Comparison of Root Characteristics of Conventionally Grown Cowpeas and Cowpeas Grown without Added Nitrogen Fertilizer

Abstract

<jats:p>Field experiments were conducted in Oklahoma in 1993 and 1994. Cowpeas [<jats:italic>Vigna unguiculata</jats:italic> (L.) Walp.] were grown using either non-inoculated seed and 23 kg·ha<jats:sup>–1</jats:sup> of preplant nitrogen fertilizer (conventional) or inoculated seed and no preplant nitrogen fertilizer (reduced input). Sample plants were excavated at first pod set and analyzed for nodulation and root morphology. Additional plants were excavated at the green-shell stage and were analyzed for nitrogen concentration. Conventional and reduced input cowpeas did not differ in nodule distribution among root morphological components, total nodule fresh weight, total root dry weight, or nitrogen concentration. Most nodules generally were located on the basal and lateral roots. Results indicate that cowpea root characteristics are not necessarily altered by differing cultural systems at a given location.</jats:p>