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| Author |
Yin, X. |
Title  |
Effects of climatic factors, drought risk and irrigation requirement on maize yield in the northeast farming region of China over 1961 to 2010 |
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| Year |
2015 |
Publication |
FACCE MACSUR Reports |
Abbreviated Journal |
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| Volume |
5 |
Issue |
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Pages |
Sp5-72 |
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| Abstract |
The Northeast Farming Region (NFR) is the most important and the largest rain-fed maize production region in China, accounting for 30% of China’s maize. We investigated the effects of climatic factors, drought risk and irrigation requirement on maize yield in different maize growth phases during 1961 to 2010 using a statistical analysis of observed yield from 44 stations in NFR. We divided the maize growing season into four growth phases, comprising seeding, vegetative, flowering and maturity. The dual crop coefficient was used to calculate crop evapotranspiration and soil water balance during the maize growing season. The effects of mean temperature, radiation, effective rainfall, water deficit, drought stress days, actual crop evapotranspiration (ETa) and irrigation requirement in different growth phases were included in the statistical model to predict maize yield. During the period 1961 to 2010, mean temperature increased significantly in all growth phases in NFR, while radiation decreased significantly in southern NFR in the seeding, vegetative and flowering phases. Effective rainfall increased in the seeding and vegetative phases leading to less water deficit, whereas decreased effective rainfall in the flowering and maturity phases enhanced water deficit. More days with drought stress were concentrated in western NFR where larger volumes of irrigation were needed. Our results indicate that the increase of mean temperature in the seeding and maturity phases was beneficial for maize yield, higher ETa in each growth phase would lead to yield increase, but too high rainfall would damage maize yield. The results also show that water deficit and drought stress days had significant negative effects on maize yield, and the absence of irrigation would manifest such effects on maize production in NFR. Therefore, the development of irrigation and drainage systems is highly needed for ensuring the stability of maize production in NFR. In addition, other adaptation measures like introducing new cultivars and optimizing soil and crop management to better conserve soil water would be beneficial for future maize production. No Label |
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MACSUR Science Conference 2015 »Integrated Climate Risk Assessment in Agriculture & Food«, 8–9+10 April 2015, Reading, UK |
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MA @ admin @ |
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2187 |
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| Author |
Lessire, F. |
| Title |
Effects of heat stress periods on milk production, milking frequency and rumination time of grazing dairy cows milked by a mobile automatic system in 2013 |
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2015 |
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FACCE MACSUR Reports |
Abbreviated Journal |
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5 |
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Sp5-37 |
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In Europe, analysis of meteorological data shows that the average temperature has increased by ~1°C over the past hundred years (IPCC, 2013). Heat stress periods are thus expected to be more frequent even in temperate areas. The use of an automatic milking system (AMS) implies the need to stimulate cows’ traffic to the robot, especially with grazing cows. Describing how heat stress influenced cows’ traffic to the robot is the aim of this study.Grazing dairy cows milked by an automatic system (AMS) experienced heat stress (HS) periods, twice during the summer 2013 in July (J) and August (A). The daily temperature humidity index (THI) during these periods were higher than 75. Each HS period was compared with a “normal period”(N), presenting the same number of cows, similar lactation number, days in milk, distance to come back to the robot and an equal access to water. The first HS period of 5 days with a mean THI of 78.4 was chosen in J, and a second that lasted for 6 days in A with a THI value of 77.3. Heat stress periods were cut off with the same duration of days with no stress (N) and mean THI <70. Milk production, milkings and returns to the robot during HS were compared with N periods.Milkings and visits to AMS were significantly more numerous in HS periods in July (HS: 2.44 vs N: 2.23, 3.97 vs 3.03) but milk production dropped from 20.3 kg to 19.3 kg milk per cow and per day. In August, MY increased slightly during HS. This could be explained by less high ambient temperatures and decreased distance to walk inducing less energy expenditure. The increase in milkings and visits to the robot during HS could be linked to water availability nearby the robot and confirmed previous findings (Lessire et al., 2014). No Label |
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MACSUR Science Conference 2015 »Integrated Climate Risk Assessment in Agriculture & Food«, 8–9+10 April 2015, Reading, UK |
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MA @ admin @ |
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2152 |
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Hoffmann, H. |
| Title |
Effects of soil and climate input data aggregation on modelling regional crop yields |
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2015 |
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FACCE MACSUR Reports |
Abbreviated Journal |
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5 |
Issue |
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Sp5-22 |
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Climate and soil data at coarse resolution are often used as input for crop models in order to simulate crop yields at larger scales, e.g. at regional or national level, potentially leading to biased yield estimates. While the response to data resolution differs between crop models, it is unknown how the spatial aggregation of different types of input data interacts and contributes to this so-called aggregation effect. An ensemble of crop models was run with soil and climate input data at different spatial resolutions from 1 to 100 km for the state of North Rhine-Westphalia, Germany. For this purpose, climate time series were averaged spatially and soil data was aggregated by selecting the dominant soil type with a representative soil profile based on a soil map at the scale of 1:50,000. Yields of winter wheat and silage maize were simulated under potential, water-limited and water-nitrogen-limited production conditions. Crop yields from soil and climate aggregation were evaluated separately.Mean of crop yields of the region and over the simulation period were reasonably reproduced by most models regardless of input data resolution, either using aggregated soil or climate as input. However, larger aggregation effects were observed at higher temporal resolution (e.g. annual yields). Models revealed similar spatial patterns in yield. Being distinct for soil and climate aggregation, these patterns indicate a larger impact of soil aggregation on the spatial distribution of simulated crop yield for this region. Additionally, models differed considerably in their susceptibility to input data aggregation. The results reveal the importance of model ensemble assessments and the relevance of data aggregation when short simulation periods are considered. No Label |
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MACSUR Science Conference 2015 »Integrated Climate Risk Assessment in Agriculture & Food«, 8–9+10 April 2015, Reading, UK |
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no |
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MA @ admin @ |
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2137 |
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| Author |
Dader, B. |
| Title |
Elevated CO2 impacts bell pepper growth with consequences in the feeding behaviour and performance of the green peach aphid, Myzus persicae |
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2015 |
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FACCE MACSUR Reports |
Abbreviated Journal |
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5 |
Issue |
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Pages |
Sp5-14 |
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Future CO2 predictions estimate an increase up to 550 ppm within only few decades away. Among the observed effects on plants, increasing CO2 stimulates growth, reduces stomatal conductance and transpiration, improves water-use efficiency and induces photosynthesis. These changes have an indirect impact on pest biology and behaviour, e.g. altering their population growth or feeding habits.Our first aim was to study the effect of ambient (400 ppm) (aCO2) and elevated CO2 (650 ppm) (eCO2) on pepper (Capsicum annuum L.). Height, leaf area, dry weight and leaf temperature by thermal imaging were measured. Chlorophyll was measured in SPAD units as an indirect indicator of nitrogen foliar content. Peppers under eCO2 were significantly taller although they had the same number of leaves than under aCO2. SPAD was significantly lower under eCO2. Leaf, stem and above-ground dry weight were significantly higher under eCO2. There was a significant decrease in specific leaf area under eCO2. Canopy temperature was 1.2 °C higher under eCO2.Secondly, pepper plants were used to assess the development and fecundity of M. persicae. The pre-reproductive period was 11% longer in eCO2 peppers. Aphids grew significantly slower and produced fewer nymphs under eCO2. Lastly, aphid feeding behaviour was studied using the Electrical Penetration Graph (EPG) technique, which provides a live visualization and recording of plant penetration by aphid mouthparts. EPG results will be presented and discussed. No Label |
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MACSUR Science Conference 2015 »Integrated Climate Risk Assessment in Agriculture & Food«, 8–9+10 April 2015, Reading, UK |
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Approved |
no |
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MA @ admin @ |
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2129 |
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Sharif, B.; Mankowski, D.; Kersebaum, K.C.; Trnka, M.; Schelde, K.; Olsesen, J.E. |
| Title |
Empirical analysis on crop-weather relationships |
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Report |
| Year |
2015 |
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FACCE MACSUR Reports |
Abbreviated Journal |
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6 |
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D-C2.5 |
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There have been several studies, where process-based crop models are developed, used and compared in order to project crop production and corresponding model uncertainties under climate change. Despite many advances in this field, there are some correlations between climate variables and crop growth, such as pest and diseases, that is often absent in process-based models. Such relationships can be simulated using empirical models. In this study, several statistical techniques were applied on winter oilseed rape data collected in some European countries. The empirical models were then used to predict yield of winter oilseed rape in the field experiments during more than 20 years, up to 2013. Results suggest that newly developed regression techniques such as shrinkage methods work well both in yield projections and finding the influential climatic variables. Many of regression techniques agree in terms of yield prediction; however, choice of significant climate variables is rather sensitive to the choice of regression technique. No Label |
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MA @ admin @ |
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2092 |
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