Fig 1.
Measured monthly (blue shaded bars) and long-term mean (red crossed line) rainfall (mm) during the fallow and crop growth periods at the Harden field site.
Table 1.
Cropping year, crop (wheat, canola), quad yield (t ha-1), stubble loads (t ha-1), header yield (grain removed from paddock (t ha-1) for (+) and (−) nutrient treatments at harvest at the Harden field site (data are means and standard errors of the mean, SEM, n = 4).
Table 2.
Calculated supplementary nutrients required (kg ha-1) each year to achieve 30% humification of above ground stubble-C on the (+) nutrient treatment at the Harden field site, and actual supplementary nutrients added (kg ha-1).
Fig 2.
Mean FF-C concentration (%) to 1.6 m depth in the <2 mm soil fraction in 2006 and in the (+) and (−) nutrient treatments in 2012.
Data are means and SEM, n = 4. (# and * indicate a significant difference between the 2006 value and the 2012 value for the (−) and (+) nutrient treatments, respectively P<0.05; ns = not significant)
Fig 3.
Mean FF-N, -P, -S concentrations (%) to 1.6 m depth in the <2 mm soil fraction in 2006 and the (+) nutrient treatment in 2012.
Data are means and SEM, n = 4. (* indicate a significant difference between 2006 value and 2012 value from (+) nutrient treatment P<0.05; ns = not significant)
Table 3.
FF-C, -N, -P and -S stocks (t ha-1) at the Harden field site in 2006 and for the (−) and (+) nutrient treatments in 2012.
Data are means and SEM. n = 4.
Table 4.
N, P, S balance (kg ha-1) for the (−) and (+) supplementary nutrient treatments in 2012 compared to the 2006 starting values.
Fig 4.
FF-C:N, -C:P, -C:S ratios to 1.6 m depth in the <2 mm soil fraction in 2006 and the (+) nutrient treatment in 2012.
Data are means, n = 4.
Table 5.
Correlation between the changing FF-C:N, -C:P and -C:S ratios with depth (0 to 1.6 m) in 2006 and for the (−) and (+) nutrient treatments in 2012, n = 16.