Identifier

etd-0903102-104034

Degree

Master of Science (MS)

Department

Plant, Environmental Management and Soil Sciences

Document Type

Thesis

Abstract

The effects of summer soil solarization on the production and economics of four lettuce cultivars were evaluated in two plantings conducted during the fall growing season of 2001, to determine the feasibility of integrating strip-solarization in plasticulture cropping systems. Soil was solarized for 53 and 34 days for the first and second plantings, respectively, using transparent (T4, T5) and black films (T6) that were kept in place as plastic mulches in raised beds through the fall season. Soil temperatures were recorded at 5 and 10-cm depths at 1-hour intervals during the solarization period. Mulch on T5 was painted black before planting the crop using diluted oil-based paint. Non-solarization treatments included bare ground (T1), fall black plastic mulch (T2) and fall plastic mulch + soil pesticides (T3). Soil pesticides applied on T3 during the first and second plantings were Mefenoxam (MEF) and a mixture of 1,3-Dichloropropene and Chloropicrin (TC-35), respectively. Temperature regimes below clear and black plastic mulches were equivalent, although clear film consistently showed longer periods of sustained high temperatures. Solarization with clear and black mulches equally increased lettuce yield by enhancing plant growth and head weight, as plant stand was uniform for all the treatments. MEF did not affect yield, and TC-35 decreased head weight due to phytotoxicity. Solarization reduced weed densities, especially from grasses. Enhanced weed suppression was achieved by using black plastic for solarization and mulching. MEF increased weed populations while TC-35 caused maximum weed suppression. Cost analysis revealed that yield increases required to cover solarization expenses in bare-ground and fall-mulch systems are generally lower than yield increases reported in previous solarization research.

Date

2002

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Carl Motsenbocker

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