Ground cover was measured on 2007 and 2008 crops, by classifying randomly chosen points on a digital photo of the crop taken from waist height. This was done for 8 photos for each paddock, at the same time as for dry matter harvests.
In most of the paddocks, soil made up a large proportion of ‘ground cover’, especially in early measurements (Figure 33, Figure 34 and Figure 35). Straw was generally (Minyip 2008 was the exception) a greater proportion of ground cover in No-Till paddocks, but never more than 23%. As the crop grew, it tended to increase at the expense of the straw proportion of ground cover, after which (in high biomass crops) it also covered the soil. Weeds were only measured as a small proportion of ground cover, at Sea Lake Till in 2008, and Yaapeet no Till in 2007.
In some paddocks (No-Till at Donald and Patchewollock 2007, Minyip 2008) the proportion of ground cover due to crop declined between GS30 and GS65; this happens in some cereal crops when stem elongation converts a crop comprised mostly of horizontal leaves to vertical stems. It is has a more pronounced effect at wider row spacing.
|
a. Culgoa
|
 |
|
b. Donald
|
 |
Figure 33. Ground cover measured at Culgoa (a) and Donald (b) for No-Till and Till paddocks in 2007 and 2008.
|
a. Minyip
|
 |
|
b. Patchewollock
|
 |
Figure 34. Ground cover measured at Minyip (a) and Patchewollock (b) for No-Till and Till paddocks in 2007 and 2008.
|
a. Sea Lake
|
 |
|
b. Yaapeet
|
 |
Figure 35. Ground cover measured at Sea Lake (a) and Yaapeet (b) for No-Till and Till paddocks in 2007 and 2008.