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Birte Boelt

Modelling critical NDVI curves in perennial ryegrass

Research output: Contribution to book/anthology/report/proceedingArticle in proceedingsResearchpeer-review

Standard

Modelling critical NDVI curves in perennial ryegrass. / Gislum, R; Boelt, B.

Proceedings of the 7th International Herbage Seed Conference. ed. / G R Smith; G W Evers; L R Nelson. 2010. p. 60-63.

Research output: Contribution to book/anthology/report/proceedingArticle in proceedingsResearchpeer-review

Harvard

Gislum, R & Boelt, B 2010, Modelling critical NDVI curves in perennial ryegrass. in GR Smith, GW Evers & LR Nelson (eds), Proceedings of the 7th International Herbage Seed Conference. pp. 60-63, The 7th International Herbage Seed Conference, Dallas, Texas, United States, 11/04/2010.

APA

Gislum, R., & Boelt, B. (2010). Modelling critical NDVI curves in perennial ryegrass. In G. R. Smith, G. W. Evers, & L. R. Nelson (Eds.), Proceedings of the 7th International Herbage Seed Conference (pp. 60-63)

CBE

Gislum R, Boelt B. 2010. Modelling critical NDVI curves in perennial ryegrass. Smith GR, Evers GW, Nelson LR, editors. In Proceedings of the 7th International Herbage Seed Conference. pp. 60-63.

MLA

Gislum, R and B Boelt "Modelling critical NDVI curves in perennial ryegrass"., Smith, G R Evers, G W Nelson, L R (editors). Proceedings of the 7th International Herbage Seed Conference. 2010, 60-63.

Vancouver

Gislum R, Boelt B. Modelling critical NDVI curves in perennial ryegrass. In Smith GR, Evers GW, Nelson LR, editors, Proceedings of the 7th International Herbage Seed Conference. 2010. p. 60-63

Author

Gislum, R ; Boelt, B. / Modelling critical NDVI curves in perennial ryegrass. Proceedings of the 7th International Herbage Seed Conference. editor / G R Smith ; G W Evers ; L R Nelson. 2010. pp. 60-63

Bibtex

@inproceedings{a0200b604d1911df8b17000ea68e967b,
title = "Modelling critical NDVI curves in perennial ryegrass",
abstract = " The use of optical sensors to measure canopy reflectance and calculate crop index as e.g. normalized difference vegetation index (NDVI) is widely used in agricultural crops, but has so far not been implemented in herbage seed production. The present study has the purpose to develop a critical NDVI curve where the critical NDVI, defined as the minimum NDVI obtained to achieve a high seed yield, will be modelled during the growing season. NDVI measurements were made at different growing degree days (GDD) in a three year field experiment where different N application rates were applied. There was a clear maximum in the correlation coefficient between seed yield and NDVI in the period from approximately 700 to 900 GDD. At this time there was an exponential relationship between NDVI and seed yield where highest seed yield were at NDVI ~0.9. Theoretically the farmers should aim for an NDVI of 0.9 and intervene in case of a lower NDVI, which means to apply more nitrogen (N). However, this might be impossible in some years. From a practical point of view aims are therefore to obtain the highest NDVI as late as possible in the growing season and if NDVI has to increase this is done by an additional N application at a time where the crop is able to take up and utilise the applied N.",
author = "R Gislum and B Boelt",
year = "2010",
language = "English",
pages = "60--63",
editor = "Smith, {G R} and Evers, {G W} and Nelson, {L R}",
booktitle = "Proceedings of the 7th International Herbage Seed Conference",
note = "null ; Conference date: 11-04-2010 Through 13-04-2010",

}

RIS

TY - GEN

T1 - Modelling critical NDVI curves in perennial ryegrass

AU - Gislum, R

AU - Boelt, B

PY - 2010

Y1 - 2010

N2 -  The use of optical sensors to measure canopy reflectance and calculate crop index as e.g. normalized difference vegetation index (NDVI) is widely used in agricultural crops, but has so far not been implemented in herbage seed production. The present study has the purpose to develop a critical NDVI curve where the critical NDVI, defined as the minimum NDVI obtained to achieve a high seed yield, will be modelled during the growing season. NDVI measurements were made at different growing degree days (GDD) in a three year field experiment where different N application rates were applied. There was a clear maximum in the correlation coefficient between seed yield and NDVI in the period from approximately 700 to 900 GDD. At this time there was an exponential relationship between NDVI and seed yield where highest seed yield were at NDVI ~0.9. Theoretically the farmers should aim for an NDVI of 0.9 and intervene in case of a lower NDVI, which means to apply more nitrogen (N). However, this might be impossible in some years. From a practical point of view aims are therefore to obtain the highest NDVI as late as possible in the growing season and if NDVI has to increase this is done by an additional N application at a time where the crop is able to take up and utilise the applied N.

AB -  The use of optical sensors to measure canopy reflectance and calculate crop index as e.g. normalized difference vegetation index (NDVI) is widely used in agricultural crops, but has so far not been implemented in herbage seed production. The present study has the purpose to develop a critical NDVI curve where the critical NDVI, defined as the minimum NDVI obtained to achieve a high seed yield, will be modelled during the growing season. NDVI measurements were made at different growing degree days (GDD) in a three year field experiment where different N application rates were applied. There was a clear maximum in the correlation coefficient between seed yield and NDVI in the period from approximately 700 to 900 GDD. At this time there was an exponential relationship between NDVI and seed yield where highest seed yield were at NDVI ~0.9. Theoretically the farmers should aim for an NDVI of 0.9 and intervene in case of a lower NDVI, which means to apply more nitrogen (N). However, this might be impossible in some years. From a practical point of view aims are therefore to obtain the highest NDVI as late as possible in the growing season and if NDVI has to increase this is done by an additional N application at a time where the crop is able to take up and utilise the applied N.

M3 - Article in proceedings

SP - 60

EP - 63

BT - Proceedings of the 7th International Herbage Seed Conference

A2 - Smith, G R

A2 - Evers, G W

A2 - Nelson, L R

Y2 - 11 April 2010 through 13 April 2010

ER -