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David T. Tingey

Abstract

Data on plant response to stress are used to implement the Toxic Substances Control Act, the Clean Air Act, and other federal regulations. Phytotoxicological data are essential in assessing the environmental hazards inherent in waste, sludge and/or dredge spoil disposal methods and in evaluating the potential or existing impacts of various industrial and/or energy processes.

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Carol Miles, Lisa DeVetter, Shuresh Ghimire, and Douglas G. Hayes

.g., straw, woodchips). However, PE mulch removal and disposal can be costly ( Galinato et al., 2012 ; Galinato and Walters, 2012 ; Ghimire and Miles, 2016 ), and there are only a handful of agricultural plastic recyclers that will accept PE mulch due to

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Carlos Vinicius Garcia Barreto, Rhuanito Soranz Ferrarezi, Flávio Bussmeyer Arruda, and Roberto Testezlaf

). Subirrigation also has the potential to improve vegetative growth of citrus rootstocks ( Teixeira et al., 2009 ) and shorten the crop cycle with minimal water wastage ( Landis, 2005 ; Verdial et al., 1998 ). Moreover, this system eliminates the disposal of

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Shuresh Ghimire, Arnold M. Saxton, Annette L. Wszelaki, Jenny C. Moore, and Carol A. Miles

oceans originates from disposal on land ( Li et al., 2016 ). Biodegradable plastics are degradable plastic in which the degradation results from the action of naturally occurring microorganisms such as bacteria, fungi, and algae ( ASTM International, 2011

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Erika N. Kocsis, Ronald F. Hooks, and James N. McCrimmon

The use of grasses native to New Mexico are preferred for revegetating Albuquerque's sewage sludge disposal site. A greenhouse study was conducted to determine the most appropriate grass species that could be used in revegetation. Nine grasses grown in soil collected at Albuquerque's sludge disposal site were compared based on germination measurements, including plant height and density. Final shoot and root weights also were taken for comparison. Plant tissue was analyzed for the accumulation of metals and salts. With 200 ml of water applied weekly, plant height was greatest in spike dropseed (Sporobolus contractus A. S. Hitchc.) at 33.86 cm; plant density was greatest in alkali sacaton (Sporobolus airoides Torr.). Results indicate the grasses that have the best potential for use in revegetation are blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Griffiths], sideoats grama [Bouteloua curtipendula (Michx.) Torr.], and alkali sacaton.

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Wojciech J. Florkowski and Orville M. Lindstrom

Leyland cypress (×Cupressocyparis Leylandii) is becoming increasingly important as a live-cut Christmas tree yet it differs from trees currently familiar to most customers. Results of a consumer survey provide an opportunity for growers to adjust planting and marketing decisions. Questionnaires were completed while respondents displayed the tree at their residences. Opinions about the tree referred to tree features and compared them with features of other types of Christmas trees and inquired about the care given to the tree and its disposal. In general, respondents were consistent in their favorable assessment of Leyland cypress as a live Christmas tree with respect to several characteristics including tree shape twig density, and maintenance of fresh appearance over time. Recycling was the primary form of tree disposal.

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Jeffrey S. Karns

The use of microbes and/or microbial processes for the bioremediation of soils contaminated with pesticides is an idea that has enjoyed considerable interest over the past several years. Many microbes with specific pathways for the degradation of particular pesticides, or classes of pesticide, have been isolated and characterized. Unfortunately, most sites that are heavily contaminated with pesticides contain a mixture of the many different types of pesticides that have been used over the last 5 decades. This complex mixture of compounds may inhibit microbial degradation or may require multiple treatments to assure that all the chemicals are degraded. Treatment of wastes before they contaminate the environment is one way to avoid the problems associated with mixed wastes. We have isolated a number of microorganisms that detoxify insecticides, such as carbaryl of parathion via the action of hydrolase enzymes. These enzymes can be used to treat waste pesticide solutions before disposal. A system was developed for the disposal of one high-volume organophosphate insecticide waste by treatment with parathion hydrolase, followed by ozonation to yield harmless products that were readily degraded by other soil microorganisms. A second method for disposal of this waste involves altering the environmental conditions in the waste to stimulate the growth of microorganisms naturally present in the material utilizing the pesticide as a carbon source. This accomplishes degradation of the material over a 2-week period. Many, if not all, pesticides are degradable to some degree by microorganisms, and this fact can be exploited to provide cost-effective methods for the safe disposal of pesticide wastes.

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Philip E. Nelson

Abstract

Those familiar with the fruit and vegetable processing industries are aware of the serious problems of the seasonal processor. The short and hectic harvest season produces a number of conditions that reduces the effectiveness of these horticultural industries. Some of the more serious problems include the following:

  1. Short supply of labor

  2. Processing bottlenecks

  3. Over production of certain products

  4. Large capital investment

  5. Sizable inventory expenses

  6. Large warehousing costs

  7. Large waste disposal load over a short period of time

  8. Raw product scheduling

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Sung Do Oh and Robert F. Carlson

Abstract

Water suspensions from seeds, root and shoots of peach (Prunus persica (L.) Batsch) influenced growth of peach, apple and bean seedlings when applied to soil of potted plants. Different levels of amygdalin were found in plant parts of peach and apple. Synthetic amygdalin applied to potted peach seedlings was not toxic. Certain nutrient elements were altered due to the soil treatment. Disposal of plant parts is suggested as a practical sanitation practice to possibly reduce peach tree decline on old soil.

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S. A. Mackintosh and R. J. Cooper

Environmental concerns associated with traditional methods of sludge disposal have spurred research exploring alternate avenues of disposal. A potentially significant alternative is the beneficial use of sludge as a turfgrass fertilizer. Studies were initiated during 1991 to compare a commercially available pelletized sludge to urea; 12-4-6; Ringer Lawn Restore; and Milorganite. Fertilizers were evaluated for their effect on turfgrass quality, color, and growth rate. Treatments were applied to a stand composed of 65% Kentucky bluegrass (Poa pratensis L. `Baron') and 35% Perennial ryegrass (Lolium perenne L. `Manhattan II') in South Deerfield, MA. Urea and 12-4-6 were applied at 49 kg N ha-1. Ringer Lawn Restore and Milorganite were applied at 98 kg N ha-1. Pelletized sludge was applied at 98, 196, 294, and 392 kg N ha-1 with all rates providing acceptable to good turfgrass color throughout the season. Rates of 294 or 392 kg seldom provided quality better than the 196 kg rate. While urea initially produced quality superior to pelletized sludge, all rates of sludge resulted in quality equal to or better than urea beginning one month after application and lasting approximately 11 weeks. Turf receiving similar rates of either pelletized sludge or Milorganite performed similarly. No sludge application rate produced burning or foliar discoloration. Clipping production was directly related to sludge application rate. Pelletized sludge applied at 98 kg N ha-1 resulted in growth comparable to similar applications of Ringer Lawn Restore and Milorganite. In summary, using pelletized sewage sludge as a turfgrass fertilizer promotes healthy turfgrass while creating an alternate avenue of sludge disposal.