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United States Department of Agriculture

Agricultural Research Service

Research Project: Enhanced System Models and Decision Support Tools to Optimize Water Limited Agriculture

Location: Agricultural Systems Research Unit

Title: Sustainability and environmental assessment of fertigation in an intensive olive grove under Mediterranean conditions

Authors
item Cameira, M -
item Pereira, A -
item Ahuja, Lajpat
item Ma, Liwang

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 4, 2014
Publication Date: N/A

Interpretive Summary: Over application of water and nitrogen is a major concern for intensive olive groves in South of Portugal. In this study, field experimental measurements were integrated with a system model, Root Zone Water Quality Model (RZWQM) to assess the sustainability and environmental impact of fertigation in an intensive olive grove. After the model was calibrated for predictions of evapotranspiration, soil water content, and soil nitrate, it is then used to develop best management strategies for intensive olive groves. Based on model simulation, under current management practices, 57 % of the irrigation applied was lost via drainage, while 71% and 5% of fertilizer N inputs were lost through leaching and denitrification, respectively. Simulation results also showed that drainage and N leaching could be reduced by 47% and 90 %, respectively, without affecting the growth of olive groves. Water drainage and N leaching could be reduced further by 13-15% with only 5% reduction in olive growth if irrigation was reduced by another 25%.

Technical Abstract: Over application of water and nitrogen is a major concern for intensive olive groves in South of Portugal. In this study, field experimental measurements were integrated with a system model, Root Zone Water Quality Model (RZWQM) to assess the sustainability and environmental impact of fertigation in an intensive olive grove. After the model was calibrated for predictions of evapotranspiration, soil water content, and soil nitrate, it is then used to develop best management strategies for intensive olive groves. Based on model simulation, under current management practices, 57 % of the irrigation applied was lost via drainage, while 71% and 5% of fertilizer N inputs were lost through leaching and denitrification, respectively. Simulation results also showed that drainage and N leaching could be reduced by 47% and 90 %, respectively, without affecting the growth of olive groves. Water drainage and N leaching could be reduced further by 13-15% with only 5% reduction in olive growth if irrigation was reduced by another 25%.

Last Modified: 12/22/2014
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