1、 ANSI/ASABE S623.1 JAN2017 Determining Landscape Plant Water Demands American Society of Agricultural and Biological Engineers ASABE is a professional and technical organization, of members worldwide, who are dedicated to advancement of engineering applicable to agricultural, food, and biological sy
2、stems. ASABE Standards are consensus documents developed and adopted by the American Society of Agricultural and Biological Engineers to meet standardization needs within the scope of the Society; principally agricultural field equipment, farmstead equipment, structures, soil and water resource mana
3、gement, turf and landscape equipment, forest engineering, food and process engineering, electric power applications, plant and animal environment, and waste management. NOTE: ASABE Standards, Engineering Practices, and Data are informational and advisory only. Their use by anyone engaged in industry
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6、ata approved after July of 2005 are designated as “ASABE“. Standards designated as “ANSI“ are American National Standards as are all ISO adoptions published by ASABE. Adoption as an American National Standard requires verification by ANSI that the requirements for due process, consensus, and other c
7、riteria for approval have been met by ASABE. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily u
8、nanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution. CAUTION NOTICE: ASABE and ANSI standards may be revised or withdrawn at any time. Additionally, procedures of ASABE require that action be taken periodically to reaf
9、firm, revise, or withdraw each standard. Copyright American Society of Agricultural and Biological Engineers. All rights reserved. ASABE, 2950 Niles Road, St. Joseph, Ml 49085-9659, USA, phone 269-429-0300, fax 269-429-3852, hqasabe.org S T A N D A R D ANSI/ASABE S623.1 JAN2017 Copyright American So
10、ciety of Agricultural and Biological Engineers 1 ANSI/ASABE S623.1 JAN2017 Approved January 2017 as an American National Standard Determining Landscape Plant Water Demands Proposed by the Irrigation Association; approved by the ASABE Natural Resources and Environmental Systems Technical Community; a
11、pproved by ASABE October 2015; approved by ANSI as an American National Standard October 2015, revised by ASABE and approved by ANSI as an American National Standard January 2017. Keywords: landscapes, turfgrass, plants, trees, shrubs, water, water budget, irrigation, sprinklers, soil 0 Foreword Thi
12、s standard was created to provide science-based guidelines for determination of the minimum plant water demands for mixed species landscapes that maintain adequate aesthetic quality. Plant water demands can be met by any combination of precipitation and irrigation. The plant factors and other inform
13、ation in this standard are broad in nature and based on available science. Localized climate data, if available, should be used to corroborate or customize as applicable. The plant categories are purposely broad for general applicability. If scientifically-proven reasons for altering the plant facto
14、rs are available, the numbers may be adjusted accordingly. An informative annex of information and techniques for application of the plant factors is included. This annex may also be used to aid decisions for potential deficit watering to maintain minimum survival requirements for plants under low w
15、ater availability. 1 Scope This methodology will provide an estimate of plant water demands of permanently installed, non-production based, established landscape materials. The standard will provide minimum water demands for acceptable plant appearance and function. This standard does not cover plan
16、ts for sports fields, golf courses, or food production. This methodology is applicable for planning and design of planted landscape areas as defined in section 3. It is assumed throughout this standard that the soil around the plants in question are wetted uniformly by precipitation or irrigation. 2
17、 Normative References The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies unless noted. For undated references, the latest approved edition of the referenced document (including any amendments) applies. ASCE
18、Environmental and Water Resources Institute (EWRI) standardized reference evapotranspiration equation. 2005. Reston, Virginia: American Society of Civil Engineers. 3 Definitions 3.1 acceptable plant appearance: a plant that is maintaining its intended health, coloration, growth and function is consi
19、dered “acceptable” for purposes of this standard. ANSI/ASABE S623.1 JAN2017 Copyright American Society of Agricultural and Biological Engineers 2 3.2 climate: for purposes of this standard, climate refers to the typical annual precipitation and temperature of geographically delimited regions. 3.3 dr
20、ought: a period of abnormally dry weather for a climate region sufficiently prolonged to where the amount of water available in the soil no longer meets the demands of the landscape area to meet expectations of acceptable plant appearance. 3.3.1 drought resistance: physiological and phenological mec
21、hanisms by which a plant may withstand periods of dry weather. 3.4 evapotranspiration (ET): the loss of water from the earths surface through the combined processes of evaporation (from soil and plant surfaces) and plant transpiration (i.e., internal evaporation) (ASCE-EWRI, 2005). 3.4.1 reference e
22、vapotranspiration (ETo): the evapotranspiration (ET) from a defined vegetated surface (cool season grass) which serves as an evaporative index by which ET can be predicted for a range of vegetation and surface conditions For purposes of this standard, the ASCE-EWRI Standardized Reference Evapotransp
23、iration Equation (ETos) is used. 3.5 planted landscape area: managed and maintained plantings of turf, woody plants (including trees), desert plants, annual flowers and herbaceous perennials located in or around urban residential premises, public or commercial facilities, parks, workplaces, care fac
24、ilities, or recreational areas. The landscape area does not include footprints of buildings or structures, sidewalks, driveways, parking lots, decks, patios, gravel or stone walks, other pervious or non-pervious hardscapes, and other areas permanently designated to not be planted or irrigated. 3.6 l
25、andscape plant: a plant in a planted landscape area. 3.7 plant factor (PF): the fraction of reference evapotranspiration (ETo) required for acceptable plant appearance. When multiplied by ETo, the plant factor estimates the depth of water required by plants. This standard implements PF rather than t
26、raditional “crop coefficients” (K values) to acknowledge the variability inherent in empirical water use adjustments for landscapes, rather than the implied precision of a coefficient. 4 Plant Water Demands 4.1 Plant factor table. Table 1 indicates, for various broad categories of plant types used i
27、n planted landscape areas, accepted plant factors: fractions of reference evapotranspiration (ETo) based on the required acceptable appearance of the landscape. Numbers given are intended as guidelines for assisting in calculating landscape plant water demand which can be used for scheduling irrigat
28、ion frequency and duration and for determining plant water allocation to planted landscape areas. Plant water demand is calculated by multiplying the plant factor for a given plant type from Table 1 by ETo, with other required adjustment factors also included (see section 5). Table 1 is the plant wa
29、ter demand by fraction of ETo. It is not irrigation demand, which may include factors to account for system non-uniformity. The numbers in Table 1 are plant factors (see Section 4.2) for the average water demands during the portion of the year where the plant is actively transpiring. These numbers a
30、re based on available science. Applying these numbers to water allocation, irrigation design, and scheduling may require the end user to make adjustments up or down to supply the appropriate amount of water to meet plant water demand. Plants that are not fully or near fully established will typicall
31、y require more frequent water but will typically not require a greater fraction of ETo. During the transition period from dormancy to active growth or vice versa, the plant may not require the full fraction of ETo, but that change in amount is not sufficiently documented for inclusion in this standa
32、rd. As described in the sections below, areas with 20 in. of annual precipitation, especially if it occurs during the growing season, should be considered “wet” in regards to Table 1. Areas with lower growing season precipitation should be considered “dry” or may even require desert plants for survi
33、val without supplemental irrigation. Cool-season and warm-season turfgrasses are described in sections 4.1.1.2 and 4.1.1.3. ANSI/ASABE S623.1 JAN2017 Copyright American Society of Agricultural and Biological Engineers 3 Table 1 Annual average fraction of ETo for acceptable appearance of established
34、landscape plants Plant Type Recommended Plant Factor Turf, cool season 0.8 Turf, warm season 0.6 Annual flowers 0.8 Woody plants and herbaceous perennials, wet 1)0.7Woody plants and herbaceous perennials, dry 0.5 Desert plants 0.3 1)Tropical plants: for tropical plants with precipitation the majorit
35、y of months, a plant factor of 0.7 applies. Where monsoonal climates are present, 0.7 applies for the wet season, and 0.5 during the dry season. 4.1.1 Plant categories 4.1.1.1 turfgrass: grasses managed and maintained as a monoculture (a.k.a. “lawns”), rather than ornamental grasses or sedges. 4.1.1
36、.2 turf, cool season: cool-season grasses, which do better in the cooler times of the year and thrive in temperatures from 65 to 75 F. Examples include, but are not limited to, bluegrass, tall fescue, perennial ryegrass, and fine fescues. 4.1.1.3 turf, warm season: warm-season grasses, which are bes
37、t adapted to temperatures between 80 and 95 F. Examples include, but are not limited to, bermudagrass, zoysia, St. Augustine, seashore paspalum and buffalograss. 4.1.1.4 annual flowers: annual plants grown in a usually formal, high-visibility area for seasonal display of colorful flowers or attracti
38、ve foliage; often referred to as bedding plants. 4.1.1.5 woody plants and herbaceous perennials, wet: trees, shrubs, vines, ground cover, and herbaceous perennials adapted to grow in a wet environment (20 in. of average annual precipitation) where soil water deficits and dry air (low humidity) do no
39、t restrict transpiration. This includes plants from habitats and climates where both soil and atmospheric water deficits are infrequent and irregular. This includes species growing in high summer rainfall regions (adapted to infrequent atmospheric and soil water deficits). These environments typical
40、ly support a permanent forest cover. 4.1.1.6 woody plants and herbaceous perennials, dry: trees, shrubs, vines, ground cover, and herbaceous perennial species adapted to grow in non-desert climates or habitats being grown in sufficiently dry climates (10 20 in. of average annual precipitation) where
41、 atmospheric water deficits (low humidity) can restrict transpiration. 4.1.1.7 desert plants: plants that can survive a very dry (10 in. of annual precipitation) environment. 4.2 plant factor (PF): Water demands of landscape plants are effectively defined as the fraction of reference evapotranspirat
42、ion (ETo) (ASCE-EWRI, 2005) required to maintain their acceptable appearance and intended landscape function (Pittenger et al., 2001; Shaw and Pittenger, 2004). The ETo calculation assumes the following standard conditions for a hypothetical cool-season turfgrass surface: a uniform plant canopy that
43、 governs how foliage connects to the atmosphere, uniformly adequate soil water, and plant water use that is tightly synchronized and linearly related with changes in ETo (ASCE-EWRI, 2005). The ETo algorithm was developed for agriculture; the product of ETo multiplied by a species-specific fraction t
44、hat estimates the depth of water a specific crop requires. The species-specific fraction assumes uniform crop canopies tightly synchronized to ETo. However, the ETo multiplied by a species-specific fraction algorithm has limited accuracy in estimating water demands of urban landscapes. The algorithm
45、 is not robust enough to account for the spatially and biologically complex mixes of turfgrass, woody, and herbaceous plant types (St. Hilaire et al., 2008) in urban landscapes. These plant types differ in canopy architecture, plant structure and leaf size in ways that do not conform to the standard
46、 conditions under which ETo is defined. Water demands of many non-turf landscape plant species are not tightly synchronized to ETo and may respond non-linearly to weather factors used to estimate ETo (Choudhury and Montieth, 1986). Also, unlike agricultural crops, urban landscape plants are grown fo
47、r their aesthetic ANSI/ASABE S623.1 JAN2017 Copyright American Society of Agricultural and Biological Engineers 4 appearance and functional value achieved over a range of water applications, rather than optimum growth and yield based on precise water application targets. Nevertheless, this standards
48、 approach to estimating landscape plants water demands as a fraction of ETo using an adjustment factor (plant factor, PF) value is rational, reasonable, scientific, and climate-based. This approach is sufficiently accurate and effective in estimating water demands for a landscape design grouping spe
49、cies with similar plant factors (Kjelgren et al., 2000; Eching and Snyder, 2006). Understanding the limitations of ETo PF is crucial to success in applying the standard to manage landscape water for the range of different landscape plant types. 4.2.1 turf: Estimating water demands of turfgrass as ETo PF is an effective tool in estimating water demands and managing irrigation because turfgrass closely mimics the standard conditions of ETo estimation (Richardson et al., 2012; Devitt et al., 1992; Gibeault et al., 1985). A similar approach
