Long-term Effects of Rows per Bed and In-row Spacing on Yield and Spear Size of Asparagus

Abstract

Three studies were conducted at Clinton, N.C., to investigate the relationship between number of rows per bed, in-row spacing, and spear yield of asparagus (Asparagus officinalis L.) over 11 to 13 years. In the first study, increasing plant densities from 21,550 to 43,100 plants/ha by doubling the number of rows/bed increased the cumulative yield from 64% to 80% for three hybrid lines (`UC 157', `WSU 1', and `WSU 2') but only 6% for `Rutgers Beacon'. The effects of doubling the plant density were still apparent 13 years later. In the second study, yields of `Princeville' (`Mary Washington' selection) crowns, grown at densities from 14,000 to 86,000 plants/ha, were also increased for 8 years by doubling rows at various in-row spacings. In a third study, in which densities ranged from 21,000 to 387,900 plants/ha, the magnitude of the response to rows/bed was dependent on in-row spacing. Efficient use of bed space and the avoidance of crowding exerted a larger influence on productivity than did average planting density. The yield response to rows/bed was greater and more persistent through the years for wider in-row spacings. Spear size was only marginally responsive to rows per bed and in-row spacing.