Root Characteristics and Seed Yields of Cowpeas Grown with and without Added Nitrogen Fertilizer

Abstract

Field experiments were conducted in Oklahoma in 1993 and 1994. Cowpeas [Vigna unguiculata (L.) Walp.] were grown using either noninoculated seed and 23 kg·ha -1 of preplant nitrogen (N) fertilizer (conventional) or Rhizobium-inoculated seed and no preplant N fertilizer (reduced input). Sample plants were excavated at first pod set and analyzed for nodulation and root morphology. Additional plants were harvested at the green-shell stage to determine seed yield and plant N concentration. Conventional and reduced input cowpeas did not differ in dry weight of root mass components, total root dry weight, shoot dry weight, shoot : root ratio, nodule distribution among root morphological components, total nodule fresh weight, plant N concentration, or green-shell seed yield. Most of the nodule fresh weight generally was associated with nodules on the basal and lateral roots. Results indicate that cowpea root characteristics are not necessarily altered by the presence or absence of added N fertilizer at a given location.

Conservation agriculture increases soil organic carbon stocks but not soil CO2 efflux in two 8-year-old experiments in Zimbabwe

“…We assumed that 5 % of the maize aboveground vegetative biomass remained in the field because maize stalk slashing at harvesting did not remove the whole stem. A root:shoot ratio of 0.16 and 0.06 for maize and cowpea, respectively (Amos & Walters, 2006;Kahn & Schroeder, 1999;Kimiti, 2011) was used to estimate the contribution of roots to organic C inputs to the soils. Organic C input contribution from weeds was assumed insignificant since there was effective control of weeds through the use of pre-emergence herbicide (glyphosate) and timely manual weeding throughout the cropping season.…”

Effect of rooting media and number of nodes on growth and leaf yield of chaya (Cnidoscolus aconitifolius McVaugh) at Dire Dawa, Eastern Ethiopia

“…An extremely high S/R may lead to root redundancy, which reduces shoot growth, yield, and water and nutrient use efficiencies (Zhang, 1995). Therefore, it is important to grow cuttings on proper growing media to attain balanced root and shoot growth and maximize dry matter accumulation and water and nutrient use efficiencies (Kahn & Schroeder, 1999;Tomar et al, 1997).Plants with a greater S/R usually have a relatively greater water and nutrient uptake capacity, higher yield stability, and greater drought resistance (Passioura, 1983)…”