An agricultural seeder (10) for research plots includes a front gang (21) of planting units (22) and a rear gang (23) of planting units (24) spaced a distance behind the front gang. Metering systems (14) are provided for metering seed to the planting units (22, 24) of the front and rear gangs (21, 23). A tripping system (27) is used to start and stop the seed metering systems (14) and to change seed between plots while planting. A programmable logic controller (28) is programmed with the distance between the front and rear gangs (21, 23) and is used to delay the tripping of the metering system (26) for the rear gang (23) relative to the metering system (25) for the front gang (21) until the seeder (10) has traveled the distance (L) between the front and rear gangs (21, 23). The delayed tripping for the rear gang (23) keeps the planted rows and alleyways created by the front gang planting units (22) laterally aligned with those created by the rear gang planting units (24).
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