Influence of certain nitrogen fertilizers on quality and growth of lawngrasses in Louisiana

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1 Luisiana State University LSU Digital Cmmns LSU Agricultural Experiment Statin Reprts LSU AgCenter 1982 Influence f certain nitrgen fertilizers n quality and grwth f lawngrasses in Luisiana E P. Barris Fllw this and additinal wrks at: Recmmended Citatin Barris, E P., "Influence f certain nitrgen fertilizers n quality and grwth f lawngrasses in Luisiana" (1982). LSU Agricultural Experiment Statin Reprts This Article is brught t yu fr free and pen access by the LSU AgCenter at LSU Digital Cmmns. It has been accepted fr inclusin in LSU Agricultural Experiment Statin Reprts by an authrized administratr f LSU Digital Cmmns. Fr mre infrmatin, please cntact gcste1@lsu.edu.

Influence 1 f Certain Nitrgen Fertilizers, n Quality and

$LEGER \ Ki BTiiwr LOUISIANA STATE UNIVERSITY AND AGRICULTURAL$ AND MECHANICAL COLLEGE Center fr Agricultural Sciences And

2 Influence 1 f Certain Nitrgen Fertilizers, n Quality and GrwthMm f Lawngrasses in Luisiana E. P. BARRIOS. L. G. JONES and L. P. LEGER \ Ki BTiiwr LOUISIANA STATE UNIVERSITY AND AGRICULTURAL AND MECHANICAL COLLEGE Center fr Agricultural Sciences And Rural Develpment ALVIN C. HARPER, CHANCELLOR STATION DOYLE CHAMBERS, DIRECTOR AGRICULTURAL EXPERI M ENT. Bulletin N. 739

Cntents Page Materials and Methds 4 Results and Discussin 6 Summary, 19 Literature Cited 20 Acknwledgments The authrs wuld like t express their appreciatin t the fllwing fr their cperatin and

, LSU Department f Agrnmy, fr advice and suggestins in cnducting sil and fertility analyses thrugh the Sil Testing Labratry at LSU; Jseph G.

3 Cntents Page Materials and Methds 4 Results and Discussin 6 Summary, 19 Literature Cited 20 Acknwledgments The authrs wuld like t express their appreciatin t the fllwing fr their cperatin and assistance in the cnduct f this research: Dr. D. W. Newsm, head, LSU Department f Hrticulture; Prfessrs R. H. Brupbacher and J. E. Sedberry, Jr., LSU Department f Agrnmy, fr advice and suggestins in cnducting sil and fertility analyses thrugh the Sil Testing Labratry at LSU; Jseph G. Kwalczuk and Pete Keller f the LSU Feed and Fertilizer Labratry fr fliar analyses; Dr. Kenneth L. Knce and Debrah K. Babcck, LSU Department f Experimental Statistics, fr statistical analyses f the data; Rbert H. Cper, Jr., frmer Research Assciate, fr initial establishment and maintenance f the plts, and members f the evaluatin panel wh made great cntributins f time and effrt Claude S. Blackwell, Dr. Rysell Cnstantin, Ned Larsn, Dr. Russell Miller, Al Watts, and Ben R. Williams. The Luisiana Agricultural Experiment Statin fllws a nndiscriminatry plicy in prgrams and emplyment.

V ^ Influence f Certain Nitrgen Fertilizers On Quality and Grwth f Lawngrasses in Luisiana E. P.

Numerus trees limit shade-intlerant bermudagrasses t sunny areas, and high maintenance requirements further restrict their usage n lawns.

Augustine, centipede, and Flratam are the principal lawngrasses in Luisiana, with smaller amunts f carpetgrass lcated in areas where sil elevatins are lwer and mre misture is present.

4 V ^ Influence f Certain Nitrgen Fertilizers On Quality and Grwth f Lawngrasses in Luisiana E. P. Barris, L. G. Jnes and L. P. Leger 1 Many grass species are used as lawngrasses in Luisiana due t variatins in climate, sil, native stands, and individual preferences. Numerus trees limit shade-intlerant bermudagrasses t sunny areas, and high maintenance requirements further restrict their usage n lawns. Zysiaerasses are als generally planted nly where equipment and persnnel are available t manage them prperly. Presently, St. Augustine, centipede, and Flratam are the principal lawngrasses in Luisiana, with smaller amunts f carpetgrass lcated in areas where sil elevatins are lwer and mre misture is present. Estimates indicate that abut 80 percent f Luisiana lawns are planted with St Augustine, fllwed by centipede and Flratam turfgrasses The widespread prevalence f St. Augustine decline (SAD) virus in suthern Luisiana has resulted in mst lawns being established since 1975 with centipede r Flratam. N newly released St. Augustine varieties tested here have shwn levels f resistance t the SAD virus that are sufficient t justify that they replace thse presently used. Hwever, this species culd cntinue t represent the largest lawngrass acreage in Luisiana fr sme time, depending n the virulence and spread f the disease and the vanetal resistance that may be develped by turfgrass breeders Turfgrasses require mre nitrgen (N) than any f the ther essential elements supplied by sils and fertilizers, nrmally cntaining frm 2 t b percent N in dried fliar samples (10, 15, 25 2 ). Nitrgen has a great influence n the grwth rate f turfgrass, which usually increases with the applicatin f larger amunts f this element t certain levels (5, 24). Ihc clr and density f turf are generally imprved by the additin f the prper amunt f N (12, 21). Hwever, excessive N fertilizatin f turfgrasses prmtes thatching and susceptibility t sme diseases (9, 11). Nitrgen deficiency may cause reduced cld hardiness f lawngrasses, but excesses f this element are especially respnsible fr winter damage t turf (4, 17). 1 Prfes~srs and Research Assciate, respectively, Department f Hrticulture, LSU, Batn Ruge, La Italic numbers in parentheses refer t Literature Cited, page 20. 3

Nitrgen fertilizer surces fr lawngrass use are numerus, ranging frm very sluble frms, such as ammnium nitrate and urea, t slw-release types, including principally ureafrmaldehyde (UF), isbutylidene

Sme N surces are cmbined in a mixed fertilizer, usually als cntaining phsphrus (P) and ptassium (K), such as 8-8-8 r 12-12-12.

5 Nitrgen fertilizer surces fr lawngrass use are numerus, ranging frm very sluble frms, such as ammnium nitrate and urea, t slw-release types, including principally ureafrmaldehyde (UF), isbutylidene diurea (IBDU), and sulfur-cated urea (SCU). Mst dry fertilizers fr lawns presently cntain UF as a surce f N, but many lawn-care cmpanies use UF and/r urea in a liquid frm that is sprayed n the grass. Sme N surces are cmbined in a mixed fertilizer, usually als cntaining phsphrus (P) and ptassium (K), such as r All three f these elements are necessary in certain critical amunts fr prductin f a high-quality lawn (8). Hwever, in areas f high rainfall and temperature, such as Luisiana, maintenance f an adequate supply f N is difficult since these envirnmental factrs cause the rapid lss f this element frm the sil fllwing applicatin. Studies were cnducted at the Burden Research Center in Batn Ruge during 1978 and 1979 t determine the influence f several N surces, rates, and applicatin frequencies n the quality and grwth f the three lawngrasses mst grwn in Luisiana. The sil type at this lcatin (Mississippi River Terrace) represents frm 10 t 15 percent f that n which lawns are planted in Luisiana. The results presented here, therefre, wuld be valid nly fr this sil r clsely similar sils, and might nt apply t grass species and N surces ther than thse used in this research. Materials and Methds The experimental design was a randmized blck with three replicatins f 18 N treatments and three lawngrasses (centipede, Flratam, and St. Augustine). Nitrgen surces used were UF, IBDU, and liquid urea (LU), applied at three rates and tw frequencies in Octber (Table 1) and 1979 frm April t Plts f 3 feet by 6 feet each were planted by slid sdding in the spring f 1977 s that all grasses were at a cmparable stage f maturity in April f 1978 when the initial N treatments were applied. A preplant starter fertilizer, cnsisting f 1 pund f N (ammnium nitrate) and 5 punds each f P (treble superphsphate) and K 2 0 (ptassium chlride) per 1,000 square feet, was incrprated int the sil t a depth f 4 inches prir t sdding. During the summer f 1977, the turf was maintained by applying 1 pund f N (ammnium nitrate) and 5 punds each f P and K 2 0 per 1,000 square feet in July. The sil at this lcatin was a silt lam f the Calhun series, with a ph varying frm 5. 7 t 6.4 amng plts. In February f 1979 the ph range was unchanged, with ex tractable P 3 and K 4 ranging Extracted with 0. 1 N HC N NH 4 F at a rati f 1 part medium t 20 parts extractant. "Extracted with 1.0 N NH 4 OAc buffered at ph 7.0 at a rati f 1 part medium t 10 parts extractant. 4

Treatment n. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Table 1.

mnthly IBDU mnthly LU mnthly UF bimnthly IBDU bimnthly LU bimnthly N rate per applicatin 2 0.5 0.5 0.5 1.0 1.0 1.0 1.0 1.0 1 0 2.0 2.0 2.0 1.5 1.5 1.5 3.0 3.

per 1,000 ft 2, April t Octber (applied April 3, May 3, June 2, July 3, August 3, and September 7). 3.0 3.0 3.0 3.0 3 0 3.0 6.0 6.0 6.0 6.0 6.0 6.0 9.

6 Treatment n Table 1. Nitrgen fertilizer treatments, 1978 and 1979 Treatment 1 UF mnthly IBDU mnthly LU mnthly UF bimnthly IBDU bimnthly LU bimnthly UF mnthly IBDU mnthly LU mnthly UF bimnthly IBDU bimnthly LU bimnthly UF mnthly IBDU mnthly LU mnthly UF bimnthly IBDU bimnthly LU bimnthly N rate per applicatin Ttal N per year 3 'Surce and applicatin frequency (UF = ureafrmaldehyde; IBDU = isbutylidene diurea; LU - liquid urea). 2 Lbs. per 1,000 ft 2 per applicatin. 3 Lbs. per 1,000 ft 2, April t Octber (applied April 3, May 3, June 2, July 3, August 3, and September 7) amng plts frm 72 t 225 ppm and 54 t 168 ppm, respectively. Calcium (Ca) and magnesium (Mg) levels varied amng plts frm 990 t 1,750 ppm and 209 t 281 ppm, respectively, with cpper (Cu) and zinc (Zn) varying frm 1 t 6 ppm, irn (Fe) frm 49 t 188 ppm, and rganic matter frm 1.2 t 3.2 percent (6). Sil levels f extractable nutrients ther than N were mnitred peridically during 1978 and 1979, with P and K applied (frm treble superphsphate and ptassium chlride) when sil analyses indicated they were necessary. During the 1978 grwing seasn, P varied amng plts frm 24 t 306 ppm, K frm 17 t 206 ppm, Ca frm 670 t 1,600 ppm, Mg frm 114 t 319 ppm, and ph frm 5.4 t 6.9. On the last sampling date (August), Cu ranged frm 1 t 3 ppm, Fe frm 20 t 68 ppm, Zn frm 1 t 2 ppm, and rganic matter frm 0.7 t 2.4 percent. The sil analyses frm June t Octber f 1979 shwed the fllwing extractable nutrient levels: P varied amng plts frm 17 t 265 ppm and K frm 14 t 168 ppm, bth being highest at the end f the seasn. Ca and Mg variable, ranging frm 646 t 2,057 ppm and 113 t 351 ppm, were still respectively, while the ph was frm 5.5 t 7.0, but generally lwer than in Sil rganic matter increased slightly, varying frm 0.6 t 3.7 percent. 5

The final sil sample was btained in April f 1980, shwing that extractable nutrient level ranges amng plts were: P, frm 10 t 230 ppm; K, frm 26 t 150 ppm; Ca, frm 678 t 1,642 ppm, and Mg, frm 1 17 t

Extractable P, K, Ca, Mg, and ph and rganic matter levels were smewhat variable in the area used fr this research.

7 The final sil sample was btained in April f 1980, shwing that extractable nutrient level ranges amng plts were: P, frm 10 t 230 ppm; K, frm 26 t 150 ppm; Ca, frm 678 t 1,642 ppm, and Mg, frm 1 17 t 290 ppm. Sil ph varied frm 5.4 t 7.0, and rganic matter cntent was frm 1.1 t 2.8 percent, increasing smewhat ver that f Extractable P, K, Ca, Mg, and ph and rganic matter levels were smewhat variable in the area used fr this research. It was recgnized that this was an undesirable situatin; hwever, since it was the nly available space with this sil type and there was a pressing need fr hme lawn turfgrass fertility data, the plts were lcated at that site. The turfgrasses were mwed weekly at a height f 2.5 inches, with a 26-inch wide reel-type mwer equipped with a basket t remve clippings. The same mwer was used t btain yield samples. Plts were dethatched nce each year during the same week f July. Standard insect and disease cntrl measures were practiced (n SAD virus was indicated in the St. Augustine plts during 1978 r 1979). Althugh rainfall fluctuated cnsiderably, at least 1 inch f misture per week was maintained by supplemental irrigatin when necessary. Experimental data were btained mnthly (April t Octber) f each year. Yields f clippings were cllected frm grass that was nt wet with dew r rain, unmwed fr the previus 7 days. The same clippings were als used fr fliar analyses fr N, P, K, Mg, Cu, Fe, and Zn cntent (22). Fliar samples were dried at 95 F (35 C) fr 48 hurs and grund in a stainless steel Wiley mill prir t analysis. Turf quality was evaluated visually by a panel f five faculty members within 48 hurs after yield data were btained. The panel was cmpsed f the same members thrughut the experiment, with ratings based n a visual scale f 1 (prest) t 9 (best) in appearance and density in 1978 and The 1980 evaluatin was changed (0 = dead, 8 = best) because f cld damage t the turfgrasses, especially at higher N rates, during the winters f and (Tables 2 and 3). A rating f less than 4.5 was nt cnsidered as acceptable quality lawngrass during any f the 3 years. Six sets f yield recrds and quality evaluatins were made in each f the 1978 and 1979 grwing seasns. Results and Discussin Grass quality and yield apparently were nt assciated with ne anther (Tables 2, 3, and 4). On the average, treatment (N surce, rate r frequency) had n significant influence n quality (means f three grasses and 2 years). These data are dissimilar t thse btained here in N research with Tifgreen bermudagrass n glf greens, using generally higher rates but with tw f the same surces f the element ( / ). Sht density has been prpsed as a better measurement f glf green turfgrass quality than 6

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Table 4. Effect f treatment and year n yield f three lawngrasses (means f 12 harvest dates in 1978 and 1979) 1 Treatment n. 1 2 3 4 5 6 7 3 9 10 11 12 13 14 15 16 17 18 St.

150 89 173 168 115 183 Grams fresh weight/plt 13 ft 2 90 107 126 35 87 104!

10 Table 4. Effect f treatment and year n yield f three lawngrasses (means f 12 harvest dates in 1978 and 1979) 1 Treatment n St. Augustine Flratam Centipede Yearly means Grams fresh weight/plt 13 ft ! !04! Seven days grwth, 2V2-inch height f cut. clipping yields (20). Evaluatin panel members in the lawngrass study cnsidered clr as the mst imprtant criterin f quality in a lawngrass, with density f smewhat lesser imprtance. This type f turfgrass is grwn primarily fr verall esthetic value, rather than the appearance and texture necessary fr glf green grasses. The visual rating, hwever, is still cnsidered the best methd f any turf quality evaluatin if perfrmed by cmpetent individuals independently f ne anther (3). Centipede was f significantly higher quality (P<.05) in 1978 and 1979 than the ther lawngrasses, irrespective f treatment r year in which the N was applied. There was n significant quality difference between St. Augustine and Flratam during the same perid f time (Table 2). Yields f centipede als appeared higher than thse f the ther tw grasses, but there were n significant differences in yield amng them (Tables 2 and 4). The sil ph, which ranged frm 5.4 t 7.0 during this research, may have had an influence n quality f the three grasses. Centipede reprtedly attains ptimum quality at a ph f 5.0 t 5.7 (79). At high ph levels, this grass was lighter green in clr than when grwn in mre acid sil, which is indicative f an irn deficiency. Irn chelate, sprayed n the turf t temprarily alleviate the chlrsis, was recmmended ( 1 9). N data were fund in the literature reviewed cncerning ptimum ph levels fr St. Augustine and Flratam turfgrasses, but they are grwn n sils in Luisiana that may vary in ph frm less than 4.9 t mre than 6.9, depending n the lcatin (7). 9

The quality f all lawngrasses was highest in 1978, with centipede shwing the least and St. Augustine the largest decrease in 1979, while Flratam was intermediate in this respect (Table 3). All St.

The highest quality (1978 and 1979 means f all grasses) was bserved n the August 23 evaluatin date.

11 The quality f all lawngrasses was highest in 1978, with centipede shwing the least and St. Augustine the largest decrease in 1979, while Flratam was intermediate in this respect (Table 3). All St. Augustine plts in 1979 were belw the acceptable quality level f 4.5 n the visual evaluatin scale, with nly tw Flratam plts given similar ratings. Centipede plts were rated frm 5.9 t 6.7 in The highest quality (1978 and 1979 means f all grasses) was bserved n the August 23 evaluatin date. Quality was lwest n April 25, remaining relatively cnstant in August but generally decreasing in September (Table 5). Lawngrass yields (means f three grasses and 2 years) shwed n significant differences (Table 4). Althugh centipede had the highest ttal fresh weight (means f bth years), there were n significant yield differences amng grasses. Generally higher yields ccurred in 1979 than in 1978 in all three lawngrasses, but St. Augustine shwed the smallest difference between years. These data shw there was n psitive relatinship between quality and yield in this study, since quality was highest in 1978, when yields were lwest. The smallest yield in bth years was n the April 25 harvest date and the highest n July 16, decreasing in August and September (Table 5). Mean quality f the three grasses was nt highest n the same date that yields were largest, again shwing the lw degree f assciatin between these tw plant respnses t N treatment and the envirnmental influences f yearly and mnthly climate. St. Augustine and Flratam lawngrasses were slwer t reach high quality levels than centipede, generally nt attaining until July the same apprximate quality that centipede had reached in May. These data indicate centipede is mre tlerant f cler temperature fr grwth than the ther tw grasses, althugh it is mre susceptible t fliar brwning when the air temperature is near the freezing pint (Tables 6, 7, and 8). Flratam apparently had the highest ttal yield amng the grasses in July (Table 7), but nt significantly higher. Yields and quality f the lawngrasses were nt related in this study. Little research cncerning lawngrass fliar nutrient cncentratin has been reprted. Limitatins presently exist in develping prper sampling techniques and interpreting the results, althugh the actual analysis may be very accurate fr all 16 essential turfgrass elements (2). Seasnal fluctuatins are cnsidered t be a surce f errr, alng with maturity f the tissue sampled. Cnsiderably mre data are necessary n levels f essential nutrients in the tissues f varius turfgrass species grwn under different fertility levels and envirnmental cnditins fr tissue analyses t becme mre useful in the diagnsis f turfgrass nutrient status (2, 14, 16). Lawngrass fliar analyses reprted here represent data btained with the grass species, sil, nutritinal levels, and envirnment previusly described. 10

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Fliar nutrient levels in this research were generally lwer than thse reprted ( 14, 16) with ther grass species grwn under lwer temperature and rainfall cnditins and differing sil and nutritinal

Earlier data btained in N fertility trials with Tifgreen bermudagrass grwn in a mstly sand glf green medium with higher levels f N, als shwed higher tissue cncentratins f sme f the same elements

16 Fliar nutrient levels in this research were generally lwer than thse reprted ( 14, 16) with ther grass species grwn under lwer temperature and rainfall cnditins and differing sil and nutritinal levels. Earlier data btained in N fertility trials with Tifgreen bermudagrass grwn in a mstly sand glf green medium with higher levels f N, als shwed higher tissue cncentratins f sme f the same elements reprted here ( / ) Treatment had n apparent influence n any f the fliar nutrient levels studied in this research (Table 9). Nitrgen levels in fliage f the three grasses were especially lw cmpared with thse reprted fr ther species, ranging frm 2.1 t 2.6 percent instead f 4 t 5 percent. This difference may have been partially due t the amunts f N generally applied being lwer, but sme treatments cntained as much r mre f the element than thse used in earlier research with Tifgreen bermudagrass and with tw f the same surces f N. In additin, mre lss f N frm leaching wuld be expected in a glf green medium cnsisting f 70 percent sand than in the medium-textured sil where the lawngrass study was cnducted ( / ). Therefre, the three species f lawngrasses d nt seem t be as efficient in the utilizatin f N as sme ther species, based n fliar analyses. Quality ratings fr Tifgreen, at the same rates f N, were much higher in previus research by the authrs than thse fr the lawngrasses in this study, and the fliar N percentage was crrelated (r=0.58**) with grass quality (/). Table 9. Effect f treatment n fliar nutrient cncentratin f lawngrasses (means f all grasses and three ana lyses in 1978) 1 2 Treatment N P K Mg Cu Fe n. (%) (%) (%) (%) (ppm) (ppm) fliar anal/sis samples cllected n April 25, June 19, and September 27 harvest dates. 2 Dry weight basis. 15

Fliar P cncentratins in lawngrass clippings were apprximately the same as thse in Tifgreen bermudagrass, while the percentage f K was smewhat higher (Table 9) The amunts f fliar K in the bermudagrass.

16*) in previus research, while the amunt f P present in clippings was nt assciated with panel ratings (/). Fliar N alne in this study had n relatinship with quality.

17 Fliar P cncentratins in lawngrass clippings were apprximately the same as thse in Tifgreen bermudagrass, while the percentage f K was smewhat higher (Table 9) The amunts f fliar K in the bermudagrass. ranged frm 1.5 t 1.9 percent, but generally averaged apprximately 1.6 as cmpared with 1.9 percent in the three lawngrasses. The fliar K cncentratin was related t turfgrass quality (r=0.16*) in previus research, while the amunt f P present in clippings was nt assciated with panel ratings (/). Fliar N alne in this study had n relatinship with quality. The fliar cncentratins f Cu were apprximately equal t thse reprted in the literature ( 14), except where Milrganite (activated sewage sludge) was applied. Milrganite cntained significant amunts f Cu, which was crrelated (r=0.56**) with bermudagrass turf quality (/). Amunts f fliar Mg were higher in the three lawngrasses in this study than thse previusly reprted (7), but again leaf Mg was nt assciated with quality. Magnesium levels in grass clippings frm plts fertilized with Milrganite, which cntains sme Mg, were apprximately the same as thse in clippings frm plts treated with fertilizers that did nt have any Mg(7). The fliar Fe cntent f the grasses (Table 10) was cnsiderably lwer than that f Tifgreen bermudagrass (200 t 400 ppm), even where the same tw N surces were utilized in earlier research (/). The tpsil in the research reprted here cntained higher amunts f Fe 49 t 188 ppm cmpared with 49 t 66 ppm in the bermudagrass medium. This may indicate the bermudagrass species was mre efficient in utilizatin f Fe than the three lawngrass species, r that its Fe requirement was higher. Overall turfgrass quality was nt influenced by fliar Fe cncentratin in either this r the earlier research, perhaps shwing that critical levels f this element in the grass fliage had been attained r surpassed. The amunt f fliar P was significantly lwer (P<.05) in centipede than in the ther grasses (Table 10). Amng varieties, fliar P was nt directly assciated with quality, since centipede was given higher panel evaluatin Table 10. Fliar cncentratins f P, Cu, and Fe in three lawngrasses (means f three analyses in 1978) 1 St. Augustine Flratam Centipede P 2 Cu 2 Fe 3 P 2 Cu 2 Fe 3 P 2 Cu 2 Fe 3 (%) (%) (ppm) (%) (%) (ppm) (%) (%) (ppm) 0.53 a 18 b a 22 a b 13 c 25 1 Dry weight basis, samples cllected n April 25, July 16, and September 27 harvest dates. 2 Mean separatin, Duncan's Multiple Range Test; within nutrient means with at least ne letter in cmmn are nt different at the 5% level. 3 N significant difference.

ratings (P<.05). Centipede reprtedly requires nly small amunts f this element, and medium t high amunts f sil P made Fe unavailable t this turfgrass in a previus study ( 19).

Perhaps the mst significant data btained in this research was that which pinted ut the influence f N rates, applicatin dates, and lw temperatures n quality f the lawngrasses (means f all N

18 ratings (P<.05). Centipede reprtedly requires nly small amunts f this element, and medium t high amunts f sil P made Fe unavailable t this turfgrass in a previus study ( 19). Hwever, in this study the fliar levels f these tw elements did nt influence the quality f centipede, but may have had sme indirect influence n the Flratam and St. Augustine turfgrasses. Perhaps the mst significant data btained in this research was that which pinted ut the influence f N rates, applicatin dates, and lw temperatures n quality f the lawngrasses (means f all N treatments, Tables 2 and 3). The evaluatin n June 19, 1980 (Table 2) shwed that cld damage during the winters f and resulted in the death f abut 85 percent f all the turfgrasses, with little r n reestablishment ccurring, based n evaluatins in July, August, and September f The quality decrease began in the winter f , with all three grasses being rated lwer in 1979 than in St. Augustine shwed the greatest decline frm 1978 t 1979 (41 percent), fllwed by Flratam (13 percent). Centipede shwed the least decline (2 percent), with sme plts even imprving in quality during that time. All St. Augustine plts, and ne f Flratam, were rated belw the acceptable quality level f 4.5 in 1979, but n centipede treatment was belw 5.9 that year (Table 3). In 1978, St. Augustine and Flratam were f the same quality (5.6) in mean ratings, including all N treatments, while centipede was ranked at a level f 6.4. During 1979, St. Augustine was evaluated at 3. 3, Flratam at4.9,and centipede at 6.3. Hwever, centipede and Flratam shwed the greatest decline in quality in 1980, each decreasing apprximately 70 percent, cmpared with a decline f abut 50 percent fr St. Augustine by June 19 f that year. Sme research has shwn that N rates frm 6 t 12 punds per 1,000 square feet (April t Octber) resulted in greater winter injury t St. Augustine and Flratam turfgrasses than rates frm 0 t 3 punds (18). Others have reprted that the least amunt f cld damage t St. Augustine ccurred when N was nt applied after September, with the greatest damage being dne when N was applied in Nvember and December (27). A study with centipedegrass shwed that N rates f 1 t 2 punds per 1,000 square feet per year prmted greater susceptibility t winter injury. Nitrgen rates f l A t Vz pund per 1,000 square feet were cnsidered adequate fr clr and grwth withut prmting excess thatch and higher susceptibility t cld damage (23). Centipede decline is believed t be due t ver fertilizatin with N and accumulatin f thatch, causing large chlrtic (yellw) patches in late summer r early fall and subsequent death f the grass in these areas. Centipede decline usually required several years t affect this grass, but the applicatin f 1 r 2 punds f N per 1,000 square feet per year and small amunts f Fe, with lw t medium P levels, prevented r cntrlled the prblem in ther areas (13). 17

The N rates in this study were generally higher than thse that mst Luisiana lawngrasses receive. Many lawns in Luisiana are never fertilized with nitrgen.

Thse wh cntract with lawn-care cmpanies fr such services generally have frm 3 t 6 r mre punds f N applied n a regular basis during the year.

19 The N rates in this study were generally higher than thse that mst Luisiana lawngrasses receive. Many lawns in Luisiana are never fertilized with nitrgen. Hwever, this study was designed t determine the influence f N rates and applicatin dates that a large number f hmewners and thers use n their turfgrasses (3 punds per 1,000 square feet per year). Thse wh cntract with lawn-care cmpanies fr such services generally have frm 3 t 6 r mre punds f N applied n a regular basis during the year. Sme lawn-care cmpanies als suggest that lawns be fertilized with N (and/r P and K) during December, January, and February, ften in cmbinatin with pesticides. Cld injury t the turfgrasses was anticipated in this study, with the bjective f determining the rates and timing f N that might prvide data fr future research with ther (lwer) rates, applicatin dates, and surces f the element. The results shwed that N rates f 3 r mre punds per 1,000 square feet per year were t high fr the turfgrasses used and the cnditins that existed during this study. Applicatins f N at annual rates f 3 t 9 punds shuld nt be made after September 1 because new grwth resulting frm fertilizatin may nt reach prper maturity befre temperatures fall lw enugh t cause cld damage. Temperatures at the Burden Research Center in Batn Ruge during 1978 reached minimums f 44 F n Octber 9, 38 F n Nvember 9, and 26 F n December 7. The mean minimum temperature during December was 41 F, with the lwest reading f 25 F ccurring n December 12. The average minimum temperature during the last week f December, 1978, was abut 50 F, with the maximum abut 65 F. The lwest minimum temperatures during this research, hwever, were n January 2 and 3 f 1979, 16 and 15 F, with maximums f nly 27 and 38 F, respectively a drastic decrease in minimum temperatures within 10 days. The mean minimum temperature during the first week f January, 1979, was belw freezing (31 F). These temperatures were prbably the factr cntributing mst t the lwer quality ratings given t all lawngrasses in the 1979 grwing seasn, and influenced St. Augustine mre than Flratam r centipede. Rainfall and temperatures during April t Octber in 1978 and 1979 shwed n significant differences, which might therwise have influenced this plant respnse. The lwest minimum temperatures during the winter f 1979 and 1980 were 24 F n February 1 and 22 F n March 2 and 3 f The 25-year weather recrds fr Batn Ruge shw that the mean date when a 24 F r lwer temperature ccurs is January 2 1, with a 75 percent chance that these minimums may ccur as early as January and 1 1, nly a 10 percent chance f ccurrence by January 8. The mean minimum temperature in January f 1979 was 33 F, while it was 44 F in January f The 25-year mean minimum January temperature in Batn Ruge is 40.4 F, s the average f 33 F in January f 1979 was 7.4 degrees lwer, with minimums f 17 Fand 18 Fn January 9 and 15, 1979, respectively. 18

Research has been cnducted in Mississippi n the effects f lw temperatures n centipedegrass at several levels f N, P, and K (26).

A minimum f apprximately 4 punds f N per 1,000 square feet was needed t btain acceptable quality, but higher rates resulted in decreased cld tlerance.

It was cncluded that fr hme lawns under these cnditins, centipede shuld be fertilized with apprximately 4 punds f N, 2 punds f P 2 0 5, and 4 punds f K 2 0 per 1,000 square feet annually.

20 Research has been cnducted in Mississippi n the effects f lw temperatures n centipedegrass at several levels f N, P, and K (26). The results indicated that sil fertility levels did influence the cld tlerance f this lawngrass. A minimum f apprximately 4 punds f N per 1,000 square feet was needed t btain acceptable quality, but higher rates resulted in decreased cld tlerance. Phsphrus fertilizatin had little effect n the hardiness f this turfgrass, but K fertilizatin increased hardiness. It was cncluded that fr hme lawns under these cnditins, centipede shuld be fertilized with apprximately 4 punds f N, 2 punds f P 2 0 5, and 4 punds f K 2 0 per 1,000 square feet annually. Rates f K used in the research described here were cnsiderably lwer than thse reprted abve, averaging nly abut 2 punds r less f K 2 0 per 1,000 square feet per year. Ptassium is difficult t maintain in cnstant supply in the sil fr turfgrass grwth as it is heavily leached by rainfall in sme sils in Luisiana, becming unavailable t the plant. Cld damage t St. Augustine, Flratam, and centipede frm N applicatins and lw temperatures might have been lwer if the K rates and/r frequencies f applicatin had been higher. Future research will be cnducted using lwer rates f N and larger amunts f P and K t determine their pssible influences n the quality, grwth, and cld hardiness f these lawngrasses in Luisiana. Summary Nitrgen surce, rate, r frequency f applicatin generally had n significant influence n the quality r yield f centipede, St. Augustine, r Flratam lawngrasses in 1978 and Centipede, hwever, was f significantly higher quality during that perid than either f the ther tw grasses, and als appeared t utyield them. Treatment (N surce, rate, r frequency) did nt significantly affect cncentratins f the fliar nutrients studied in this research. Levels f elements in grass clippings were generally lwer than thse reprted with ther species grwn in different envirnments and sils and under different nutritinal cnditins. Winter damage, irrespective f treatment, resulted in the death f 85 percent f all lawngrasses by June f The greatest injury ccurred during the winter f , being less severe in the winter f when temperatures were mre mderate. Nitrgen rates f 3 punds r mre per 1,000 square feet per year shuld nt be used n these turfgrasses, grwn under the described cnditins, nr shuld any N be applied after September 1. Lwer N rates, alng with P and higher amunts r frequencies f K, appear necessary t reduce r avid cld injury t the three lawngrasses mst generally grwn in Luisiana. 19

Literature Cited 1. Barris, E. P., L. G. Jnes and K. Knce. 1979. The relatinship between sme nitrgen fertilizer surces, rates, applicatin frequencies, and quality f Tifgreen' bennudagrass. J. Amer.

4. and P. E. Rieke. 1966. The influence f nitrgen, ptassium and cutting height n the lw temperature survival f grasses. Agrn. Abstr. p. 35. 5. Blaser, R. E., R. E. Schmidt, and F. B. Stewart. 1967.

21 Literature Cited 1. Barris, E. P., L. G. Jnes and K. Knce The relatinship between sme nitrgen fertilizer surces, rates, applicatin frequencies, and quality f Tifgreen' bennudagrass. J. Amer. Sc. Hrt. Sci. 104: Beard, J. B Turfgrass science and culture. Prentice-Hall, Englewd Cliffs, NJ, pp Turfgrass science and culture. Prentice-Hall, Englewd Cliffs, NJ, pp and P. E. Rieke The influence f nitrgen, ptassium and cutting height n the lw temperature survival f grasses. Agrn. Abstr. p Blaser, R. E., R. E. Schmidt, and F. B. Stewart Rate and seasns f applying nitrgen n turf quality and physilgy. Agrn. Abstr. p Brupbacher, R. H., W. P. Bnner and J. E. Sedberry, Jr Analytical methds and prcedures used in the sil testing labratry. La. Agr. Exp. Sta. Bui , J. E. Sedberry, Jr., W. P. Bnner, W. J. Peevy and W. H. Willis Fertility levels and lime status f sils in Luisiana. La. Agr. Exp. Sta. Bui. 644, pp Calhun, C. R Effect f phsphrus, ptassium and ureafrmaldehyde nitrgen n predictins f quality in bluegrass turf. Agrn. Abstr. p Cuch, H. B Nitrgen applicatins in brwn patch cntrl. Glfdm. 31(4): Davis, R. R Nitrgen fertilizatin f turfgrasses. Agrn. Abstr. p Engel, R. E Develpment f puffiness in V* inch bentgrass turf with varied nitrgen fertilizatin. NJ Agr. Exp. Sta. Bui. 818, pp Gary, J. E The vegetative establishment f fur majr turfgrasses t mwing height, nitrgen fertilizatin, and light intensity. M.Sc. Thesis, Mississippi State University, pp Hagan, A Centipede decline. N. AL Turfgrass Assc. Newsletter, pp Hall, J. R. and R. W. Miller Effect f phsphrus, seasn and methd f sampling n fliar analysis f Kentucky bluegrass. Prc. f the 2nd Int. Turfgrass Res. Cnf., Amer. Sc. f Agrn., Madisn, WI, pp Hdges, T. K Nutrient absrptin by plants. 6th Illinis Turfgrass Cnference Prc, pp Hull, R. J. and L. M. Smith Phtsynthate translcatin and metablism in Kentucky bluegrass turf as a functin f fertility. Prc. f the 2nd Int. Turfgrass Res. Cnf., Amer. Sc. f Agrn., Madisn, WI, pp Juska, F. V Effect f nitrgen surces, rates and time f applicatin n the perfrmance f Kentucky bluegrass turf. Prc. Amer. Sc. Hrt. Sci. 90: Laiche, A. J., Jr Effects f nitrgen fertilizatin n the grwth and winter survival f 'Flratam' St. Augustinegrass in Suth Mississippi. Miss St. Univ. Res. Rpt. 4 (II). 19. Ledeber, F. B. and L. C. Miller Centipedegrass and its prblems. Clemsn Univ. Ext. Mime. 0-7, pp Madisn, J. H Turfgrass eclgy. Effects f mwing, irrigatin and nitrgen treatments f Agrstis palustris Huds. 'Seaside' and Agrstis tenuis Sibth. 'Highland' n ppulatin, yield, rting and cver. Agrn. J. 54:

21. Mantell, A., and G. Stanhill. 1966. Cmparisn f methds fr evaluating the respnse f lawngrass t irrigatin and nitrgen treatment. Agrn. Jur. 58:465-468. 22.

1975. Assc. f Official Analytical Chemists. 24. Miller, L. C. 1980. Cultural management f centipedegrass. Clemsn Univ. Prg. Rpt. (File 60; CRIS Rpt., Feb.

$1974. Influence f mineral nutritin n the cld tlerance and sluble prtein fractin f centipedegrass. Prc. f the 2ndlnt. Turfgrass Res. Cnf., Amer. Sc. f Agrn.$

22 21. Mantell, A., and G. Stanhill Cmparisn f methds fr evaluating the respnse f lawngrass t irrigatin and nitrgen treatment. Agrn. Jur. 58: Markland, F. E Influence f nitrgen fertilizers n 'Washingtn' creeping bentgrass, Agrstis palustris Huds., Agrn. Jur. 61: Methds f Analysis Assc. f Official Analytical Chemists. 24. Miller, L. C Cultural management f centipedegrass. Clemsn Univ. Prg. Rpt. (File 60; CRIS Rpt., Feb. 1980, p. 80). 25. Oertli, J. J Nutrient disrders in turfgrass. Cal. Turfgrass culture. 3(3): Palmertree, H. D., C. Y. Ward and R. H. Pluenneke Influence f mineral nutritin n the cld tlerance and sluble prtein fractin f centipedegrass. Prc. f the 2ndlnt. Turfgrass Res. Cnf., Amer. Sc. f Agrn., Madisn, WI, pp Reeves, S. A., Jr., andg. G. McBee Nutritinal influence n cld hardiness f St. Augustinegrass {Stentphmm secundatum). Agrn. J. 64:

DESIGNING FERTILIZER PROGRAMS FOR YOUR TURF. Shawn BcBurney and Paul E. Rieke Department of Crop and Soil Sciences Michigan State University

DESIGNING FERTILIZER PROGRAMS FOR YOUR TURF Shawn BcBurney and Paul E. Rieke Department f Crp and Sil Sciences Michigan State University Planning a fertilizer prgram fr athletic fields, parks, and cemeteries