12 first. In the Cote d'lvoire some cotton-producing villages are unreachable in the rainy season (DCGT, 1986, p.32). Or, if storage at the ginnery is more expensive than in the field, it might be desirable to match the flow of raw material to the ginnery to its processing capacity, by sending some trucks to nearby zones and others to remote zones. In the Cote d'lvoire, the ginneries are not cqu!pnrd **iv!th6 Stnr!ir2;f** ?lt'rg,b **0t01ns T** ti", nr5<sup>t</sup> **cm-1** Ht1 tn ltlbli'h thit this situation is optimal.

32. When the crop must first undergo transformation at dispersed processing centers, another question arises: Should delay in evacuation be positively related to: (1) distance to the ginnery; (2) distance from the ginnery to the port; or (3) total distance. The example of Table 6 neglects this distinction because there is no processing.

33. The answer should be distance to the ginnery if either of the following conditions holds: (1) the costs to be avoided cease after the crop is picked up from the farm and the farmer is paid. This may account for the bulk of the losses, or it may not. Presumably, the crop is most vulnerable to physical deterioration before it is processed, some crops more than others. In the case of cotton, important sources of postharvest loss, specifically rains and fires, cease after the crop leaves the farm. Furthermore, because farmers provide the storage facilities, the cost of preventing post-harvest losses occurs at the farm level. Also, interest rates that farmers face are presumably higher than those faced by the government, but, just as clearly the government does not face a zere rate of interest, and, so other tlhings equal, it benefits from a rapid movement of the cotton from the ginneries to the ports. (2) If it is optimal to operate all ginneries at full capacity as soon as it is possible, then enough transport must be allocated to supply all ginneries. The question is then not which ginneries should receive cotton first (a distance to the port question) but which zones should be first to provide cotton to the ginneries. Certainly, in the Cote d'Ivoire, there is no hint that ginneries are being idled for lack of transport. For these reasons, it seems correct io concentrate on the relationship between the timing of evacuation and the distance to the ginnery.

34. Otherwise the analysis would proceed in a two-tier fashion - first supply the nearest-in ginneries to speed evacuation from ginneries to the port, and then choose the zones nearest to these (near-in) ginneries to supply them first. Afterwards, there would be a decision that could go either way to supply the port from the near-in zones of the further-out ginneries or from the further-out zones of the near-in ginneries, and total transport time would be the operative criterion.

35. What is the pattern of harvest evacuation by the CIDT? The CIDT provides information on the pattern over time of the planting of cotton and its evacuation after harvest, by zone. **Ts,hlp S** **_r-cc_ Inrtvicle-** the mean niimher of **mnonthc after May '1 ,until th.e cottAn** jc **n1nnted,** by zone, as well as the mean, standard deviation, minimum and maximum of the variable. Table 5, col. 2 provides the mean number of months after October 1 until the cotton is purchased by the CIDT, by zone, as well as statistics on this variable. If the cotton takes approximately the same amount of time to mature in each zone, then the difference between these two variables is a measure of the delay in evacuation. The correlation between this measure of delay and the distance of the zone from the ginnery is -0.50 with an extremely high statistical significance of 0.0001. An alternative measure of possible post-harvest loss from delayed evacuation is the mean number of months after April **1** until the crop is evacuated. Apparently, late March to mid-April initiates a period of heightened vulnerability to loss (DCGT, 1986, p. 10). Again, the correlation between this measure of delay and distance from