The objective of this paper is to develop a dynamic linear programming model to analyse the effects of different limiting factors on the conversion process of farms over time. The model is developed for a typical arable farm in The Mazandaran, and is based on two models, conventional and organic. The objective of the model is to maximize the net present value over a 10-year planning horiz on. The data for analysis has collected from the Agricultural Research Organization of Mazandaran province in 201 1. The results of the analysis of a basic scenario show that conversion to organic farming is more profitable th an staying conventional. Sensitivity analysis shows that if depreciation is 25% higher than conventional fixed costs due to machinery made superfluous by conversion, conversion is less profitable than staying conventional. Also the availability of hired labour has a s trong effect on the cropping plan and the amount of area converted. Further analysis shows that a slight drop (2%) in organic prices lowers the labour income of the farmer and makes conversion less profitable than conventional farming. For farmers, a minimum labour income can be required to ‘survive’. The analysis shows that constraint on minimum labour income makes stepwise conversion the best way for farmers to overcome economic difficulties during conversion

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