The system of land tenure (that is, land ownership and labour organization) and the technological and economic conditions are not independent factors. Their concrete form is interlaced with the natural and social conditions found in each specific area.

The natural conditions not only influence the production factors- generally good and poor soil, enough precipitation, and temperatures favourable for growth and working- but also influence what types of ownership are found in an area: large farms are seldom found, for example, in regions where the soil conditions are poor and the topography is mountainous.

Even more important is the relation between the agrarian structure and the existing social conditions in the individual countries and regions. Feudal, capitalistic, and socialistic social orders result in very different conditions of land ownership, systems of labour organization, and forms of cultivation. The social system, in other words, makes up the framework within which agrarian structures can evolve. In this process the state as well as tribes, landlords, communes, and colonial powers can determine the conditions. Within the framework of social conditions, the agricultural sector's economic goals, the function land fulfils, and the political and social system play significant roles. The economic goal can vary from self sufficiency and satisfying one's needs, maintaining the farm, earning rent or interest on capital, production for the market, maximizing profits, or meeting economic plans. In doing so, land can function as a basis for earning one's livelihood, home, means of production, a commodity, an asset, annuity, power basis, or prestige object. Several functions can be combined.

The above mentioned factors are not independent, but rather are embedded within a system; that is, a change in any factor results in a change in all of the other factors. The term"agrarian system" bas been coined in order to conceptualize this complex system. The "agrarian system" consists of the "institutional, economic, socio-organizational, and ethical patterns found in the agricultural sector and rural areas that are oriented towards the superordinate economic and social system" (RÖHM)

The following brief summary of the most important agrarian systems is by no means exhaustive and stresses in particular the most significant agrarian systems found in the developing countries.