Site-specific variation in wheat grain protein concentration and wheat grain yield measured on an Australian farm using harvester-mounted on-the-go sensors
Brett M. Whelan A C , James A. Taylor A and James A. Hassall B
A Australian Centre for Precision Agriculture, McMillan Building A05, University of Sydney, NSW 2006, Australia.
B ‘Kiewa’, Gilgandra, NSW 2827, Australia.
C Corresponding author. Email: email@example.com
Crop and Pasture Science 60(9) 808-817 http://dx.doi.org/10.1071/CP08343
Submitted: 9 October 2008 Accepted: 3 March 2009 Published: 8 September 2009
Accurately measuring and understanding the fine-scale relationship between wheat grain yield (GY) and the concomitant grain protein concentration (GPC) should provide valuable information to improve the management of nitrogen inputs. Here, GPC and GY were monitored on-harvester for three seasons across 27 paddocks on an Australian farming enterprise using two independent, on-the-go sensing systems. A Zeltex Accuharvest measured GPC (%) and a John Deere GreenStar system measured GY (t/ha). Local calibration in each season for Australian spring wheat significantly improved the prediction accuracy, precision, and bias of the Zeltex Accuharvest when compared with the initial factory calibration. Substantial variation in GPC and GY was recorded at the field scale, with the least variation recorded in both parameters in the wetter season. GY (CV = 38%) was twice as variable on average as GPC (CV = 19%) across the enterprise. At this enterprise scale, a negative correlation between GPC and GY was observed for a composite of the field data from all seasons (r = –0.48); however, at the within-field scale the relationship was shown to vary from positive (max. = +0.41) to negative (min. = –0.65). Spatial variation in GPC and GY at the within-field scale was described best in the majority of cases by an exponential semivariogram model. Within-field spatial variability in GPC is more strongly autocorrelated than GY but on average they share a similar autocorrelated range (a′ = ~190 m). This spatial variability in GPC and GY gave rise to local spatial variation in the correlation between GPC and GY, with 85% of the fields registering regions of significant negative correlations (P < 0.01) and significant positive correlations observed in 70% of fields. The spatial pattern in these regions of significantly different correlations is shown to display spatial coherence from which inferences regarding the relative availability of soil nitrogen and moisture are suggested. The results point to the suitability of these on-the-go sensors for use in more sophisticated agronomic and environmentally targeted nitrogen-use analysis.
Additional keywords: precision agriculture, nitrogen, management.
A new look at the statistical model identification.
IEEE Transactions on Automatic Control
Grain yield mapping: yield sensing, yield reconstruction, and errors.
Field-scale variability of soil properties in central Iowa soils.
Soil Science Society of America Journal
Within-field variations in grain protein content—relationships to yield and soil and nitrogen consistency in maps between years.
A multiple comparison procedure for comparing several treatments with a control.
Journal of the American Statistical Association
Nitrogen response characteristics of wheat protein in relation to yield responses and their interactions with phosphorus.
Australian Journal of Agricultural Research
Application of probability analysis to assess nitrogen supply to grain crops in northern Australia.
Causes of negative correlations between grain yield and grain protein concentration in common wheat.
Method for precision nitrogen management in spring wheat: II. implementation.
(2005) On-combine sensing and mapping of wheat protein concentration. Crop Management, doi:10.1094/CM-2005-0527-01-RS Online at: www.plantmanagementnetwork.org/pub/cm/research/2005/protein/
Measuring grain protein concentration with in-line near infrared reflectance spectroscopy.
(2005) Evaluation of an on-combine wheat protein analyzer on Montana hard red spring wheat. In ‘Precision Agriculture ’05: Proceedings of the 5th European Conference on Precision Agriculture’. (Eds JV Stafford et al.) pp. 385–392. (Wageningen Academic Publishers: Wageningen, The Netherlands)
On-line measurement of grain quality with NIR technology.
Transactions of the American Society of Agricultural Engineers
(1997) Spatial variability in soil—implications for precision agriculture. In ‘Precision Agriculture ’97: Proceedings of the 1st European Conference on Precision Agriculture’. (Ed. JV Stafford) pp. 3–31. (BIOS Scientific Publishers Ltd: Oxford, UK)
(2005) ‘VESPER.’ Australian Centre for Precision Agriculture, University of Sydney. Online at: www.usyd.edu.au/su/agric/acpa
National Measurement Institute (2004) ‘NMI M8 – Pattern approval specifications for protein measuring instruments for grain.’ (National Measurement Institute: Lindfield, NSW)
Spatially attributed automatic combine data acquisition.
Computers and Electronics in Agriculture
The relation between yield and protein in cereal grain.
Journal of the Science of Food and Agriculture
Within-field variation in wheat quality: implications for precision agricultural management.
Australian Journal of Agricultural Research
(1999) An investigation into the within-field spatial variability of grain quality. In ‘Precision Agriculture ’99: Proceedings of the 2nd European Conference on Precision Agriculture’. (Ed. JV Stafford) pp. 353–361. (Sheffield Academic Press: Sheffield, UK)
Site-specific durum wheat quality and its relationship to soil properties in a single field in northern New South Wales.
(1997) Fertilisers and manures. In ‘Sustainable crop production in the subtropics’. (Eds AL Clarke, PB Wylie) pp. 214–234. (QDPI: Brisbane, Qld)
(2007) On-the-go grain quality monitoring: a review. In ‘Proceedings of the 4th International Symposium of Precision Agriculture SIAP07’. Vicosa, Brasil. (Universidade Federal de Vicosa: Vicosa, Brasil)
(2005) Monitoring wheat protein content on-harvester—Australian experiences. In ‘Precision Agriculture ’05: Proceedings of the 5th European Conference on Precision Agriculture’. (Ed. JV Stafford) pp. 369–375. (Wageningen Academic Publishers: Wageningen, The Netherlands)
Yield protein relationships in wheat grain, as affected by nitrogen and water.
(1999) Grain quality variations within fields of malting barley. In ‘Precision Agriculture ’99: Proceedings of the 2nd European Conference on Precision Agriculture’. (Ed. JV Stafford) pp. 287–296. (Sheffield Academic Press: Sheffield, UK)