Abstract:

The water resource is short in the loess area of western Henan Province. To achieve efficient use of local rainwater resource, the Jensen model is adopted under the guidance of deficit irrigation principle and water-saving agriculture theory. The objective function is the maximum ratio of actual yield to possible maximum yield per unit area at each stage of summer maize growth, the decision-making variables are the irrigation amount and actual evapotranspiration, and state variables are the allocated water amount and available water amount in planned moisture layer. The model is solved by successive approximation method of dynamic programming to derive the optimal system of deficit irrigation for summer maize. The optimized results are in good agreement with the experimental data, indicating the applicability of Jensen’s model in the area.

Key words: deficit irrigation, summer maize, Jensen model, dynamic programming, successive approximation method