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This article in SSSAJ

  1. Vol. 62 No. 5, p. 1418-1427
    Received: July 16, 1997

    * Corresponding author(s): letey@ucracl.ucr.edu


Development and Evaluation of ENVIRO-GRO, an Integrated Water, Salinity, and Nitrogen Model

  1. X. P. Pang and
  2. J. Letey 
  1. Department of Soil and Environmental Science, Univ. of California, Riverside, CA 92521



Development of a multicomponent model for crop yield and potential groundwater degradation applicable for irrigated agriculture is important. The ENVIRO-GRO model was developed to simulate (i) water, salt, and N movement through soil with a growing plant; (ii) plant response to matric potential, salinity, and N stresses; (iii) drainage and salt and N leaching; and (iv) cumulatively relative transpiration and relative N uptake, and consequent crop relative yield. This model does not account for denitrification. The utility of the model was illustrated by simulating the effects of irrigation amount, irrigation salinity, and N application on yield and N leaching. The results demonstrated the effects of complex interactions and feedback mechanisms in the plant-soil-water-salinity-N system. Factors leading to reduced plant growth caused lower transpiration, which created more leaching of salts and N. The simulated interactions are consistent with observed behaviors. Evaluation was done by comparing simulated results with published results of an experiment that had N application rates of 0, 90, 180, and 360 kg N ha-1 and water application rates of 21, 63, and 105 cm. Agreement between simulated and observed corn (Zea mays L.) relative yield and total N uptake was generally good. The difference between mean observed and predicted values was <0.06 for corn relative yield and 1.34 kg N ha-1 for total N uptake. Linear regression analyses revealed excellent agreement results for the 63-cm irrigation and a tendency for the model to overpredict results for the 21-cm irrigation and underpredict results for the 105-cm treatment.

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