Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2004
Publication Date: 10/7/2004
Citation: Fain, G.B., Knight, P.R. 2004. Irrigation and fertilizer placement in container tree production. Meeting Abstract, pg. 11.
Technical Abstract: Weed control in container production is achieved primarily through use of preemergence herbicides, along with hand-weeding; however, most programs are not 100% effective. Therefore, growers are continually evaluating new strategies to improve weed control in their nurseries. Past research has show that fertilizer placement affects weed control. The objective of this research was to determine the effect of fertilizer placement and irrigation method (specifically the introduction of irrigation water below the substrate surface) on plant and weed growth in production of Quercus shumardii. On April 24, 2003, three gallon liners were potted into #15 containers using a standard nursery mix. Treatment design was a 3 x 2 x 2 factorial with two fertilizer placements, three irrigation methods, and two herbicide rates. Fertilizer 17N-2.9P-9.8K (17-7-12) was dibbled (placed 10.2 cm below the surface of the container media at potting) or top-dressed at a rate of 280 g per container. Irrigation was applied using one of three methods: 1) a spray stake attached to an 11.4 liter per hour pressure compensating drip emitter; 2) a surface pressure compensating drip ring delivering water at a rate of 8.9 liters per hour; and 3) the same drip ring placed 10.2 cm below the container substrate surface. Rout® (oxyfluorfen + oryzalin) was applied at 0 or 112 kg/ha . At 75 DAT containers with no herbicide and topdressed fertilizer had a percent weed coverage of 46% compared to 18% for dibbled containers with no herbicide. Weed top dry weight was also greater for topdressed containers compared to dibbled. None of the treatments in the study had any effect on height increase. Trees irrigated with drip rings at the surface had a 28% greater caliper increase among the dibbled fertilizer treated containers. Trees irrigated with the drip ring placed below the surface and fertilizer topdressed had the smallest caliper increase. Irrigation method had no effect on weed control in this study, however a repeat fall application showed a significantly greater weed control with the drip ring below surface compared to the spray stake. This work further supports previous research which indicated topdressed fertilizer applications result in increased weed populations compared to dibbled applications.