Triple Creek Journal:  To fertilize or not to fertilize.

I have been interested in soils and their management for a long time.  Everything we grow comes from the soil, and soil health is often the limiting factor for forage production and system resilience.  On my own farm we have areas that have been under good management for a long time, and these are also the better soils on the farm.  We have other fields, basically the back half of the farm, with hills and very thin soils.  Because of the lay of the land the better fields also have had more management attention, making the differences in productivity even greater. 

High density grazing helps improve nutrient cycling, potentially reducing the need for fertilizer.  This is stockpiled crabgrass, tall fescue, and dallisgrass.  Fertilizer was not used, but this hill is used in winter to unroll hay.                                     

When I returned to the Raleigh area in 1990, the back half of the farm was primarily in blackberries, broomsedge (called broomstraw around  Virgilina) and some Kentucky31 tall fescue, and had a very low carrying capacity.  We called it “the Outback”. 

We took soil samples, limed it to correct a low pH, corrected a low phosphorus status, and put out nitrogen both spring and fall for about a decade.  We never sprayed it but just mowed it once a year in August.  We limed and added phosphorus several times again according to soil test.  We also frost seeded Will ladino clover and red clover several times.  It was amazing how that transformed this formerly underproductive area into a very productive part of our system.   What happened is that the blackberries and broomstraw gradually disappeared, and the tall fescue became a nearly pure stand.  The nitrogen application in March really helped the fescue dominate the stand, and then the nitrogen application in the late summer really drove a heavy stockpile.

It didn’t take long to realize that the spring fertilization was growing a lot of grass we didn’t need, and it also was making fescue toxicosis a major problem for our herd.  We were calving in January then, and because of a couple of experiences with devastating winter storms, we decided to shift calving to late February.  That meant turning the bulls out the first of May, and I knew very well how costly a May heatwave might be on our breeding rate.  It turned out to be a very hot May, and we only got 70% of the cows bred. Given the situation and the aging status of my parents, we made the decision to switch to fall calving. This was a costly move, but was a partial solution to the tall fescue toxicosis problem that I don’t regret. 

Another thing we did to address fescue toxicosis was to eliminate our spring fertilization with nitrogen in the Outback.  Stopping the spring nitrogen allowed for a lot more legumes to come in. We now have a lot of red clover, white clover and vetch that puts out a lot of growth in the spring (and we have not frost seeded in 20 years!).  Gradually the fescue has declined in these pastures as other species including dallisgrass, orchardgrass, purple top, crabgrass, Johnsongrass and Gamagrass make up a significant part of the grasses, so stockpiles are no longer just tall fescue.

Finally, another important rule is we don’t graze heavy stockpiled tall fescue stands until winter…..our general plan is to start grazing the Outback after Christmas.  Research in Missouri and North Carolina has shown that toxins drop to low levels after the first of the year.  We use up the summer pastures and/or feed some hay during the fall and save stockpile for January, February and March.

One thing that really interests me about Regenerative Grazing is the number of farmers that say they don’t use fertilizer or lime at all.  I have always been suspect of that and know that fertility management is key to restoring land like mine. In recent years I have been putting more and more into grazing management, and today I really like to move cows every day.  The benefits for soil health of high density grazing include increased cycling of nutrients through the build up of organic matter.  This is all under research now, but the truth is all the nutrients needed for plant growth are in your soil, it is just a matter of availability whether they are there for the plants.  For example, a healthy acre of pasture has a ton or more of Nitrogen in the surface 6 inches!  If biological activity in the soil is high, the nitrogen will cycle through available forms and plants will have a shot at picking it up.

I have recently been working with Dr. Alan Franzluebbers who is a USDA soil scientist working at NCSU on soil health management.  He recently published a series of papers showing that on many farms with good grazing management there was little benefit of putting nitrogen on tall fescue stands in September to stimulate stockpile. There were some soils that did benefit, but they tended to be the newer plantings and those with low levels of grazing management.  This was a sobering finding, considering that one of the sites was my own farm.   The plots on our farm were located on one of our best fields where I have been managing the grazing intensively for about 30 years.  This field showed high soil biological activity, and had very good yields of stockpiled fescue even without nitrogen. Putting on nitrogen increased the protein in the grass some, but the total response could not pay for more than 10 lbs of nitrogen per acre!  We didn’t test the Outback, but from what I know I would say we still have a ways to go with soil test biological activity back there.

After that experience I think a lot harder about where I am putting out fertilizer.  We still use some but very sparingly.  This year nitrogen is really expensive, but we still put some out on the Outback.  One place we still put significant nitrogen is a piece of old crop land that is planted to Novel Endophyte Tall Fescue.  We typically put 60 lbs of nitrogen per acre, both in the spring and fall on that stand and it is very productive.  This is one of the worst pieces of land we have because of it’s history with tobacco and corn silage.  Because the Novel Endophyte Tall Fescue does not have the problem with high toxins, we can take a good cutting of non-toxic hay in the Spring and then can graze it before we graze the rest of the stockpile in the fall, so it makes sense for us to use some fertilizer there. 

We were fortunate to get a few good rains after applying nitrogen to this cropland pasture, and the Novel Fescue is really growing strong. We plan to move our first calf heifers to that after they finish calving here in about 10 days, and I know they will be happy to have fresh non-toxic grass.

As a final word I will say we have a lot to learn about how to optimally manage fertility in grazing systems.  Using more active grazing management to effectively increase animal density on the land will potentially change how nutrients cycle on your farm, helping you grow more grass with lower inputs.   Improving our ability to predict nitrogen availability through tests like “Soil Test Biological Activity” will prove key in achieving the goal of growing grass without fertilizer. ~ Matt Poore


The Alliance for Grassland Renewal is a national organization focused on enhancing the appropriate adoption of novel endophyte tall fescue technology through education, incentives, self-regulation and promotion.  For more resources or to learn more about the Alliance for Grassland Renewal, go to http://www.grasslandrenewal.org

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: