Patent ID: 8033230

Claim:
A method of supplying seed entrained in a forced air flow from a centralized source to a plurality of row units, comprising: for a first set of row unit assemblies, forcing air, with seed entrained therein, to the first set of row unit assemblies and allowing air to escape from the first set of row unit assemblies at a first flow rate as the seed is collected in the first set of row unit assemblies; and for a second set of row unit assemblies, forcing air, with seed entrained therein, to the second set of row unit assemblies and allowing air to escape from the second set of row unit assemblies at a second flow rate less than the first flow rate as the seed is collected in the second set of row unit assemblies; wherein the second set of row unit assemblies are flow coupled to the centralized source via conduits that are shorter in length than those flow coupling the first set of row unit assemblies to the centralized source; wherein each row unit assembly has a hopper, an air/seed inlet, a seed outlet, and an air outlet, and further comprising a first set of cover plates mounted to the first set of on-row hoppers, the first set of cover plates having a plurality of orifaces therethrough to allow air exhaustion from the first set of on-row hoppers through the orifaces; and a second set of cover plates mounted to the second set of on-row hoppers, the second set of cover plates being free of orifaces to substantially prevent air exhaustion from the second set of on-row hoppers through the second set of cover plates.