Occurrence and Stand Density of Tridens flavus (L.) Hitchc. as Related to Some Soil Factors¹

Abstract

Surface soil samples were collected from within 47 stands of Tridens flavus (L.) Hitchc. “purpletop.” Plant stands were rated as thin, medium, or thick according to the approximate distance between bunches and stand sites were classified as wet, mesic, or dry. The soils were tested for pH, extractable phosphorus (P2 test), readily extractable phosphorus (P1 test), potassium, and texture. There was some indication that occurrence of the species might be associated with phosphorus availability and pH. Occurrence of the species was not associated with any particular soil texture contrary to previous reports. Thick stands of Tridens flavus tend to occur on sites where some soil condition is not particularly favorable for the growth of other plants. These conditions may be of excessively dry or wet soils caused by either topography or a high sand content; or high pH and the resulting relative low availability of phosphorus and other elements.

A Comparison of Breeding Systems and Seed Physiologies in Three Species of Portulaca L.

“…Soil type which differs in moisture retention and temperature characteristics can influence germination and establishment in nature (Foote and Jackobs 1966). Three field sites, previously used for Portulaca growth experiments, permitted germination comparisons to be made.…”

Edaphic Requirements and Characteristics of Purpletop1

“…At two sites, the soil from the area with purpletop had a higher clay content than the soil from the area without purpletop; but in these cases the sand content was 8 and 10 percentage units higher in soil from areas with than without purpletop. Foote and Jackobs (1966), who also determined texture in the top 15 em of the soil profile, concluded that the presence of purpletop was not well coordinated with soil textural analysis; but suggested from their data on standard deviations of sand, silt, and clay content that clay was the most and sand the least important component of soil texture relative to the occurrence of purpletop. Results from our study confirmed their conclusion that purpletop occurrence is not highly associated with soil texture, but our results indicate that purpletop presence is more closely associated with sand than clay content.…”

“…Each site with and without purpletop was characterized relative to primary use and past management. All study sites were subjectively rated as to soil moisture conditions on the basis of visual observations concerning topography, soil texture, and vegetative characteristics as described by Foote and Jackobs (1966). A scale of I to 7 was used with 1 being extremely wet and 7 being extremely dry.…”

“…Purp1etop occurs in stands of varying densities but the factors influencing its presence are unknown. Foote and Jackobs (1966) examined purpletop stands of varying densities in Illinois to determine the factors influencing stand density and occurrence. They concluded that the clay fraction was the most important soil physical property while sand was the least important.…”

Germination Responses of Purpletop and Big Bluestem Caryopses Subjected to Distilled Water or Potassium Nitrate Prechilling, Sodium Hypochlorite, and Storage

“…Purpletop is a warm-season perennial grass native to the United States that grows in dry fields or along roadsides in 36 states (Brown, 1979;USDA-NRCS, 2009b). It is able to grow within a variety of soil types and pH levels, including soils that are highly eroded (Foote and Jackobs, 1966). Removal of the palea and lemma of the caryopsis fruit (dehulling) and stratification for 14 d at 3°C overcomes purpletop dormancy (USDA-NRCS, 2006); however, dehulling does not increase purpletop stand establishment (USDA-NRCS, 1996).…”