Soil Test Results Example - University of Illinois Extension

0 downloads 139 Views 2MB Size Report
and sodium that increase the soil pH. A periodic soil test is the only practical way to monitor these changes in the soi
Lawn Care Recommendations To maintain a healthy lawn, a certain level of mowing and watering needs to be done. Likewise, a certain level of fertility must be maintained for the lawn to remain healthy and in good condition. Lawn grasses live in what is basically an unnatural environment. They are crowded together and compete with each other, as well as neighboring trees and shrubs, for water and nutrients. They are mowed regularly and clippings are often removed. Because of this competition and the unnatural demands placed on lawns, they must be fertilized. Just as a balanced diet works best for people and animals, the same is true of lawns. They need fertilizer for sustenance. Properly fertilized, the lawn will maintain good color, density, and vigor. It will not easily succumb to insects, diseases, or weeds. Under fertilized, the lawn is not only less attractive, but is considerably more susceptible to environmental stress and damage. Soil test information can help decide what maintenance procedures will benefit the lawn the most. Each sample should represent similar areas in the lawn, whether 1 or several samples are taken. Take several 3-4" deep cores in the area and mix to make one sample. Each sample should contain 1 to 2 cups of soil for analysis. pH ADJUSTMENT Scales measuring pH run from 0 to 14 with 7 being neutral. Values below 7 are generally referred to as "sour" or acid soils while soil pH's above 7 are referred to as "sweet" or alkaline soils. Lawns grow best in the range of 6 to 7. It is very difficult to change the soil pH once a lawn is established, so proper initial soil preparation is very important. Rainwater percolating is very important. Rainwater percolating through the soil and the use of acidifying fertilizers tend to gradually reduce the pH. On the other hand, irrigation water tends to

SGS North America Inc.

1511 E Main Street 117 E Main Street

add bases like calcium, magnesium, potassium, and sodium that increase the soil pH. A periodic soil test is the only practical way to monitor these changes in the soil pH. Adding limestone according to the amounts in Table 1 can change acidic soils with a pH of less than 6.0. The recommendations are based on soil tests of samples taken to a depth of 3-4 inches in established turf. For a new seedbed, apply limestone at double the rates shown, and till in to a 6-inch depth. Table 1 Recommended Limestone Amounts for Turf Soil Texture pH Sandy Loamy Clayey lbs. per 1000 sq. ft. 6.0-5.5 25 35 45 55-5.0 40 55 70 5.0-4.5 55 75 105

Individual applications on established turf should not exceed 30 to 50 pounds per 1000 sq ft. Alkaline soils –that above pH will result in reduced turf growth because of lower availability of nutrients. Sulfur can be applied to these soils according to Table 2 to lower soil pH. Individual applications of elemental sulfur on established turf should not exceed 5 pounds per 1000 sq. ft. The best time for application of either lime or sulfur is in the spring or fall. Table 2

Recommended Sulfur Amounts to Lower the Soil pH to 6.5 Soil Texture Original soil pH Sandy Clayey lb. per 1000 sq. ft. 7.5 10-15 20-25 8.0 25-23 35-40 805 35-40 40-50

Individual applications should not exceed 5 pounds per 1000 sq. ft. Both limestone and sulfur applications are more effective in conjunction with cultivation (aerifying). NITROGEN Turf grasses are most responsive to nitrogen, assuming that adequate levels of the other essential nutrients are present. However,

PO Box 175 Belleville, IL 62221 t (618) 233-0445 f (618) 233-7292 PO Box 540 Toulon, IL 61483 t (309) 286-2761 f (309) 286-6251 www.cropservices.sgs.com, www.sgs.com

care must be taken as to the amount and the type of nitrogen fertilizer that is applied. Fertilizers such as ammonium nitrate and urea, commonly found in the less expensive fertilizer blends, can easily cause excessive growth or burning of the turf if over applied. Generally the "cheap" fertilizers should be applied carefully. Apply on dry turf and apply less than the recommended but more often to reduce the chance of excessive growth or burning. The longer lasting, good quality fertilizers are more expensive but provide more safety and longer, more even feeding of the turf. Table 3

Annual Nitrogen requirements for Various Turf grasses Species lbs. Nitrogen/1000 sq. ft. Kentucky Bluegrass Improved types Common types Fine Fescue

4 to 6 2 to 4 1 to 3

Tall Fescue Ryegrass Zoysiagrass Bermudagrass

3 to 5 3 to 4 2 to 4 4 to 8

Improved Kentucky Bluegrasses are varieties such as Adelphi, Baron, Bonniblue, and Parade. Common types are Kenblue, Delta, Park, and Newport. Table 3 gives the preferred amounts of nitrogen for various turf grasses for a season. Application rates are given as a range due to variations in climate, soil texture, and cultural practices such as amount of irrigation, and quality of turf desired. Use the lower end of the range for shady or low maintenance conditions. Without sufficient nitrogen, growth stops and the lawn becomes pale and yellowish. Nitrogen fertilizers are of 2 general types – organic and inorganic. Organic types include processed manures, sludge, and other so-called processed waste products. Usually the action of the organics is very slow. However, they have a very low nutrient content so it is necessary to apply a much larger quantity. Cost may or may not be less than conventional fertilizers. Inorganic types are divided into several groups – water soluble, slowly soluble, and slow release. Water-soluble fertilizers provide rapid response after application but with potential for burn and excessive growth. Examples are ammonium nitrate and urea. SGS North America Inc.

1511 E Main Street 117 E Main Street

The slowly soluble forms such as the organics listed above, urea-formaldehyde, and IBDU provide nitrogen in more of a gradual release to the turf. The slowly soluble forms are more expensive but provide a higher degree of safety, especially during summer periods. They usually feed the turf for 6 to 8 weeks. An example is sulfur-coated urea (SCU). Applications of water-soluble types should be limited to one-pound actual nitrogen per 1000 sq. ft. or less at a time and apply several times during the season. Slowly soluble types can be used at higher rates (up to 3-5 pounds of nitrogen per 1000 sq. ft.) applied less frequently. PHOSPHORUS Phosphorus is the next most important element needed for healthy turf. It is required for strong root growth. It stimulates early root formations so is particularly essential for new seedlings. It is not readily flushed from the soil and is needed by grass in small quantities; therefore, most balanced lawn fertilizers contain only a low percentage. Soil testing before seeding will show whether adequate levels of phosphorus are in the soil. If not, use a "starter" type fertilizer that is high in phosphorus. Table 4 is a guide for determining phosphorus rates to build up the soil to a desired phosphorus level. Table 4

Recommended Phosphorus Amount for Lawn Application.

P1 soil test

Phosphorus*

lb./acre Less than 25 25 to 50 50-75 More than 75

lb./1000 sq. ft. 1-2 .4 to 6 .2 to .4 0

* Based on 2 to 4 applications per year of 29-3-4 or similar. POTASSIUM Potassium is the third element of critical importance. Like nitrogen, it is flushed out by water but at a much slower rate. It is very important to the hardiness and disease resistance of turf, and helps promote wear ability. Potassium is needed in about the same quantity as nitrogen. Soil minerals supply a fair amount of potassium, therefore, not as much is added as fertilizer. However, if clippings are removed, more

PO Box 175 Belleville, IL 62221 t (618) 233-0445 f (618) 233-7292 PO Box 540 Toulon, IL 61483 t (309) 286-2761 f (309) 286-6251 www.cropservices.sgs.com, www.sgs.com

potassium needs to be applied – usually about one half the amount of nitrogen. Table 5

Recommended Potash Application Based on Soil Tests K soil test Potash (K2O)* lb./acre lb./1000 sq. ft. Less than 50 2 50 to 100 1 100 to 200 .5 200 to 300 .1 More than 300 0

*Based on 2 to 4 application per year of 29-3-4 or similar. MICRONUTRIENTS The micronutrient levels in most soils are usually adequate for turf growth. Iron is the element most often found to be deficient. An overall yellow coloring of the leaves, little or no response to nitrogen, and a general thinning of the turf characterize iron deficiency. Iron problems occur most often where soils are high in pH (>7.5) and phosphorus levels are high. Other micronutrients deficiencies are uncommon by high pH may cause deficiencies of zinc (Zn) or manganese (Mn). FERTILIZER APPLICATION Besides fertilizer, some irrigation may be necessary for best results. A well-maintained lawn might require about 1" of water per week during the summer months. Mow frequently enough so that no more than 1/3 of the top growth is removed at one time. This may require mowing more often in the spring or after a fertilizer application. Be sure to have a sharpened blade on the mower to reduce the stress on the grass. For new seedlings, always test the soil first so any major corrections can be made to the area before seeding. Limestone for pH correction and fertilizer required should be tilled into the soil prior to seeding to be most effective. Fertilizer applications should be made carefully so excess fertilizer is not applied to some areas of the lawn nor is any unused fertilizer allowed to escape into the environment. With drop-type spreaders, overlap paths enough to avoid "striping" the lawn. Make all fertilizer applications on dry grass, except "weed and feed" types. Long, wet grass will clog the holes of the spreader and give an uneven application. Patterns from fan-type spreaders are more susceptible to

SGS North America Inc.

1511 E Main Street 117 E Main Street

wind drift, which can also give a "striping" effect to the lawn. A complete fertilizer is one that contains all three of the primary nutrients: nitrogen, phosphorus, and potassium (potash). Every state requires that the percentages of these three elements be prominently displayed on the bag. Always, the first number is nitrogen (N), the second phosphate (P2O5), and the third is potash (K2O). An example is 24-4-12. These numbers state the percentages of nutrients in the bag compared to the total contents of the bag. As a general guide, a ratio of 3-1-2 or 3-13 has proven to be good for home lawns. It is not critical for a fertilizer to have exactly this ratio, but something close is recommended. A "starter" fertilizer will usually have a ratio about 1-3-1. If the soil test indicates that only nitrogen is needed, an analysis of 4-1-1 or 5-1-1 can be used. For example, suppose we want to apply 2 pounds of nitrogen per 1000 sq. ft. using a fertilizer with an analysis of 24-4-12. We would need to apply a total of 8.3 lbs. of fertilizer per 1000 sq. ft. to apply 2 lbs. of nitrogen to that area (2.0 #N / .24). The .24 is the percent N in the fertilizer divided by 100. Generally, the fertilizer bag will give spreader settings as a guide for application. To determine the actual amount of nutrient that will be applied, multiply the total bag weight by the % nutrient (50# of 24-4-12 fertilizer = 12# of actual N in the bag). The bag of fertilizer also contains 2 # of actual phosphate and 6# of actual potash. The rest is filler, which makes it easier to spread. Then divide that by the area to be covered with the fertilizer. In this case we will say 5000 sq. ft. Therefore we will apply 12/5=2.4# of actual N to each 1000 sq. ft. of lawn. We would also apply 0.4 # of phosphate and 1.2 # of potash at the same time. See your local nurseryman or Extension agent for additional information and actual fertilizer analysis available in your area. Information taken from U of I Extension publication "Fertilizer Recommendations for Turf"

PO Box 175 Belleville, IL 62221 t (618) 233-0445 f (618) 233-7292 PO Box 540 Toulon, IL 61483 t (309) 286-2761 f (309) 286-6251 www.cropservices.sgs.com, www.sgs.com