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  • Author or Editor: E. J. Kinbacher x
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Abstract

Urea frequently is applied to turfs in liquid formulation at low water application rates which enhance potential foliar N uptake. This study was conducted to evaluate foliar N uptake by several cool-season turfgrasses treated with urea applied at low water volume (35 ml · m−2). Urea was applied foliarly to 8 turfgrasses at 2.5 g N m−2 in 35 ml m−2 of water. Verdure was harvested prior to treatment and after treatment at 24, 48, and 72 hr. Total N-uptake increases were primarily a response to increased the percentage of N, since dry matter production was stable for each turfgrass throughout the 72 hr. Maximum N-uptake occurred 24 hr after treatment. Any significant decrease in N-uptake over time suggested N-movement out of the sampling zone. Turfgrass species and cultivars showed differences in total N-uptake which resulted from initial variations in dry matter, percentage of tissue N, and variations in N-uptake rate. The percentage of N recoveries ranged from 31% to 61% for ‘Park’ Kentucky bluegrass and ‘Highlight’ chewings fescue, respectively. Cultivar differences indicated that ‘Baron’ Kentucky bluegrass was more efficient in relation to foliar N-uptake than ‘Park’ Kentucky bluegrass.

Open Access

Abstract

Bensulide [0,0-diisopropyl phosphorodithioate S ester with N-2-mercaptoethyl) benzenesulfonamide] at 13.6 kg/ha reduced sod transplant rooting of ‘Park’, ‘Merion’, and ‘Baron’ Kentucky bluegrass (Poa pratensis L.) when applied either to sod or sodbed. Prosulfalin [N-[[4-(dipropylamino)-3,5-dinitrophenyl] -S,S -dimethylysulfilimine] at 2.3 kg/ha applied to the sodbed reduced sod transplant rooting of ‘Park’ and ‘Baron’. Benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) at 2.3 kg/ha reduced rooting of ‘Baron’ when applied to the sodbed. Sod transplant rooting of ‘Baron’ was significantly reduced by siduron [l-(2-methylcyclohexyl)-3-phenylurea] at 13.6 kg/ha, oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropyoxyphenyl)-△2-1,3,4-oxadizolin-5-one] at 4.6 kg/ha, prosulfalin at 2.3 kg/ha, and benefin at 2.3 kg/ha when applied to sod prior to transplanting. ‘Merion’ and ‘Park’ were not influenced by these treatments. Regardless of herbicide treatment, ‘Baron’ had a lower sod transplant rooting strength when compared to ‘Park’ and ‘Merion’.

Open Access

Abstract

This study was conducted on ‘Park’ Kentucky bluegrass (Poa pratensis L.) established on a Sharpsburg silty clay loam (Typic Argiudoll). Urea was applied at 0, 0.8, 1.6, 2.4, and 3.2 g N/m2 in 35 ml·m–2 of distilled water. Treatments were applied at 3-week intervals beginning 29 Apr. 1980 and ending 2 Sept. 1980. Turfgrass color, quality, clipping yield, total N percentage in clippings, and tissue succulence were highest for 3.2 g N/m2. Maximum N-rate responses occurred during spring and fall and were highest 1 week after treatment. Acceptable turfgrass quality was maintained at 1.6 g N/m2 per application. Nitrogen recoveries based on clipping removal were 49%, 60%, 59%, and 59% for 0.8, 1.6, 2.4, and 3.2 g N/m2, respectively.

Open Access

Abstract

Oat straw mulch reduced plant production and quality. Turfgrass clipping mulch produced 2.5 times the fresh plant weight of the no mulch treatment and 5 times that of the oat straw mulch. All mulches reduced weeds when compared to no mulch. Alfalfa hay and turfgrass clippings were more effective than oat straw. Water vapor loss and soil temperatures were reduced by the mulches. Soil moisture beneath the oat straw was less than the other mulches. Oat straw had the lowest N content but did not reflect lower N in plants growing in it. Kentucky bluegrass mulch ranked best of the species tested, perennial ryegrass was second. While, tall fescue, fine fescue, and buffalograss were intermediate in ranking. Creeping bentgrass gave the poorest performance and ranked the same as the no mulch treatment.

Open Access

Abstract

Sixty Kentucky bluegrass (Poa pratensis L.) cultivars and experimental lines and 24 bluegrass blends were investigated for thatching tendency. Cultivars and experimental lines differed in thatch accumulation during the course of this 5-year study. Increasing N level from 10 to 20 g N m-2 season -1 had no effect on thatch accumulation. Thatch accumulation in cultivars and experimental lines was correlated (r = 0.87) to verdure, indicating vigorous cultivars had greater thatching tendency. Thatching tendency of cultivars was correlated (r = 0.74) to their total cell-wall content expressed on a mg dm-2 basis. Accumulation of thatch in blends approximated the mean accumulation for cultivars growing in pure stands. These results indicate a potential for reducing thatch accumulation in Kentucky bluegrass lawns through blending of appropriate cultivars.

Open Access

Abstract

Twenty-one Kentucky bluegrass (Poa pratensis L.) cultivais differed significantly in their thatching tendency during 4 years of study. ‘Glade’, ‘Cheri’, and ‘Victa’ accumulated the most thatch, while ‘S-21’, ‘A-34’, and ‘Park’ accumulated the least. Increasing mowing heights from 2.5 cm to 5.0 cm significantly increased the tendency to accumulate thatch. Increasing nitrogen nutritional levels from 10 g m−2 to 20 g m−2 did not increase thatching tendency.

Open Access

Abstract

Ammonia (NH3) volatilization was determined from 15N-labeled urea applied foliarly in 35 ml·m−2 water at 1.7 and 3.4 g N/m2 to a ’Park’ Kentucky bluegrass (Poa pratensis L.) turf that was grown on Sharpsburg silty clay loam (Typic Argiudoll). Field measurements of NH3 volatilization were made 1, 5, 9, 13, and 25 hr after treatment (HAT). Additional volatilization measurements were made at 2, 3, and 4 days after treatment (DAT). Maximum NH3 losses of 9.7 and 23.0 mg N/m2 per hr at 5 and 25 HAT occurred with the 3.4 g N/m2 treatment. Maximum volatilization during 25 HAT coincided with periods of high leaf surface moisture followed by rapid drying. On the second day after treatment, the maximum NH3 loss of 14.0 mg N/m2 per hr occurred from the 3.4 g N/m2 treatment. Cumulative 4-day NH3 volatilization losses for foliar-applied urea at 1.7 and 3.4 g N/m2 were 35% and 31%.

Open Access