Regional Science Bureau for Asia and the Pacific UNESCO

Jakarta, Indonesia

Regional Science Bureau for Asia and the Pacific UNESCO

Jakarta, Indonesia
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Kang Y.,Sichuan Agricultural University | Kang Y.,Northwest University, China | Ma X.,Northwest University, China | Khan S.,Regional Science Bureau for Asia and the Pacific UNESCO
Irrigation and Drainage | Year: 2014

Climate change impacts on food supply and water use efficiency have become an urgent issue for the agricultural researchers and governments. With climate change, water resources will be a restricting factor for agriculture, especially in arid and semi-arid areas. This paper mainly discusses the changing tendency of water balance components, maize yield and water use indices under rainfed and irrigated conditions in subareas of the Loess Plateau under the A2 and B2 scenarios with the SWAGMAN® Destiny model. The results show that evapotranspiration will increase in future for both rainfed and irrigated maize under both scenarios. The water use indices mentioned in this paper have the same tendency under both scenarios in the same subareas, but variability under the A2 scenario is higher than that under B2. The crop yield and water use indices will decrease for rainfed maize production in the whole Loess Plateau. With irrigation, crop yield will increase in Clay Loam-2 and Clay Loam-1 while it will decrease in Light Loam and Sandy Loam under the A2 scenario and B2 scenarios in 2020, 2050 and 2080 respectively. The evapotranspiration efficiency and ratio of evapotranspiration and irrigation under irrigated maize will increase in Clay Loam-2, Clay Loam-1, Light Loam and Sandy Loam under both scenarios. Crop water use efficiency, irrigation water use efficiency and total water use efficiency will decrease under the A2 and B2 scenarios during irrigated maize growth. Therefore, for the rainfed crop, it is necessary to improve water harvesting technology so as to meet the increasing crop water requirements with climate change; while, for the irrigated crop, it is vital to enhance soil water capacity in order to make good use of the irrigated water. © 2013 John Wiley & Sons, Ltd.


Kang Y.,Sichuan Agricultural University | Kang Y.,Northwest University, China | Khan S.,Regional Science Bureau for Asia and the Pacific UNESCO | Ma X.,Northwest University, China
Irrigation and Drainage | Year: 2015

Climate change impacts on food production and water use efficiency are becoming more and more important. This paper mainly discusses the climate change effects on water use indices and maize yield under rainfed and irrigated conditions projected by three climate models in the Murray Darling Basin, Australia in 2020, 2050 and 2080 under A2 and B2 scenarios. The climate prediction results show that it is similar to the future precipitation and temperature projected by three climate models for the same time slices. For rainfed and irrigated maize, the crop yield, the potential and actual evapotranspiration will increase by 3-32, 3-12, 30-45 and 32-45, 3-15, 6-15% under both scenarios in the future during the maize growth period compared with the baseline respectively. Water use indices of maize under rainfed conditions will decrease and the variable increment will gradually be larger in the future, including evapotranspiration efficiency, crop water use efficiency and total water use efficiency. However, all the water use indices analysed under irrigated conditions will increase. The variation for evapotranspiration efficiency, ratio of evapotranspiration and irrigation is around 20%, but the variation for the other three indices is more than 30%. The projection results also indicate that the indices under the B2 scenario are smaller than those under A2 although the variable tendency and range are consistent. The conclusions suggest that it is significant to develop irrigated agriculture so as to mitigate climate change effects on crop production in the Murray Darling Basin. © 2015 John Wiley & Sons, Ltd.


Yang Y.,Hubei Engineering University | Cui Y.,Hubei Engineering University | Luo Y.,Hubei Engineering University | Lyu X.,Anhui University of Science and Technology | And 4 more authors.
Agricultural Water Management | Year: 2016

Short-term daily reference evapotranspiration (ETo) forecasts are required to facilitate real-time irrigation decision making. We forecasted daily 7-day-ahead ETo using the Penman–Monteith (PM) model and public weather forecasts. Public weather forecast data, including daily maximum and minimum temperatures, weather types and wind scales, for six stations located in a wide range of climate zones of China were collected. Weather types and wind scales were converted to sunshine duration and wind speed to forecast ETo. Meanwhile, daily meteorological data for the same period and locations were collected to calculate ETo, which served as reference standard for evaluating forecasting performance. The results showed that the forecasting performance for the minimum temperature was the best, followed by maximum temperature, sunshine duration and wind speed. Also, it was found that using public weather forecasts and the PM model improved the forecasting performance of daily ETo compared to those obtained when using the HS model with temperature forecasts as the only input data, and this improvement was because the weather type and wind scale forecasts also have positive influence on ETo forecasting. Further, the greatest impact on ETo forecasting error was found to be caused by the errors in sunshine duration and wind speed, followed by maximum and minimum temperature forecasts. © 2016 Elsevier B.V.


Luo Y.,Hohai University | Jiang Y.,Hohai University | Peng S.,Hohai University | Cui Y.,Wuhan University | And 3 more authors.
Paddy and Water Environment | Year: 2013

An ex post facto investigation of the effects of climate change on rice production over the past few decades will be helpful for planning future climate change. Here, a simulation study was carried out to evaluate the impacts of climate change on the yields, irrigation requirements, and water productivity of rice in Kaifeng, China from 1951 to 2010. The rice growth model ORYZA 2000 was adopted to simulate the yields and irrigation requirements (IR); then, water productivity in terms of irrigation water (WPI), evapotranspiration (WPET), and total water use (WPI+R) was calculated, and the Mann–Kendall test was employed to detect the trends in the variables. The reduction in yield was caused by the shortened GSL, increased temperature, and decreased hours of sunshine. The decreased seasonal IR resulted from both the increased rainfall and decreased ETc, while the latter played a dominate role. The WPI seemed not sensitivity to climate change, while WPET and WPI+R were strongly linked with climate change. More productive crop variety or changing the planting schedule could avoid the negative effects posed by global warming, stilling, and dimming. © 2013, The International Society of Paddy and Water Environment Engineering and Springer Japan.


Luo Y.,Hohai University | Chang X.,Hohai University | Peng S.,Hohai University | Khan S.,Regional Science Bureau for Asia and the Pacific UNESCO | And 3 more authors.
Agricultural Water Management | Year: 2014

Accurate daily reference evapotranspiration (ET0) forecasting is necessary for real-time irrigation forecasting. We proposed a method for short-term forecasting of ET0 using the locally calibrated Hargreaves-Samani model and temperature forecasts. Daily meteorological data from four stations in China for the period 2001-2013 were collected to calibrate and validate the Hargreaves-Samani (HS) model against the Penman-Monteith (PM) model, and the temperature forecasts for a 7-day horizon in 2012-2013 were collected and entered into the calibrated HS model to forecast the ET0. The proposed method was tested through comparisons between ET0 forecasts and ET0 calculated from observed meteorological data and the PM model. The correlation coefficients between observed and forecasted temperatures for all stations were all greater than 0.94, and the accuracy of the minimum temperature forecast (error within ±2°C) ranged from 60.48% to 76.29% and the accuracy of the maximum temperature forecast ranged from 50.18% to 62.94%. The accuracy of the ET0 forecast (error within ±1.5mmday-1) ranged from 77.43% to 90.81%, the average values of the mean absolute error ranged from 0.64 to 1.02mmday-1, the average values of the root mean square error ranged from 0.87 to 1.36mmday-1, and the average values of the correlation coefficient ranged from 0.64 to 0.86. The sources of errors were the error in the temperature forecasts and the fact that the effects of wind speed and relative humidity were not considered in the HS model. The applications illustrated that the proposed method could provide daily ET0 forecasts with a certain degree of accuracy for real-time irrigation forecasts. © 2014 Elsevier B.V.

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