A combined simulation and linear programming method for scheduling organic fertiliser application

Logistics have been used to analyse agricultural operations, such as chemical application, mineral or organic fertilisation and harvesting-handling operations. Recently, due to national or European commitments concerning livestock waste management, this waste is being applied in many crops instead of other mineral fertilisers. The organic fertiliser produced has a high availability although most of the crops it is applied to have strict timeliness issues concerning its application. Here, organic fertilizer (as liquid manure) distribution logistic system is modelled by using a combined simulation and linear programming method. The method applies in certain crops and field areas taking into account specific agronomical, legislation and other constraints with the objective of minimising the optimal annual cost. Given their direct connection with the organic fertiliser distribution, the operations of cultivation and seeding were included. In a basic scenario, the optimal cost was assessed for both crops in total cultivated area of 120 ha. Three modified scenarios are presented. The first regards one more tractor as being available and provides a reduction of 3.8% in the total annual cost in comparison with the basic scenario. In the second and third modified scenarios fields having high nitrogen demand next to the farm are considered with one or two tractors and savings of 2.5% and 6.1%, respectively, compared to the basic scenario are implied. Finally, it was concluded that the effect of distance from the manure production to the location of the fields could reduce costs by 6.5%.