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Liu Y.,Key Laboratory of Agricultural Environment | Liu Y.,Chinese Academy of Agricultural Sciences | Liu Y.,China Agricultural University | Yang X.,China Agricultural University | And 2 more authors.
Regional Environmental Change | Year: 2014

El Niño-Southern Oscillation (ENSO) contributes to climate anomalies, especially those related to regional rainfall, which affect crop production. Although the North China Plain (NCP) is the most important agricultural production region in China, the impact of ENSO events on local climate and crop production has received only limited attention. Therefore, the impact of different phases of ENSO on local climate and production of winter wheat and summer maize, both rain fed and irrigated, was investigated at three sites using the agricultural production systems simulator model. Data on daily temperature, precipitation, and sunshine hours for 50 years (1956-2006) were analysed to build climate scenarios for three categories of ENSO: years with El Niño events, years with La Niña events, and neutral years. The pattern of climate change was generally similar across the three sites: annual precipitation decreased slightly and annual mean sunshine hours decreased significantly, whereas annual mean minimum temperature increased significantly, leading to a significant increase in mean air temperature. Precipitation decreased and temperature and sunshine hours increased in both El Niño and La Niña years but remained stable in neutral years. Under full irrigation, the probability of exceeding distribution that crop yield would be higher was not markedly affected (P > 0.05), although the yields in both El Niño and La Niña years differed markedly from those in neutral years, especially in maize. Under rain-fed conditions, the yield of maize was decreased greatly (P < 0.05), the probability distribution of such reduction being the highest in La Niña years at all the sites (P < 0.05). At the provincial level, yields from well-managed fields differed (P > 0.05) with the ENSO category: production of maize was more vulnerable than that of wheat in El Niño and La Niña years. El Niño and La Niña had similar effects on climatic variables across the NCP: low yields in El Niño and La Niña years due to lower precipitation and high yields in neutral years due to longer sunshine hours and additional irrigation. © 2013 The Author(s).

Chen M.P.,Institute of Environment and Sustainable Development in Agriculture | Chen M.P.,Key Laboratory of Agricultural Environment | Guo B.L.,Institute of Environment and Sustainable Development in Agriculture | Guo B.L.,Key Laboratory of Agricultural Environment | And 5 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

Phosphorus (P) is one of three nutrients (together with nitrogen and potassium) essential for plant growth. It is also an important non-renewable, non-metal mineral resource. With economic development and population increases, phosphorus scarcity has become an important global challenge to the sustainability of agriculture, the economy, and the environment. To analyze human influences on phosphorus flow, research has simulated anthropogenic-centered phosphorus flows within socioeconomic systems and sub-systems. This paper reviewed recent progress in phosphorus flow analysis, identified the characteristics and insufficiencies of existing studies, and projected future avenues of development for phosphorus flow analysis. Existing studies may be categorized according to the scale of the socioeconomic system (or sub-system) into four levels-global, national (including multi-national), regional, or city level-as well as either enterprise or product level. Presently, most studies have been conducted at the global or national (or multi-national) levels, while few has been performed at regional or city levels, or at enterprise or product levels. So far, more than 15 countries and multi-national regions have carried out phosphorus flow analyses, most of which focused on disturbances due to agriculture and food production and consumption. A few studies have examined disturbances due to forestry, iron and steel production, and energy sector activities, and the potential for increasing phosphorus use efficiencies in these sectors. In addition, most current studies use static models, and few employ dynamic models that consider long-term changes in phosphorus stocks. Fewer studies combines classical methods and tools, such as life-cycle analysis or input-output analysis, with material flow analysis or substance flow analysis (MFA or SFA). We identified five topics for future researches:(1) dynamic simulations of phosphorus flow with consideration of long-term changes in important driving forces (population, diet, bio-energy development, etc.) and in phosphorus stocks, (2) phosphorus footprint analyses at various scales or for various sectors of economic development, (3) the critical need for phosphorus for social and economic development, compared to that of other elements (such as metals or rare earth elements), (4) the vulnerability of phosphorus to global changes (particularly climate change), and (5) the relationship between phosphorus and other important elements (such as carbon, nitrogen, or metal elements). To meet future research demands, it is necessary to develop a dynamic model of phosphorus flow and to combine traditional material flow analyses with current tools and models, both from industrial ecology and from other disciplines. These may include economic models, input-output analyses, life-cycle analyses, network analyses, and computable general equilibrium models, and agent-based models, all required to project the effects of global changes, socio-economic development, and technological innovation on phosphorus flow and the resulting environmental impacts. © 2015 Ecological Society of China. All rights reserved.

Liu X.-R.,Chinese Academy of Agricultural Sciences | Liu X.-R.,Key Laboratory of Agricultural Environment | Ren J.-Q.,Chinese Academy of Agricultural Sciences | Li S.-G.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | And 2 more authors.
PLoS ONE | Year: 2015

Effects of simulated nitrogen (N) deposition on soil net nitrogen mineralization (NNM) were examined in situ during two growing seasons, using the resin-core technique in the semiarid meadow steppe in Inner Mongolia, China. The aim of this study is to clarify the effect of N levels (0, 10, and 20 kg N ha-1yr-1) and forms (NH4 + and NO3) on soil mineral N and NNM. Our results showed that N levels had no significant differences on soil mineral N and NNM. In the first year, three N treatments ((NH4)2SO4, NH4Cl and KNO3) increased soil NH4 + concentrations but had no significant effects on soil NO3 - concentrations. In the second year, (NH4)2SO4 treatment increased soil NO3-concentrations, NH4Cl and KNO3 treatments decreased them. Three N treatments significantly decreased soil NH4 + concentrations in the later stages of the second year. As for the soil NNM, three N treatments had no significant effects on the rates of soil NNM (Rm) and net nitrification (Rn) in the first year, but significantly decreased them in the second year. The contribution of N addition to Rm was higher from (NH4)2SO4 than from NH4Cl and KNO3. However, Soil Rm was mainly affected by soil water content (SWC), accumulated temperature (Ta), and soil total N (TN). These results suggest that the short-term atmospheric N deposition may inhibit soil NNM in the meadow steppe of Inner Mongolia. © 2015 Liu et al.

Liu Y.,Chinese Academy of Agricultural Sciences | Liu Y.,Key Laboratory of Agricultural Environment | Liu Y.,National Engineering Laboratory of Efficient Water | Liu B.,Chinese Academy of Agricultural Sciences | And 8 more authors.
Journal of Water and Climate Change | Year: 2016

Evapotranspiration integrates atmospheric demand and surface conditions. The Penman-Monteith equation was used to calculate annual and seasonal reference evapotranspiration (ET0) and thermodynamic and aerodynamic components (ETrad and ETaero) at 77 stations across northeast China, 1961–2010. The results were: (1) annual ETrad and ETaero had different regional distribution, annual ETrad values decreased from south to north, whereas the highest ETaero values were recorded in the eastern and western regions, the lowest in the central region; (2) seasonal ETaero distributions were similar to seasonal ET0, with a south–north longitudinal pattern, while seasonal ETrad distributions had a latitudinal east-west pattern; and (3) in the group for ET0 containing 69 sampling stations, effects of climatic variables on ET0 followed sunshine hours>relative humidity>maximum temperature>wind speed. Changes in sunshine hours had the greatest effect on ETrad, but wind speed and relative humidity were the most important variables to ETaero. The decline in sunshine duration, wind speed, or both over the study period appeared to be the major cause of reduced potential evapotranspiration in most of NEC. Wind speed had opposite effects on ETrad and ETaero, and therefore the effect of wind speed on ET0 was not significant. © IWA Publishing 2016.

Yang J.-Y.,Chinese Academy of Agricultural Sciences | Yang J.-Y.,State Engineering Laboratory of Efficient Water Use and Disaster Reduction for Crops | Yang J.-Y.,Key Laboratory of Dryland Agriculture | Liu Q.,Chinese Academy of Agricultural Sciences | And 12 more authors.
Journal of Integrative Agriculture | Year: 2013

Climate change will have important implications in water shore regions, such as Huang-Huai-Hai (3H) plain, where expected warmer and drier conditions might augment crop water demand. Sensitivity analysis is important in understanding the relative importance of climatic variables to the variation in reference evapotranspiration (ET0). In this study, the 51-yr ET0 during winter wheat and summer maize growing season were calculated from a data set of daily climate variables in 40 meteorological stations. Sensitivity maps for key climate variables were estimated according to Kriging method and the spatial pattern of sensitivity coefficients for these key variables was plotted. In addition, the slopes of the linear regression lines for sensitivity coefficients were obtained. Results showed that ET0 during winter wheat growing season accounted for the largest proportion of annual ET0, due to its long phenological days, while ET0 was detected to decrease significantly with the magnitude of 0.5 mm yr-1 in summer maize growing season. Solar radiation is considered to be the most sensitive and primarily controlling variable for negative trend in ET0 for summer maize season, and higher sensitive coefficient value of ET0 to solar radiation and temperature were detected in east part and southwest part of 3H plain respectively. Relative humidity was demonstrated as the most sensitive factor for ET0 in winter wheat growing season and declining relativity humidity also primarily controlled a negative trend in ET0, furthermore the sensitivity coefficient to relative humidity increased from west to southeast. The eight sensitivity centrals were all found located in Shandong Province. These ET0 along with its sensitivity maps under winter wheat-summer maize rotation system can be applied to predict the agricultural water demand and will assist water resources planning and management for this region. © 2013 Chinese Academy of Agricultural Sciences.

Liu Y.,Chinese Academy of Agricultural Sciences | Liu Y.,Key Laboratory of Agricultural Environment | Liu B.,Chinese Academy of Agricultural Sciences | Liu B.,Key Laboratory of Agricultural Environment | And 6 more authors.
Regional Environmental Change | Year: 2014

Studying the causes of drought is important because the formation of large regional droughts is linked to global atmospheric system abnormalities in China. Information about the effects of drought on crop production is needed in order to improve understanding of a region’s drought vulnerability and to improve food production safety in the North China Plain. This paper uses agricultural statistics and monthly Southern Oscillation Index data between 1961 and 2007 to quantitatively evaluate regional agricultural meteorological disasters and to assess the regressive models used to predict the grain yield and climatic yield losses caused by drought disasters. The data showed that the drought-covered area ratios declined, but the drought-affected area ratios rose. During the La Niña stage, the probability of a drought disaster was higher than during the El Niño stage, especially in Hebei. In the El Niño years, there were negative trends for the drought-covered, -affected and -destroyed area ratios in winter and positive trends in the other three seasons. In the La Niña years, the drought disaster area ratios were positive for all seasons. In Neutral years, there was more likely to be a drought event in autumn. The regression analyses for the three provinces showed that the grain climatic yield loss was significantly associated with the grain yield loss caused by drought disasters. This showed that regional grain yield simulations and evaluations of agro-meteorological disasters reliably predicted the field measured statistical data for drought disasters. Therefore, our results showed that there is a mixed seasonal trend in the drought disaster areas in the El Niño years, but a consistent upward trend for all seasons in the La Niña years. We also showed that the damage caused by drought disasters can be quantified by estimating the yield loss. © 2014 Springer-Verlag Berlin Heidelberg

Chen M.,Chinese Academy of Agricultural Sciences | Chen M.,Key Laboratory of Agricultural Environment | Xia X.,Chinese Academy of Agricultural Sciences | Xia X.,Key Laboratory of Agricultural Environment | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013

Partitioning soil respiration components is a very important step before we understand the carbon cycling in terrestrial ecosystem. Studies on processes and mechanisms between different soil respiration components in cropland ecosystem will help to promote greenhouse gases mitigation, carbon sequestration and storage, climate change adaptation, food security and sustainable development of agriculture. In this context, this paper reviews theoretical and technical development of soil respiration component partitioning in recent decades, including the theoretical premises, the development and classification of partitioning techniques. This paper also compares the advantages and disadvantages of most partitioning techniques, analyzes their applicability for different systems, and summarizes the application of current soil respiration partitioning techniques in cropland ecosystem in China as well as in world. Generally speaking, since most soil respiration partitioning techniques are developed in the studies of forest ecosystem, they are not suitable for cropland ecosystem. Presently, isotope methods, root excised method and regression method are major applied techniques of soil respiration partitioning in cropland ecosystem. Due to the differences in theoretical premises and techniques choices for soil respiration partitioning, results from different researches are difficult to compare. Further development of partitioning techniques relies on the breakthrough of soil respiration partitioning theories and future breakthroughs in the researches related to soil respiration partitioning will lie in the following aspects: (1) Component integration methods and root excised method will be improved to better apply in cropland ecosystem by making best of present soil respiration monitoring technologies and systems. The simultaneously monitoring of soil respiration components and environmental factors will be strengthened and cropland carbon budget will be more physically-based and reliable. (2) Large-scale modeling on carbon cycling will take advantages of existing long-term on-site monitoring data to upscale soil respiration processes and mechanisms. With this, existing global carbon cycling models could improve or change current carbon-nitrogen processes and adopt important soil respiration processes. (3) With FACE (free-air carbon dioxide enrichment) experiments, researchers could evaluate the impacts of climate change on different soil respiration components and identify the adaptive mechanisms of soil-plant carbon cycling to climate change. (4) The interaction between soil respiration components and plant-soil-nutrient will be examined to evaluate the integrated impacts of cropland management practices.

Xu J.W.,Chinese Academy of Agricultural Sciences | Xu J.W.,Key Laboratory of Agricultural Environment | Ju H.,Chinese Academy of Agricultural Sciences | Ju H.,Key Laboratory of Agricultural Environment | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014

It is widely recognized that the frequency and intensity of extreme weather events and climate disasters have strongly increased with global warming. The area of influence of climate disasters has also increased, which has had adverse effects on sustainable social and economic development. Drought is a recurring natural phenomenon, and is associated with a deficit of water resources over a large geographic area and long duration. Drought is attracting increased attention from scholars, with a focus on its intensity, duration and areal extent in northern China within the context of global change. Investigation of the variation of drought and regional response to climate change is very important to agricultural production, and can provide a reference fordeveloping appropriate measures to reduce droughts on the Huang-Huai-Hai(3H) Plain. At present, relevant research is more inclined to study meteorological drought itself, without consideration of drought characteristics in different phases in crop-growing seasons and the climate background of global change. In this paper, we determine drought characteristics in all four seasons and the winter wheat growing season on the 3H Plain, together with the effects of climate change. Based on data of 34 meteorological stations from 1961 to 2011, a relative moisture index was calculated to investigate the spatial pattern and temporal variability of drought characteristics on the 3H Plain. The results show varying degrees of drought in spring, winter and the winter wheat growing season. Drought frequency exceeded 90% over the past 50 years on the plain, with spring and winter the driest seasons. There were high-frequency drought areas in central and northern parts of the plain during spring, winter and the winter wheat growing season. The regional distribution of drought intensity and frequency showed an increasing tendency from south to north. A wet trend was detected on the plain in the winter wheat growing season over the last 50 years. However, the relative moisture index changed since 1978. That is to say, the index had an increasing trend from 1961 to 1980 when the plain was wetter; the index decreased from 1980 to 2011 when it was drier. Overall, although drought eased over the entire analysis period, a serious drought tendency has emerged over the last 20 years. In addition, temporal variability of the relative moisture index was significantly correlated with precipitation, solar radiation and relative humidity. This indicates that drought characteristics of the plain were more sensitive to these three climate variables. This has received increased attention in recent years with respect to addressing climate change. The results of our study indicate an arid trend, with increase of temperature in spring and summer on the 3H Plain. Therefore, relevant agencies should create an early warning system of extreme weather events and natural disasters, toward improvement of future regional agricultural scientific management and decision support systems in agricultural production. These agencies should also adapt to climate change by selecting strongly drought-resistant crop varieties and by adjusting cultivation methods and management measures, especially irrigation measures aimed at spring drought on the 3H Plain.

Hu W.,Chinese Academy of Agricultural Sciences | Hu W.,Key Laboratory of Dryland Agriculture | Yan C.R.,Chinese Academy of Agricultural Sciences | Yan C.R.,Key Laboratory of Dryland Agriculture | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014

This paper investigated impacts of climate change on irrigation water requirement for winter wheat with consideration to growing period in the North China Plain(NCP), benefitting to make irrigation scheduling and adaptive strategy. Based on data from 4 typical meteorology stations including Beijing Miyun and Shijiazhuang Nangong stations in the west and Tianjin Baodi and Xingtai Nangong stations in the east and phenology data of winter wheat during 1981 to 2010, the objective of this study is to investigate impacts of climate change on winter wheat irrigation water requirements in growth stages. The results showed that the dates of sowing stage and seeding stage delayed and the more variation of trend was at high latitudes, while the others showed an advanced trend. Then the spatial variation of irrigation water requirement in the NCP was decreasing from south to north in the past 30 years. And in temporal distribution study, there was a marked increase in east, but it was opposite in west area. The irrigation water requirement during the different growth stages made a different change with time. Except for a slight rise during the seeding to jointing stage in two stations and milky to maturity, the irrigation water requirements were reduced during the other growth periods. In the whole growth stages, the west sites were decreased by 6. 72 mm/ 10a and 8. 3 mm/ 10a, respectively. However, in the east sites, there was an increasing tendency of irrigation water requirements with 2. 6 mm/ 10a and 7. 08 mm/ 10a, respectively. Besides the order of annual fluctuation was: sowing to seeding stage>milky to maturity>heading to milk stage>jointing to heading stage>seeding to jointing stage > sowing to maturity. The influence of different meteorological elements on irrigation water requirement was relatively various. The relationship between irrigation water requirement and effective precipitation and related humidity was negative significant, to the contrary, the impact of wind speed, sunshine duration and mean temperature was positive. And correlation was slightly negative between irrigation water requirement and growth period length. The consequence would be more precise if growth period length was taken into consideration in the formula. Therefore, the main climatic factors influencing the irrigation water requirements were different in each growth stage. The prior impact factor was related humidity in jointing to heading stage, while the main factors were different between Beijing Miyun station and others even during the same period of heading to milky stage due to the different districts, which were mean temperature and related humidity, respectively. But for other growth stages, the influence of effective precipitation on irrigation water requirement was more important than other factors. Thus the results could become more realistic, which provided theoretical basis for the reasonable irrigation system and strategies of adapting to climate change.

Xu J.W.,Chinese Academy of Agricultural Sciences | Ju H.,Chinese Academy of Agricultural Sciences | Ju H.,Key Laboratory of Agricultural Environment | Liu Q.,Chinese Academy of Agricultural Sciences | And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014

With the purpose of probing the drought characteristic in growth stages and its possible climate factors of winter wheat in Huang-Huai-Hai plain (3H plain) under climate change,based on meteorology data of 5 selected meteorological stations from 1981 to 2010, relative moist index has been calculated to investigate the temporal variability of drought characteristic in five growth stages of winter wheat in 3H Plain in recent 30 years.The results indicated that on the temporal variation, an increasing drought trend was detected in sowing to seeding stage in southern of 3H plain while a contrary trend was found in northern of 3H plain, and the same slight tendency was detected in whole growth period. The drought of growth stages except seedling stage was reduced from north to south. The most severe drought occurred in the seeding to jointing stage and a slight increasing drought trend was detected in north while a decreasing drought trend in south in this stage. A drought trend was detected in heading to maturity, with higher magnitude in south than in north. Tianjin and Shijiazhuang stations were observed to be medium drought and serious drought primarily in whole growth period, the frequency of varying degrees of droughts in Shenxian station was equivalent while Xuzhou and Zhumadian stations were observed to be primarily slight drought from 1981 to 2009. Continuous drought of Tianjin and Shijiazhuang station was serious while sustained drought was not found in Zhumadian station in recent 30 years. With the temperature increasing, aridification might be enhanced in Tianjin and Shijiazhuang stations while a contrary trend was found in Shenxian, Xuzhou and Zhumadian stations in whole growth period of winter wheat. The trend of drought will be alleviated with the temperature decreasing in jointing to heading stage and heading to maturity statge. Drought in sowing to seeding stage will be more obvious in Tianjin and Xuzhou stations with the solar radiation increasing. There was a drought trend detected in Shijiazhuang and Zhumadian stations with the relative humidity decreasing in growth stages. Besides, with the wind speed decreasing, moisture tendency will be found in whole growth period and heading to maturity in southern of 3H Plain. The research results can provide a reference for the simulation study on the impact of drought on yield of winter wheat and developing appropriate measures to reduce droughts in the 3H plain.

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