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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).

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.

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.

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.

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