Irrigation and potassium effects on a Kentucky bluegrass fairway turf

Irrigation and potassium effects on Kentucky bluegrass (Poa pratensis L.) turf were studied under field conditions to: (1) determine irrigation and potassium nutrition effects on Kentucky bluegrass fairway playing conditions; (2) evaluate irrigation and potassium treatment effects on water conservation; (3) assess irrigation and traffic effects on Kentucky bluegrass potassium uptake; and (4) test a load bearing capacity device designed to differentiate a turfgrasses ability to bear weight.; In each study (i.e. trafficked and nontrafficked) irrigation treatments based on 60%, 80% and 100% potential evapotranspiration (ETp) replacement and potassium at 0, 20, 40 and 60 g K {dollar}cdot{dollar} m{dollar}sp{lcub}-2{rcub}cdot{dollar} season{dollar}sp{lcub}-1{rcub}{dollar} were applied to Kentucky bluegrass turf. The turf was mowed four times weekly (22 mm). Turfs were exposed to a simulated traffic treatment twice per week in the trafficked study. Data were collected on soil and tissue potassium contents, turfgrass load bearing capacity, ball roll, canopy temperature, soil compaction, turfgrass color, quality and water use.; A load bearing capacity (LBC) device was designed to differentiate turfgrass ability to support weight per unit area. In preliminary tests the LBC device proved satisfactory for determining differences among species and cultivars, and mowing heights under field conditions.; In the nontrafficked study, irrigation did not influence potassium content in soil or plant tissue. Turfgrass LBC was reduced at the 60% ETp and 0 g K {dollar}cdot{dollar} m{dollar}sp{lcub}-2{rcub}cdot{dollar} season{dollar}sp{lcub}-1{rcub}{dollar} treatment. Water savings ranged from 15% to 22% for 80% ETp and 27% to 42% for 60% ETp treatments, when compared to 100% ETp during the 1989 growing season. Water savings for June through August 1989 totaled 415 m{dollar}sp3cdot{dollar} ha{dollar}sp{lcub}-1{rcub}{dollar} and 866 m{dollar}sp3cdot{dollar} ha{dollar}sp{lcub}-1{rcub}{dollar} for the 80% and 60% ETp treatments, respectively. Acceptable turfgrass color and quality were maintained at all ETp treatments. Kentucky bluegrass was maintained at 60% and 80% ETp without loss of turfgrass quality.; Under traffic conditions, soil and tissue potassium contents were affected by irrigation. Soil potassium content decreased at 40 and 60 g K {dollar}cdot{dollar} m{dollar}sp{lcub}-2{rcub}cdot{dollar} season{dollar}sp{lcub}-1{rcub}{dollar} as percentage ETp increased from 60% to 100%. At 100% ETp and the 40 and 60 g K {dollar}cdot{dollar} m{dollar}sp{lcub}-2{rcub}cdot{dollar} season{dollar}sp{lcub}-1{rcub}{dollar} treatments more K uptake occurred in comparison to 60% ETp. Soil penetrometer measurements were not influenced by K treatment.