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Integrated strategies for maize irrigation and fertilization under water scarcity and environmental pressure in Bulgaria
Author(s) -
Popova Zornitsa,
Kercheva Milena
Publication year - 2004
Publication title -
irrigation and drainage
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 38
eISSN - 1531-0361
pISSN - 1531-0353
DOI - 10.1002/ird.104
Subject(s) - irrigation , leaching (pedology) , environmental science , agronomy , human fertilization , irrigation scheduling , water scarcity , precipitation , growing season , water resources , soil water , geography , soil science , biology , ecology , meteorology
Integrated management of irrigation and fertilization could meet global increasing demand from maize production and environmental pressures under water scarcity. The objective of this paper was to evaluate the long‐term impact of irrigation scheduling and rates and timing of fertilization on water stress indicators, nitrogen uptake and leaching under maize on Chromic Luvisol (Sofia region). Modeling of the soil–plant system by the CERES‐maize model was used. Adjusted and modified CERES‐maize was run with different irrigation and fertilization scenarios and 30‐year weather data. Scenario analyses proved that grain yield and N‐uptake were severely affected on drylands under the conditions studied. Drought indicators showed that irrigation was required in 70% of the years. The sensitivity of maize drylands to precipitation in the critical (15 July–15 September) period caused great variability in maize yield ( C v =42%) and N‐uptake ( C v =25%) under nonlimited fertilization conditions. In addition, low vegetative precipitation proved to be a reason for fallow state leaching on drylands. All the irrigation scheduling tested improved N‐uptake efficiency, mitigated drought and significantly reduced yield and N‐uptake variability ( C v =5–6%). An integrated management strategy of N‐application timed to coincide with the period of maximum crop uptake and irrigation scheduled at 85% of field capacity reduced N available for leaching in the risky years. A drainage‐controlling scenario, developed for 75–80% of the required irrigation depth and satisfying predominantly the most sensitive phases of maize development, saved up to 95 mm yr −1 of water and reduced drainage in medium wet to wet fallow states by 30–40%. Significant early‐season N‐losses (25% of applied N) were associated with precipitation extremes and poor N‐dressing and could potentially happen in 3% of the years studied. Exceedance frequency of N‐uptake under nonlimited fertilization conditions and different irrigation strategies was used to adjust more accurately the fertilizer rates and timing for the soil and climate variability studied. Copyright © 2004 John Wiley & Sons, Ltd.