Water resources for outdoor areas, such as lawns and landscapes,
continues to become limited in many urban areas, especially in times of acute
drought stress. Lawn species selection and cultural practices, such as mowing
height, can strongly influence overall seasonal water needs. While previous
research has reported various lawn species water use rates and differences in
the ability of some cultivars to maintain green coverage during acute drought
stress, little is known regarding the irrigation requirements of cool-season
lawn species when using a deficit irrigation strategy based on a green coverage
target threshold (e.g. 60-80% green) approach. Two greenhouse studies were
conducted to screen various candidate species and seed mixtures in a sandy media.
The highest water use and worst appearance/green
coverage was associated with an inexpensive commercial lawn mixture; and the
lowest water use and best appearance was generally associated with improved Kentucky
bluegrass (<i>Poa pratensis</i> L.:
KBG) cultivars. Field studies were conducted
to quantify the irrigation requirements of drought susceptible (DS) and
improved, drought tolerant (DT) KBG and tall fescue [<i>Schedonorus arundinaceus</i> (Schreb.): TF] cultivars, blends and
mixtures at two mowing heights (5.1 or 8.9 cm). Results from a 74-day field study using
a deficit irrigation replacement approach with a 70% green coverage threshold
(GCT<sub>70</sub>) irrigation trigger, demonstrated water savings of
approximately 73 to 78% when using a DT TF (60.3 mm) as compared to 100%
evapotranspiration (ET<sub>o</sub>) replacement (223.4 mm) and a conventional
lawn irrigation approach (268.5 mm), respectively. The time to reach the GCT<sub>70</sub>
generally ranked: TF=TF:KBG mixture>KBG and ranged from 18.0 days for DS
‘Right’ KBG and 52.5 days for DT ‘RainDance’ TF. Among TF and KBG cultivars
using the GCT<sub>70 </sub>irrigation approach, DT TF required 35 to 68% less
supplemental irrigation compared to DT and DS KBG cultivars (92.1 vs. 187.3
mm), respectively. Within KBG cultivars, the DT ‘Desert Moon’ required one-half
the irrigation of DS Right (92.1 vs. 187.3 mm), while there were no differences
among TF cultivars for irrigation needs. Mowing height did not affect KBG irrigation
needs, but TF at 5.1 cm showed increased visual quality and green coverage, and
significantly reduced irrigation requirements. Field research also compared species
mixtures and blends using DS and DT KBG and TF to determine the amount of a DT
species/cultivar that would enhance drought performance with ratios ranging
from 25-100% DT as well as 90:10 TF:KBG mixtures. The quantity of a DT KBG in a
blend, and DT TF in a TF:KBG mixture reduced irrigation needs, whereas the
drought rating of the KBG cultivar in a TF:KBG mixture had no significant
effect. In summary, these studies continue to demonstrate that significant
supplemental lawn irrigation savings can be achieved by the selection of
superior DT species and cultivars combined with a deficit irrigation replacement
approach compared to other cool-season species and conventional irrigation practices.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/8024093 |
| Date | 14 May 2019 |
| Creators | Jada S Powlen (6620417) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Strategies_for_Reducing_Supplemental_Irrigation_of_Cool-Season_Lawns_through_Species_Selection_Mowing_Practices_and_Irrigation_Scheduling/8024093 |
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