Response of Japanese Privet to Plastic Mulch Applied over Nonspaced Containers

Abstract

Mulches have many positive benefits for the production of plants, ranging from weed suppression to water conservation. In this study, a novel method of using plastic film mulch for container-grown plants was evaluated. Plots of 25 japanese privet (Ligustrum japonicum) in #1 (2.5 qt) nonspaced containers were wrapped with 1.25-mil white or black plastic mulch over the top and sides of containers. Small plants were planted through the plastic and grown for 22 weeks with overhead irrigation. Water application amount was determined by moisture sensors placed in the substrate of each treatment. Plant growth, dry weights (DWs), weed fresh weights, weeding time, substrate electrical conductivity (EC), substrate temperature, total water applied, and mulch costs were determined. Black plastic (BP) and white plastic (WP) mulch reduced water applied by 82% and 91%, respectively, compared with the nontreated control (NT). Nontreated control plants grew faster and had greater DW at the end of the experiment. Mulched containers had fewer weeds and required less labor to remove weeds than the NT treatment. Substrate EC level was greater in BP and WP treatments than for the NT after 20 weeks, and plastic mulch did not result in different substrate temperatures. Plastic mulch added $4.94/1000 containers ($2.24 input cost and $2.70 removal cost) to production costs, not including disposal costs. This novel method of mulching nonspaced plants reduced irrigation water, herbicide applications, and weeding labor, but probably added 2–3 weeks to finish time.