Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Jeffrey Norrie x
Clear All Modify Search

Residues and by-products resulting from papermaking and recycling are receiving increased attention as beneficial soil amendments. Our research examines de-inked and primary paper sludge as a principal constituent of several substrate mixtures used as soil amendments in landscape horticulture. Three factors will be examined in a strip-split-plot design with four replications: substrate mixture (with organic soil and sand), fertilizer level, and plant species. Several paper sludge–organic soil–sand mixtures (maximum 50% sludge) were compared to an organic soil–sand control. A 15-cm layer of each mixture was incorporated into existing soil to a depth of 30 cm. Species of Spiraea, Physpcarpus, and Thuja were grown in addition to Kentucky bluegrass (seed and sod) and ryegrass (seed). Growth, rooting, and plant nutrition (foliar analysis) were examined. Preliminary results indicate poor ground cover and N deficiency in plants grown in all unfertilized plots. For sod and seeded grasses, control plots were slightly more healthy than sludge-amended plots, which was likely due to a greater concentration of available N from the organic soil. The bush species exibited similar responses. We conclude that a base fertilization is needed to decrease the C: N ratio of these substrates to ≈20 to 30 for sustained plant growth regardless of sludge amendments. Toxicity effects were due to the presence of organic contaminants, heavy metals, or both.

Free access

Consumer demand for chemically free produce has increased; however, producers have become increasingly dependent on unreliable chemical defenses for control of diseases and pests. These dilemmas, along with the desire to maintain healthy farmland, have led to the research and development of environmentally sound practices. It is hypothesized that predisposing plants to photo, physical, and mechanical (PPM) mechanisms can allow plants to better withstand stress. Plants exposed to one form of PPM mechanism could confer resistance to a range of biotic and abiotic stresses. Such cross-resistance is commonly seen, but not well-understood. In this study, various PPM factors, including UV-C radiation, leaf brushing, and canopy trimming, were applied to field-grown carrots (Daucus carotae L.). The degree of blight and white mold infection was measured. Preliminary analyses showed that UV-C radiation at 4 weeks post-emergence or brushing at 4 or 8 weeks significantly reduced carrot blight and/or white mold. This implies that certain PPM mechanisms may induce plant defenses, allowing the crop to better defend itself against future biotic stress.

Free access

Field experiments were conducted in 2002 and 2003 to evaluate the effects of selected plant growth regulators on propagule production in Hemerocallis `Happy Returns' and Hosta `Gold Standard'. Benzyladenine (BA), chlormequat chloride (Cycocel), ethephon (Ethrel), prohexadione calcium (Apogee), and an experimental preparation of commercial seaweed extract (Acadian Seaplants Limited Liquid Seaweed Concentrate) amended with BA and IBA were tested at two times of application and three rates of application. Results with Hemerocallis showed that the application of the seaweed/PGR mixture at 3000 mg·L–1, Cycocel at 3000 mg·L–1 or BA at 2500 mg·L–1 applied at flowering, increased the number of plants producing two divisions compared to control plants. In Hosta, no increase in divisions under any treatments was observed.

Free access

Field experiments conducted in 2002 and 2003 evaluated the effects of timing of inflorescence removal on propagule formation, growth and development of Astilbe ×arendsii, Hemerocallis spp. and Hosta spp. Four timings of inflorescence removal were tested: 1) no removal (control), 2) removal at inflorescence emergence, 3) removal at preflower, and 4) Removal at full flower. Propagule formation in Astilbe was not enhanced by inflorescence removal. Hemerocallis plants with their inflorescences removed at emergence produced 25% more divisions than plants with their inflorescences removed at preflower. For Hosta, plants with inflorescences removed at pre- and full flower produced respectively 40% and 53% more divisions than control plants. These results have economic implications for commercial bare-root production, which need to be verified on a larger field scale.

Free access