A 4M tápanyagmodell a növényi tápanyagellá tás tudományos megalapozására

Translated title of the contribution: 4M nutrient model to provide a scientific basis for plant nutrient supplies

Nándor Fodor, Gabriella Máthéné Gáspár, Géza J. Kovács

Research output: Contribution to journalArticle

Abstract

The primary purpose of ecological systems models (ESMs) is to describe the processes of the very complex atmosphere-soil-plant system, including human intervention, using mathematical tools and to simulate them with the help of computers. The ultimate aim, however, is to use these models to answer questions that could only otherwise be answered, if at all, by carrying out expensive and time-consuming experiments. The development of the Hungarian 4M model was necessitated by the fact that the system of conditions used in Hungary differs from that applied in the crop simulation software packages available internationally. Since the majority of crop simulation models, such as the CERES model used to develop the 4M model, do not include phosphorus or potassium modules, the nutrient module of the 4M model originally "inherited" this deficiency. Based on the results published by Hungarian and foreign experts, a nutrient module was developed and incorporated into the 4M model. This new module was calibrated and validated for phosphorus and potassium using the results of long-term and aftereffect experiments. In principle, the nutrient module could be adapted to simulate the turnover of any other nutrient by adjusting the parameters adequately. Table 1. Major input data required by the 4M model. (1) Module. a) Atmosphere (= boundary conditions); b) Soil; c) Plant; d) Initial conditions; e) Agronomic conditions. (2) Characteristic/parameter: f) global radiation, air temperature, precipitation; g) bulk density, humus content, field water capacity, saturated hydraulic conductivity; h) phyllochron interval, base temperature, length of phenophases, potential rate of grain filling; i) water and nutrient quantities and their distribution in the soil profile; j) date of agrotechnical applications and their quantitative and qualitative characteristics. Table 2. Major characteristics of the previous (4M 3.1) and latest (4Mx) version of the model. (1) Process. a) Plant development; b) Plant growth; c) Transpiration; d) Surface water runoff; e) Evaporation; f) Infiltration of water into the soil or deeper layers; g) NO3 migration; h) N transformations; i) Plant N uptake; j) P transformations; k) Plant P uptake; l) K migration; m) K transformations; n) Plant K uptake; o) Mesoelement turnover; p) Microelement turnover. (2) Capable of simulation. (3) Available parameters. Fig. 1. Simplified flow chart of the 4M model. a) Read input data: agronomical data, initial conditions, soil data, etc.; b) Estimate input data; c) Weather generator; d) Start; e) Read daily input data: temperature, precipitation, etc.; f) Water balance; g) Nutrient turnover; h) Plant development and growth; i) Write output data; j) End; k) Analyse output data. Fig. 2. Comparison of the latest (4Mx) and previous (4M 3.1) versions of the 4M model: maize in a dry year on chernozem soil under satisfactory nutrient supply conditions. R2 values: Potential yield: 0.88; Potential biomass: 0.96; Yield: 0.85; Biomass: 0.91. Fig. 3. Schematic mechanism of the nutrient turnover module of the 4Mx model. a) Plant; b) Fertilizer; c) Fresh nutrient pool; d) Available nutrient pool; e) Stabile nutrient pool; f) Soil. Fig. 4. Measured and simulated AL-P2O5 content of the upper 20 cm soil layer in the P after-effect experiment, Nagyhörcsök (1972-1992). The Y error-bar indicates the standard deviation of the measured values. Fig. 5. Measured and simulated AL-K2O content of the upper 25 cm soil layer in the K after-effect experiment, Nagyhörcsök (1989-2003). Fig. 6. Measured and simulated values of cumulated phosphorus uptake by plants grown in the P after-effect experiment, Nagyhörcsök (1972-1992). Note: There was no significant difference between the control and the highest P fertilizer rate; the difference in total phosphorus uptake was only 27 kg/ha after 21 years. Fig. 7. Measured and simulated values of cumulated potassium uptake by plants grown in the K after-effect experiment, Nagyhörcsök (1972-1992). Note: The treatment with the highest rate received 1440 kg K/ha in autumn 1989. Fig. 8. Relative yield losses (NK/NPK or NP/NPK), reported in Hungarian field experiments from 1960-2000 (grey areas) and simulated with the 4Mx model, as the result of phosphorus (A) or potassium (B) deficiency as a function of the soil AL-P2O5 (A) or AL-K2O (B) content.

Original languageHungarian
Pages (from-to)79-96
Number of pages18
JournalAgrokemia es Talajtan
Volume57
Issue number1
DOIs
Publication statusPublished - Jun 1 2008

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ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Soil Science

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