Testing simulation models for the assessment of crop production and nitrate leaching in Hungary

G. J. Kovács, T. Németh, J. T. Ritchie

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Abstract

Planning alternative land-use management requires at minimum the evaluation of crop productivity and profitability as well as the environmental consequences. Crop-simulation models are one means of making the assessments needed for planning sustainable land use. However, the systems approach must be proven to represent reality in order to be accepted by potential users. A long-term crop-rotation experiment with various N fertilizer applications, conducted in Nagyhörcsök, Hungary, from 1968 to 1988 provided an excellent data set to test the capability of crop-simulation models for estimating biomass production, yield and nitrate leaching. The rainfall, soil type and evaporation rates at the site provided a circumstance in which the nitrate leaching from the rooting zone of wheat and maize was trapped in the sub-soil at a depth of 4-5 m. This measurable nitrate in the sub-soil became the basis for testing the simulated leaching using the CERES-Wheat and CERES-Maize crop-simulation models. The models were locally calibrated for accuracy in the drainage coefficient, for wheat and maize genetic coefficients and for solar radiation estimations from sunshine hours data. The measured and simulated nitrate use by plants and the loss by leaching was within acceptable limits most of the time. The biggest errors occurred in treatments without any nitrogen added. The simulated and measured results showed that when 150 kg/ha/yr or less was applied, the leaching was minimized and about the same as no fertilizer. With a 250 kg/ha/yr application, there was about 100 kg/ha/yr leached and the yields were not improved over the 150 kg/ha treatment. The measurements of the rotation study reported herein represent less than 1% of those available from a country-wide study where soil and weather are different.

Original languageEnglish
Pages (from-to)385-397
Number of pages13
JournalAgricultural Systems
Volume49
Issue number4
DOIs
Publication statusPublished - 1995

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ASJC Scopus subject areas

  • Animal Science and Zoology
  • Agronomy and Crop Science

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