Nitrogen Use in Garlic

Abstract

<jats:p>Nitrogen is essential to development of bulbing crops such as garlic (<jats:italic>Allium sativum</jats:italic> L.). Little scientific research thus far has concentrated on the optimum timing and concentration of applied N fertilizer for garlic grown under conditions found in the northeastern United States. A trial in Freeville, N.Y., on a gravely loam soil used three levels of ammonium nitrate fertilizer, 0 kg·ha<jats:sup>–1</jats:sup>, 52 kg·ha<jats:sup>–1</jats:sup> sidedressed in mid-Apr., and 52 kg·ha<jats:sup>–1</jats:sup> applied in mid-Apr. and early June 1995. The samples included a nonbolting (softneck) garlic and a bolting (topset) clone `Spanish Roja', both grown under wheat (<jats:italic>Triticum aestivum</jats:italic>) straw mulch. A separate trial in East Ithaca studied the same clones plus another topset, Merrifield Rocambole, on a sandy loam soil, using two levels, 0 and 52 kg·ha<jats:sup>–1</jats:sup>, of ammonium nitrate applied in mid-April only. The East Ithaca trial also examined the efficacy of hairy vetch (<jats:italic>Vicia villosa</jats:italic> Roth) as an alternate N source. Application of ammonium nitrate in April increased average bulb size of topset in Freeville &gt;30%, and the average bulb size of softneck by 23%. Applying in April and June increased average bulb size of topset by 35% and of softneck by 26%. Earlier timing of the second application might enhance these increases. The East Ithaca trial found N fertilization increased average bulb size by 30% for `Spanish Roja', by 20% for Merrifield Rocambole, and 23% for softneck. Analysis of leaf tissue of garlic grown with vetch found that ammonium N increased by 22% to 28% in topset garlic and 14% to 26% in softneck. These results indicate that N fertilization, in the form of either chemical fertilizer or a legume, can benefit this crop in northeastern United States.</jats:p>