In the agricultural world of the Ancient Near East, grain was available to everyone, if only because those without access starved to death. The means of acquiring the grain differed from case to case, for institutions and individuals. The peasants would deliver it to landowners as taxes or rent, or as part of an employment arrangement. The peasants would generally keep part of their harvest, if free laborers, but might never touch any of it if they were rationed dependents or slaves.
The institutions merely had to assure that the people had sickles to harvest grain, millstones to grind it, and facilities to store it. Mercifully, Mesopotamia had enough clay for the necessary storage buildings and vessels, but virtually everything else had to be imported - including probably even much of the wood for building the ships to move the stuff around. Some of the grain could be produced locally, but the copper for the sickles and stones for the grinders had to be imported. This placed Mesopotamia in the unenviable position of concentrating on the production of manufactures and agricultural products for export, to acquire the silver to pay for the imports. The economy was thus oriented heavily towards trade and production for export.
Markets assured that imbalances were eliminated, at the cost of the poor, and to the benefit of the institutions. The international markets assured the delivery of imports, and the local markets determined the distribution of grain. The institutions would sell the grain to acquire silver. A good harvest would drive down the cost of grain, and thus punish overproduction. A bad harvest would drive the price up, and thus offer the institutions a stranglehold. Locusts and bad harvests could ruin one region, impoverishing the residents. The institutions with access to reserves or other regions could thus corner the market. One official from Mari was assigned to a district which suffered from bad harvests, locusts, and crickets in succession (Birot 1993: 73-87). The poor official was held responsible, but the palace could view such catastrophes with equanimity; at one point, a neighboring king offered to send five million liters of grain to another. The offer was proudly declined (Durand 2000: 3: 18). The institutions could cope with grain shortages. This flexibility - due to enormous reserves acquired through taxes and rents - gave them decisive leverage.