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Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Dale J. Bremer / Jack D. Fry / Irrigation management may influence nitrate leaching under tall fescue (Festuca arundinacea) and also affect its mowing requirements. Two experiments were conducted on tall fescue growing on a Chase silt loam soil near Manhattan, Kansas. Each experiment was arranged in a split-plot design, with irrigation treatments applied to whole plots: 1) frequency-based irrigation, water was applied three times weekly to deliver a total of 19 mm water wk⁻¹ regardless of weather conditions; and 2) soil moisture sensor (SMS)--based irrigation, 34 mm of water was applied when soil dried to a predetermined threshold. In the first experiment, sub-plots consisted of unfertilized turf, and N applied as urea or polymer-coated urea at 122 and 244 kg ha⁻¹ yr⁻¹. Suction lysimeters at a 0.76 m depth were used to extract nitrate leachate bi-monthly. Turf quality was rated weekly. In the second experiment, subplots were mown at 5.1 cm or 8.9 cm, based upon the 1/3 rule, with or without monthly applications of the growth regulator trinexapac-ethyl (TE). Data were collected on total mowings and visual turf quality. Soil moisture sensor-based irrigation resulted in water savings of 32 to 70% compared to frequency-based irrigation. Leaching levels did not exceed 0.6 mg L⁻¹ and no differences in leaching were observed between irrigation treatments or among N sources. All fertilized turf had acceptable quality throughout the study. In the second experiment, irrigation strategy did not influence total number of mowings. In the first year, TE application reduced total mowings by 3 in tall fescue mowed at 5.1 cm, but only by 1.5 when mowed at 8.9 cm. In the second year, mowing at 8.9 vs. 5.1 cm or using TE vs. not resulted in a 9% reduction in total mowings each. The SMS-based irrigation saved significant amounts of water applied compared to frequency-based irrigation, while maintaining acceptable quality, but irrigation treatments did not affect nitrate leaching or mowing frequency in tall fescue on fine silt-loam soil. Nitrate leaching, regardless of amount, was well below the standards set for human health (10 mg L⁻¹). Applications of TE are more beneficial for turfgrass mowed at lower cutting heights.

Call number: LD2668 .T4 1961 F45

Call number: LD2668 .T4 1962 A48

Call number: LD2668 .T4 1962 W45

Plant growth inhibitors were isolated from Haplopappus acradenius (Green) Blake and Baccharis sarothroides Gray, two desert species, found at the Boyce Thompson Southwestern Arboretum. Leaf and stem tissues of B. sarothroides were extracted with 80% methanol (v/v). This extract was reduced to an aqueous phase in vacuo and partitioned with ethyl acetate at pH 7.3 (NF, neutral fraction), pH 2.8 (AF, acidic fraction), and again at pH 2.8 following hydrolysis at pH 11 (HF, hydrolyzed fraction). Thin layer chromatography (TLC) on silica gel H in chloroform:ethyl acetate:formic acid (CHCl₃:EtOAc:HCOOH) produced a region between R(f)'s 0.5 to 0.6 from AF of B. sarothroides which inhibited wheat seed coleoptile and radicle growth 52.7% and 66.5%, respectively, using 500 ul of a 1.9 mg/ul extract. This section inhibited wheat coleoptile straight growth 38.6% at the same concentration. Additional TLC, UV spectrophotometry, spray reagents, NMR, and GC/MS indicated that the compound was 3,8-dihydroxy-5,6,7-trimethoxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one at a concentration of 265 ug/g fresh weight. This compound significantly inhibited the wheat coleoptile straight growth bioassay 18.4% using 2 to 3 ug/ul. An 80% methanol extract of H. acradenius leaves evaporated in vacuo produced an aqueous insoluble brown resin. This resin dissolved in absolute methanol and separated by TLC in CHCl₃:EtOAc:HCOOH contained a region between R(f)'s 0.6 to 0.7 that inhibited wheat seed coleoptile growth 71.8% and radicle growth 90.7% using 200 ul of 1.5 mg/ul solution. Wheat coleoptile straight growth was inhibited 53.7% in this region at the same concentration. Further examination of this region by the same methods as those used for B. sarothroides indicated the presence of a C-12 alkenyl alcohol (2 mg/ml), an aromatic heterocyclic hydrocarbon (4 mg/ml), and an alkyl substituted version of 7-hydroxycoumarin (5 mg/ml) at a concentration of 0.7, 1.4, and 1.8 ug/g fresh weight, respectively. A combination of these compounds inhibited the wheat coleoptile straight growth bioassay 41.1% using 11 ug/ul. A 2 M HCl extract of H. acradenius was partitioned with diethyl ether, which was evaporated and the residue resuspended in 95% methanol. TLC in CHCl₃:EtOAc:HCOOH separated an area between R(f)'s 0.5 to 0.6 where wheat seed coleoptile growth was inhibited 49.7% and radicle growth was inhibited 54.6% using 1000 ul of a 3.3 mg/ul solution. Identified in this region was 7-hydroxycoumarin at a concentration of 150 ug/g fresh weight. The wheat coleoptile straight growth bioassy was inhibited 13.2% using 2 to 3 ug/ul.

The Avena Coleoptile Test indicated that there were no indolyl- 3-acetic acid-like growth substances present in treated municipal wastewater from the Activated Sludge Sewage Treatment Plant in Tucson, Arizona. Using the bioassay of kinetin (6-furfurlyamino purine) as a standard in delaying chlorophyll degradation, wastewater extract was capable of maintaining chlorophyll in wheat (Triticum aestivum L.) leaf tissue; however, toxic contaminants present in municipal wastewater may have prevented a consistent dose response. In the process of repeated chromatography, kinetin broke down into two zones that were capable of retarding chlorophyll degradation. After repeated chromatography, wastewater extract and degradation products of kinetin resulted in similar Rf values. Wastewater extract obtained through repeated chromatography resulted in increased total chlorophyll retention, with increased concentrations; however, the nature of the cytokinin-like growth substances present in wastewater appeared to be unique. The high yields of high protein plant products obtained from plants grown with wastewater may have resulted from cytokinin-like growth substances present in treated municipal wastewater.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.