Abstract:
Potato is one of the key food crops and China is the largest potato producer in
the world. However water scarcity is the major constraint to increase the
productivity of potato in the arid regions such as Ningxia in northwest China
where this crop is extensively cultivated. The overall objective of this study was to
optimize the irrigation for potato cultivated under the drip irrigation. To do this,
the AquaCrop model was calibrated and validated using the data obtained from
two years of field experiment. Then, the calibrated crop model was used to
simulate growth and tuber yield of potato in response to 30 different irrigation
schemes under two different irrigation scenarios. The crop model evaluation
parameters namely, the root mean square error (RMSE), the index of agreement
(d), the normalized root mean square error (NRMSE) and the coefficient of
determination (R2
) showed that the AquaCrop model could simulate the
growth and yield of potato under the drip irrigation with different irrigation
treatments with reasonable accuracy. Furthermore, yield of potato has increased
with increasing amount of total irrigation under drip irrigation; however, yield
begins to decline when the amount of total irrigation exceeds 2500 m3 ha-1. The
study also found that the optimum irrigation schedule for potato was 20 mm of
irrigation quota at 7 days of irrigation cycle (i.e., 1800 m3 ha-1 or 180 mm of total
irrigation). The above irrigation scheduling has achieved 46.77 t ha-1 of tuber yield
with 15.74 kg m-3 of water use efficiency. These findings may be evaluated in
potato cultivation across different climate and soil conditions for wide
applicability at different arid regions of the world.
