Study on Sesame Export for Sudan Based on Gravity Model

This study aimed to investigate the effect of social and economic differences between importer and exporter countries on trade flows of Sesame seed product. The analysis was carried out by estimating the gravity model. The sample covered a total of 14 countries for the period from 1997 to 2009. The results showed that the social and economic differences between countries have a significant and positive or negative effect on Sesame seeds trade. Furthermore, we found that the same language, distance and sesame production in export country have positive effect for the sesame export from Sudan.


Introduction
International trade allows many gains to countries linked to it. Efficiency gains, economies of scale, increasing competition and consequent reduction of prices, besides the increase in the variety of products at consumers' disposal, can be cited as main benefits of commercial insertion [1] [2]. The republic of the Sudan is considering as the third largest nation, with 1,861,484 square kilometers in area, which is located in northeastern Africa, and its capital is Khartoum, and the population (2012 est.; excludes the population of South Sudan): 34,206,710 Firstly, in today's world, no nation exists in economic isolation. All aspects of a nation's economy of its industries, service sectors levels of income and employment, and living standard are linked to the economies of its trading partners.
Secondly, from international movements of agricultural production trade business enterprise, this has high comparative advantage, and over the past 50 years the world's market economies have become increasingly interdependent and good facilities and agriculture resources for sesame in Sudan. Recently, many scholars use gravity model to study trade. For example, agriculture trade gravity model was mentioned by scholars [5]  In this study, the structure is listed in the following: after the introduction, the data source and method are introduced, and then the results from the gravity model are analyzed; in the end, the conclusions are supplied.

Data Source
All data about Sudan in this study originates from Food and Agricultural Organization (FAO) of United Nation [9]. Categorically the data concentrates on 5 staple crops including their cultivated area, the total output and yield. At first, the crop structure and their production are introduced, in the following, cassava, maize, rice, millet, beans, cowpeas, plusses, Bambara, peanut, oil palm, sesame, soybeans, bananas, root tuber, vegetable, sweet potatoes, coffee, tea, cotton, sugarcane [10]. The GDP data for the partner countries is form Country Economy website. The data for distance between Sudan and partner Countries is from distance between two countries website.   down till 2011, supply curve also start moving in fixed way, from 1970 to 1973 where was high increase happened then the curve rise and low for the hole period of time, food consumption line was flat moving with little increase in 1998 reach 60,000 ton, and then continue decreasing in the rest of next years, the trade curve show that the export is take progress moving with fixed a way accept in 1969,1973,1974 those three year decreased that mean 80%of sesame is for export. Similarly, Figure 2 illustrates the sesame area and yield balance in Sudan during the period of (1961-2011) as seeing below.

Modeling
Based on the purpose of this work and in the theoretical considerations, it is intended to describe the situation approach to be used. Reference is made to specifications and methods of estimation to be employed to obtain empirical gravity equations. In the following, the gravity model is given.
Y: denotes agricultural import quantity from Sudan; t: denotes year; j: denotes importer country; prod: denotes sesame production in exporter country; consum: denotes consumption (seed, waste, processing, and food) in importer country; dist: denotes the distance between the countries; border: denotes variable value one if the two border countries and zero in opposite; lang: denotes the two countries speak same languages In the model, we found the same language may be easy to communicate between partner countries, and the tendency (denoted as "t") might respect the time tend; and border could influence the trade cost. So the model covers many factors.

Results
The model results are listed in Table 1 and Table 2 which generally depict the suitable of the sesame situation by using Gravity Model results in the partner countries separately.  Sesame export price increases 1%, sesame export quantity increases 0.5534%, but the price impact is not significant. When the population increases 1%, the sesame export quantity increases also by 0.1530%, and it is significant obviously.
When sesame production on partner countries increases 1%, its import quantity increases 0.1766% absolutely. When the GDP increase 1%, the import sesame quantity increase by 0.0269, and it enable the country to use budget for import product, but it is not significant. When the distance between Sudan and partner countries is 1%, the sesame export quantity increase 0.7417%, possible reason is that agricultural structure is deferent from each other, as benefit sesame trade between them. When the sesame consumption increased by 1%, the sesame exports production decreased by 0.0431, and this influence exports quantity. When two partner countries speak same language the sesame export quantity increase by 1.899% than other countries, and it is easy for communicate trade and business. In the following, we ran the gravity model to 14 countries with Sudan, and got the relative results in the following, respectively.

Conclusion
This study provided an estimate of sesame trade determinants through an application of the gravity model between importer and exporter countries. Through our experience and this research study, we can say it seems we need different technology to enhance framer skills associated with some technical of new sesame seeds and expiate the trade partner by increase more importer countries.
The application of the model to the different groupings within the sesame gives a highly variegated picture of trade determinants. Anyway, there are two factors that should pay more attention: one is the same language; another is the population. The export countries could have a good trade with the countries with the two characteristics.