Cover crops: a complete soil health overhaul (Part 1 of 3)
A cover crop can play a valuable role in ensuring that a cropping operation grows and remains sustainable. Cover crops can be tricky to manage, however. In this first article in a series of three, veteran US farmer and cover crop coach Steve Groff explains why a farmer should not give up when trying to grow a cover crop for the first time.
The use of cover crops as a conservation agriculture tool is relatively new in South Africa. It is therefore important that the country’s farmers work together to adapt cover cropping methods to suit production conditions here if this beneficial concept is to gain widespread traction and achieve the envisaged results, says US farmer and cover crop coach Steve Groff.
“At first, not every idea will work, but teamwork and persistence will ultimately pay off,” he says. “Cover cropping is a simple and good concept, but it’s complex to achieve success with it. Like no-till, cover cropping is a tool to achieve healthy soil and resultant sustainable crop production. But a farmer must understand what the tool is intended for and how to use it properly for it to be effective.”
Groff advises newcomers to start by implementing cover cropping on only 10% of their lands.
“[In this case,] if you fail at first, it’s unlikely to have any significant negative impact on your farming business. You can then try again along a different route until you get cover cropping right. When you get it right, you can gradually expand its use across your farm.”
According to Groff, a crop farmer should manage the soil to mimic undisturbed natural conditions, where a wide variety of plants grow in the soil and help form it. While it may not always be possible for crop farmers to have diversity at all times, the goal should be to implement it whenever the opportunity presents itself. This could be in off-crop seasons, via intercropping, or on a part of the farm that is being rested.
‘TREAT COVER CROPS AS YOU WOULD CASH CROPS’
Groff stresses that one of the most important messages he can share with conservation agriculture farmers is: “If you treat your cover crops the way you treat your cash crops, you’ll set yourself up for success. Just as you are ready to plant your cash crops at the first opportunity that presents itself, you should be ready when the first opportunity to plant a cover crop presents itself. Soil health can’t be bought, it has to be made.”
He adds that every conservation agriculture farmer should have a mentor – someone who is already successful at managing cover crops. The farmer and mentor should engage regularly, even if by telephone or email, as frequent discussions stimulate the thinking and analysis that lead to solutions and progress.
“Forming farmer discussion groups is also a great help. Managing cover crops successfully is far too complex to achieve on your own. I’ve been managing cover crops for 35 years but I still consult my mentor, Frederic Thomas, who lives in France.”
A LONG ROAD TO SUCCESS
From starting with six species of cash crops and one species of cover crop in 1982 on his Cedar Meadow Farm in Pennsylvania, Groff now grows 14 cash crops and 27 cover crops. As a result of managing his conservation agriculture practices effectively, he has improved his farm’s average soil organic matter level from 2% to at least 5,5% over this time.
“My primary goal for the plants growing in my soils is diversity, diversity, diversity,” he says. “My choice of cash crops and cover crops may not be suitable for South African markets and production conditions. This is where South African farmers must talk to each other and their advisers to look at the options. And, as happened with me, South African farmers won’t achieve the diversity that I now have in only a few years. It took me 35 years. Be patient and allow yourself time to diversify gradually and properly.”
Groff is also working towards lowering his use of agrochemicals and inorganic fertilisers; phasing out production of commodity crops if this proves feasible; producing food crops with increased nutritional density; and maintaining his profitability.
His approach on Cedar Meadow Farm ensures that there are living roots in the soils year-round. In the 2016 and 2017 summer production seasons, he managed to maintain or increase the average yields of his farm’s various cash crops while reducing overall inorganic fertiliser and agrochemical usage by 39% and 57% respectively.
“But you can’t just throw on cover crop seed and expect miracles. Yes, we need to try to mimic the plant diversity found in nature, but even nature takes a long time to reclaim and rehabilitate a degraded soil. If we don’t manage and treat our soils properly, they won’t be able to harvest rainfall. And the nutrients that we apply to these soils, and the soils themselves, will simply be washed away by runoff or blown away by wind. This is money going to waste.”
THE PLOUGH IS THE PROBLEM
Many tillage farmers, on seeing surface crusting, poor water infiltration, and water and wind erosion, refuse to admit that their plough is largely responsible. These same farmers are quick to point out the pitfalls of no-till and other conservation agriculture practices.
‘allow yourself time to diversify gradually’
Groff says that he leaves the tilling of his soils to earthworms and other beneficial soil life that he has helped to thrive.
“And I don’t have to pay them to do it! They incorporate plant residues into the soil and increase soil fertility.”
He adds that tillage farmers should be asking themselves some important questions. These include: “Is my soil in better condition now than it was 20 years ago?”; “Do I want to improve my soil’s condition over the next 20 years?”; “What is the average annual loss of topsoil on my farm due to wind and soil erosion?”; “What price would I be willing to sell my soil for?”; and “What is the nutrient value of my soil?”
He says it is pointless working with a consultant such as an agronomist unless this person appreciates and supports what the farmer is aiming to achieve by practising conservation agriculture. A consultant should be helping the farmer improve levels of soil carbon and organic matter.
LEFT:Steve Groff grows 14 cash crops and 27 cover crops and, as a result, has increased his farm’s average soil organic matter content to 5,5%.