CULTIVATION
TECHNIQUES Planning an optimum programme
The first part of a two-part article reviewing the processes of identifying soil physical problems and the design of a corrective programme using appropriate cultivation techniques based on a scientific understanding of symptoms.
by MARTYN T. JONES, National Turfgrass Foundation INTRODUCTION
The soil in most putting greens in this country is far from ideal and, as an alternative to costly and disruptive reconstruction, most course managers try to improve the performance of the soil through a programme of cultivation. Each situation has a distinct set of characteristics that require accurate diagnosis. Course managers should examine their own unique situation before deciding on a particular piece of equipment or course of action. Planning an optimum programme involves a number of stages. Firstly, what is the problem, or problems, that needs to be corrected? In some cases, the overall poor state of the green may result from an assortment of deficiencies and each fault may need individual attention. Secondly, what equipment is the most appropriate to alleviate the identified problems? Where there are a number of causal defects, a range of equipment with differing actions may be required. Remember that there is never a panacea for all soil ailments. And thirdly, what intensity of treatment with appropriate equipment will be needed to achieve the desired improvement? The latter point will include timing and frequency of operations based on prevailing weather conditions, state of the soil, and degree of acceptable disruption to play.
IDENTIFYING THE PROBLEM(S)
Detailed inspection of the turf and soil is necessary to identify the problem or problems that may exist. Major problems can vary significantly from one area to another, even though the general symptoms of poor turf colour, low shoot density, restricted rooting, susceptibility to environmental stress, high disease incidence, and surface ponding may be common to all.
Some conditions are easily identified. Examples include excessive thatch accumulation, or layering in the soil profile resulting from siltation from flooding, faulty construction, or inappropriate topdressing programme. Severe soil compaction, be it at the surface or lower in the soil profile is also usually easily identifiable. However, moderate compaction is not as easily discernable and may require close inspection of rooting and moisture movement to locate the zone of compaction and its severity. A soil probe can be used to locate a hard pan in the soil or physical impedance to rooting may also reveal the problem. All too often, inexperienced turf managers jump to conclusions without adequate diagnosis. Consequently, inappropriate actions may be taken in an assumption that a treatment will be effective. In some instances, not only is the treatment ineffective but the problem can actually be aggravated.
Where a green is constructed from
fine-textured soil, identifying the causal problem is generally straightforward, whereas problems associated with high sand content constructions can be much more complex. For instance, it is not uncommon to find sand-based greens built to a perched water table specification that appear to drain rapidly, yet display shallow rooting, weakened turf, and the presence of black layer. There may be no signs of compaction, little thatch, and no visible surface water. Close inspection of the rootzone will often reveal that the material is saturated throughout its depth. Generally, unsuitable sand or an inadequate depth of rootzone material causes such a condition. Where the depth of the sand rootzone is less than the critical tension or air-entry pressure of the material, the pore spaces remain full of water, air cannot enter at the surface, and the rootzone material remains saturated. Such a problem is generally a construction fault and must be rectified by means other than cultivation techniques.
Some suggestions in the identification of soil physical problems are:
• Select an area that is a fair indicator of the general state of the green, tee or fairway. Avoid areas that are likely to be particularly wet because surface contours are simply channelling water into the area in quantities greater than the soil
There is never a panacea for all soil ailments, no matter how good the piece of equipment.
Some problems are easily identified
Reconstruction may be necessary
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