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Fertilizer, Plants, Soils and Water:
A properly watered lawn will enable the grass to with stand stress from insects, diseases and weather.
When water is applied to the soil it seeps down through the root zone very gradually. Each layer of soil must be filled to
"field capacity" before water descends to the next layer. This water movement is referred to as the wetting front. Water
moves downward through a sandy coarse soil much faster then through a fine-textured soil such as clay or silt.
If only one-half the amount of water required for healthy growth of your garden or landscape is applied at a given time, it
only penetrates the top half of the root zone; the area below the point where the wetting front stops remains dry as if no
irrigation has been applied at all.
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Influence of Soil Type on
Water-Holding Capacity and Water Use
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Water-Holding Capacity
inches of water per foot of soil |
Days to Use
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| Soil Type |
Total Water |
Available Water |
Available Water* |
| Loam |
0.6 - 1.08 |
0.4 - 1.0 |
2 - 5 |
| Sand |
2.7 - 4.0 |
1.3 - 2.0 |
2 - 5 |
| Clay |
4.5 - 4.9 |
1.8 - 1.9 |
9 - 10 |
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*Assuming an evaportranspiration rate of 0.2 inches per day and a 13 inch deep root zone. Shorter root system would take less time to use available water.
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A properly watered lawn will enable the grass to develop an deep strong root system that has more water available for a longer time.
As days become shorter and nights cooler in late summer (late August to mid-September), cool-season turf-grasses begin to perk up, provided that sufficient moisture is available. In most years, this is an ideal time to apply fertilizer because N will help the plant manufacture food reserves it needs for winter and spring, as well as speed recovery from injury sustained during summer. More root growth during the winter will help the turf to remain strong and healthy in the spring and the summer heat.
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Soil pH impacts micronutrient availability to plants
Compared to N, other turfgrass nutrients have a more subtle influence on diseases. Because their effects on disease are not as dramatic, researchers do not study these other nutrients as much. Despite our lack of detailed knowledge, we can make some generalizations about some of these nutrients and their effects on turfgrass diseases.
* Potassium.
On occasion, applications of potassium fertilizers suppress dollar spot, leaf spot, take-all patch and stripe smut. Although our understanding of the conditions under which this occurs is sketchy, the susceptible plants presumably are in need of this nutrient. Because potassium regulates many plant functions-including cell-wall thickness and the plant's water content-it is easy to see why a deficiency can lead to weaker and more disease-prone plants.
* Calcium.
Turf managers usually apply calcium to turf as lime (calcium carbonate) to raise soil pH. However, calcium also is an essential plant nutrient that plays a crucial role in cell division and cell-wall formation. The turfgrass disease that appears to be most influenced by calcium is Pythium blight. Pythium species possess pectolytic enzymes that dissolve plants' cell walls, causing a rapid disintegration of leaf tissues. Calcium inhibits the activities of pectolytic enzymes, thereby protecting cell walls. This does not mean that calcium controls Pythium blight. However, you may reduce its severity by avoiding a calcium deficiency.
If you apply too much calcium (in the form of lime) to take-all-patch-infested bent grass, it can increase the amount and severity of this disease. Do not apply materials that raise soil pH when take-all patch is a problem.
* Sulfur.
In some regions of the Northwest, sulfur applications show dramatic effects on turfgrass diseases. In certain cases, applications have provided significant control of Fusarium patch and take-all patch. While sulfur applications may provide take-all-patch suppression in other regions of the country, ammonium sulfate usually is more effective.
* Micronutrients.
For years, turf managers have used micronutrients to enhance turf color and, to some extent, growth. Now, studies are shedding more light on their disease-suppressive properties. Research at The Pennsylvania State University has revealed that applications of two micronutrients, zinc and manganese, can lessen the severity of dollar spot and red leaf spot when these diseases are present at low levels in creeping bent grass. Although more research is needed to determine the exact conditions under which this occurs, it does provide golf-course superintendents with another tool to manage these troublesome diseases.
Until more-precise information becomes available on disease management with nutrients (other than N), the best approach is to periodically conduct soil or tissue tests and fertilize according to test recommendations. Soil and tissue testing should give you enough information to avoid nutrient deficiencies. Avoiding nutrient deficiencies results in stronger, more disease-resistant plants and helps reduce the need for fungicide applications and turf repairs.
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Other Information Sources ....
Jess Stryker's, Landscape Irrigation Scheduling Tutorial web site to educate consumers on the proper watering program to maintain an healthy lawn.
Home and Garden, Landscape Irrigation information web site to educate consumers on the proper watering program to maintain an healthy lawn.
North Carolina Cooperative Extension Service, Landscape Irrigation information web site to educate consumers on the proper watering program to maintain an healthy landscape.
Ohio State University Bulletin L-187 Control of Turf grass Pests, Symptoms, fungus: When the disease becomes severe, the entire turf grass stand may appear dull white or pale green. Severely infected leaves usually turn yellow and wither and may lead to a generalized thinning of the stand. Management: Increase sunlight penetration, Reduce the humidity, Use resistant varieties, Fungicide use, and Adjust watering so areas stay drier.
Texas A&M University System, Efficient Use of Water in the Home Landscape and Garden
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