abstract the production unit size is one of the effective factors in optimum uses of inputs. since optimum size is affected by the characters and economical conditions in each district, the studies for determining the optimum farm size should be done specially for each crop and each district. in this study tried to determine the optimum rice farm size in guilan province which is one of the most...

introduction: agricultural activities increasingly use water, fertilizers and pesticides, which may generate negative impacts on environment. nowadays, nitrogen leaching from agricultural lands is a widespread global problem. therefore, alternative land management practices such as nutrient management (rate, method and time of application), tillage operations (conservation and no-tillage), and ...

The shortcoming of the standard genetic algorithm is analysed. An improved genetic algorithm with modified mutation operator and adaptive probabilities of crossover and mutation is proposed. Simulation experiments have been carried and the results show that the modifications are very effective. In this paper, an optimum charge plan for steelmaking continuous casting production scheduling is als...

An integrated approach to reservoir, irrigation, and cropping management which links four di€erent modelsÐa hydrologic model (PRMS), a crop growth simulation model (EPIC), an economic model based on linear programming, and a dynamic programming modelÐis developed and demonstrated. The demonstration is based on an irrigation district located in a subhumid climate with an irrigation reservoir lar...