Yield mapping

Cross-link density and parameters relating to the network structure can be measured by NMR by analysis of the transverse relaxation decay (cf. Section 1.3) and the longitudinal relaxation in the rotating frame [67]. Combined with spatial resolution, the model-based analysis of relaxation yields maps of cross-link density and related parameters [68]. Often the statistical distribution of relaxation parameters over all pixels provides a reduced data set with sufficient information for sample characterization and discrimination [68]. 

Certain structural features arise from a cursory analysis of any of the data sets. Each of the 3 above data sets yields maps similar to those in Figures 2 and 3 that clearly show an area of optimal chain rotation. (Because of the overlapped reflections, there is a false minimum at about 140°, 140° that aligns the chains along the shorter x axis. Chains rotated to the position of the false minima have short interatomic distances.) With similar clarity, the gg 06 position is eliminated by all of the above data sets, as exemplified in Table X, below. 

The methods described so far yield maps displaying the centers of many particles, be it microbeads or NPCs. The question then arises whether the particles... 

NIR reflection spectroscopy can be used for noncontact determination of protein in wheat grain. Laboratory equipment was installed in a combine to record grain quality in the field in order to perform yield mapping during cereal combining. The data produced during the first year allowed indirect calculation of grain protein content and the production of a field protein map. On-line measurement was possible in the second year. The first on-line measurements had standard error of 0.55% protein (37). 

When the precision fanning systems were in their infancy, it was often difficult to interpret yield maps, for instance when they were all the farmer had to go on. One cormnon dilermna was If I have an area of low yield in a field, should I put more fertihser on it to try and bring the yield up, or accept that it will always be low yielding because of other factors, and I need to put less on, thus saving money on wasted material ... 

On combine harvesters these measure grain flow and moisture content as well as recording field position, area covered and eombine speed. They can then display the yield map on an on-board screen and make it available for download. Data can be recorded as often as every second if required. 

Once data is collected or logged over time it has to be analysed by software, and then used to variably apply inputs or make other management decisions. It is often combined with other data, e.g. weather records, to help the analysis. A mass of individual pieces of data are produced from, say, a combine harvester travelling across a wheat field. Some errors will be amongst this data. To produce a yield map the data must be smoothed or kriged and it is the ability of the programmes used to do this that determines how useful and accurate the map will be. 

Anderson-Cook CM, Alley MM, Roygard JKF et al (2002) Differentiating soil types using electromagnetic conductivity and crop yield maps. Soil Sci Soc Am J 66 1562-1570... 

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