Nutrition
Characteristics of cricket wicket soils

Cricket wickets characteristically consist of heavy soils, possessing clay contents around 50-60% which have an expanding (swelling/cracking) nature when saturated with water. These clay soils are generally fertile given their obvious ability to retain greater quantities of nutrients, due to high exchangeable cation sites existing on the soil complex. The disadvantage with increased cation capacity in the soil is that water infiltration rates become inherently low (1-2mm/hr), making it difficult to leach salts through the profile and away from the rootzone. Another characteristics of cricket wicket soils are that they generally have high magnesium contents.

Soil Testing
Soil tests are the most appropriate way to plan and optimise your nutritional program. By testing on a yearly basis, the turf manager can gain greater efficiency in determining fertilisation requirements. However, soil tests on cricket wickets have to be interpreted using different criteria to what is normally used for other turfgrass situations. Hence there are a few points to keep in mind.

Firstly, in adjusting pH, lime or dolomite should be avoided when raising pH, as calcium tends to cause the soil to crumble. High calcium content is normally required to maintain soil structure with adequate pore space for air and water. The nature of cracking wicket soils provides natural aeration. Magnesium carbonate is the preferred amendment. On acid soils, Potassium phosphate can provide a rapid alkaline action, restoring pH to optimum levels (6.5).

Total soluble salts tend to accumulate on cricket wicket soils. For effective leaching of salts from the rootzone low precipitation rates are required. Do not flood the soil in trying to leach salts, as this proves ineffective.

Given that clay soils generally have high Magnesium contents, base saturation of magnesium greater than 25% will tend to restrict potassium availability.

A Calcium:Magnesium (Ca:Mg) ratio of less than 2:1 is desirable for compaction.

Why Fertilise Turf
Soils with high clay contents contain large quantities of plant available nutrients that can sustain the normal growth of turf. To accommodate the game of cricket, the turf is mowed extremely short and there is considerable wear from rolling and play. To recover quickly from wear, the turf requires more nutrient than is available in soil reserves, and fertilisers are used to satisfy this demand. The nutrients required in largest quantities by turfgrass are Nitrogen, Phosphorus and Potassium, which are the 3 main constituents of turf fertilisers. Nitrogen stimulates leaf growth, Phosphorus promotes root growth and Potassium increases stress tolerance and recovery.

Types of Fertilisers
Generally there are two types of fertilisers used on cricket wickets.

1. Organic (slow release): Natural eg. Poultry manure (TX10)

2. Inorganic: Quick Release eg. Sulphate of Ammonia

                 Slow Release eg. Sulphur Coated Urea, Methylene Urea

In determining which fertiliser to use, one major factor needs to be investigated before applying. That is the fertiliser’s salt index. The salt index is a measure of the potential for a fertiliser to increase soil salinity, and should be considered in the selection of products for use on wickets. The salt index for some of our more common fertilisers is as follows. (The higher the salt index, the greater the salt levels being placed into the profile).

Fertiliser Characteristics for Cricket Wickets
The 3 main beneficial features to look for from a fertiliser for cricket wicket maintenance. They are as follows:

1. Optimises the quantity of slow release nutrients to the plant, preventing surges in growth which create a soft leaf that is easily damaged.

2. Is a truly homogenous particle. Each granule contains the complete analysis of the fertiliser. Due to the homogenous particle, the fertiliser provides the ability to be broken or crushed (as is done in cricket wicket preparation) without effecting its nutrient releasing capacity. This differs from the poly-coated fertilisers, as once part of their coating is broken their nutrient releasing characteristics become less reliable.

3. An extremely small particle size. This allows for much of the fertiliser to move easily into the thatch layer, reducing losses from mower pick up. This provides a definite advantage for cricket wicket preparation, as due to the extremely low mowing heights that are needed, fertiliser loss is a common problem, which can now be alleviated.

Fertiliser Program
The entire wicket table is best treated uniformly with a base fertiliser program, rather than treating individual strips. The rates will depend on the time required to get a wicket back into play. For example, in a 3-wicket table each strip has 5 weeks recovery and would have to be fertilised more intensively than a larger table with more recovery time.

An average program usually applies about 2kg of Nitrogen per 100m² per season. Using slow release nitrogen every 8-10 weeks will provide adequate recovery after play. If necessary, a light rate of liquid/soluble fertiliser can be used to enhance recovery on individual strips.

Renovation: Use a starter fertiliser with a high rate of N and P (16-10-9) following scarifying and top dressing to promote root development and surface recovery.

During Season: A low N and high K fertiliser (12-0-20) every 8-10 weeks is important for maintaining a hard wearing surface.

After Season: A high Nitrogen feed (18-1-15) prior to winter will provide maximum turf coverage for the following season and assist spring green up.

Weed Control
Weed control in turf cricket wickets is an important practice, as weeds not only affect the uniformity and appearance of the wicket, but also may affect the playing characteristics of the wicket. In Australia broadleaf weeds are seldom a problem, as the mowing heights used generally prevent a broadleaf weed from establishing and spreading within the sward. It is grass and sedge weeds, which cause the greatest problem to the turf manager. With smaller populations of grass weeds, hand weeding at the early stages is often the cheapest and simplest method of weed control. It is important that if grass weeds are becoming a regular occurrence in the wicket block, the wicket soil used should be investigated. Fumigating or storing the soil away from weed seed contamination may prove the best method of weed control available to the wicket curator.

Crowsfoot Grass (Eleusine indica)
Crowsfoot is a coarse grass with a cluster a tillers that arise from a central part of the plant, which have flattened stems. Crowsfoot grass has been recorded to produce about 40 000 seeds per plant, therefore weed control is essential not just on the wicket block, but on the outfield and surrounding areas of the sporting oval. When flowering Crowsfoot grass has a distinguishing windmill like flower.

Crowsfoot is a warm season annual grass growing aggressively in spring and summer. In optimum conditions, the time it takes for Crowsfoot to grow from seedling to flowering is approximately 5 weeks. In conditions not so favourable the time frame may be as long as 4 months.

Crowsfoot seeds will not germinate until soil temperatures are quite warm, equivalent to 15-18°C. Herbicidal use is limited, due to the heavy clay soil characteristics. DSMA or Diclofop methyl (Illoxan) are the products that are available for control of Crowsfoot. Best control is achieved when the herbicides are applied to immature Crowsfoot weeds.

Summergrass (Digitaria spp.)
Summergrass leaves possess distinctly hairy leaves that do not grow very long. Under some conditions, they have a reddish tinge. Summergrass is a prolific seed producer, with plants producing 150 000 each in agricultural situations. However, mown plants in turf will never produce this quantity of seed. However there is no doubt that the ability of summergrass to produce seed heads after mowing has taken place, allows them to produce enough viable seed to lay dormant in the seed bank within the soil to re-establish the following season. Summergrass germination takes place when soil temperatures reach 12-15°C, often emerging 2-3 weeks earlier than Crowsfoot in spring. For control of summergrass, the only option is DSMA or MSMA. If using cool season turfgrasses such as ryegrass on the wicket, DSMA is probably the best option for herbicidal control, as due to its slower movement through the plant, less phytotoxicity is observed.

Sedges (Mullumbimby couch and Nutgrass)
Nutgrass (Cyperus rotundus), Mullumbimby Couch (Cyperus brevifolius) and Yellow Nutgrass (Cyperus esculentus) are the 3 most common sedges occurring in cricket wickets. They are low growing perennial weeds that have leaves with triangular cross sections and are glossy green in colour. Sedges generally thrive in soils that remain wet for extended periods of time. Given the practices used in wicket preparation, an ideal environment is created for sedges to prosper and spread. Sedges are thought to release toxins into the soil, which have inhibitory affects on turfgrass growth. Therefore, in most situations control is important. Sempra (Halosulfuron methyl) is by far the best option for Nutgrass, Yellow Nutgrass and Mullumbimby Couch weed control. Rates of Sempra on cricket wickets are generally halved (65g/ha) to prevent residual activity in the soil. DSMA can also be used to control Mullumbimby couch. However, it is less effective in controlling Nutgrass and Yellow Nutgrass, as due to deep tuber chains that these sedges develop, DSMA becomes limited in its movement through the plant, resulting in poor activity.

Kikuyu (Pennisetum clandestinum)
Although Kikuyu is considered as a turfgrass in many situations, it becomes a weed in cricket wickets, as its large, aggressively growing stolons disrupt uniformity of the wicket, affecting its playing characteristics. Kikuyu has bright green folded leaf blades. Some strains of Kikuyu are capable of producing fertile seed, but vegetative growth is the predominant means of Kikuyu reproduction. There are few options for Kikuyu control. Repeated applications of DSMA in spring is a method adopted by many turf managers to control Kikuyu.

Disease Control
With repeated turf injury due to constant rolling, low mowing heights and the rigours of play, a favourable environment is often created whereby disease infection can occur. Depending on the severity and the type of disease, symptoms can be merely a loss in turf uniformity and appearance or it may be quite destructive, creating significant losses to the turf stand.

Helminthosporium (Bipolaris spp., Drechslera spp., Exserhilum spp.)
Helminthosporium is a disease common in lowly mown couch grass commonly occurring from late summer when humid conditions prevail. Symptoms can range from white spots (White Helmo), Black Spots and black melting out (Black Helmo). The disease cycle is generally short and requires extended areas of leaf wetness. There are several registered products for Helminthosporium control. Of these Rovral GT (Iprodione) gains excellent control, both curatively and preventively. Given that Helminthosporium is predominantly a leaf disease, the oil-based formulation of Rovral provides improved rain-fastness and efficiency. Mancozeb, Baycor, and Bayfidan are also effective on Helminthosporium.

Pythium (Pythium spp)
Pythium is a common disease in all turf situations and cricket wickets can also suffer from this disease. Pythium blight occurs generally in high humidity, whereby excessive moisture and warm conditions are experienced. When such optimum conditions arrive, the pythium fungus releases spores from the thatch up onto the plant leaves. These spores have the capacity to germinate quickly, especially if moisture is available, rapidly destroying plant cells. Therefore, curative and preventative control is necessary. Aliette Signature (Fosetyl-al) has proven to be a very effective fungicide in the control of pythium over a number of years. TMTD and Terrazole have also been used to control pythium.

Fairy Ring
Fairy ring is a disease generally forming a dark green band of turf in a circle or semi-circle shape. In some situations, mushrooms may be present, however depending on the numerous fungal species that are associated with this disease, they do not always develop. Fairy rings unlike many turf diseases, have no direct relationship with plant damage. The dark green bands formed by the fairy ring fungi are caused by a rapid release of Nitrogen. Frequently, just behind the nitrogen enhanced areas is browned, wilting turf, caused by a lack of water penetration due to the hydrophobic nature of the disease mycelium. When the disease progresses to this situation, control must be undertaken. In order to relieve symptoms of fairy ring the hydrophobic nature of the soil profile needs to be reversed. This can be done with effective wetting agents such as Aqueduct, which are capable of quickly saturating the soil particle allowing moisture to penetrate deeper into the profile. Fungicides such as Bayfidan can then be used to treat the disease fungi.