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Irrigation scheduling strategies for cotton to cope with water scarcity in the Fergana Valley, Central Asia
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Orientador(es)
Resumo(s)
The Central Asian countries face high water scarcity due to aridity and desertification but
excess water is often applied to the main irrigated crops. This over-irrigation contributes to
aggravate water scarcity problems. Improved water saving irrigation is therefore required,
mainly through appropriate irrigation scheduling. To provide for it, after being previously
calibrated and validated for cotton in the Fergana region, the irrigation scheduling simulation
model ISAREG was explored to simulate improved irrigation scheduling alternatives.
Results show that using the present irrigation scheduling a large part of the applied water,
averaging 20%, percolates out of the root zone. Several irrigation strategies were analyzed,
including full irrigation and various levels of deficit irrigation. The analysis focused a threeyear
period when experiments for calibration and validation of the model were carried out,
and a longer period of 33 years that provided for an analysis considering the probabilities of
the demand for irrigation water. The first concerned a wet period while the second includes
a variety of climatic demand conditions that provided for analyzing alternative schedules
for average, high and very high climatic demand. Results have shown the importance of the
groundwater contribution, mainly when deficit irrigation is applied. Analyzing several
deficit irrigation strategies through the respective potential water saving, relative yield
losses, water productivity and economic water productivity, it could be concluded that
relative mild deficits may be adopted. Contrarily, the adoption of high water deficit that
produce high water savings would lead to yield losses that may be economically not
acceptable
Descrição
Palavras-chave
irrigation requirements deficit irrigation water savings water productivity economic water productivity
Contexto Educativo
Citação
"Agricultural Water management". ISSN 0378-3774. 96 (2009) 723-735
Editora
Elsevier