Gypsum - back to the future?
Commonly now, at all levels, the recommended 'go to' solution for the greenkeeper, when treating high moisture levels in greens or, conversely, hydrophobic soils, is a surfactant of some description, but is this approach simply going around the problem, not solving it? Are we not actually exacerbating the problem or creating more issues by flooding the soil with sugars, oils or worse? Is poorly timed and reactive deep aeration and regular spiking having the desired effect or simply masking, or even stimulating, the real cause?
In a conversation with a greenkeeper recently, he asked; "why did we never have these problems (hydrophobic soils) before, and why do we all of a sudden have all of these new problems? Do you think we are causing the problems instead of solving them?"
For the past five years, I have been working closely with both fruit growers and sports turf managers in the use of traditional forms of soil improvers, gypsum and lime. Having spent all of my working life in turf production and sportsturf management, I have found the fruit growing side of the business to be a real eye opener.
The work at The Oaks Golf Centre in Surrey has confirmed this to me. At the beginning of 2013, we were asked to get involved in a recovery task. Barry Pace of Speedcut Contractors was on a mission to solve the unusual drainage problems of one his long standing customers. In Barry's eyes, fully understanding the problems at The Oaks would arm him with the understanding to aid a wider audience and achieve the ultimate goal.
Despite deep aeration, regular spiking and the usual dose of wetting agents, the playing surface still held water. Below 75mm could be dry, with the surface and top 50mm being saturated, invariably there would be a hydrophobic layer at and just below these depths.
The common challenge for greenkeepers everywhere is the movement of water through the profile and the constant battle against compaction. The Holy Grail is to continually produce a playing surface that withstands the constant damage caused by heavy footfall, as well as maintaining a balanced ecology within the rootzone. A healthy, contaminant free rootzone, with free movement of moisture and nutrients, a healthy sward, as well as the elimination of hydrophobicity, takes centre stage in the fine balancing act of greenkeeping.
Phil Benn, the club's Course Manager, explained that this is his worst green for drainage, with the worst area being the back (at the top of the slope)! He wasn't wrong either; my leather shoes soon took on water and highlighted the schoolboy error that was having left the wellies at home!
A year on and the green has dramatically changed. The area at the back of the green is now the best, with the pin being placed in places that would have been saturated and unusable twelve months ago.
The fact is that nothing has changed in the management of the surface except the application of liquid gypsum. The purpose of only treating the worst half of the green has given a clear picture of the benefits of increased flocculation promoted by the effectiveness of calcium sulphate application in the form of liquid gypsum.
Gypsum has been used for many years in the agricultural industry to improve the structure and drainage in soils; until now though, the use of gypsum in sports turf has been seemingly long forgotten or restricted to pellets due to the difficulty in application and time taken to act.
The full understanding and appreciation of the actions of calcium sulphate (gypsum) in sports turf management can sometimes be lacking. Calcium use within the fruit growing sector is universal with all growers using it in some form or another. If I asked every greenkeeper what calcium sulphate could do for them, I am confident I would get a wide range of answers which would almost certainly include "nothing".
Calcium helps plants absorb nutrients. In simplified terms, calcium is a nutrient carrier in both the soil and the plant tissue. In the soil, it helps control the water movement and conductivity, which means it can deliver more nutrients from the soil and maximise fertiliser effectiveness. In plants, calcium helps regulate water and nutrient uptake by the roots and the movement throughout the plant.
Calcium aids cell division and cell wall formation and is critical for respiration during high heat and humidity periods. A large calcium deficiency within plants could result in poor root development, and little response to nitrogen or iron applications. Also, high nitrogen applications in the spring or autumn can lead to soft leaf tissue with an increased susceptibility to disease, if the calcium in the plant is not within its desired range.
In effect, without sufficient attention to your calcium levels, you could be throwing your money down the drain on expensive fertilisers that your turf cannot use!
If a fruit grower sees an irregular level of sodium (salts) within his growing medium, in the form of soft fruit or wilting leaf, he will turn to calcium to rectify the imbalance. In the greenkeeping world, it would more likely be an additional application of iron or, perhaps, a wetting agent or even fungicide, which potentially the plant does not need or probably cannot even use due to an imbalance of calcium.
I am certainly not offering up gypsum as the silver bullet solution, but I do strongly believe that treating our turf grass ecology with the same attention to detail as I see, day in and day out, within the fruit growing sector, could possibly save greenkeepers and groundsmen a lot of headaches and, undoubtedly, a lot of money!
Andy Church, Ultra Soil Solutions Ltd.
07835 066439 • www.ultrasoil.co.uk