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1.
In order to analyze impacts of climate change on managed grassland systems and to project potential changes in farmers’ management practices in response to altered climatic conditions, we develop a modeling approach that integrates a process-based grassland model into an economic model. This economic model describes farmers’ decision making with respect to input use and accounts for production levels, production risks, fodder quality as determined by the grassland composition, and environmental protection. We apply the bio-economic model to an intensively managed grassland system with a geographic focus on the Swiss Plateau. Our results show an increase of future production risks in grassland production due to climate change. Projected changes in yield levels, grassland composition and optimal responses of risk-averse farmers are dependent on the assumptions concerning cross-compliance obligations, forage quality and particularly on the assumed effect of elevated CO2 concentrations: Grasslands yields will increase under future climatic conditions only if the benefits of rising atmospheric CO2 concentrations are taken into account. Without this potential benefit, climate change will lead to less intensive input use and lower grassland yields.  相似文献   

2.
Based on future climate change projections offered by IPCC, the responses of yields and water use efficiencies of wheat and maize to climate change scenarios are explored over the North China Plain. The climate change projections of 21st century under A2A, B2A and A1B are from HadCM3 global climate model.A climate generator (CLIGEN) is applied to generate daily weather data of selected stations and then the data is used to drive CERES-Wheat and Maize models. The impacts of increased temperature and CO2 on wheat and maize yields are inconsistent. Under the same scenario, wheat yield ascended due to climatic warming, but the maize yield descended. As a more probable scenario, climate change under B2A is moderate relative to A2A and A1B. Under B2A in 2090s, average wheat yield and maize yield will respectively increase 9.8% and 3.2% without CO2 fertilization in this region. High temperature not only affects crop yields, but also has positive effect on water use efficiencies, mainly ascribing to the evapotranspiration intensification. There is a positive effect of CO2 enrichment on yield and water use efficiency. If atmospheric CO2 concentration reaches nearly 600 ppm, wheat and maize yields will increase 38% and 12% and water use efficiencies will improve 40% and 25% respectively, in comparison to those without CO2 fertilization. However, the uncertainty of crop yield is considerable under future climate change scenarios and whether the CO2 fertilization may be realized is still needed further research.  相似文献   

3.
以渭北旱塬合阳和长武2个试验站点为研究区域,通过多年的玉米田间试验数据评估CERES-Maize模型的适用性,再利用区域气候模式Reg CM4.0输出的气象数据对2050年前玉米单产及生产水足迹进行预测。结果表明:CERES-Maize模型可以很好地模拟雨养玉米产量和物候期,多数年份二者的绝对相对误差(Absolute relative error,ARE)在10%以内,CERES-Maize模型在渭北旱塬旱作农业区有很好的适用性。应用CERES-Maize模型模拟玉米生产水足迹,较传统水足迹计算方法得到的结果更为精确可靠。在RCP2.6气候情景下,随着温度升高和生育期有效降水量的增加,玉米产量呈上升趋势;在RCP8.5气候情景下,随着温度升高和生育期有效降水的减少,玉米产量呈下降趋势。气温上升幅度过大对玉米单产有明显的负面影响,降水与玉米用水效率呈正相关。为有效应对气候变化对旱作作物产量造成的负面影响,应采取减少温室气体排放量、增强土壤蓄水保墒能力、发展集雨补灌、筛选和培育节水抗旱新品种等措施。  相似文献   

4.
The East African region exhibits considerable climatic and topographic variability. Much spatial and temporal variation in the response of different crops to climate change can thus be anticipated. In previous work we showed that a large part of this variation can be explained in terms of temperature and, to a lesser extent, water effects. Here, we summarise simulated yield response in two crops that are widely grown in the region, maize and beans, and investigate how the impacts of climate change might be addressed at two levels: the agricultural system and the household. Regionally, there are substantial between-country and within-system differences in maize and bean production responses projected to 2050. The arid-semiarid mixed crop-livestock systems are projected to see reductions in maize and bean production throughout most of the region to 2050. Yields of these crops in the tropical highland mixed systems are projected to increase, sometimes substantially. The humid-subhumid mixed systems show more varied yield responses through time and across space. Some within-country shifts in cropping away from the arid-semiarid systems to cooler, higher-elevation locations may be possible, but increased regional trade should be able to overcome the country-level production deficits in maize and beans caused by climate change to 2050, all other things being equal. For some places in the tropical highlands, maize and bean yield increases could have beneficial effects on household food security and income levels. In the other mixed systems, moderate yield losses can be expected to be offset by crop breeding and agronomic approaches in the coming decades, while more severe yield losses may necessitate changes in crop types, movement to more livestock-orientated production, or abandonment of cropping altogether. These production responses are indicative only, and their effects will be under-estimated because the methods used here have not accounted for increasing weather variability in the future or changes in the distribution and impacts of biotic and other abiotic stresses. These system-level shifts will take place in a context characterised by high population growth rates; the demand for food is projected to nearly triple by the middle of this century. Systems will have to intensify substantially in response, particularly in the better-endowed mixed systems in the region. For the more marginal areas, the variability in yield response, and the variability in households’ ability to adapt, suggest that, even given the limitations of this analysis, adaptation options need to be assessed at the level of the household and the local community, if research for development is to meet its poverty alleviation and food security targets in the face of global change.  相似文献   

5.
Three economic models varying in aggregation, crops analyzed, and regions modeled are used to determine potential impacts of the use of improved climate forecasts on agriculture. Different regions and crops both within a region and between regions may be affected differently. Expected values of variables such as costs, yields, input usage, etc., may increase or decrease with the use of improved climate forecasts. Further, current changes in the US Federal Farm Program may increase the value of improved climate forecasts because of the elimination of most planting restrictions, acreage reduction, and disaster assistance. The addition of catastrophic crop insurance appears to decrease the value of improved forecasts.  相似文献   

6.
Impacts of climate variability and climate change on regional crop yields are commonly assessed using process-based crop models. These models, however, simulate potential and water limited yields, which do not always relate to observed yields. The latter are largely influenced by crop management, which varies by farm and region. Data on specific management strategies may be obtained at the field level, but at the regional level information about the diversity in management strategies is rarely available and difficult to be considered adequately in process-based crop models. Alternatively, understanding the factors influencing management may provide helpful information to improve simulations at the regional level.In this study, we aim to identify factors at the regional level that explain differences between observed and simulated yields. Observed yield data were provided by the Farm Accountancy Data Network (FADN) and Eurostat. The Crop Growth Monitoring System (CGMS), based on the WOFOST model, was used to simulate potential and water limited maize yields in the EU15 (i.e., the old member states of the European Union). Differences between observed and simulated maize yields were analysed using regression models including: (i) climatic factors (temperature and precipitation), (ii) farm size, (iii) farm intensity, (iv) land use, (v) income and (vi) subsidies. We assumed that the highest yields observed in a region were close to the yield potential as determined by climate and considered the average regional yields as also influenced by management. Model performance was analysed with respect to spatial and temporal yield variability.Results indicate that for potential yield, the model performed unsatisfactory in southern regions, where high temperatures increased observed yields which was in contrast to model simulations. When considering management effects, we find that especially irrigation and the maize area explain much of the differences between observed and simulated yields across regions. Simulations of temporal yield variability also diverted from observed data of which about 80% could be explained by the climatic factors (35%) and farm characteristics (50%) considered in the analysis. However, effects of specific factors differed depending on the regions. Accordingly, we propose different groups of regions with factors related to management which should be considered to improve regional yield simulations with CGMS.  相似文献   

7.
Assessing the impact of climate change on agriculture is a new challenge for quantitative model-based policy analysis. The impact of climate change will vary strongly across regions depending on pre-existing climatic, agronomic, and political conditions. Most of the present modeling approaches, which aim to analyze the impact of global change on agriculture, deliver aggregated results both with regard to content and spatial resolution. To deliver results with a higher spatial resolution and to produce a more detailed picture of agricultural production, the county-based agro-economic model known as ACRE-Danube was developed. The German and Austrian part of the Upper Danube basin, a study area with great diversity in agricultural landscapes and climatic conditions, was chosen for study. For the analysis, two scenarios of climatic and socio-economic change were derived. The first and more economically and globally oriented scenario, termed “Full Liberalization,” included significant temperature increases. The second and more environmentally and regionally oriented “Full Protection” scenario included a moderate temperature increase. Both scenarios produce different results regarding agricultural income and land use. While the developments in the Full Protection scenario are small, the Full Liberalization scenario yields extreme regional changes in agricultural income, an increase in cereal production and extensive grassland farming.  相似文献   

8.
Ethanol from various plant resources, especially maize, is increasingly being used as a substitute for fossil fuels. The production potential of ethanol from maize varies with weather and climatic conditions and crop management practices. The merits and prospects of ethanol production have been evaluated based on its impact on greenhouse gas emissions, economic viability and national energy security. The net energy value (NEV), i.e. the output energy after all non-renewable energy inputs have been accounted for, is a measure of energy gain. At the same time, the NEV can be an indicator for the long-term sustainability of bio-ethanol production, regardless of other conditions e.g. climate change scenarios, global trade restrictions, or local variability in natural resources such as water availability. Crop management practices directly affect the NEV of ethanol. Moreover, both crop management practices and climate variability affect the NEV through the grain yield. The objective of this study was to assess the impact of crop management practices and climate variability on grain yield of maize for ethanol production and ethanol NEV for conditions that represent the southeastern USA. Maize grain yield was simulated with the dynamic crop growth model CSM–CERES–Maize and ethanol NEV was calculated using the simulated yield levels and crop management practices. The simulations were conducted for conditions representing Mitchell County, Georgia, USA, using weather data from 1939 to 2006 and local soil profile information. The impact of irrigation, nitrogen fertilizer, planting date and El Niño Southern Oscillation (ENSO) phases were determined for the maize cultivars DeKalb DKC 61-72 (RR2), Pioneer 31D58 and Pioneer 31G98. Crop management practices and ENSO phase had a significant impact on ethanol feedstock production and NEV. The NEV of ethanol produced from irrigated maize was more than two times higher and varied less than the NEV of ethanol from rainfed maize. NEV of ethanol produced from maize grown during La Niña years was significantly higher than maize grown during El Niño years, both under rainfed and irrigated conditions. This study showed the importance of crop management practices and climate variability on ethanol feedstock productivity and long-term energy sustainability as assessed by the NEV. We discuss methods of implementing the findings of this study in practical farming e.g. through market mechanisms and governmental initiatives.  相似文献   

9.
武功地区气候变化及其对夏玉米单产的影响   总被引：1，自引：0，他引：1  
基于陕西武功站1935-2010年的逐月气象数据及夏玉米产量等资料,采用Mann-Kendall法、直线滑动平均模拟法和通径分析法,分析了武功地区1935-2010年各个气象因子的变化特征以及气候变化对夏玉米单产的影响．结果表明:该地区最低气温呈上升趋势,风速、日照时数呈下降趋势;夏玉米生育期最低气温和相对湿度呈上升趋势,最高气温、日照时数和风速均呈下降趋势,变化速率分别为0116 ℃／10a,0006／10a,-0158 ℃／10a,-26707 h／10a和-0063 m／(s·10a),SPI呈减小趋势,气候朝干旱演变;夏玉米生育期各气象因素能综合其他气象因素的信息对单产产生作用,日照时数对夏玉米单产综合决定能力最高,决策系数为2309％,降水量呈减小趋势是夏玉米单产增加的主要限制性气象因素,决策系数为-673％;通过技术创新等人为因素作用,可在一定程度上缓解气候变化给武功地区夏玉米生产带来的负面影响．  相似文献   

10.
适宜的播种时期和密度是玉米生长及产量形成的关键因素。以蠡玉37品种为试验对象,研究辽西地区不同播期、密度对玉米生长性状及产量的影响,探讨适宜辽西半干旱地区气候条件的玉米种植技术,以实现玉米生产高产高效。  相似文献   

11.
Crop yield responses to climate change in the Huang-Huai-Hai Plain of China   总被引：3，自引：0，他引：3  
Global climate change may impact grain production as atmospheric conditions and water supply change, particularly intensive cropping, such as double wheat-maize systems. The effects of climate change on grain production of a winter wheat-summer maize cropping system were investigated, corresponding to the temperature rising 2 and 5 °C, precipitation increasing and decreasing by 15% and 30%, and atmospheric CO2 enriching to 500 and 700 ppmv. The study focused on two typical counties in the Huang-Huai-Hai (3H) Plain (covering most of the North China Plain), Botou in the north and Huaiyuan in the south, considering irrigated and rain-fed conditions, respectively. Climate change scenarios, derived from available ensemble outputs from general circulation models and the historical trend from 1996 to 2004, were used as atmospheric forcing to a bio-geo-physically process-based dynamic crop model, Vegetation Interface Processes (VIP). VIP simulates full coupling between photosynthesis and stomatal conductance, and other energy and water transfer processes. The projected crop yields are significantly different from the baseline yield, with the minimum, mean (±standardized deviation, SD) and maximum changes being −46%, −10.3 ± 20.3%, and 49%, respectively. The overall yield reduction of −18.5 ± 22.8% for a 5 °C increase is significantly greater than −2.3 ± 13.2% for a 2 °C increase. The negative effect of temperature rise on crop yield is partially mitigated by CO2 fertilization. The response of a C3 crop (wheat) to the temperature rise is significantly more sensitive to CO2 fertilization and less negative than the response of C4 (maize), implying a challenge to the present double wheat-maize systems. Increased precipitation significantly mitigated the loss and increased the projected gain of crop yield. Conversely, decreased precipitation significantly exacerbated the loss and reduced the projected gain of crop yield. Irrigation helps to mitigate the decreased crop yield, but CO2 enrichment blurs the role of irrigation. The crops in the wetter southern 3H Plain (Huaiyuan) are significantly more sensitive to climate change than crops in the drier north (Botou). Thus CO2 fertilization effects might be greater under drier conditions. The study provides suggestions for climate change adaptation and sound water resources management in the 3H Plain.  相似文献   

12.
《Agricultural Systems》2007,94(1-3):191-214
The response of arable crops and grasslands to climatic changes and increasing CO2 concentration has implications for the operation of farms, in particular for the management of resources such as nitrogen. A simple dynamic farm model (Stella© model ‘CH-Farm’) was used to analyze the shift in the ratio of N lost via leaching, denitrification and volatilization to N exported with products from dairy or arable production (here defined as relative N loss). The model was run for two types of farms typical of Swiss conditions. Growth parameters for two sequentially grown crops (winter wheat and maize) and grass were determined with the process-oriented models Pasture Simulation Model (PaSim) and CropSyst, respectively. CH-Farm was forced with two assumptions about the transient change in temperature and precipitation, and with or without CO2 effects. Relative N loss for the baseline was around 1.33 for the dairy-type farm and around 1.05 for the arable-type farm and increased progressively over the 100-year simulation period, with the largest shift in response to the dry/hot scenario. Soil N pools decreased with all scenarios, but at different rates. CO2 fertilization alleviated the effect of climate change due to increased productivity and N fixation in plants. Adjustment of the growth parameters to progressively increasing temperatures reduced the difference between farm types and positively affected relative N losses mainly through increased productivity and reduced fallow periods between crops. The results suggest that the impact of climate change on relative farm-level N loss depends on physiological adjustments to climatic scenarios, whereas the distribution of land between dairy and arable crop production is less important, and that simple cultivar adjustments can help to mitigate negative effects of climate change on farm-level N use.  相似文献   

13.
Despite the importance of livestock to poor people and the magnitude of the changes that are likely to befall livestock systems, the intersection of climate change and livestock in developing countries is a relatively neglected research area. Little is known about the interactions of climate and increasing climate variability with other drivers of change in livestock systems and in broader development trends. In many places in the tropics and subtropics, livestock systems are changing rapidly, and the spatial heterogeneity of household response to change may be very large. While opportunities may exist for some households to take advantage of more conducive rangeland and cropping conditions, for example, the changes projected will pose serious problems for many other households. We briefly review the literature on climate change impacts on livestock and livestock systems in developing countries, and identify some key knowledge and data gaps. We also list some of the broad researchable issues associated with how smallholders and pastoralists might respond to climate change. The agendas of research and development organisations may need adjustment if the needs of vulnerable livestock keepers in the coming decades are to be met effectively.  相似文献   

14.
Recent changes in the climatic yield potential of various crops in Europe   总被引：1，自引：0，他引：1  
Recent changes in the simulated potential crop yield and biomass production caused by changes in the temperature and global radiation patterns are examined, using the Crop Growth Monitoring System. The investigated crops are winter wheat, spring barley, maize, winter rapeseed, potato, sugar beet, pulses and sunflower. The period considered is 1976-2005. The research was executed at NUTS2 level. Maize and sugar beet were the crops least affected by changing temperature and global radiation patterns. For the other crops the simulated potential yield remained stable in the majority of regions, while decreasing trends in simulated potential yields prevailed in the remaining regions. The changes appear in a geographical pattern. In Italy and southern central Europe, temperature and radiation change effects are more severe than elsewhere, in these areas potential crop yields of more than three crops significantly decreased. In the UK and some regions in northern Europe the yield potential of various crops increased.In a next step the national yield statistics were analyzed. For a large majority of the countries the yield increases of wheat, barley and to a lesser extent rapeseed are leveling off. Several explanations could be given, however, as the simulated yield potential for these crops decreased in various regions, the changing temperature and radiation patterns may also contribute to the diminishing yield increases or to the stagnation. In more than 50% of the investigated countries the maize, potato and sugar beet yields continue to increase. This can be attributed to improving production techniques, new crop varieties, sometimes in combination with an improving climatic potential. In some regions in northern Europe, yields continue to increase.  相似文献   

15.
More efficient use of water in agricultural systems is widely needed. However, most irrigated systems are characterized by heterogeneous climate and soil conditions that interact strongly with irrigation management, making optimal irrigation decisions difficult to achieve. Here we investigated the impact of reduced irrigations on spring wheat yields in the Yaqui Valley of Mexico, a region experiencing increased water scarcity. Two years of field experiments containing three irrigation treatments each were used to evaluate the CERES-wheat crop model, with good agreement between observed and modeled yields. The model was then used in a sensitivity analysis whereby seven irrigation strategies were applied across a range of possible soil and climatic conditions. Results indicated that yield losses from reduced irrigations depend greatly on year, corresponding to large variations in rainfall between growing seasons. Estimates of the best timing strategy for a given number of irrigations were more robust with respect to climate variability. Soils also exhibited a strong interaction with irrigation, with the difference between initial soil moisture and wilting point deemed particularly important in this system. The optimal economic strategy was determined for each hypothetical soil based on the observed historical distribution of growing season climatic conditions. The results of this study demonstrate the need to consider soil and climate variability when interpreting experimental results, and the ability of the CERES model to serve this need by quantifying the relative importance of different heterogeneous factors.  相似文献   

16.
1960年以来河南省玉米气候生产潜力估算与种植空间优化   总被引：1，自引：0，他引：1  
农作物生长直接依赖于降水、光照及温度等自然要素,对全球气候变化的影响最为敏感。基于河南省1960—2015年气候观测和太阳辐射量数据,采用逐步订正法估算了159个县级空间单元的玉米气候生产潜力,并进行河南省玉米种植空间的优化。结果表明：在全球气候变化背景下,受气温和降水双因素驱动,河南省玉米气候生产潜力在1960—2015年间呈倒U形的动态变化,玉米生产高气候潜力空间持续向豫西迁移,弱势气候潜力区自2000年来聚集于河南省北部地区。61.11%的河南省玉米生产优势气候潜力区与玉米优势种植区现状重合,但其他各类型潜力区与种植区现状偏差较大。种植规模分为适当增加、逐步减少、保持稳定3种类型,提出河南省玉米种植空间优化方案和对策建议。  相似文献   

17.
【目的】明确清镇市1985—2015年气候变化特征与粮食产量的相关性。【方法】利用清镇市1985—2015年逐年平均气象数据(风速、海平面气压、降水、平均气温、日照时间、相对湿度、蒸发量),通过M-K检验、小波分析、HP滤波、RDA等方法,分析了气候变化特征及其与产量间的相关性。【结果】气温升高极显著,1994年、1997年出现突变,其他因子呈降低或减少趋势,日照时间突变最频繁;各因子振荡周期不一,变化周期以28 a最突出,目前除气温处于偏高期外,其他因子均处在偏低期;气候变化对粮食产值的影响有正有负,正影响最大值出现在2009年,在1990年和2011年负作用力达到最大。【结论】Monte Carlo Test表明,气候因子均与产量之间显著相关(P<0.05),粮食产量的43.3%能被选取的气候因子解释,气候产量与降水量、气温以及相对湿度正相关,与风速、海平面气压、蒸发量、日照时间负相关。  相似文献   

18.
ISAREG is a model for simulation and evaluation of irrigation scheduling. The model performs the soil water balance and evaluates impacts of water stress on yields for different crops. It is now being used to support a water saving irrigation scheduling program in a pilot area in the North China plain. This paper reports on the calibration and validation of the model using independent data sets relative to winter wheat and summer maize. Data are originated from the Wangdu experimental station and concern a set of drainage lysimeters where diverse irrigation treatments were applied representing different strategies of deficit irrigation. The calibration of the model was performed by deriving the crop coefficients adapted to the local climatic conditions, and considering the soil freezing during winter. The validation of the model was performed using different data sets. Results show that the relative errors to estimate the soil water content averaged 5.3% for summer maize and 7.3% for the winter wheat. These results support the use of the model in the practice.  相似文献   

19.
环境变化对河北省水资源量的影响   总被引：6，自引：3，他引：6  
分析了气候变化、地下水超采、地表径流及粮食产量变化等方面对水资源的影响，结论认为，在新一轮水资源评价中，要充分考虑环境变化对水资源量的影响，加强地下水位大埋深条件下地表产流量、地下水补给量以及作物产量水平提高对水资源影响的实验研究，以提高新一轮水资源评价成果的精度。  相似文献   

20.
等离子体种子处理技术是一项农业新技术。以玉米和水稻为例,验证等离子体种子处理技术的实际效果。试验结果表明：水稻和玉米种子经过处理后,最高增产分别达到106．0kg／667m^2、125．0kg／667m^2,且作物长势旺盛,基本不发生病虫害,减少了农药支出,有利于农业生态环境的保护,具有良好的经济效益和享十会效益,  相似文献   

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