Emergence of snap beans (Phaseolus vulgaris L.) in field soil in 1993–95 was enhanced by the biocontrol agent Gliocladium virens J.H. Miller, J.E. Giddens, & A.A. Foster. The fungus was applied to each seed at planting as a wheat bran alginate pellet formulation in 1993–95. Preemergence and postemergence damping-off were reduced in plots treated with G. virens. Nodulation on the roots of treated plants was numerically increased in 1993 and 1994 compared to nontreated plots. Efficacy of G. virens was reduced in 1995, probably due to high ambient temperatures at the time of planting. In plots with reduced stand, leaf area was increased and yield on a per-plant basis was larger than in plots with a better stand. Total yield also was increased in plots with fewer plants, except in 1994. Fungi isolated from failed seedlings included Fusarium spp., Pythium spp., and Rhizoctonia solani Kühn.
Emergence of snap beans (Phaseolus vulgaris L.) in field soil in 1995 to 1997 was reduced by the addition of dried, ground canola [Brassica napus L. ssp. oleifera (Metzg.) Sinsk. f. biennis] leaves and petioles to the furrow at planting. Soil amendment with the tissue increased the number of nodules on bean roots in all years. In plots with reduced stand, leaf area was increased and yield on a per-plant basis was larger than in plots with a better stand. Total yield was increased in plots with fewer plants only in 1995. Frequency of isolation of fungi that cause damping-off was not affected by the addition of canola at planting. When used as a seed treatment and incorporated at planting, canola residues were detrimental to emergence of snap bean.
J.A. LaMondia, V.L. Smith, and T.M. Rathier
Laura Elisa Acuña-Maldonado, Michael W. Smith, Niels O. Maness, Becky S. Cheary, Becky L. Carroll, and Gordon V. Johnson
Nitrogen was applied to mature pecan (Carya illinoinensis Wangenh. C. Koch.) trees annually as a single application at 125 kg·ha-1 N in March or as a split application with 60% (75 kg·ha-1 N) applied in March and the remaining 40% (50 kg·ha-1 N) applied during the first week of October. Nitrogen treatment did not affect yield, and had little effect on the amount of N absorbed. Nitrogen absorption was greater between budbreak and the end of shoot expansion than at other times of the year. Substantial amounts of N were also absorbed between leaf fall and budbreak. Little N was absorbed between the end of shoot expansion and leaf fall, or tree N losses met or exceeded N absorption. Pistillate flowers and fruit accounted for a small portion of the tree's N; ≈0.6% at anthesis and 4% at harvest. The leaves contained ≈25% of the tree's N in May and ≈17% when killed by freezing temperatures in November. Leaves appeared to contribute little to the tree's stored N reserves. Roots ≥1 cm diameter were the largest site of N storage during the winter. Stored N reserves in the perennial parts of the tree averaged 13% of the tree's total N over a three year period. Current year's N absorption was inversely related to the amount of stored N, but was not related to the current or previous year's crop load.