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Assessing the impact of climate change on sugarcane and adaptation actions in Pakistan

Farooq Nageen, Gheewala Shabbir. H.

Acta Geophysica

2020

Vol. 68, no. 5

1489--1503

Climate change is a challenging global issue for the sustainable production of various crops around the world as change in climatic patterns can create a stressful environment for plant growth. This study assesses the impact of climate change on future water demand and sugarcane yield in Pakistan for the baseline (1981–2005) and future timescales (2020s, 2050s and 2080s). For evaluating the crop water requirement and yield under future climate, CROPWAT 8.0 and AquaCrop models were used, respectively. For the estimation of future climate, three diferent Regional Climatic Models were applied under two projection scenarios i.e. RCP 4.5 and RCP 8.5. Maximum temperature, precipitation and minimum temperature displayed an increasing trend under the projected future climatic conditions. The results revealed a growth in the crop water requirement with a subsequent escalating irrigation demand caused due to rise in projected temperature; this is because the projected increase in precipitation under forecasted weather conditions cannot compensate for the increased evaporative demand. Moreover, the results showed a general increasing trend of sugarcane yield under projected climate. By delaying the crop calendar, an overall decrease in crop water requirement in the range of 10.7–12.6% and increase in the yield in the range of 0.37–6.48 tha−1 can be observed under both climate change scenarios. Moreover, 90% of control irrigation level proved benefcial in terms of saving around 10% irrigation water with acceptable yield reduction. The outcomes of the study are supportive for growers to gain more yield using less amount of water and to adapt to changing climate. The results are also helpful for policy makers to develop adaptation strategies to improve sugarcane productivity and to address water stress in Pakistan.

CropSyst model for wheat under deficit irrigation using sprinkler and drip irrigation in sandy soil

Noreldin T., Ouda S., Mounzer O., Abdelhamid M. T.

Journal of Water and Land Development

2015

no. 26

57--64

CropSyst (Cropping Systems Simulation) is used as an analytic tool for studying irrigation water management to increase wheat productivity. Therefore, two field experiments were conducted to 1) calibrate CropSyst model for wheat grown under sprinkler and drip irrigation systems, 2) to use the simulation results to analyse the relationship between applied irrigation amount and the resulted yield and 3) to simulate the effect of saving irrigation water on wheat yield. Drip irrigation system in three treatments (100%, 75% and 50% of crop evapotranspiration – ETc) and under sprinkler irrigation system in five treatments (100%, 80%, 60%, 40%, and 20% of ETc) were imposed on these experiments. Results using CropSyst calibration revealed that results of using CropSyst calibration revealed that the model was able to predict wheat grain and biological yield, with high degree of accuracy. Using 100% ETc under drip system resulted in very low water stress index (WSI = 0.008), whereas using 100% ETc sprinkler system resulted in WSI = 0.1, which proved that application of 100% ETc enough to ensure high yield. The rest of deficit irrigation treatments resulted in high yield losses. Simulation of application of 90% ETc not only reduced yield losses to either irrigation system, but also increased land and water productivity. Thus, it can be recommended to apply irrigation water to wheat equal to 90% ETc to save on the applied water and increase water productivity.

CrosSyst (ang. Cropping Systems Simulation) wykorzystano jako narzędzie analityczne do zarządzania wodą do nawodnień w celu zwiększenia produktywności pszenicy. Przeprowadzono dwa eksperymenty terenowe w celu: 1) kalibracji modelu CropSyst w odniesieniu do pszenicy uprawianej w warunkach nawodnień deszczownianych i kroplowych, 2) zastosowania wyników symulacji do analizy zależności między wielkością nawodnień a plonem i 3) symulacji wpływu oszczędności wody użytej do nawodnień na plon pszenicy. W eksperymentach zastosowano trzy warianty nawodnień kroplowych (100%, 75% i 50% ewapotranspiracji – ETc) i pięć wariantów nawadniania deszczownianego (100%, 80%, 60%, 40% i 20% ETc). Wyniki kalibracji wykazały, że wartość RMSE wynosiła 0,03 i 0,14 t·ha–1 odpowiednio dla ziarna i biomasy. Model umożliwiał symulację dobowego stresu wodnego w ciągu całego sezonu wegetacyjnego. W wariancie 90% ETc nie tylko stwierdzono zmniejszenie strat plonu w każdym z systemów nawodnień, ale także zwiększenie produktywności wody. Dlatego można zalecić stosowanie dawki 90% ETc w celu oszczędności wody i zwiększenia jej produktywności.