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Plany Analysis: An Important Tool in Turf Production

C. Owen Plank and R.N. Carrow
Associate Professor and Professor, University of Georgia

One of the major factors affecting the growth of turfgrass and turf quality is its nutritional status. The nutrient status of turfgrass is often an "unseen" factor, except when the concentration of a nutrient becomes so acute that it adversely affects the desired growth characteristics, or deficiency or toxicity symptoms appear on the grass.

Plants require specific amounts and balances of nutrients for optimum growth and reproduction. A deficiency of one essential nutrient or an imbalance between two nutrients during a critical growth stage can reduce the desired growth characteristics. The extent this effect may have on growth is related to the degree of nutrient deficiency or imbalance. In some cases a deficiency or a toxic level of a nutrient can cause total plant failure in a very short period of time.

As a result of modern technology, the nutrient status of turfgrass can be rapidly assessed through plant analysis techniques. Plant analysis is a process in which plant samples are collected from a plant at a specified time during the growing season and analyzed for various essential nutrients. The nutrients of primary concern are: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), manganese (Mn), iron (Fe), boron (B), copper (Cu), and zinc (Zn). In addition to the analyses, most plant analysis programs also include an evaluation of the analytical data to determine whether an element is low, sufficient, or high.

One should not confuse plant analysis or plant tissue analysis with tissue testing. As noted in a later section plant analysis is conducted in a laboratory using wet chemistry methodology or a combination of wet chemistry and combustion methodologies. Tissue testing is conducted in the field, and the process includes conducting colorimetric procedures on freshly extracted tissue sap using test papers, vials, and color charts. An advantage for this type of analysis is that it provides immediate results and has a lower cost than wet chemistry and combustion methods. However, these tests are not quantitative and are limited to nitrate (NO3), phosphate (PO4), and potassium (K) analyses (Jones et al., 1991).

USES OF PLANT ANALYSIS

Plant analysis can be used by turf managers to:

  • Confirm suspected nutrient deficiency symptoms;
     
  • Verify toxicities;
     
  • Reveal hidden hunger; i.e., plants show no visible symptoms, but the nutrient content is low enough to reduce growth or affect quality characteristics;
     
  • Aid in evaluating the efficiency of applied fertilizers;
     
  • Assist in formulating fertilization practices, and
     
  • Monitor the nutrient status of plants throughout the growing season to determine whether each nutrient is present in sufficient concentration for optimum growth characteristics.

Plant analysis is a proven and effective means of predicting fertilizer needs for many crops. However, it does not completely replace a soil test. Soil and plant analysis serve different purposes and when properly used they compliment each other in providing detailed information for maximizing the efficiency of fertility programs.

Soil testing is based on the concept that the concentration of a particular nutrient in a given volume of soil reflects whether or not the nutritional level of that soil is adequate for optimum crop growth or production. Plant analysis is based in part on the concept that the amount of a specific nutrient in the plant tissue is related to the plant availability of that element in the soil. However, plant analysis also reflects nutrient uptake conditions in the soil. Soil properties such as compaction, impervious layers or poor drainage may inhibit the uptake of nutrients by plants. Or a low concentration of one nutrient in the plant may result from the excessive application of another nutrient. Conversely, favorable soil physical properties and optimum soil moisture may accentuate nutrient uptake even though the soil may not have an abundant supply of nutrients.

As a result of these soil-plant interactions, there are certain instances when contradictions occur between soil and plant analysis results. For example, assume turf is growing on a soil in which the soil tests revealed a medium level of extractable magnesium. A plant analysis from the area a few weeks later indicates that magnesium is low. Immediately, the validity of the test results are questioned, which is an absolutely normal response. However, a closer examination of the plant analysis results revealed that the calcium and potassium concentrations of the turf were high. Upon checking the information supplied on the history sheet accompanying the plant analysis results, it was noted that calcitic limestone had been used as the liming material and a high rate of potassium was applied in the fertilizer program. As a result of these two management practices, the level of calcium and potassium in the soil were sufficient to reduce the uptake of magnesium.

This is one example of how soil testing and plant analysis can be used together for making better nutrient management decisions. Plant analysis can also be used to supplement a soil testing program. It is particularly useful in distinguishing between nitrogen and sulfur deficiencies in turf as deficiency symptoms of the two elements are similar. Plant analysis offers an excellent means of delineating which element is deficient (which cannot be ascertained through soil testing). If this distinction is not made properly and the wrong corrective treatment is applied, plant growth can be affected appreciably.

In the case of most turfgrasses, a soil analysis prior to active growth in the fall or spring makes it possible to determine whether limestone, phosphorus, potassium, or magnesium applications will be needed. Plant analysis of the turfgrass during the growing season will indicate if the applied materials were effective and whether the preplant prediction by soil analysis was correct.
In order for a plant analysis program to be successful it must include the following essential components:

  • A representative sample of the area in question
     
  • Proper sample preparation for analysis
     
  • Accurate analysis of the sample
     
  • Correct interpretation of the results
     
  • Proper recommendations based on the analytical data and historical information supplied with the sample

SAMPLING

Sampling is one of the most critical phases of a plant analysis program. Most laboratories provide plant analysis sampling kits which contain detailed sampling instructions along with a history form and envelope for submitting samples to the laboratory. The sampling instructions should be followed carefully. A sample taken improperly provides little or no information about the problem at hand.

When sampling turf from areas other than golf greens, hand clippings are preferred to mower clippings. Make sure that the instruments (clippers or scissors) used to collect the clippings are clean and free of any rust. Collect  2 to 3 handfuls of tissue, place in brown paper bag or plastic container, and save for additional preparation, washing and drying, prior to shipment or on-site analyses.
Generally, the surfaces of golf greens are relative free of foreign debris. However, at certain times of the year leaf fall from adjacent trees may result in leaves on the surface of the greens. These should be removed with a backpack blower or other suitable device prior to sampling.

Mower clippings from golf greens can be used for turfgrass analysis using the normal mowing height at the site. Clean mower baskets are acceptable for catching the clippings. However, care should be taken to wash off any soil that may contaminate the clippings. After the area has been mowed, randomly remove 3 to 4 handfuls of clippings from the basket of walking mowers or 2 to 3 handfuls from each basket of Triplex mowers and place in a brown paper bag or plastic bucket. (If clippings are transferred to a bucket, be sure to use plastic as metal containers may result in contamination of the sample.) Mix the sample thoroughly and withdraw three handfuls and place in a labeled container (plastic or double-lined paper bag). Save the sample for additional preparation, washing and drying, prior to shipment or on-site analyses.

Do not sample within a week after fertilizer or other chemicals have been applied to turf. These materials can contaminate the sample and invalidate analytical results. Other common contaminates on turfgrass that can affect analytical results are sand and soil particles. Particulate matter on clippings from golf greens have been shown to adversely affect both the consistency and reliability of analytical results for unwashed samples (McCrimmon, 1994). Failure to remove sand from samples using proper washing techniques generally, with the exceptions of iron and aluminum, results in lower nutrient concentrations as compared to washed samples. When samples are contaminated with sand or soil particles, the analytical results for both iron and aluminum are high. To minimize the amount of sand in samples from golf greens, do not take samples immediately after topdressing. Wait until the sand is watered in and settled. This may require several days. Also, avoid taking samples on days the grooming heads are attached to the mowers. The grooming heads result in increased sand and other foreign materials in the sample and prolongs the washing procedure.  If dust or contaminates are expected on the leaves, the leaves can be placed in a colander; washed with a weak soap solution  (couple drops of soap per liter) for 5-10 seconds; immediately rinse with good quality tap water; and lay out leaves to air dry.

Do not include diseased or dead plant material in a sample. Also, avoid sampling plants which have been damaged by insects and nematodes, stressed extensively by cold, heat, moisture deficiencies, or by excess moisture.

The frequency of sampling depends upon whether the results will be used for diagnostic or monitoring purposes.

Diagnostic Sampling

The diagnostic role has been the traditional use of plant analysis for turfgrass situations. It is used to confirm a suspected nutrient deficiency or toxicity prior to applying corrective measures. Samples are obtained from (a) an area exhibiting the deficiency symptoms; (Note: Samples from turf where the symptoms are just appearing are much better than from areas with severe symptoms; areas with dead turf should be avoided); and (b) an adjacent normal-appearing area.


Monitoring Sampling

Use of plant tissue analysis to monitor the nutrient status during the growing season has been a common practice for irrigated-annual, orchard and greenhouse crops. However, interest has increased over the past 10 to 15 years for monitoring turfgrass sites, especially greens. On USGA spec greens, rainfall and/or frequent irrigation can leach nutrients such as nitrogen, sulfur, and to a lesser extent potassium from the root zone. By monitoring the greens regularly turf managers can correct nutrient problems before deficiencies occur. For monitoring, tissue samples are collected as described previously except samples should be taken from the same location on a periodic basis. For example, if clippings are collected from the entire green, use clippings from the entire green throughout the monitoring period. Don’t collect clippings from the front of the green one time and from the back the next time. . Frequency of sampling normally varies from monthly to biweekly, depending upon local situations.

Sample Preparation

Regardless of precautions taken in sampling, turfgrass clippings often contain sufficient amounts of chemicals, sand, or soil on the leaves to influence analytical results. In order to remove the contaminants the samples must be washed or rinsed. For clippings that are relatively free of contaminants place the sample in a plastic or metal sieve and rinse briskly with running tap water. Remove the sample and place on a paper towel and blot. Then transfer the sample to a dry paper towel, place in an area free of chemicals and dust, and allow to air dry.

Greens that have been recently topdressed usually contain considerable amounts of sand or soil particles and merely rinsing the sample in a sieve is not effective in removing these particles. They can be removed more effectively by placing the sample into a wide mouth-container about ¾ filled with tap or distilled water. Swirl the sample gently with a plastic stirring rod or fingers; pause for about 30 seconds to allow the sand to settle to the bottom of the container; quickly remove the sample and place in a sieve or screen and allow to drain; remove and place on a paper towel and blot to remove excess moisture. Then transfer the sample to a dry paper towel, place in an area free of chemicals and dust, and allow to air dry. Discard the wash water, rinse the vessel, fill ¾ full with tap or distilled water and proceed with the next sample.

Samples taken from areas where chemicals have recently been applied should be washed using a weak soap solution (0.1 - 0.3%) rather than tap or distilled water alone (Plank, 1989; Campbell and Plank, 1992). After the sample has been washed place it into a metal or plastic sieve and rinse with distilled, deionized, or tap water. If iron, manganese or zinc deficiency is suspected, distilled or deionized water should be used as the rinse.

Washing should only be performed on fresh samples and never on dry samples. Washing dry or partially-dried samples can result in significant leaching of the soluble elements from the tissue. The washing and rinsing procedures should be done rapidly. Do not prolong the washing procedure or allow the sample to “stand” in either the wash or rinse baths. Allowing samples to remain in the wash or rinse water too long results in low analytical results for elements such as nitrogen and potassium.
After the samples have been air dried remove about 2 handfuls of the sample and place into a plant analysis kit for shipment to the laboratory. If plant analysis kits are not available, paper bags are preferred for shipping rather than polyethylene or plastic, which can speed decomposition. Where analysis equipment, such as NIRS, is available on the site, drying should be according to the manufacturer’s protocol.

Information requested on the history form, which is included with each plant analysis kit, should be as complete as possible. This information is very important to the individual interpreting the results and making the recommendation. The better the information, the more complete the recommendation. Also, when doing diagnostic work don't forget to take soil samples from the same area that the plant samples are taken.

SAMPLE ANALYSIS

Conventional plant analysis laboratories analyze plant samples for the total quantity of 12 to 13 elements. Plant tissue samples previously dried, ground, and weighed are prepared for elemental analysis by destroying the organic matter using either wet chemical or thermal digestion procedures (Campbell and Plank, 1998). Wet chemical digestion involves the destruction of organic matter through the use of both heat and acids. Acids that have been used in this procedure include sulfuric, nitric, and perchloric acids, either alone or in combination. This is a rather time-consuming procedure and may require up to 16 hours for complete digestion. A relatively new accelerated wet chemical procedure for organic matter destruction utilizes pressure and high temperature to shorten the digestion process to approximately 1 hour. Dry ashing is conducted in a muffle furnace at temperatures of 500o to 550o C for 4 to 8 hours. Once the organic matter has been destroyed, the elements are dissolved in dilute nitric or hydrochloric acid, or a mixture of both such as aqua regia (Campbell and Plank, 1992; Campbell and Plank, 1998).

The recent developments in accelerated sample digestion coupled with new innovations in high-speed analytical equipment such as inductively-coupled argon plasma emission spectrographs (ICAP) and combustion apparatus for nitrogen and sulfur analyses make it possible for scientists to complete a plant analysis in 24 hours or less. ICAP instruments have the capability of simultaneously analyzing samples for 10 to 12 elements at the rate of one sample per minute and combustion units analyze samples for nitrogen and sulfur at the rate of one sample per 5 minutes. Although the instruments generate results rapidly, they achieve a very high degree of accuracy because they are calibrated against both known chemical and plant standards. Data are collected via computers and promptly returned electronically to clients. These advancements have made conventional laboratories very attractive to turf managers in the last few years for obtaining rapid and accurate analyses.

The Near Infrared Reflectance Spectroscopy (NIRS) procedure has been promoted by some commercial firms as a means to obtain rapid tissue analysis information for diagnostic or monitoring purposes using either an on-site NIRS unit or by shipping samples to a laboratory that utilizes NIRS (Carrow, 2000). Results can be obtained quickly because NIRS is a non-destructive procedure and precludes the digestion phase required with wet chemistry procedures. Sample preparation usually only involves drying and grinding the sample. Once the sample has been prepared for analysis, scanning or analysis time typically is less than 3 minutes. Elements analyzed include N, P, K, Ca, Mg, S, Zn, Cu, Fe, Mn, B, and Na. Although this technology has been used for several decades for determining N, total protein, carbohydrates, lipids, other organic chemicals, and moisture content in forages, grains, and oil crops (Clark et al., 1998; Foley et al., 1998; Masoni, et al., 1996; Stowell, 1995; Vazquez, et al., 1995) its application in turfgrass tissue analysis is still being developed.

The basis of NIRS is to determine reflectance of specific wavelengths over the infrared range (750 to 2500 nm) and relate the degree of reflectance to a specific compound or element. Infrared wavelengths are absorbed mainly by:

  • C-H bonds; common in carbohydrates
     
  • N-H bonds; common in proteins, amides, and amino acids
     
  • O-H bonds; common in water

If the wavelength radiation matches the vibrational or rotational frequency of the chemical bond within a particular plant compound, it is absorbed.

Statistical procedures are used to correlate the reflectance of one or more specific wavelengths to the true level of a compound or nutrient as measured by wet laboratory methods. A regression equation is developed that estimates the quantity of a nutrient or compound based on the strength of reflectance from these wavelengths. This equation is then entered into the computer software for use by NIRS on future samples where wet laboratory analysis will not be conducted (Carrow, 2000). However, achievement of statistically significant equations with high correlation (R2 or coefficient of multiple determination; R2>0.90; 1.0 is perfect) has not been demonstrated for nutrients except for N (Plank, unpublished data 1990; Stowell, 1995; Stowell and Gelernter, 1998; Rodriquez and Miller, 2000). Carrow (2000) noted that except for nitrogen, none of the nutrient elements are directly involved in a C-H, N-H, or O-H bond. Reflected wavelengths are, therefore, always indirectly related to a nutrient rather than directly. This results in lower correlations of NIRS nutrient values (except for N) versus wet lab values than achieved for organic components, which usually exhibit correlation coefficients of determination of r2 >0.95 (1.0 is a perfect correlation) because they are directly involved in C-H, N-H, or O-H bonds.

This does not preclude the use of NIRS in certain turf management programs because it can be effectively used for monitoring potential excessive or deficient levels of nitrogen.  Nitrogen management is very important in turf because nitrogen influences numerous growth factors directly or indirectly. These include:

  • Color
     
  • Density
     
  • Growth rate
     
  • Root growth
     
  • Thatch accumulation
     
  • Disease and insect tolerance

The uses of NIRS in turf management could possibly be expanded through additional research that may improve calibration equations for the majority of elements currently being analyzed using this technology.

INTERPRETATION

Interpretation of plant analyses for turfgrass can be very complex although the quantitative association between absorbed nutrients and growth has been studied by several investigators. Reliable interpretive data are lacking for a number of turf species, particularly at different stages of growth and for nutrient concentrations near or at toxicity levels. Other factors that make the interpretative process complex are the effects that variety or hybrid, nematodes, and environmental factors such as soil moisture, temperature, light quality and intensity have on the relationship between nutrient concentration and plant response.

Several different methods have been proposed and used to interpret plant analysis data. Initially, single-concentration values were used to identify nutrient sufficiency, but research showed that ranges in concentration would better describe the nutrient status of the plant. Another method of interpretation is based on "critical values," the concentration below which a 10% reduction in growth may occur. This does not imply that a severe deficiency exists as 90% of maximum yield is still possible. This approach was developed for row crops and forage crops where yield data is easily attained. For several years this system of interpretation had a serious limitation since it defined only the lower limit at which a 10% yield reduction might be expected, providing no guidance when the concentration found exceeded sufficiency. However, Ohki (1987) proposed the use of two critical levels, one defining the critical deficiency level (CDL) and one defining the critical toxicity level (CTL) with the nutrient levels in between the two points being adequate. Defining the “critical value,” “CDL,” or “CTL” for turfgrasses is somewhat more complex than for most agronomic crops because of the various cultural practices employed in managing certain turfgrasses. A more useful method of interpretation is based on sufficiency ranges- the optimum concentration range below which a nutrient is low or deficiency occurs, and above which a nutrient is excessive or toxicity occurs. This system of evaluation is currently in use in the University of Georgia Plant Analysis Laboratory and most other government and commercial laboratories.

Ideally sufficiency ranges are developed by plotting yield or plant growth with nutrient concentration. However, sufficiency ranges have also been developed for some crops utilizing survey data from large populations of normal appearing plants and establishing the upper and lower boundaries of sufficiency using the population nutrient mean plus or minus one standard deviation. Figures 1 and 2 illustrate two ways in which growth is related to nutrient concentration in plants.


          Fig. 1. The relationship between nutrient concentration in plants and yield.



       Fig. 2. The relationship between nutrient concentration in plants and growth or yield.

It is significant to note the differences in the slopes of the two curves on the left side; the slope in Fig. 2 is quite steep whereas the one in Fig. 1 is more gradual. The curve in Fig. 2 more nearly typifies one for micronutrients and the one in Fig. 1 typifies one for macronutrients. This illustrates the importance of accurate analyses and interpretations for micronutrients because at the low end of the sufficiency there is a small difference in nutrient concentration between sufficiency and a severe deficiency. Fortunately, with most turfgrasses micronutrient deficiencies are not common occurrences. The graph in Fig. 2 illustrates that for most macronutrients a greater change in concentration occurs between sufficiency and deficiency.

A defined sufficiency range may not apply to all situations or environments. In plants nutrient concentrations are not absolute with respect to sufficiency or deficiency because nutrient uptake and internal mobility, nutrient ratios, as well as dry-matter changes, can affect the nutrient concentrations in plant tissues. Consequently, nutrient concentrations are not static; they change during the growing season in response to environmental and management conditions. Figure 3 shows the fluctuations in nitrogen content of well maintained bentgrass greens during a growing season.


              Fig. 3. Range in nitrogen content of 18 bentgrass greens during 1991.

Concentration and dilution occur due to the difference between plant growth and nutrient absorption as well as movement of the nutrients within and between plant parts. Under normal growing conditions, nutrient absorption and plant growth closely parallel each other during most of the vegetative growth period. However, if the normal rate of growth is interrupted, nutrient accumulation (higher than expected nutrient values) or dilution (lower than expected nutrient values) can occur. Some of the factors that can result in nutrient accumulation include: extremes in temperature for the grass species; heat or moisture stress; stress due to traffic, or other cultural practices; and stunting (reduced growth) due to a soil deficiency of a particular nutrient or nematode infestations. Nematodes can produce nutrient deficiencies similar to those resulting from low soil levels. When elements such as calcium and phosphorus are deficient in the plant tissue, but soil pH and soil test phosphorus and calcium are adequate, this is a good indication that nematodes are the cause of the problem. Factors that can result in dilution are growth factors that stimulate rapid growth, which may include highly favorable climatic conditions, and rapid growth response to nitrogen applications (Carrow, 2000). As noted, several factors can affect a plant analysis result and this is why it is important to supply historical information requested on plant analysis history forms when submitting samples to plant analysis laboratories, and the need to have an expert practitioner interpret plant analysis results.

It is a good policy to maintain a record of soil tests, plant and water analyses and refer to them each time a lime and fertilizer program is formulated. Evaluate upward or downward trends in soil pH and nutrient levels in both the soil and plants. Having this information, coupled with visual observations of the turfgrass and knowledge of field conditions, you can adjust lime and fertilizer applications to maintain the nutrient content of the soil and turfgrass within the sufficiency range for the majority of elements tested.

The following tables are provided as guides for interpreting plant analysis results for some turfgrasses. They have been taken from various published reports and modified based on plant analysis surveys conducted by the senior author. The interpretative guidelines are for use with plant analysis data from conventional laboratories. They are not applicable for interpreting data generated by NIRS instruments

RECOMMENDATIONS

Because of the numerous ways in which different turfgrasses are utilized and managed, no attempt is made to formulate specific recommendations for corrective treatments when a nutrient level falls outside the sufficiency range. Good recommendations depend on the integration of soil, plant and irrigation water analysis results, historical information relative to treatments and visual observations (Plank, 1989; Carrow, et al., 2001). It should be noted that water quality analysis for irrigation suitability is becoming increasingly important as part of the overall nutrient assessment for turf in many areas. This is due to the fact that more turf managers are irrigating with nonpotable water that often contains various nutrient, element, and salinity levels. However, some general observations and comments can be made with respect to the following nutrients (Plank, 1989).

Nitrogen (N):   Nitrogen is the nutrient most commonly found to be low in turfgrasses and is generally due to inadequate fertilization, heavy leaching rains, over-irrigation or possible root damage. However, in many instances with golf greens low N may be due to management practices implemented to obtain the desired putting surface characteristics. N deficiency may be manifested as a light green color, slow growth rate or excessive seed head production. If a deficiency is detected, base N applications on soil test recommendations being sure to split applications where leaching may be a problem.

Phosphorus (P):    Deficiency is usually due to low soil P, cool-wet growing conditions, nematodes, or excessively low soil pH. If deficiency is detected, apply phosphorus and limestone based on soil test recommendations.  High levels of P generally pose more problems with intensively-managed turf than deficiencies. Excessive P levels in the leaves can cause deficiencies of other nutrients, particularly iron. High P to K ratios in leaf tissue increases winterkill in bermudagrass and St. Augustinegrass. When high P is detected, omit P from the fertilization program until P is within acceptable limits. In most instances three or more years may be required. When low P is detected in the tissue and soil pH and soil test P are adequate check for nematodes.

Potassium (K):       Low K is generally due to low soil test K levels,  inadequate K fertilization or when grass is grown on coarse-textured sandy soil that is subject to leaching. Low K may also be associated with low N fertilization. When soil K is adequate, N fertilization increases the uptake of K by the grass. When low K is detected in the tissue, apply potash and nitrogen based on soil test recommendations.

When K drops below 1.00% in the tissue, deficiency symptoms appear and are characterized by spindly growth (narrow leaves, thin turf), leaf tip burn, reduced wear, cold and disease tolerance and reduced growth rate.

 Excessive K levels may induce Mg deficiency and suppress the uptake of Ca and Mn. If high K levels are detected in the tissue, reduce the K fertilization rate or omit K from the program until K is within the sufficiency range.

Calcium (Ca):    Grasses are able to take up Ca under a wide range of soil conditions and is rarely deficient. If low levels are detected, check for low soil pH and apply limestone based on recommendations. If soil pH and soil test Ca levels are adequate check for nematodes. A high Ca level may indicate some other nutrient deficiency or disorder.

Magnesium (Mg):    Low levels may occur on sandy soils, on soils with low pH and low Mg, where high rates of NH4-N and K fertilizers have been applied and where clippings are continuously removed. If low levels are detected, include Mg in the fertilization program at the rate of 0.50 lb. Mg per 1000 sq. ft., or if soil pH is low and limestone is required, apply dolomitic limestone according to soil test recommendations. Excessively high Mg in tissue is not a common occurrence.

Sulfur (S):    Low S may occur on sandy soils low in organic matter where S-free fertilizers have been used, following extensive periods of heavy rainfall where grass has been over-irrigated, and where high application rates of N have been applied. The ratio of N to S is as important as the S level itself and should not exceed 20:1. Ideally the N:S ratio should be approximately 14:1 for optimum growth and turf quality. If S is low and/or the N:S ratio exceeds 20:1 include 0.25-0.50 lb. S per 1000 sq. ft. in the fertilization program. Sulfur may be supplied as gypsum, elemental sulfur or sulfur-containing fertilizers.

Manganese (Mn):    Deficiencies are rare but may occur occasionally on sandy soils that are low in Mn, high in organic matter and when the soil pH is 6.8 or higher. Frequent use of foliar Fe may contribute to deficiencies by suppressing Mn uptake. Turfgrasses grown on areas receiving high sodium (Na) inputs may also be more susceptible to Mn deficiency. Mn deficiencies can be corrected by applying a foliar application of manganese sulfate or manganese chelate by dissolving 2 ounces of manganese sulfate or 1 ounce of manganese chelate in 1 gallon of water and spraying at the rate of 0.5 gallon per 1000 sq. ft. Repeated applications will be required to prevent reoccurrence of the deficiency.

Excessive Mn levels can occur in some turfgrasses when the soil pH is less than 5.5 or where soils are consistently over-watered. High Mn levels can be corrected by proper liming, proper irrigation practices and by improving drainage on poorly-drained soil.

Iron (Fe):   Iron determinations are invalid unless samples are properly washed to remove soil contaminates. Generally if Fe and Al levels are both high it is due to contamination rather than inherent levels in the grass. Iron deficiency can occur on high pH soils (7.0 or higher), during periods with cool-moist growing conditions, and where soil P levels are excessively high. Iron deficiency is best controlled by applying a foliar application of iron as iron sulfate or iron chelate at a rate of 0.50 ounce of Fe per 1000 sq. ft. Repeated applications may be needed indefinitely to prevent reoccurrence of the deficiency. Do not apply foliar applications of iron to grasses in the heat of the day.  Soil applications of Fe materials are not recommended for correcting Fe deficiencies.

Boron (B):   Deficiency is very rare; however, toxicity is possible with some sources of irrigation water, particularly along the coastal areas. Boron content of irrigation water should be less than 0.5 ppm to guard against the possible development of toxic soil levels.

Copper (Cu):   Deficiency is not likely to occur except on organic soils or sandy soils with a pH of 7.0 or higher. Excessive Cu levels can result from application of soil amendments containing high concentrations of copper.

Zinc (Zn):   Deficiencies are not common on turfgrasses unless grown under alkaline soil conditions. In some cases low Zn levels will be detected in grass grown on soils that are excessively high in P or when grown on compacted-waterlogged soils. Deficiency symptoms do not show up unless the Zn content is less than 10 ppm. Zinc deficiencies can be corrected with foliar applications of zinc sulfate or zinc chelate at the rate of 0.5 ounce per gallon of water per 1000 sq. ft. High Zn levels may occur when soil amendments containing Zn have been applied over several years, or the soil amendment contains a high concentration of Zn. Most turf species can tolerate higher Zn concentrations than most agronomic crops.

REFERENCES

Campbell, C.R. and C.O. Plank. 1992. Sample preparation. p. 1-11. In: C.O. Plank (ed). Plant Analysis Reference Procedures for the Southern Region of the United States. Southern Cooperative Series Bulletin 368.

Campbell, C.R. and C.O. Plank. 1998. Preparation of plant tissue for laboratory analysis. p 37-49. In Y.P. Kalra (ed) Handbook of Reference Methods for Plant Analysis. CRC Press, Boca Raton, FL.

Campbell, C. R. and C. O. Plank. 2000. Foundation for practical application of plant analysis. In C. R. Campbell (ed). Reference Sufficiency Ranges for Plant Analysis in the Southern Region of the United States. Southern Cooperative Series Bulletin 394.

Carrow, R.N. 2000. Plant tissue analysis as a management tool. Proceedings from the Millennium Turfgrass Conference. 6-9 June 2000. Melbourne, Australia. AGCSA, Glenn Waverly, VIC, Australia.

Carrow, R.N., D.V. Waddington, and P.E. Rieke. 2001. Turfgrass Soil Fertility and Chemical Problems: Assessment and Management. Ann Arbor Press, Chelsea, MI.

Foley, W.J., A. Mc Ilivee, I. Lawler, L. Aragones, A.P. Woolnough, and N. Berding. 1998. Ecological applications of near infrared spectroscopy - a tool for rapid, cost-effective prediction of the composition of plant and animal tissues and aspects of animal performance. Oecologia 116: 293-305.

Jones, J.B.,Jr., B. Wolf, and H.A. Mills. 1991. Plant analysis handbook. MicroMacro Pub. Inc., Athens, GA.

Masoni, A., L. Ercoli, and U Mariotti. 1996. Spectral properties of leaves deficient in iron sulfur, magnesium, and manganese. Agron. J. 88:937-943

McCrimmon, J.N. 1994. Comparison of washed and unwashed plant tissue samples utilized to monitor the nutrient status of creeping bentgrass putting greens. Comm. Soil Sci. Plant Anal. 25(7, 8): 967-988.

Mills, H.A. and J.B. Jones, Jr. 1996. Plant Analysis Handbook II: A Practical Sampling, Preparation, Analysis, and Interpretation Guide. MicroMacro Pub. Inc., Athens, GA.

Ohki, K. 1987. Critical nutrient levels related to plant growth and some physiological processes. J. of Plant Nutrition. 10:1583-1590.

Plank, C.O. 1989. Plant Analysis Handbook for Georgia. Cooperative Extension Service Pub., Univ. of Georgia, Athens, GA. 63 pages.

Rodriguez, I.A. and G.L. Miller. 2000. Using near infrared reflectance spectroscopy to schedule nitrogen applications on dwarf-type bermudagrass. Agron. J. 92:423-427.

Sartain, J.B.  2002. Tifway bermudagrass response to potassium fertilization. Crop Sci. 42:507-512.

Snyder, G.H and J.L. Cisar. 2000. Nitrogen/potassium fertilization ratios for bermudagrass turf. Crop Sci. 40:1719-1723.

Stowell, L. 1995. Near infrared reflectance spectroscopy (NIRS), atomic aemission spectroscopy (AES), and automatic N analysis (ANA). Pace Insights 1(3): 1-2. Pace Turfgrass Institute, San Diego, CA.

Stowell, L.T. and W. Gelernter. 1998. Tissue Analysis: Guidelines and NIRS revisited. Pace Insights 4(11): 1-4.

Vazquez de Aldana, B.R., B.G. Criado, A.G. Civdadi, and M.E.P. Corona. 1995. Estimation of mineral content in natural grasslands by near infrared reflectance spectroscopy. Comm. Soil Sci. Plant Anal. 26(9,10): 1383-1396.


Sufficiency Ranges

 

Table. 1. Sufficiency ranges for creeping bentgrass greens. (Modified from Campbell and Plank, 2000)

 

Element

Category

Low

Sufficient

High

Nitrogen (N), %

<4.00

4.00 - 5.00

>5.00

Phosphorus (P), %

< 0.30

0.30 - 0.60

>0.60

Potassium (K), %

<2.20

2.20 - 3.50

>3.50

Calcium (Ca), %

<0.25

0.25 – 0.75

>0.75

Magnesium (Ca), %

<0.20

0.20 – 0.40

>0.40

Sulfur (S),%

<0.25

0.25 – 0.75

>0.75

Boron (B), ppm

<3

3 – 20

>20

Copper (Cu), ppm

<5

5 – 15

>15

Iron (Fe), ppm

<50

50 – 300

>300

Manganese (Mn), ppm

<25

25 – 300

>300

Zinc (Zn), ppm

<20

20 – 70

>70

Important Ratios: The N:S ratio should be 10 to 18:1. N:S ratios greater 20:1 signify potential sulfur deficiency. The N:K ratio should be 1.2 to 2.2.

 

 

 

Table 2. Sufficiency ranges for  Tifgreen (or Tifton 328) bermudagrass greens . (Modified from Campbell and Plank, 2000 and Snyder and Cisar, 2000)

 

Element

Category

Low

Sufficient

High

Nitrogen (N), %

<3.00

3.00 - 4.30

>4.30

Phosphorus (P), %

< 0.20

0.20 - 0.40

>0.40

Potassium (K), %

<1.60

1.60 - 2.25

>2.25

Calcium (Ca), %

<0.25

0.25 – 0.50

>0.50

Magnesium (Ca), %

<0.15

0.15 – 0.30

>0.30

Sulfur (S),%

<0.15

0.15 – 0.65

>0.65

Boron (B), ppm

<5

5 – 60

>60

Copper (Cu), ppm

<5

5 – 20

>20

Iron (Fe), ppm

<50

50 – 500

>500

Manganese (Mn), ppm

<20

20 – 300

>300

Zinc (Zn), ppm

<15

15 – 200

>200

Important Ratios: The N:S ratio should be 10 to 18:1. N:S ratios greater 20:1 signify potential sulfur deficiency.

 

 

 

 

 
 

 

 

Table 3. Sufficiency ranges for perennial ryegrass (Modified from Mills and Jones, 1996)

 

 

Nutrient

Sufficiency Range

Nitrogen (N), %

3.34 - 5.10

Phosphorus (P), %

0.35 - 0.55

Potassium (K), %

2.00 - 3.42

Calcium (Ca), %

0.25 - 0.51

Magnesium (Mg),%

0.16 - 0.32

Sulfur (S), %

0.27 - 0.56

Boron (B), ppm

5 - 17

Copper (Cu), ppm

6 - 38

Iron (Fe), ppm

50 - 500

Manganese (Mn), ppm

30 - 250

Zinc (Zn), ppm

14 - 64

 

 

Table 4. Sufficiency ranges for St. Augustinegrass (Modified from Mills and Jones, 1996)

 

 

Nutrient

Sufficiency Range

Nitrogen (N), %

1.90 - 3.00

Phosphorus (P), %

0.20 - 0.50

Potassium (K), %

2.00 - 4.00

Calcium (Ca), %

0.30 - 0.50

Magnesium (Mg),%

0.15 - 0.25

Sulfur (S), %

no data

Boron (B), ppm

5 - 10

Copper (Cu), ppm

10 - 20

Iron (Fe), ppm

50 - 300

Manganese (Mn), ppm

40 - 250

Zinc (Zn), ppm

20 - 100

 

 

Table 5. Sufficiency ranges for ’Emerald’ Zoysiagrass (Mills and Jones, 1996)

 

 

Nutrient

Survey Range*

Nitrogen (N), %

2.04 - 2.36

Phosphorus (P), %

0.19 - 0.22

Potassium (K), %

1.05 - 1.27

Calcium (Ca), %

0.44- 0.56

Magnesium (Mg),%

0.13 - 0.15

Sulfur (S), %

0.32 - 0.37

Boron (B), ppm

6 - 11

Copper (Cu), ppm

2 - 4

Iron (Fe), ppm

188 - 318

Manganese (Mn), ppm

25 - 34

Zinc (Zn), ppm

36 - 55

*Data obtained from survey of field test plots

 

 

In This Section

Introduction
Sampling
Plant Analysis
Extraction
Interpretation
Recommendations
Soil pH
Reference

 

   

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