NEITHER GREEN NOR WHITE ASPARAGUS SPEARS ARE AFFECTED BY SUPPLEMENTAL NITROGEN

Abstract

`Jersey Giant' asparagus (Asparagus officinalis L.), grown in an Enders silt loam mineral soil near Booneville, Ark., was given an application of 80 kg/ha of Supplemental nitrogen (N, as NH4N O3) either prior to or after the Cutting season in 1993. Neither N treatment affected spear objective Color, Pigments, soluble solids concentration (SSC), or yield. Supplemental N decreased spear Ca and K levels. Green asparagus had higher levels of total-N, K, S, P, Ca, Mg, Fe, Zn, Al, Mn, and Cu, but lower levels of NO3 than did white asparagus. As the Cutting season progressed, spear SSC, S, Ca, NO3 (NO3 in White spears only), Zn, Mn, and Cu (Cu in white spears Only) levels decreased, While spear K and Al (Al in white spears only) increased on a dry weight basis. Fall residual soil NO3 levels were not affected by N application, but organic matter was lower in soil which received early supplemental N.