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Nitrogen Fertilization Influences Shear Strength and Quality of Kentucky Bluegrass Sod Grown on Clay
Author(s) -
Li Deying,
Fang Wenjuan,
Han Liebao
Publication year - 2011
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2010.0470
Subject(s) - seeding , poa pratensis , zoology , agronomy , cultivar , nitrogen , environmental science , shear strength (soil) , human fertilization , soil water , biology , chemistry , poaceae , soil science , organic chemistry
Shipment costs and easiness of handling sometimes make it necessary to produce sod on non‐ideal soils, such as clay. The objective of this study was to test the effects of N rate and N‐application timing, seeding rate, and mowing height on sod shear strength of Kentucky bluegrass ( Poa pratensis L.) produced on a clayey soil under the climate conditions of the upper Midwest in the United States. A blend of four Kentucky bluegrass cultivars were seeded at 50 or 100 kg ha −1 in 2004 and 2005 and maintained at 4.5‐ or 7.5‐cm mowing height. Annual N rates of 120 or 210 kg ha −1 were applied from April to September in different splits. Sod was harvested at 14 or 23 mo after seeding. By 14 mo after seeding, all N treatments had turfgrass visual quality above 6.0 except the unfertilized control and the 120 kg ha −1 yr −1 rate applied mainly in summer or spring. Sod shear strength reached a minimum acceptable level of 0.9 kg m −2 ×10 4 about 23 mo after seeding. Highest sod shear strength (1.18–1.36 kg m −2 ×10 4 ) with acceptable visual quality could be achieved through an N program of 8, 16, 24, 32, and 40 kg ha −1 in May, June, July, August, and September, respectively. Based on a 23‐mo production time line, a seeding rate at 50 kg ha −1 and a 7.5‐cm mowing height is recommended for economic reasons. Applying more than 40 kg ha −1 of N in June and July is not recommended.