December: The impact of the fallow

Pre-grazing pasture cuts taken in October show a significant difference in the dry matter yield is between the fallow (B) and non-fallow (A) paddocks. The improved growth rate applied to the weeds (predominantly annual ryegrass), as well as to the desired species. Even though the fallow was only for a couple of months, it benefited in several ways:

  • Reduced trash on the fallowed paddock at sowing resulted in better regulation of sowing depth and reduced mulch effect
  • Increased moisture in the fallow paddock
  • Increased fertility. February 2020 was the first significant wet month after three years of drought. High rainfall over this period would have resulted in significant mineralisation of soil nutrients. The plants growing in paddock A would have continued to utilise these nutrients through to May when they were sprayed out, whereas the fallow paddock had no plants growing in it to utilise that fertility. Consequently, much of this nutrient would have still been available to the newly establish perennial plants when they started to grow in May.

Pre-grazing feed tests show a statistically significant increased crude protein % and Metabolisable Energy (ME) of the pasture in paddock B. The species are similar between the plots in each paddock, so this also demonstrates increased soil fertility (more available N and sulphur) in paddock B.   The higher ME in paddock B would be due to an increased leaf %/area in plants in plot B as a result of a better root system/available fertility increasing growth rates

  • We plan to do another plant counts in January or February, and it will be interesting to see how much of this increased productivity is because of increased desirable species in plot B.