Thesis Archive
A three level multi-period multi-location and multi-crop sustainable supply chain model (2008)
Patricia Rovie B. Quadra
Justine M. Rodriguez
Marie Christianne R. Terol
Abstract:
-The supply chain of agri-foods, as any other supply chain, is a network of organizations working together in different processes and activities in order to bring products and services to the market, with the purpose of satisfying customers’ demands (Christopher, 2005). Agricultural supply chains differ from other supply chains because of important factors such as food quality and safety as well as weather related variability. Also, other important characteristics of agri-foods are the limited shelf life, demand as well as price variability which makes the agricultural supply chain more complex and harder to manage than other supply chains. There is a particular lack of adequate models for planning for production/harvest and distribution for perishable crops. Moreover, the modern agricultural practices are adopted at the expense of sustainability of different resources such as land fertility since repeated use of land for the same crop have impaired soil structures in most countries today. Agriculture worldwide has come to use increasing amounts of chemical pesticides, herbicides and synthetic fertilizers and methods that are not sustainable in nature which results to unbalanced crop rotation and pollution of crops and environment. In addition, the use of synthetic fertilizers can impact micro-organisms in soil, which impairs plants’ ability to absorb nutrients, thus lowering production yield.
Because of this, a three level multi-period, multi-location and multi-crop sustainable supply chain model is formulated. The model deals with three levels of the agricultural supply chain which are the resource level, production level and distribution level. More consideration is given to the relevant costs within this chain such as cost of procurement of raw materials, cost of planting and penalty cost for not meeting demand. The objective of the model is to minimize the total cost of the system with decision variables such as amount of seeds to plant in a certain period, amount of chemical or organic fertilizer to use as well as when and where to harvest the crops. The model was translated into the General Algebraic Mathematical Model (GAMS) language and was run in the software.
From the validation it was determined that the model was able to capture the expected behavior. Cropping techniques were chosen based on their effect on the value of pH. The value of pH determines if land sustainability is being considered or not. Also, the time and place of procurement, planting and distribution was chosen based on the impact on the total cost.
From the sensitivity analysis it was determined that relationships between the use of the crop fallow, crop rotation and intercropping cropping techniques with pH change due to chemical or organic fertilizer, the pH change due to the said cropping techniques as well as perishability time and transportation time are significant. Also, another relationship that is significant is the combination of the crop rotation and intercropping techniques with pH change due to the fertilizer and due to the cropping techniques. Included also is the perishability and transportation time. Moreover, the relationship of the ratio of chemical and organic fertilizer with the pH changes is also significant. This means that these relationships determine which variable causes the most change in another variable. It informs the user of the model which parameters could be manipulated so as to be able to achieve the desired solution.
Recommendations for future studies would be to incorporate more cropping techniques as compared to the ones used in this study. With this, more alternatives could be chosen by the model which could have varying effects on the land sustainability aspect. Also, non-instantaneous behavior of raw material procurement could be considered so as to have a more realistic representation of the actual system as well as the inclusion of pest control.
Adviser:
Mr. Dennis Cruz
[email protected]