A prototype punch planter for no-till corn was developed to provide different seed spacings. Plantpopulation was adjusted by changing planter punch wheels. Seed spacings of 136, 165, and 210 mmwere obtained by constructing three punch wheels with different punch lengths, represented byexternal diameters of 650, 825, and 1,000 mm, respectively. Laboratory and field tests wereconducted at speeds of 1.5, 2.0, and 2.5 m/s to evaluate the effect of the punch lengths and speeds.Field tests were conducted in three different residue covers (corn, grain sorghum, and soybean).Overall, high values for quality of feed index (spaces between seeds or plants within 0.5 and 1.5 thetheoretical seed spacing) were observed. Despite problems with synchronization between the seedmeter and punch wheels, the length of the punches offered no performance limitations at the speedstested. A soil cleaning device was designed to reduce soil sticking to the punches and reduce soildisturbance. The volume of soil displaced by the smallest punch wheel (650 mm) was less than halfof that displaced by a commercial no-till planter Differences in planting depth due to residue coverand punch wheel diameter were minimal. Emergence was delayed under the corn residue cover andmay have influenced the lower performance of the planter prototype as compared to the other tworesidue types.
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