Is pasture rest TIME or TIMING

The question has to be asked, what are we really trying to achieve with pasture rest?

The answer: Achieving the flow of carbon to all the parts of the paddock that it needs to flow into, above and below ground. Animals will reduce the flow of carbon if not managed properly. 

Some see pasture rest as an exercise in growing more pasture for sheep and cattle to eat. While this is an important outcome, there is more to it than this.

What pasture rest sets out to achieve

There is an element of the present and the future with pasture rest.

The present is growing more feed for sheep and cattle to eat, remembering that pasture (ground cover) is 45% carbon. Creating ground cover also protects the soil and soil life in the short term.

The future is building paddock resilience. Paddock resilience relies on plant resilience and soil resilience. When paddocks are resilient, they have the capacity to produce to their maximum each time it rains, i.e. to generate max flows of carbon.

To remain resilient, plants need carbon flowing into them to maintain energy reserves and build extensive root systems, necessary for sourcing water and nutrients out of the soil.

Pasture rest is also about maintaining the health of the soil in which plants grow. To be productive, plants require a healthy soil that supplies them with water and nutrients. For the soil to remain healthy (resilient), plants need to be allowed to provide carbon compounds to feed all the soil life responsible for keeping the soil well structured and fertile.

Rainfall/moisture activates soil microbes as well as plants

If pasture rest is seen in terms of generating carbon flows, then we have to consider all the processes that contribute to generating flows.

It is so easy to give all the credit to plants for generating carbon flows and overlook the important role soil microbes play in helping plants grow (photosynthesise) after rain.

It is moisture that activates the soil microbes to consume organic matter and start the process of releasing the nutrients in organic matter into forms suitable for plant uptake.

I was told recently that the bulk of the action with soil microbes consuming organic matter occurs in the first 48 hours after rain. Another person conceptualised it for me by saying there is a puff of carbon coming out of the soil after rain, i.e. microbes are like us in that they release carbon dioxide as they consume carbon compounds.   

Growing plants support soil microbes directly by releasing energy directly to them through root exudates (liquid carbon). Plants also make soluble carbon available to mycorrhizal fungi which are located on their roots. This allows the fungi to extend out into the soil and source extra nutrients for the plants. This is a case of carbon bargained for nutrients.

It is after rain that soil microbes produce growth promotants for plants. Some of the activated soil microbes are also bringing in nitrogen from the atmosphere.

Livestock should be feeding on pastures’ excess growth, not the first flush after rain. Otherwise, they are hindering all the processes just discussed.

The logic behind why pasture rest is TIMING and not TIME

Hang in there “cell grazers”, what you stand for is not being challenged here.

Nature has designed the system so that water activates the flow of carbon into the landscape via photosynthesis.

The bulk of the carbon arrives from the atmosphere in the short period following rain.

Straight after rain is when plants and microbes are working together. This is the time when plants have most in their favour to grow and produce carbon flows.

Straight after rain is when plants and microbes are working together. This is the time when plants have most in their favour to grow and produce carbon flows. 

Nature does not have a predictable pattern. Stated simply, we must allow nature to transfer carbon from the atmosphere to the landscape according to its time frame. This is why pasture rest is TIMING, i.e. “strategic rest” after rain.

Basing resting decisions on a certain period of TIME is no guarantee that carbon will come into the paddock because there is no guarantee that it will rain.   

I first raised TIMING versus TIME in a report in 1998. It was included in a paper I wrote with CSIRO for the proceedings of the 1999 International Rangelands Congress. The title of my poster, judged the best, at the 2008 Australian Rangelands Conference was, “Is pasture rest time or timing?”

When is pasture rest achieved?

Pasture rest is long enough when enough carbon has flowed to all of the areas in the landscape, above and below ground, that it needs to. This explains why paddocks lacking resilience require a longer rest period. 

After talking to a cross section of scientists and producers, it would appear that the required rest period after rain is about 4-6 weeks, remembering that temperature influences plant growth.

Why some are thinking TIME

It may be a misunderstanding of the cell grazing concept that is responsible for some land managers taking the position that pasture rest is about time. Cell grazing is often referred to as “time controlled grazing”.

I asked one of Australia’s leading cell grazers if he had a problem with me saying pasture rest is timing and not time, given that he locks up his cells for 120 days on average, which is time. He said he did not. He said the bulk of the outcomes he achieved over the 120 days was achieved in the short period after rain. He made the point that most of the cells did not have livestock in them after rain, so produced maximum flows. He also commented that he could achieve full recovery in four weeks. 

Cell grazing is just one of many methods producers use to increase carbon flows.

TIME relates to consumption

It is important not to confuse management of flows with consumption of existing stocks.

Resting for set periods of time when it is not raining, is a consumption issue (maintaining ground cover), and should not be confused with strategic / tactical rest after rain. The exception is when a regeneration event has occurred and freshly germinated perennial seedlings need to be protected to allow them to establish.

How much ground cover is consumed is important, but it is the second decision a producer makes, not the first. What sets the level of ground cover in the first place is the amount of carbon a particular form of management allows to enter the paddock after rain.

Provided it is not excessive, grazing is beneficial as it removes rank pasture that can inhibit pasture growth next time it rains.

Commercial practicalities of seeing pasture rest as TIMING

The practical aspect of seeing pasture rest as a short, but strategic, period of time, is that an alternative home for livestock only has to be found for a short time.

If pasture rest is seen as time, then animals have to be sold or agisted.

Conclusion

The people who achieve the most in land regeneration are not the ones who lock up country for the longest time. Instead, it is the ones who act when something can be achieved.

A rest at the right time is the basic catalyst for maintaining paddock resilience.

The only time you can prepare for drought is when it rains.

Next week’s discussion:   “Techniques for pasture spelling”

Alan Lauder