Partridge pea frequently occurs on non-stable sites and in Illinois occurs most often on silty clay loam soils. There· was no tendency to occur on· sandy sites as has been previously reported. Partridge pea occurs on soils with a wide range of pH values and on sites with both low and high phosphorus values. Low phosphorus values predominate in both the slowly and readily available forms. Partridge pea stands generally occur on soils with very high levels of available potassium but also occur on sites quite deficient in potassium. Total, mineral, and extractable calcium (measured as CaO) were pre·sent in partridge pea site soils in amounts ranging from .40 to 2.55%, .22 to 1.31 o/o, and .03 to 1.27%, respectively. Soils with partridge peas growing on them have a wide range in total nitrogen content but low values less than .181% predominate. These soils also generally have a low rate of nitrate production. Low nitrate production and/or low levels of available phosphorus may restrict the growth of other species on sites where C. fasciculata occurs. Total nitrogen and nitrate production, however, were not related to the amount of phosphorus. Subsoil clay content did not seem to be a factor in partridge pea stand occurrence. The species' ability to grow under some adverse conditions and on non-stable sites, including eroding areas, indicates that it is a species which might have a use similar to Korean lespedeza (Lespedeza stipulacea L.).

MH (1,2-dihydro-3,6-pyridazinedione) was applied at 4 to 6 lb/A, in spring and fall, with and without (2,4-dichlorophenoxy)acetic acid (2,4-D), on roadsides normally mowed from 2 to 12 times a year. MH at 6 lb/A applied in spring generally reduced grass height. Lower rates and fall applications were generally ineffective. Depending on area, rural or urban, and retardant effectiveness, between zero and five mowings per year were saved. When the MH was effective and the turf was not strong and vigorous, annual weeds such as crabgrass (Digitaria spp. Heist.), foxtail (Setaria spp. Beauv.), and ragweed (Ambrosia spp. L.) often increased and gave the roadside an undesirable appearance. When MH was used without 2,4-D, the roadside generally had a poorer appearance than when not treated. When MH was applied with 2,4-D and no application ‘'skips” or annual weed infestation occurred, the roadside sometimes had a satisfactory appearance. The time when MH can be effectively applied is short (about 2 weeks). Rains, winds, and springtime roadway work make proper timing of applications difficult under Minnesota conditions. Applications of 2,4-D alone or with MH were effective in reducing roadside weeds.

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.

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