Starch was analyzed leaves of field-grown cotton plants (Gossypium hirsutum L.) exposed to elevated CO₂ during daylight hours from ring-shaped array of emitters. In part, this experiment was to see how leaf starch behaved to the CO₂ release and whether leaf starch could be used as an indicator of the effectiveness of such an aeril release array. During June, starch in leaves both inside and outside the emitter ring was relatively high (ca. 8-15 g.m^-2) and did not cycle diurnally. From July on to September, leaf starch was lower (ca. 2g.m^-2) than in June and cycled appreciably during the day. The ring of aerial release could be distinguished in the data obtained and no significant lowering was noted in the ring center, suggesting that the aerial release method was relatively uniform across the aerial release ring.