Project Title:Water Conservation Practices for Michigan Container Nurseries
Project # MDAHF - 2006-09
Principal Investigator: R.T. Fernandez
E-mail:
Department: Horticulture
Mail Address: Dept. of Horticulture, MSU
Team Members: A.L. Warsaw, B.M. Cregg, J.A. Andresen
Reporting Period:July 1, 2006 – June 30, 2007
Accomplishments During Reporting Period
Water use and conservation is a growing concern for Michigan container nurseries. Public Act 148 (2003) and Public Act 35 (2006) require that heavy water users report water use, conservation practices, and implementation plans to the MDA annually. Irrigating according to plant demand is a key concept in water conservation, however, little information exists on the water requirements of container-grown woody ornamentals. The objective of this project is to quantify the daily water requirement (DWR) of container-grown ornamentals so that irrigation can be applied based on plant demand. Knowing the DWR of container-grown plants will allow growers to avoid over-watering and group plants with similar DWR together, resulting in water conservation and reduced runoff. This information can be used through extension programs and publications to assist growers in developing and implementing water conserving irrigation schedules.
In 2006, ten taxa (Table 1) of landscape shrubs were grown under 4 irrigation treatments at the Horticultural Teaching and ResearchCenter. DWR was determined by using a ThetaProbe to measure volumetric substrate moisture content 1 hour and prior to irrigation the following day with the difference between the two measurements equaling the irrigation rate to apply. DWR was compared with a traditional irrigation rate to see if irrigating according to DWR would conserve water. Irrigation treatments were 1. control rate of 0.75 inches per day, 2. irrigation applied to replace 100% DWR, 3. irrigation applications alternating 100% DWR on the first day with 75% DWR on the second day, 4. irrigation applied on a three day cycle of 100%-75%-75% DWR. Plant response to treatments was recorded by measuring 1. monthly growth index, 2. gas exchange every two months, 3. end of season internode length, 4. end of season leaf area.
Table 1:
Plants Used 2006 ABR. / Plant Used ABR.Callicarpa dichotoma ‘Early Amethyst’ CD / Syringa x hyacinthiflora ‘Asessippi’ SH
Cornus sericea ‘Farrow’ CS / Syringa prestoniae ‘Donald Wyman’ SP
Deutzia gracilis ‘Duncan’ DG / Thuja plicata ‘Atrovirens’ TD
Kerria japonica ‘Albiflora’ KJ / Viburnum dentatum ‘Ralph Senior’ VD
Symphoricarpos x doorenbosii ‘Kordes’ SD / Viburnum opulus ‘Roseum VO
Figure 1 shows the average water applied daily during the experiment for the four treatments. Irrigating according to plant demand conserved water for all taxa in the experiment when compared to the control treatment of 0.75 inches per day. Taxa were classified as low, moderate, or high water users based on average DWR (Figure 2). Scheduling irrigation according to the highest water user within each class would result in water savings of 32%, 60%, and 70% for high, moderate, and low water users when compared to the control treatment.
Growth index for eight out of the 10 taxa was higher under the 100% DWR treatment as compared to the control indicating that larger plants were grown using less water. This was likely due to water-logging and/or nutrient leaching from the containers in the control treatment and will be investigated in a runoff collection experiment in 2007. Data for internode length, leaf area, and photosynthesis has been analyzed with the majority of taxa showing no differences among treatments (data not shown).
Figure 1 Figure 2
Planned Activities for Next Reporting Period
Currently, the experiment is being conducted for 10 different taxa (Table 2). In addition to measurements taken in 2006, a data logger, 12 ThetaProbes, 12 Thermisters, an air temperature/relative humidity probe, and net radiometer have been installed at the nursery production site to collect data on 15 minute averages for Spirea fritschiana Pink Parasols®. Data will be used to formulate models to schedule irrigation based on DWR. Twelve 10ft. x 20ft. production areas previously used for a phytoremediation study have been set up to collect runoff water from four taxa used in the 2006 experiment. Total runoff will be collected and water samples tested for nitrate and phosphorus content. This experiment will allow comparison between treatments to determine the extent of nutrient leaching and runoff reductions of irrigation based on DWR compared to traditional irrigation rates.
Table 2:
Plants Used 2007 / Plant UsedCaryopteris x clandonesis 'Dark Knight' / Rosa'Winnipeg Parks'
Cotinus coggygria 'Young Lady' / Spiraea fritschiana 'Pink Parasols'
Forsythia x 'New Hampshire Gold' / Thuja occidentalis 'Techny'
Hydrangea arborescens 'White Dome' / Viburnum x burkwoodii 'Chenault'
Hydrangea paniculata 'Unique' / Weigela florida'Wine and Roses'
Preliminary data from 2007 (figure 3) shows reductions in runoff water captured under the 100% DWR and 75% DWR irrigation rates compared to the control. Total nitrate and phosphorus captured in runoff (mg) were also lower in the 100% DWR and 75% DWR irrigation rates compared to the control (figure 4).
Other Funding/Contributions: Project GREEEN FY06 $24,000; Spring Meadow Nursery $3,500; Renewed Earth $1,000; Harrell’s Inc $300.
Publications/Outreach:Results for 2006 have been presented at 4 grower meetings and at the 2007 ASHS conference held in Scottsdale, Arizona from July 16th through the 19th.
Figure 3: Figure 4: