Wet years are over emphasised for regeneration

Thinking a wet period on its own can improve a paddock’s productive capacity and resilience is like thinking a runner can win a race without adequate preparation. To understand the true driver of paddock regeneration it is what you do in the average years that matters just as much as the wet years.


The foreground had a deficiency of carbon above and below ground prior to the wet period, so hardly regenerated

Thinking a wet period on its own can improve a paddock’s productive capacity and resilience is like thinking a runner can win a race without adequate preparation. To understand the true driver of paddock regeneration it is what you do in the average years that matters just as much as the wet years. 

 

How successful wet periods are at regenerating paddocks is determined by how well carbon flows have been managed in the lead up-years.

 

Wet periods can either fast forward all the good work you have been doing in average years, or if you have been a poor manager of carbon flows, then when the wet period has ended, you can find yourself in the same position you were in before it started.

It is carbon flows over time that prepare the soil to allow better germination and establishment of perennial grasses. This is because carbon flows generated by plants, feed the soil life that are responsible for restructuring the soil and making it more fertile. Poorly managed plants only generate small flows of carbon, which means soil life is limited in what it can do.

If a paddock is degraded, then plants can struggle to establish, even in good seasons.

The photo above is of a paddock that was locked up for 15 months during a period of above average rainfall. It shows that wet periods are more successful at regenerating better functioning areas. The area in the foreground, reinforces that what wet periods can achieve is highly dependent on the state of the landscape prior to the favourable rain.

The 15 months rest was able to regenerate a lot of the paddock, but not change the area in the foreground, where carbon flows had fallen too low over time. The next photos are close ups.

Close up of where we are standing in the above picture

Where we are standing, the greener grass is the productive paspalum. It re -entered the landscape following rest, while in the foreground of the first photo, only useless galvanised burr is growing.

The rest period had sufficient rain for regeneration of grass from seed on several occasions, yet the area in the foreground was not able to respond. There was little water infiltration in this area and the soil was not able to maintain moisture on the surface long enough to allow germination. Little ground cover, to keep the wind and sun off the soil, was another issue limiting germination.


Close up of the area that didn't respond to the wet period

 

The role of weeds

 

Think of weeds as nature’s repair agent. When paddocks start to degrade, nature sends in weeds as an alternative way to generate some carbon flows. The blue galvanised burr in the foreground of the first photo, is playing this role. We all know that when the perennial grasses come back, the weed population immediately drops.

 

Why wet periods can be misleading

 

Wet years can be very deceiving. There is often a good coverage of pasture and it looks like the paddock has regenerated. But has it? Look closer, and a lot of the ground cover is annuals, which will disappear when the rain stops. The fact water keeps arriving in wet periods and has more opportunities to soak in, masks the reality that the soil condition has not changed. This is not to discount the value of the extra plant carbon that is introduced into the paddock by the short term prolific growth. This plant carbon could be the beginning of soil improvement if management changes and starts to focus on improving carbon flows.

 

What extra plants remain long-term when the wet period has ended, is the true test of what has been achieved.

 

Maintaining a seed base

 

Regeneration of perennials relies on an adequate seed base, which is why resting after rain in average seasons is critical. 

 

There is not enough time in a wet period to produce the necessary seed, then see it germinate, and finally, see seedlings establish.   

 

Conclusion

 

If there are not more perennials after the completion of the wet period, then little has been achieved. Naturally, this comment does not apply to pastures in very good condition that had already achieved the maximum possible coverage of perennials. 

 

The “so called” average years are really part of the regeneration process. Good management is ongoing. This is why I feel uncomfortable when somebody suggests that all we need is a wet season to undo degradation.

 

Next week’s discussion:   “Practical facts that provide understanding”