The Species Selection Tool section of MatchClover will aid you in selecting the “best” clover for your location's climate and soil conditions, and your intended use and management level. For each of these parameters, you will select from a drop-down menu the conditions representative of your locale. The tool will then identify the clovers best suited to your conditions.
The following flowchart provides the steps involved in selecting an appropriate clover species.
1. Identify and Characterize your Location
In the Species Selection Tool, climate is defined by temperature extremes and annual precipitation. Soil conditions are defined by pH, drainage, and salinity levels.
The USDA Plant Hardiness Zone map is based on coldest temperatures. Each zone is identified by its average annual extreme minimum (coldest) temperature. Identify your Plant Hardiness Zone from the above-linked map; e.g. select Oregon as state, enter 97330 as zipcode; zone is identified as 8b: 15-20 °F, -9.4 to -6.7 °C.
Determining the hottest temperatures can be done from The PRISM Group 30-year normal July mean maximum temperature map is the source for average annual mean maximum (hottest) temperature; e.g. for the Willamette Valley, Mean Maximum July Temperature range is 80-84 degrees F.
Also find annual precipitation for your location from the PRISM Group 30-year normal precipitation map; e.g. for the Willamette Valley, this is 50-60 inches.
The USDA Natural Resources Conservation Service (NRCS) Web Soil Survey (WSS) information is the source for soil pH, drainage class, and salinity. Find user instructions for the WSS here: https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm.
The 8 soil pH categories for clover species are: (1) Very strongly acid to strongly alkaline, 4.5–9.0; (2) Very strongly acid, 4.5–7.3; (3) Strongly acid, 5.1–7.3; (4) Moderately acid, 5.6–7.3; (5) Moderately acid to moderately alkaline, 5.6–8.4; (6) Slightly acid to moderately alkaline, 6.1–8.4; (7) Near neutral, 6.1–7.3; and (8) Alkaline, 6.7–9.0.
The 7 soil drainage classes are: (1) VPD, very poorly drained; (2) PD, poorly drained; (3) SPD, somewhat poorly drained; (4) MWD, moderately well drained; (5) WD, well drained; (6) SED, somewhat excessively drained; and (7) ED, excessively drained.
The 5 soil salinity classes, expressed in electrical conductivity (EC) units (deciseimens per meter (dS/m)) are: (1) 0 < 2 Non-saline; (2) 2 < 4, Very slightly saline; (3) 4 < 8, Slightly saline; (4) 8 < 16, Moderately saline; (5) ≥ 16 Strongly saline. Clover tolerance to soil salinity is divided into three categories: (1) Tolerant, 6–10 dS/m; (2) Moderately Tolerant, 3–6 dS/m; and (3) Moderately Sensitive, 1.5–3 dS/m.
2. Define Your Intended Use
Intended Uses include one or more of the following: pasture, hay, silage, using the species as a monoculture or mixture, soil improvement (green manure), soil protection (cover crop), benefitting pollinators, seed production, wildlife feed or habitat, or beautification.
Stand life choices are: biennial, short-lived perennial, long-lived perennial, summer annual, and winter annual.
3. Define Your Management Level
Management Level can be high, medium or low. A high level of management implies following best management practices for fertilization, irrigation, defoliation, and pest control. Low implies few inputs and periods of ill-timed or overly severe defoliation. Medium management falls somewhere between the two.
4. Search Database for Matches
Make selections from the dropdown menus for the categories of interest (one or all). To avoid numerous "no match found" incidents, select one or two most important categories and conduct the search, then add additional filters to your search results.
Select multiple uses by holding down the Ctrl key. For all other categories, select the menu choice that best matches your conditions.
Species Characteristics for Matching: Once you have indicated the search parameters, the tool will return matches by comparing your choices with the species database information.
5. Select Best Matching Clover
Optimize the selection process by reviewing additional information about the species recommended by the tool. Click on the link to the species name to review details. Other considerations include availability of seed and previous experience in establishing and managing the proposed species.