Bryobia spp. on Winter Grain crops
Experimental and Applied Acarology, 2010Co-Authors: Aston L. Arthur, Andrew R. Weeks, Paul A. Umina, Ary A. HoffmannAbstract:Balaustium medicagoense and Bryobia spp. have recently been identified as emerging pests of Winter crops and pastures in Australia. These mites have a high natural tolerance to currently registered pesticides, highlighting the need to develop alternative control strategies such as cultural controls which require an understanding of plant associations. In shade-house experiments, Bryobia spp. survived and reproduced successfully on pasture, lupins and oats, but progeny failed to reach the adult stage on canola and wheat. Balaustium medicagoense progeny failed to produce a generation on any crop but parental adults survived a few months on all crops, particularly wheat. Bryobia spp. damaged canola, pasture and lupins, but caused minimal damage to oats and wheat, whereas Ba. medicagoense caused considerable damage to wheat and lupins, but only moderate damage to canola, oats and pasture. Field survey data, taken from approximately 450 sites across southern Australia, combined with analysis of historical pest reports, suggest broadleaf crops such as canola, lucerne, lupins and weeds appear particularly susceptible to attack by Bryobia species. Balaustium medicagoense was more commonly found on cereals and grasses, although they also attacked broadleaf crops, particularly canola, lucerne and lupins. These findings show that the mites have the potential to be an important pest on several Winter Grain crops and pasture, but there are important differences that can assist in management strategies such as targeted crop rotations.
O. Wetter - One of the best experts on this subject based on the ideXlab platform.
-
Spring-summer temperatures reconstructed for northern Switzerland and southwestern Germany from Winter rye harvest dates, 1454–1970
Climate of the Past, 2011Co-Authors: O. Wetter, C. PfisterAbstract:Abstract. This paper presents a unique 517-yr long documentary data-based reconstruction of spring-summer (MAMJJ) temperatures for northern Switzerland and south-western Germany from 1454 to 1970. It is composed of 25 partial series of Winter Grain (secale cereale) harvest starting dates (WGHD) that are partly based on harvest related bookkeeping of institutions (hospitals, municipalities), partly on (early) phenological observations. The resulting main Basel WGHD series was homogenised with regard to dating style, data type and altitude. The calibration and verification approach was applied using the homogenous HISTALP temperature series from 1774–1824 for calibration (r = 0.78) and from 1920–1970 for verification (r = 0.75). The latter result even suffers from the weak data base available for 1870–1950. Temperature reconstructions based on WGHD are more influenced by spring temperatures than those based on grape harvest dates (GHD), because rye in contrast to vines already begins to grow as soon as sunlight brings the plant to above freezing. The earliest and latest harvest dates were checked for consistency with narrative documentary weather reports. Comparisons with other European documentary-based GHD and WGHD temperature reconstructions generally reveal significant correlations decreasing with the distance from Switzerland. The new Basel WGHD series shows better skills in representing highly climate change sensitive variations of Swiss Alpine glaciers than available GHD series.
-
Spring-summer temperatures reconstructed for northern Switzerland and south-western Germany from Winter rye harvest dates, 1454–1970
2011Co-Authors: O. Wetter, C. PfisterAbstract:Abstract. This paper presents a unique 517 yr long documentary data – based reconstruction of spring-summer (MAMJJ) temperatures for northern Switzerland and south western Germany from 1454 to 1970. It is composed of 25 partial series of Winter Grain (secale cereale) harvest starting dates (WGHD) that are in one part based on harvest related bookkeeping of institutions (hospitals, municipalities), in the other part to (early) phenological observations. The resulting main Basel WGHD series was homogenised with regard to dating style, data type and altitude. The calibration and verification approach was applied using the homogenous HISTALP temperature series from 1774–1824 for calibration (r = 0,78) and from 1920–1970 for verification (r = 0.75). The latter result even suffer from the weak data basis available for 1870–1950. Temperature reconstructions based on WGHD are more influenced by spring temperatures than those based on grape harvest dates (GHD), because rye in contrast to vines already begins to grow as soon as sunlight brings the plant to above freezing. The earliest and latest harvest dates were checked for consistency with narrative documentary weather reports. Comparisons with other European documentary-based GHD and WGHD temperature reconstructions generally reveal significant correlations decreasing with the distance from Switzerland. The new Basel WGHD series shows better skills in representing highly climate change sensitive variations of Swiss Alpine glaciers than available GHD series.
J.e. Olesen - One of the best experts on this subject based on the ideXlab platform.
-
Spatial and temporal variability of nitrous oxide emissions in a mixed farming landscape of Denmark
Biogeosciences, 2012Co-Authors: K. Schelde, Pierre Cellier, T. Bertolini, T. Dalgaard, T. Weidinger, M.r. Theobal, J.e. OlesenAbstract:Nitrous oxide (N2O) emissions from agricultural land are variable at the landscape scale due to variability in land use, management, soil type, and topography. A field experiment was carried out in a typical mixed farming landscape in Denmark, to investigate the main drivers of variations in N2O emissions, measured using static chambers. Measurements were made over a period of 20 months, and sampling was intensified during two weeks in spring 2009 when chambers were installed at ten locations or fields to cover different crops and topography and slurry was applied to three of the fields. N2O emissions during spring 2009 were relatively low, with maximum values below 20 ng N m−2 s−1. This applied to all land use types including Winter Grain crops, grasslands, meadows, and wetlands. Slurry application to wheat fields resulted in short-lived two-fold increases in emissions. The moderate N2O fluxes and their moderate response to slurry application were attributed to dry soil conditions due to the absence of rain during the four previous weeks. Cumulative annual emissions from two arable fields that were both fertilized with mineral fertilizer and manure were large (17 kg N2O-N ha−1 yr−1 and 5.5 kg N2O-N ha−1 yr−1) during the previous year when soil water conditions were favourable for N2O production during the first month following fertilizer application. Our findings confirm the importance of weather conditions as well as nitrogen management on N2O fluxes.
-
Nitrous oxide emissions at the landscape scale: spatial and temporal variability
2011Co-Authors: K. Schelde, Pierre Cellier, T. Bertolini, T. Dalgaard, T. Weidinger, Mark R. Theobald, J.e. OlesenAbstract:Abstract. Nitrous oxide (N2O) emissions from agricultural land are variable at the landscape scale due to variability in land use, management, soil type, and topography. A field experiment was carried out in a typical mixed farming landscape in Denmark, to investigate the main drivers of variations in N2O emissions, measured using static chambers. Measurements were done over a period of 20 months, and sampling was intensified during two weeks in spring 2009 when chambers were installed at ten locations or fields to cover different crops and topography and slurry was applied to three of the fields. N2O emissions during the spring 2009 period were relatively low, with maximum values below 20 ng N m−2 s−1. This applied to all land use types including Winter Grain crops, grassland, meadow, and wetland. Slurry application to wheat fields resulted in short-lived two-fold increases in emissions. The moderate N2O fluxes and their moderate response to slurry application were attributed to dry soil moisture conditions due to the absence of rain during the four previous weeks. Measured cumulated annual emissions from two arable fields that were both fertilized with mineral fertilizer and manure were large (17 kg N2O-N ha−1 yr−1 and 5.5 kg N2O-N ha−1 yr−1, respectively) during the previous year when soil water conditions were favourable for N2O production during the first month following fertilizer application, confirming the importance of the climatic regime on N2O fluxes.
J A Stuedemann - One of the best experts on this subject based on the ideXlab platform.
-
soil physical responses to cattle grazing cover crops under conventional and no tillage in the southern piedmont usa
Soil & Tillage Research, 2008Co-Authors: Alan J Franzluebbers, J A StuedemannAbstract:Grazing of cover crops in Grain cropping systems can increase economic return and diversify agricultural production systems, but the environmental consequences of this intensified management have not been well documented, especially under different tillage systems. We conducted a multiple-year investigation of how cover crop management (grazed and ungrazed) and tillage system (conventional (CT; initial moldboard plowing and thereafter disk tillage) and no tillage (NT)) affected soil physical properties (bulk density, aggregation, infiltration, and penetration resistance) on a Typic Kanhapludult in Georgia. Responses were determined in two cropping systems: summer Grain/Winter cover crop and Winter Grain/ summer cover crop. Soil bulk density was reduced (P = 0.02) with CT compared with NT to a depth of 30 cm at the end of 0.5 year, but only to a depth of 12 cm at the end of 2, 2.5, and 4.5 years. Grazing of cover crops had little effect on soil bulk density, except eventually with 4.5 years of management. Water- stable macroaggregation was reduced (P � 0.01) with CT compared with NT to a depth of 12 cm at all sampling times during the first 2.5 years of evaluation. Stability of macroaggregates in water was unaffected by grazing of cover crops in both tillage systems. Across 7 sampling events during the first 4 years, there was a tendency (P = 0.07) for water infiltration rate to be lower with grazing of cover crops (5.6 mm min � 1 ) than when ungrazed (6.9 mm min � 1 ), irrespective of tillage system. Across 10 sampling events, soil penetration resistance was greater under NT than under CT at a depth of 0-10 cm (P = 0.001) and the difference was greater in ungrazed than in grazed systems (P = 0.06). Biannual CT operations may have alleviated any surface degradation with animal traffic, but the initially high level of soil organic matter following long-term pasture and conversion to cropland with NT may have buffered the soil from any detrimental effects of animal traffic. Overall, the introduction of cattle to consume the high-quality cover crop forage did not cause substantial damage to the soil.
-
crop and cattle responses to tillage systems for integrated crop livestock production in the southern piedmont usa
Renewable Agriculture and Food Systems, 2007Co-Authors: Alan J Franzluebbers, J A StuedemannAbstract:Integration of crops and livestock has the potential to provide a multitude of benefits to soil and water conservation and nutrient cycling efficiency, while reducing economic risk and increasing profitability. We conducted a field study from May 2002 to October 2005 to determine crop and cattle responses to three management factors on a Typic Kanhapludult in Georgia, USA. Summer Grain/Winter cover [sorghum (Sorghum bicolor L. Moench) or corn (Zea mays L.)/rye (Secale cereale L.)] and Winter Grain/summer cover [wheat (Triticum aestivum L.)/pearl millet (Pennisetum glaucum L. R. Br.)] were managed with either conventional tillage (CT) or no tillage (NT) and with or without cattle grazing of cover crops. All crops were successfully established, irrespective of tillage and cover crop management. Although pearl millet was often lower in the plant stand with NT than with CT, plants compensated with greater biomass on an area basis. Across years, Grain yield of sorghum (1.9 Mg ha -1 during three seasons) and corn (7.3 Mg ha -1 in one season) was 25% greater under NT than under CT when the cover crop was not grazed. Wheat Grain yield (2.7 Mg ha -1 during three seasons) was unaffected by tillage and cover crop management. Unharvested stover production of summer Grain crops was greater with NT than with CT (6.5 versus 4.1 Mg ha -1 ; P < 0.001). Grazing rye rather than allowing it to accumulate as surface residue reduced summer Grain yield 23% and reduced standing Grain-crop dry matter 26% under NT, but had no effect under CT. In contrast, grazing pearl millet rather than allowing it to accumulate as surface residue increased wheat standing dry matter yield by 25 – 14% (mean – standard deviation among 3 years and two tillage systems). Ungrazed cover crop production was greater under NT than under CT for rye (7.0 versus 6.0 Mg ha -1 ; P = 0.03) and pearl millet (10.2 versus 7.6 Mg ha -1 ; P = 0.01). Calf daily gain was either greater or tended to be greater under NT than under CT on rye (2.27 versus 2.09 kg head -1 d -1 ; P = 0.15) and pearl millet (2.05 versus 1.81 kg head -1 d -1 ; P = 0.05). Total cattle gain per grazing season was either greater or tended to be greater with NT than with CT on rye (350 versus 204 kg ha -1 ; P = 0.01) and pearl millet (324 versus 277 kg ha -1 ; P = 0.15). Net return over variable costs was greater with grazing than without grazing of cover crops (US$302 versus - US$63 ha -1 ; P < 0.001). Livestock grazing of cover crops had variable effects on subsequent crop production, but increased economic return and diversity overall. Therefore, an integrated crop‐livestock production system with conservation tillage is recommended as a viable option for producers to diversify farming operations to avoid risk, improve ecological production of crops, and potentially avoid environmental damage from soil erosion and nutrient loss.
