3. JUSTIFICACIÓN
6.6. PROTOCOLO DEL ESTUDIO, RECOLECCIÓN Y PROCESAMIENTO DE
Figure 47 shows the spatial variation in yields at the Flawborough F1 field between 2002 and 2013. The rectangular whole in the map in 2010 is where the chessboard trial was located. Some
features are evident in most years, but other areas show large relative changes between crops and years.
2002 Winter wheat (1st)
6.1-12.9 t/ha; mean 9.9 t/ha 2004 Wnter wheat (1
st)
8-13.9 t/ha; mean 10.9t/ha 2-6t/ha; mean 4.3t/ha 2005 OSR
2006 Winter wheat (1st)
7-13 t/ha; mean 9.8 t/ha 1.2-5t/ha; mean 3.0t /ha 2007 OSR 2008 Winter wheat (1
st)
8-14 t/ha; mean 11.1 t/ha
2009, Spring Beans
2-6t/ha; mean 4.1t/ha
2010, Wheat (1st)
6-14t/ha; mean 9.9 t/ha
2013, Wheat (1st)
5-12t/ha; mean 8.7 t/ha
Figure 47. Yield Maps from field F1. The symbology uses Jenks Natural breaks to best show spatial variation. Blue = low yield; red = high yield. Range and mean is given for each crop.
A 10 m grid was imposed on the field to allow data from different years to be integrated and
compared. The cluster analysis was restricted to only those grid squares where data was available from all years.
Cluster Map Average yield (all crops) Average yield (wheat)
Average normalised yields Average normalised wheat
Figure 48. Integrated Yield Maps from field F1
Average yield per cluster group Normalised yield per cluster group
Figure 49. Mean (a) and Normalised (b) centroid yield values for the Cluster Groups for field A2 for groups shown in Figure 49a
The line graphs in Figure 49 shows the performance of each cluster group in each year. There is evidently some consistency between groups with cluster group 5 always being lower yielding and group 1 nearly always giving the highest yields. Group 3 is less consistent, having highest yields in 2 years but low yields in 2007.
The past yields, averages, normalised averages and cluster groups for the other chessboard fields are reported below.
5.2.2 Flawborough F6 2011 2002 Pea
1-3.5 t/ha; mean 2.0 t/ha 2003 Wnter wheat (1
st)
6-13 t/ha; mean 9.2t/ha 2.2-4.7 t/ha; mean 3.7t/ha 2004 OSR
2005 Wheat (1st)
6.5-14.3 t/ha; mean 9.7t/ha 2006 OSR (1
st)
1.5-6.7 t/ha; mean 4.2 t/ha 2007 Wheat (1
st)
5.3-13t/ha; mean 9.1t /ha
2008 OSR
1.5-7 t/ha; mean 4.1 t/ha 2009, Wheat (1
st)
5.5-14t/ha; mean 9.7t/ha 1.4-7t/ha; mean 5.0 t/ha2010,OSR
2011, Wheat (1st)
6-14t/ha; mean 9.6 t/ha 2012, Wheat (2
nd)
5-12.8t/ha; mean 8.7 t/ha
Figure 50. Yield Maps from field F6. The symbology uses Jenks Natural breaks to best show spatial variation. Blue = low yield; red = high yield. Range and mean is given for each crop.
Cluster Map Average yield (all crops) Average yield (wheat)
Average normalised yields Average Normalised wheat
Figure 51. Integrated Yield Maps from field F6
Average yield per cluster group Normalised yield per cluster group
Figure 52. Mean (a) and Normalised (b) centroid yields for the Cluster Groups for field A2 for groups shown in Figure 51a
There is considerable spatio-temporal variability in field F6, as shown by Figure 51 and Figure 53, which is not entirely captured by the normalised average yield map. Cluster Group 1 on the eastern
edge gives highest yields in some years but lowest in others, whilst group 3 (western corner) is generally lower yielding but has some years with high yields.
5.2.3 Burford A2 2011
2000 Vetch
t/ha; mean t/ha 2001 Winter wheat (1
st)
t/ha; mean t/ha 2003 Winter wheat (1
st)
t/ha; mean t/ha
2004 OSR
/ha; mean t/ha
2005 Wheat (1st)
t/ha; mean t/ha
2007 Wheat (1st)
t/ha; mean t /ha
2008 OSR
t/ha; mean t/ha
2009, Wheat (1st)
t/ha; meant/ha
2010,OSR
t/ha; mean t/ha
Figure 53. Yield Maps from field A2. The symbology uses Jenks Natural breaks to best show spatial variation. Blue = low yield; red = high yield. Range and mean is given for each crop.
Cluster Map Average yield (all crops) Average yield (wheat)
Average normalised yields Average Normalised wheat
Figure 54. Integrated Yield Maps from field A2
Average yield per cluster group Normalised yield per cluster group
Figure 55. Mean (a) and Normalised (b) centroid yields for the Cluster Groups for field A2 for groups shown in Figure 54a
Field A2 also demonstrates substantial spatio-temporal variation. The characteristic Y-shape from the physical valley is clearly apparent from the yield maps in only some years, notably 2001. However it comes through strongly in the averaged yield maps and is present in the cluster map as Group 4, with considerable variability year to year, having high yields in the droughted year of 2007 but less well in other years.
5.2.4 Burford A3 2012
2000 Winter wheat (1st)
t/ha; mean t/ha t/ha; mean t/ha 2001 OSR 2002 Winter wheat (1
st)
8-13.9 t/ha; mean 10.9t/ha
2003 OSR
t/ha; mean t/ha 2006 Wheat (1
st) (1st)
t/ha; mean t/ha 2007 Wheat (1
st)
t/ha; mean t /ha
2008 OSR
- t/ha; mean t/ha 2010, Wheat (1
st)
- t/ha; mean t/ha t/ha; mean t/ha2011, peas
Figure 56. Yield Maps from field A3. The symbology uses Jenks Natural breaks to best show spatial variation. Blue = low yield; red = high yield. Range and mean is given for each crop.
There is substantial year to year yield variation in A3. In particular the clay bank that runs E-W across the field is distinctly evident in 2000 but less so in other years. It comes through in the normalised average yield but not in the cluster groups (Figure 58). Figure 59 shows the northern corner (cluster 5) to be consistently low yielding and the eastern corner to be consistently high yielding.
Cluster Map Average yield (all crops) Average yield (wheat)
Average normalised yields Average Normalised wheat
Figure 57. Integrated Yield Maps from field A3
Average yield per cluster group Normalised yield per cluster group
Figure 58. Mean (a) and Normalised (b) centroid yields for the Cluster Groups for field A2 for groups shown in Figure 57a
5.2.5 Bedfordia B2 2011
2004 Winter wheat (1st)
- t/ha; mean t/ha 2005 Wnter wheat (2
nd)
- t/ha; mean t/ha 2006 Spring Beans - t/ha; mean t/ha
2007 Wheat (1st)
-t/ha; mean /ha - t/ha; mean t/ha 2008 Wheat () -t/ha; mean .t /ha2009 Wheat ()
2010 Wheat
- t/ha; mean t/ha - t/ha; mean .t/ha2011, OSR
Figure 59. Yield Maps from field B2. The symbology uses Jenks Natural breaks to best show spatial variation. Blue = low yield; red = high yield. Range and mean is given for each crop.
Cluster Map Average yield (all crops) Average yield (wheat)
Average normalised yields Average Normalised wheat
Figure 60. Integrated Yield Maps from field B2
Average yield per cluster group Normalised yield per cluster group
Figure 61. Mean (a) and Normalised (b) centroid yields for the Cluster Groups for field B2 for groups shown in Figure 60a
5.2.6 Shipton by Beningborough C2 2011
2002 Wnter wheat (1st)
t/ha; mean t/ha 2003 Wnter wheat (2
nd)
- t/ha; mean t/ha 2008 Spring beans - t/ha; mean t/ha
2011 OSR
- t/ha; mean t/ha
Figure 62. Yield Maps from field C2. The symbology uses Jenks Natural breaks to best show spatial variation. Blue = low yield; red = high yield. Range and mean is given for each crop.
Available yield data from C2 was too limited to conduct further analyses.
fields (King et al., 2003; 2005). EMI and EC sensors measure the apparent electrical conductivity of the soil, hence indicating available water content and soil texture. If used when the soil has reached field capacity they can be especially useful for interpretation of yield maps and delineation of management zones (King et al., 2005).
F1 Shallow F1 Deep F6 Shallow F6 Deep A2 Shallow A2 Deep A3 shallow A3 Deep B2 Shallow B2 Deep
C2 Shallow C2 Deep
Figure 63. Soil Electrical conductivity maps from commercial soil sensors
The variation shown by the soil conductivity maps generally tends to reflect the variation seen in yields and the yield cluster maps.
5.3.1 Elevation maps
The topography of fields often closely corresponds to variability in soil properties and crop
performance. Figure 64 shows altitude from the 6 fields measured whilst taking the soil EC scans. These can be turned into digital elevation maps and slope angles can be derived, as can change in the angle of slope. Such maps can be useful in defining the boundaries of areas of the field that behave differently.
F1 F6
A2 A3
B C2
Figure 64. Altitude maps from commercial soil sensors for the six chessboard fields