Detecting brown patch and dollar spot development on Kentucky bluegrass by spectrometer sensing and tissue nitrate-N monitoring

Li, Deying and Smith, Ronald and Kinzer, Kasia and Neate, Stephen (2008) Detecting brown patch and dollar spot development on Kentucky bluegrass by spectrometer sensing and tissue nitrate-N monitoring. In: 2nd International Conference on Turfgrass Science and Management for Sports Fields (ISHS 2007), 24-29 Jun 2007, Beijing, China.

Official URL: http://www.bfuturf.com

Abstract

Nitrogen affects all aspects of turf quality including color, density, stress tolerance, and susceptibility to diseases. Soil analysis usually does not include the available N in soil because it changes rapidly and the test is very time-consuming. Clipping yield is often used by turf managers as an indicator of N sufficiency. The primary objective of this study was to investigate if there was a correlation between Nitrate (NO3 -)-N concentration in grass tissues and disease index for dollar spot and brown patch in Kentucky bluegrass (Poa pratensis L. 'Moonlight'). A second objective was to test the feasibility of using NO3-ion specific electrode and/or spectral radiance to monitor disease severity. N amounts (0, 50, 100 and 200 kg ha-1) were main plots and disease inoculations were subplots in trials conducted in 2004 and 2005. The normalized difference vegetation index (NDVI) from a spectral radiance measurement was very sensitive to disease stress level and N status. In both experiments, shoot and leaf NO3-N concentrations were significantly different among the N fertilization amounts in 70% of the sampling dates. In 2004, correlation coefficients between tissue NO3-N and N application amounts were 0.07 to 0.27 and 0.03 to 0.87 for leaf and shoot, respectively. In 2005, the correlation coefficients between tissue NO3-N and N application amounts were 0.30 to 0.51 and 0.29 to 0.78 for leaf and shoot, respectively. Dollar spot severity was negatively correlated to N nutrient levels in shoots and leaves with correlation coefficients as -0.60 and -0.61, respectively in 2004. Correlation coefficients between dollar spot severity and N nutrient levels in shoots and leaves were -0.87 and -0.81 for 3.8-cm mowing height, and -0.79 and -0.61 for 7.8-cm mowing height, respectively. Tissue NO3-N levels have potential to be used in dollar spot forecasting models in combination with environmental condition monitoring. Brown patch disease was less affected by tissue N levels but rather by microenvironment in the turf canopy.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Paper)
Refereed: Yes
Item Status: Live Archive
Additional Information: Series: Acta Horticulturae v.783. ©2008 by the International Society for Horticultural Science (ISHS). No part of this book may be reproduced and/or published in any form or by any means, electronic or mechanical, including photocopying, microfilm and recording, or by any information storage and retrieval system, without written permission from the publishers. Published version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 13 Jun 2014 02:43
Last Modified: 02 Jul 2014 05:48
Uncontrolled Keywords: disease forecast; nitrogen; prediction model
Fields of Research : 06 Biological Sciences > 0607 Plant Biology > 060701 Phycology (incl. Marine Grasses)
07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070308 Crop and Pasture Protection (Pests, Diseases and Weeds)
10 Technology > 1001 Agricultural Biotechnology > 100101 Agricultural Biotechnology Diagnostics (incl. Biosensors)
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences
URI: http://eprints.usq.edu.au/id/eprint/25295

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