Published online April 3, Poultry Litter Application to Loblolly Pine Forests: Growth and Nutrient Containment

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1 Pulished online April 3, 26 Poultry Litter Appliction to Lololly Pine Forests: Growth nd Nutrient Continment Alexnder L. Friend,* Scott D. Roerts, Stephen H. Schoenholtz, Junit A. Moley, nd Ptrick D. Gerrd Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. ABSTRACT Forestlnd ppliction of poultry mnure offers n lterntive to the conventionl prctice of psturelnd ppliction. Before such prctice is considered vile, however, it must e demonstrted tht the forest ecosystem is cple of soring the nutrients contined in poultry mnure, especilly nitrogen (N) nd phosphorus (P). From the forestry perspective, it must lso e demonstrted tht tree growth is not diminished. We investigted these questions using lololly pine (Pinus ted L.) stnds growing in centrl Mississippi in n re of high poultry production. Stockpiled roiler litter ws pplied to newly thinned, 8-yr-old stnds t, 4.6, nd 18.6 dry Mg h 21, supplying, 2, nd 8 kg N h 21 nd, 92, nd 37 kg P h 21, respectively. Levels of nitrte in soil wter, monitored t 5-cm depth with porous cup tension lysimeters, exceeded 1 mg N L 21 during the first two yers fter ppliction in the 18.6 Mg h 21 rte ut only on two occsions in the first yer for the lower rte of ppliction. Phosphte ws lrgely sent from lysimeter wter in ll tretments. Other mcronutrients (K, C, Mg, S) were elevted in lysimeter wter in proportion to litter ppliction rtes. Soil extrctle nitrte showed similr trends to lysimeter wter, with sustntil elevtion during the first yer following ppliction for the 18.6 Mg h 21 rte. Mehlich III extrctle phosphte peked in excess of 1 mgpg 21 soil during the third yer of the study for the 18.6 Mg h 21 rte. The 4.6 Mg h 21 rte did not ffect extrctle soil P. Tree growth ws incresed y the poultry litter. Totl stem cross-sectionl re, or sl re, ws pproximtely 2% greter fter 2 yr for oth rtes of litter ppliction. Overll, the nutrients supplied y the 4.6 Mg h 21 rte were contined y the pine forest nd resulted in fvorle increses in tree growth. The higher rte, y contrst, did pose some risk to wter qulity through the moiliztion of nitrte. These results show tht, under the conditions of this study, ppliction of poultry litter t moderte rtes of pproximtely 5 Mg h 21 to young stnds of lololly pine offers n lterntive disposl option with miniml impcts to wter qulity nd potentil increses in tree growth. A.L. Friend, USDA Forest Service, North Centrl Reserch Sttion, 41 McInnes Drive, Houghton, MI 49931; S.D. Roerts nd J.A. Moley, Deprtment of Forestry, Mississippi Stte University, Box 9681, Mississippi Stte, MS S.H. Schoenholtz, Deprtment of Forest Engineering, 267 Pevy Hll, Oregon Stte University, Corvllis, OR ; P.D. Gerrd, Deprtment of Mthemtics nd Sttistics, Mississippi Stte University, P.O. Drwer MA, Milstop 9715, Mississippi Stte, MS Received 12 June 25. *Corresponding uthor (friend@fs.fed.us). Pulished in J. Environ. Qul. 35: (26). Technicl Reports: Wste Mngement doi:1.2134/jeq ª ASA, CSSA, SSSA 677 S. Segoe Rd., Mdison, WI USA 837 WATER POLLUTION from excess nutrients is of gret current concern throughout the world. The principl prolems re ground wter contmintion y N, s NO 2 3, nd surfce wter eutrophiction y N nd P in vrious forms (Dniel et l., 1998; Sims nd Wolf, 1994). Intensive nd concentrted niml production hs een implicted s significnt thret to oth wter qulity prolems ut especilly to eutrophiction (Mllin, 2). In the cse of poultry production, niml wste hs trditionlly een pplied to psturelnds with little environmentl concern. However, s demnd for poultry products increses nd psturelnds ecome nutrient sturted, wter qulity concerns re eing reported (Gllimore et l., 1999; Suer et l., 1999; Vervoort et l., 1998). Forestlnd offers n ttrctive lterntive to the conventionl prctice of psturelnd ppliction. Severl dvntges exist. First, poultry production fcilities re often locted in rurl res with undnt forestlnd within rnge of economic trnsport of poultry wste. Most of the top poultry-producing counties of the Southern United Sttes lso hve n undnce of southern pine forests (Fig. 1). Second, forests re frequently nutrient limited nd routinely fertilized with N nd P (Binkley et l., 1999). Third, ctively growing forests hve n immense potentil for rpid nutrient uptke (O Neill nd Gordon, 1994), immoiliztion (Vitousek et l., 1992), nd sediment trpping (Tylor et l., 199). Previous studies in the southestern United Sttes hve oserved promising growth responses of forests to poultry litter ppliction (Smuelson et l., 1999); however, little informtion exists out the degree to which these forest ecosystems retin the ssocited nutrients nd prevent eutrophiction. Trees sor nutrients in direct proportion to their growth rte (Colemn et l., 1998; Ingestd, 1982). However, forests hve dditionl mechnisms for nutrient retention such s immoiliztion (Vitousek et l., 1992) nd retention of ions on the soil exchnge complex (Pritchett nd Fisher, 1987). Forest ecosystems re highly uffered with respect to the mount of nutrients lost to strem or ground wter fter nutrient ddition. With the exception of forests sturted with N due to tmospheric deposition nd low soil uffering cpcity, fertilized forests generlly relese miniml N or P to stremwter (Binkley et l., 1999). In the Pcific Northwest, lrge pplictions of N (7 kg N h 21 ) nd P (5 kg P h 21 ) to Dougls-fir [Pseudotsug menziesii (Mirel) (Frnco)] stnds in the form of municipl iosolids resulted in miniml impcts to stremwter qulity (Grey nd Henry, 22). Biologiclly ville P, PO 4 P, nd NH 4 N were the sme efore nd fter iosolids ppliction. Nitrte N, while douled in ssocition with the ppliction, ws less thn 1 mg N L 21 or one-tenth of the USEPA stndrd for drinking wter. In summry, estlished, fst-growing forests hve lrge potentil for retining nutrients, especilly when pplied s iosolids. We nticipted tht poultry mnure could e pplied to pine forests t rtes in excess of tree growth demnds due to the high potentil of forests to retin nutrients. Two concerns shed dout on this potentil, however. First is the concern tht lrge mounts of inorgnic N in poultry litter would led to more N leching thn the

2 838 J. ENVIRON. QUAL., VOL. 35, MAY JUNE 26 Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. USA 55 1,1 Kilometers sme mount of N pplied in purely orgnic form. Poultry litter cn contin 25 to 5% of totl N s mmoni (Willims et l., 1999), nd the use of inorgnic N fertilizers (e.g., NH 4 NO 3 ) hs resulted in greter leching of N thn orgnic N fertilizers (e.g., ure) (Binkley et l., 1999). Second is the concern tht the control of understory vegettion, s is commonly prcticed in southern pine stnds (Clson, 1993; Luer et l., 1993), could undermine ecosystem nutrient retention y eliminting the nutrient retention of vigorously regrowing woody nd herceous understory plnts (Jokel et l., 199). Vigorous prolifertion of competing vegettion following iosolids ppliction is well documented, nd is often controlled with hericides (Torert nd Johnson, 1993; Young et l., 1993). To ddress this concern, we used n intensive hericide regimen to control competing vegettion, thus helping ensure tht the nutrient retention we report is representtive of wht intensively mnged pine forests could retin. Consequently, the results reported in this study represent the most conservtive cse. The ojective of our study ws to evlute the potentil for using lololly pine stnds for poultry litter ppliction in poultry producing regions of the South. Lololly pine ws selected ecuse of its undnce (Fig. 1) nd its economic importnce. Two questions Concurrence Not Applicle Fig. 1. Concurrence of poultry production nd the distriution of southern pine forests, y county. Light nd drk shding indicte low nd high concurrence, respectively, for the presence of southern pine forest lnd nd the undnce of chickens in irds h 21. For detils see Mterils nd Methods. Low High were ddressed: (i) Will these forests retin the nutrients ssocited with poultry wste?, nd (ii) Will litter ppliction enhnce tree growth? Representtive pine stnds were thinned to permit ccess nd given one-time litter pplictions t rtes designed to meet nd exceed tree nutrient demnd. Continment ws ddressed y nlyzing mcronutrients in soil wter, ville N nd P in soil extrcts, nd N nd P content of the folige nd forest floor. Growth ws ddressed y mesurements of tree heights nd stem dimeters. Mesurements were collected over 5 yr. MATERIALS AND METHODS Lnd Cover Lnd Use Anlysis We mpped the concurrence of poultry production nd forest coverge in southern pine for counties in Arknss, Louisin, Mississippi, Alm, Georgi, Florid, South Crolin, nd North Crolin, USA (Fig. 1). Poultry production is sed on the numer of chickens older thn 3 mo per hectre s reported in the U.S. Geologicl Survey Distriuted Sptil Lirry, using 1987 poultry dt, ctegorized s C1 (.62 irds h 21 ), C2 ( h 21 ), nd C3 ( h 21 ). Stndrdized southern pine re (hectres of lololly short lef pine or longlef slsh pine types per hectre of lnd in ech county) is sed on Smith et l. (24) using 22 forest dt, ctegorized s P1 (.115 h h 21 ), P2 ( h h 21 ),

3 FRIEND ET AL.: POULTRY LITTER APPLICATION TO LOBLOLLY PINE FORESTS 839 Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. nd P3 ( h h 21 ) clsses. The figure presents concurrence s: (i) not pplicle: counties with no pine or no chickens reported, (ii) low: counties with either low chickens (C1) or low pines (P1), or (iii) high: counties with moderte to high chickens (C2 or C3) nd moderte to high pine (P2 or P3). Study Site The study site ws young lololly pine stnd ner Newton, Mississippi, USA (32829 N, W), growing on fine sndy lom in the Shuut series (fine, mixed, semictive, thermic Typic Pleudults) (USDA, 196). Mesured soil properties efore tretment were 65% snd, 22% silt, 13% cly, ph 5.1 in wter, nd ph 4.4 in CCl 2 for the - to 8-cm lyer; nd 59% snd, 17% silt, 24% cly, ph 4.9 in wter, nd ph 4. in CCl 2 for the 8- to 24-cm lyer. Soil nutrient vilility efore tretment is represented y the control vlues of experimentl results (Tle 1, Fig. 2 5). Averge nnul dily high temperture for Newton County is pproximtely 248 nd the low is pproximtely 118C. Annul precipittion is pproximtely 14 mm. The setting ws gently sloping with 2 to 5% slopes nd n elevtion of 125 m. The stnd ws cut in 199 nd plnted, though vigorous regenertion from seed resulted in excessively high stem densities. Nine m plots were estlished in the winter of Ech plot ws mnully thinned to sl re of pproximtely 11 m 22 h 21. All trees from the thinning opertion were crefully removed from the plots y hnd to minimize disturnce to the litter nd soil orgnic horizons. Non-pine vegettion ws controlled nnully through mnul ppliction of Arsensl (77 ml, 53% ctive ingredient; BASF, Ludwigshfen, Germny) nd Escort (5.7 g, 6% ctive ingredient; DuPont, Wilmington, DE) with surfctnt in wter mix of 15 L per.4 h plot. The plots were positioned on the lndscpe with independent dringe. All smpling nd mesurements were tken from the inner m portion of ech plot. Poultry litter ws pplied on 13 Mr. 2 using stockpiled cke collected from locl roiler growing opertion ner Tle 1. Chrcteristics of current yer folige for three rtes of litter ppliction. Newton, MS. Ech plot receiving litter tretment ws divided into 16 sections. Litter ws pplied mnully y evenly spreding the pproprite mount to ech section. At the time of field ppliction the moisture content of the litter ws 21%. Elementl composition on dry weight sis ws C 38%, N 4.3%, P 2.%, K 3.2%, C 2.8%, Mg.7%, S.6%, Zn 59 ppm, B 6 ppm, Mn 68 ppm, Fe 987 ppm, nd Cu 969 ppm. Three experimentl rtes of mnure were pplied to three plots ech in completely rndomized design:, 4.6, nd 18.6 dry Mg h 21. These rtes were sed on the N ssy of the litter to supply, 2, nd 8 kg N h 21 nd resulted in P dditions of, 92, nd 37 kg P h 21. The 2 kg N h 21 rte is representtive of conventionl forest fertiliztion prctices (Allen, 1987) nd the 8 kg h 21 rte ws used to intentionlly push the soil plnt N uptke system y pplying more N thn usul. Smpling nd Anlyses Soil wter ws smpled using porous cup suction lysimeters (5-cm dimeter; Soilmoisture Equipment, Snt Brr, CA) instlled t three loctions within ech plot. Lysimeters were instlled t 5-cm depth y hnd uger nd seled t the soil surfce with entonite (Morrison, 1983). The depth ws selected to e elow the rgillic horizon (2- to 45-cm depth) nd representtive of wter likely to escpe root uptke. Instlltion took plce etween Jnury nd Ferury 2. Soil wter smples were collected under tension of pproximtely 6 kp the week efore mnure ppliction, nd every month therefter when soil moisture ws dequte. To ccount for sesonl vriility in lysimeter yield, dtsets from given collection dte were only nlyzed if smples could e collected from t lest seven of the nine possile lysimeters in ech tretment. Solution smples were nlyzed for ctions (NH 4, K, Mg, C) nd nions (NO 3,PO 4,SO 4 ) using DX5 ion chromtogrph (Dionex, Sunnyvle, CA). All ionic concentrtions re expressed on n elementl sis (i.e., NH 4 N, NO 3 N, nd PO 4 P). Elementl concentrtions were highly vrile mong lysimeters in given plot, with some missing vlues. Evlution of tretment effects ws mde using mixed Dte Mg litter h Mg litter h Mg litter h 21 Nitrogen concentrtion (g N kg 21 dry wt.) June Decemer June Decemer June Decemer Cron to nitrogen rtio (g g 21 ) June Decemer June Decemer June Decemer Phosphorus concentrtion (g kg 21 ) Flush 1 Flush 2 Flush 1 Flush 2 Flush 1 Flush 2 June Decemer June Decemer June Decemer Vlues presented re mens 6 stndrd error. Similr letters within row indicte no significnt tretment differences ( 5.5) for tht dte ccording to Duncn s Multiple Rnge Test. Nitrogen concentrtion nd cron to nitrogen rtio mens verge Flush 1 nd Flush 2 s flush differences were not significnt. Men seprtion letters for phosphorus indicte differences, s discussed ove, ut within the sme flush.

4 84 J. ENVIRON. QUAL., VOL. 35, MAY JUNE 26 1 A NH 4 -N Mg h Mg h Mg h B NO 3 -N Mg h Mg h Mg h Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. (mg L -1 ) (mg L -1 ) (mg L -1 ) Jn- My- Sep- Jn-1 My-1 C E 5 Jn- My- Sep-1 Jn-2 Dte K Jn- My- Sep- Jn-1 My-1 Sep-1 Jn-2 My-2 Sep-2 Sep- Jn-1 My-1 Dte Mg Sep-1 Jn-2 Dte My-2 Sep-2 Jn-3 My-3 Sep-3 Jn-3 My-2 Sep-2 Jn-3 Jn-4 Mg h Mg h Mg h -1 My-3 Sep-3 Jn-4 My-3 Sep-3 Jn-4 (mg L -1 ) (mg L -1 ) Jn Jn- D My- Sep- My- Sep- Jn- My- Sep- Jn-1 My-1 Sep-1 Jn-2 My-2 Sep-2 Jn-3 Jn-1 My-1 Jn-1 My-1 Sep-1 Dte C Sep-1 Jn-2 Dte Dte My-2 Sep-2 Jn-2 My-2 Sep-2 Jn-3 My-3 Sep-3 Jn-4 Jn-3 My-3 Sep-3 Jn-4 4 Mg h -1-1 F SO 4 -S 4.6 Mg h -1 Mg h 18.6 Mg h Mg h Mg h -1 (mg L -1 ) Mg h Mg h Mg h -1 My-3 Sep-3 Jn-4 Fig. 2. Poultry litter tretment effects on soil solution concentrtions from suction lysimeters instlled t 5-cm depth in ech plot. Mens re shown y smpling dte for () mmonium, NH 4 N, () nitrte, NO 3 N, (c) potssium, K, (d) clcium, C, (e) mgnesium, Mg, nd (f) sulfte, SO 4 S. Similr letters (or no letters) mong the three tretments indicte no significnt tretment effects ccording to Tukey s test ( 5.5). models pproch, llowing for unequl tretment popultion vrinces. Pirwise lest squres mens comprisons were performed in SAS ( 5.5) (SAS Institute, 21). Aville N nd P from soil were determined monthly. Minerl soil ws collected from upper ( 8 cm) nd lower (8 24 cm) depths from five rndom loctions in ech plot using 2.5-cm-dimeter push tue. Smples were dried t 328C to constnt weight (48 h) nd sieved to remove ny corse frction (.2 mm). Aville N ws determined y extrcting soil with 2 M KCl followed y spectrophotometric nlysis on n

5 FRIEND ET AL.: POULTRY LITTER APPLICATION TO LOBLOLLY PINE FORESTS A - 8 cm Mg h Mg h Mg h -1 Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved Jn Jn- B My- My- Sep- Sep- Jn-1 Jn-1 My-1 My-1 Sep-1 Sep-1 Jn-2 Dte 8-24 cm Jn-2 Dte My-2 My-2 Sep-2 Sep-2 Jn-3 Mg h Mg h -1 Jn-3 My Mg h -1 Fig. 3. Poultry litter tretment effects on soil KCl extrctle NO 3 from the () - to 8-cm depth (excluding O horizon) nd () 8- to 24-cm depth presented s microgrms of N per grm of soil. Plotted re tretment mens for ech smpling dte. Similr letters (or no letters) mong the three tretments indicte no significnt tretment effect t tht dte ccording to Tukey s test ( 5.5). My-3 Sep-3 Sep-3 Jn-4 Jn-4 Auto Anlyzer II (Technicon, Trrytown, NY) following stndrd procedures (Mynrd nd Klr, 1993). Aville P ws determined y cid extrction with Mehlich-III solution (see Trn nd Simrd, 1993) followed y nlysis using inductively coupled plsm spectrometry techniques (Jones nd Cse, 199) with 32DV Optim ICP (PerkinElmer, Wellesley, MA).

6 842 J. ENVIRON. QUAL., VOL. 35, MAY JUNE A - 8 cm Mg h Mg h Mg h Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved Jn Jn- My- B My- Sep- Sep- Jn-1 Jn-1 My-1 My-1 Sep-1 Sep-1 Jn-2 Jn-2 My-2 c Sep-2 Dte 8-24 cm My-2 Sep-2 Dte Jn-3 Jn-3 My-3 My-3 Sep-3 Sep-3 Jn-4 Jn-4 My-4 Mg h Mg h Mg h -1 Fig. 4. Soil Mehlich III extrctle PO 4 P from the () - to 8-cm depth (excluding O horizon) nd () 8- to 24-cm depth presented s microgrms of P per grm of soil. Plotted re tretment mens for ech smpling dte. Similr letters (or no letters) mong the three tretments indicte no significnt tretment effect t tht dte ccording to Tukey s test ( 5.5). My-4 Sep-4 Sep-4 Jn-5 Jn-5 Tretment effects were nlyzed seprtely for ech depth using completely rndom design nd the GLM procedure in SAS ( 5.5) (SAS Institute, 21). Folige nd forest floor were smpled for determintions of totl N nd P in June nd Decemer of ech yer. Current yer folige ws collected from the upper-third of three tree crowns

7 FRIEND ET AL.: POULTRY LITTER APPLICATION TO LOBLOLLY PINE FORESTS A FOREST FLOOR 4 Mg h Mg h Mg h -1 Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. N CONTENT(kg N h -1 ) P CONTENT(kg P h -1 ) Jn Jn- B Jul- Jul- Jn-1 Jn-1 Jul-1 Jul-1 Jn-2 Jn-2 Jul-2 Dte FOREST FLOOR Jul-2 Dte Jn-3 Jn-3 Jul-3 Jul-3 Jn-4 Jn-4 Mg h Mg h Mg h -1 Fig. 5. Nitrogen nd phosphorus content of forest floor (O horizon) collected from plots treted with poultry litter. Plotted re the tretment men vlues during the first five growing sesons fter ppliction. Similr letters (or no letters) mong the three tretments indicte no significnt tretment effect t tht dte ccording to Tukey s test ( 5.5). Error rs indicte 6 one stndrd error of the men. Jul-4 Jul-4 Jn-5 Jn-5 per plot, nd seprted into first- nd second-flush folige. Forest floor ws collected from three.25-m 2 frmes in ech plot. All folige nd forest floor susmples were collected from rndom loctions nd composited into one smple per plot. Smples were dried t 658C to constnt weight (48 h) nd ground through 6-mesh sieve. Totl N nd C were nlyzed with Fisons 15 NA NCS Anlyzer (ThermoQuest Itli, Miln, Itly) using Dums comustion techniques

8 844 J. ENVIRON. QUAL., VOL. 35, MAY JUNE 26 Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. (Jones nd Cse, 199). Totl P ws nlyzed from resoluilized sh using inductively coupled plsm spectrometry s descried ove. Minerl soil ws nlyzed for totl N nd totl C using the methods descried ove. Tree growth ws recorded efore tretment nd t the end of ech growing seson y mesuring stem dimeter (t 1.3 m height ove the soil surfce) nd the totl height of every tree within the interior m of ech plot. Bsl re, the cross-sectionl re of tree stem t 1.3 m, ws clculted for ech tree. Plot sl re (m 2 h 21 ) ws derived from the sum of the sl res of ll trees on plot. Plot verge tree height, qudrtic men stem dimeter, nd plot sl re were nlyzed using completely rndom design nd the GLM procedure in SAS ( 5.5) (SAS Institute, 21). RESULTS AND DISCUSSION Soil Lysimeter Wter The first mesurle effect of the dded litter on soil wter ws spike in mmonium concentrtion in the first 2 mo fter ppliction (Fig. 2). The sttisticl significnce of this effect ws mrginl ( p vlues from.6 to.14) ecuse it ws oserved spordiclly; nonetheless, it occurred consistently during the first four smple periods. Ammonium N is undnt in poultry litter (Willims et l., 1999), ut is redily immoilized y soil microes nd on the soil exchnge complex, mking the detection of undnt mmonium t 5-cm depth n unusul finding. We speculte tht some lysimeters were collecting soil wter tht drined rpidly through soil mcropores following precipittion events, with little exposure to the soil exchnge complex. With the exception of this trnsitory elevtion ssocited with plots receiving litter, mmonium N remined elow 1 mg L 21 for ll plots throughout the study. Nitrte N showed no tretment effects until 8 mo fter litter ppliction (Fig. 2) when soil wter showed lrge pulse of nitrte N for oth the 4.6 nd 18.6 Mg h 21 tretments. The fll pulse occurred gin during the second yer fter ppliction, ut ws only significnt for the 18.6 Mg h 21 tretment. Nitrte ws pprently generted in the soil during the growing-seson months, especilly in the litter plots, ut ws only detected in the fll when site wter lnce ecme positive. It should e noted tht lysimeters were dry from t lest June to August of ech yer, so concentrtions re reported for spring nd fll only. Three yers fter ppliction, nitrte in the 18.6 Mg h 21 tretment remined elevted reltive to control, lthough concentrtions were elow 1 mg L 21 nd there ws not distinctive fll pulse. Similr results hve een reported for lrge pplictions of poultry litter or iosolids to other forest lnds. Minkr et l. (1995) found nitrte N concentrtions of 15 mg N L 21 t 61 cm fter pplying 8 kg N h 21 from poultry litter to newly plnted lololly pine stnd. Similrly, Brockwy nd Urie (1983) found nitrte N concentrtions of 24 mg N L 21 t 1.2 m fter pplying 138 kg N h 21 from municipl sludge to 4-yr-old white (Pinus strous L.) nd red pine (Pinus resinos Solnd.) stnd. It should e noted, however, tht lysimeter mesurements do not necessrily reflect export from the system. A 16-yr-old Dougls-fir stnd receiving 7 kg N h 21 from municipl sludge generted nitrte N concentrtions of less thn 1.5 mg L 21 from strem dischrge wter (Grey nd Henry, 22). The sic ctions, K, C, nd Mg, were ll elevted in lysimeter wter immeditely fter litter ppliction, y more thn n order of mgnitude in 18.6 Mg h 21 plots compred with control plots (Fig. 2c, 2d, 2e). After the initil leching of ctions from Mrch to My 2, there ws consistent sesonl pttern of elevted concentrtions in the fll ssocited with the rechrge of soil moisture, then decrese nd leveling off through winter nd spring. Elevted concentrtions of K, C, nd Mg were pronounced for the first two yers fter litter ppliction, eyond which, with the exception of K, the tretment effects were significnt ut concentrtions were on the sme order of mgnitude s in control plots. Four yers fter litter ppliction, K in lysimeter wter remined elevted y fivefold (Fig. 2c). Interestingly, the intermedite litter ppliction rte (4.6 Mg h 21 ) showed similr trend s 18.6 Mg h 21 for ll ctions, ut ws sttisticlly indistinguishle from the control plots. The elevtion of ctions in lechte from this study ws comprle to tht of similr studies, with mximum increse of out 1-fold etween tretment nd control (Medlie et l., 1994; Suer et l., 1999; Sheprd nd Bennett, 1998). Phosphte P ws less thn.4 mg P L 21 throughout the study (not grphed). Tretment differences existed only in Octoer 21, when phosphte ws,.3, nd.7 mg P L 21 in, 4.6, nd 18.6 Mg h 21 tretments, respectively. Sulfte S ws elevted y out 1.5-fold in 18.6 Mg h 21 reltive to the other two tretments. This trend lsted for the first two yers fter ppliction, then SO 4 S returned to ner-control levels (Fig. 2f). Soil Nitrogen nd Phosphorus Extrcts Unlike soil wter, which showed erly tretment effects, there were no tretment effects on KCl-extrctle mmonium N. There ws n initil spike in mmonium N in My 2 cross ll tretments nd depths. Ammonium N ws elevted to 4 mg Ng 21 soil t oth soil depths ( 8 nd 8 24 cm), ut y June 2 levels hd returned to pproximtely 6 mg Ng 21 soil in the upper depth nd 3 mg Ng 21 soil in the lower depth (dt not shown). We ttriuted this spike in soil mmonium to pulse of N minerliztion ssocited with the thinning of ll plots tht took plce over the winter of , resulting in lrge input of orgnic N nd conditions fvorle to N minerliztion. The spike ws not lrge enough, however, to impct mmonium in the lysimeter wter of the control plot which remined ner zero for the entire study (Fig. 2). Soil KCl extrctle nitrte N ws elevted in the 18.6 Mg h 21 tretment during the first month fter litter ppliction nd remined elevted throughout the first yer (Fig. 3). Sesonlly, there were peks of nitrte N in June nd Octoer, oth of which followed periods of wrm moist conditions fvorle to N minerliztion. Similr ptterns were oserved in oth upper nd lower

9 FRIEND ET AL.: POULTRY LITTER APPLICATION TO LOBLOLLY PINE FORESTS 845 Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. soil depths. The 18.6 Mg h 21 tretment lso resulted in elevted nitrte in the second nd third yers fter ppliction ut the mgnitude of the effect ws minor in comprison with the first yer, especilly in the lower soil depth. These results re generlly consistent with ptterns oserved in the lysimeter wter, except tht the elevtion of nitrte in 2 soil wter ws nerly the sme s in 21 wheres soil extrctle nitrte dropped sustntilly from 2 to 21. Such differences in mgnitude of effect could e explined y dilution concentrtion phenomenon for soil wter, or y sustntil trnsport of nitrte produced in orgnic horizons nd moving directly to lysimeter wter through mcropores. Extrctle soil phosphte P ws sustntilly elevted y the 18.6 Mg h 21 tretment (Fig. 4) compred with 4.6 Mg h 21 or control. Unlike nitrte, however, phosphte P ppered to e lrgely retined within the system. There ws strong ttenution of ville P with depth, with nerly 1-fold less t the 8- to 24-cm depth (Fig. 4) compred with the - to 8-cm depth (Fig. 4). Furthermore, PO 4 P collected from lysimeters ws less thn.4 mg L 21 (dt not shown). Even in the 18.6 Mg h 21 tretment plots, pek levels of ville P were much lower thn those seen under intensive hyfield pplictions. For exmple, nnul pplictions of poultry (Sistni et l., 24) or swine (Novk et l., 2) mnure delivering pproximtely 3 kg P h 21 yr 21 to soils supporting ermud grss result in nerly twice the level of Mehlich-extrctle P in the surfce soil (4 8 mg Pg 21 ) thn we reported with one-time ppliction of 37 kg P h 21 to forestlnd (Fig. 4). It is lso importnt to recognize tht Mehlich-extrctle P is not necessrily representtive of P vulnerle to leching. Mguire nd Sims (22) developed phosphorus sturtion index sed on extrctle P reltive to extrctle Al 1 Fe tht correlted well with phosphorus leching from soil, using the Mehlich-III extrction for oth P nd Al 1 Fe. The index is sed lrgely on Ultisol soils, s in our study. They found tht the molr P to [Al 1 Fe] rtio must e in excess of.2 for P to e leched. Therefore, in our system, with pek P vlue of 6 mg g 21 in the 8- to 24-cm depth, luminum concentrtions would need to e less thn 3 mg g 21 for P to lech. Since Mguire nd Sims (22) found no vlues less thn 4 mg g 21 in rnge of soils comprle to our study, leching of phosphte from our system is unlikely. In ddition, much of the concern with psture ppliction stems from overlnd flow directly into surfce wter. In forest systems, with well-developed forest floors, overlnd flow is fr less common (Brooks et l., 1997). The sesonl pttern of P vilility showed spordic spikes, ut in generl tretment effects were gretest during the third yer fter ppliction (Fig. 4). The lg in phosphte vilility contrsts with nitrte, which ws undnt erly nd ecme much less undnt y 22 (Fig. 3). This 2-yr lg in inorgnic P vilility likely reflects the P deficient nture of the soil nd persistent immoiliztion of P in soil orgnic mtter. High rtes of P immoiliztion were reported y Pitek nd Allen (21) in lololly pine lef litter. Becuse the current stnd ws thinned hevily immeditely efore litter ppliction, norml immoiliztion y litter ws likely enhnced y the presence of ded roots nd stumps. Folige nd Litter Nitrogen nd Phosphorus Poultry litter ppliction hd greter impcts on folir P thn on folir N concentrtions. Tretments did result in incresed folir N nd decresed C to N rtios in ll smpling dtes except the finl one (Tle 1). However, folir N ws reltively high in ll three tretments throughout the three yers of monitoring. All of our mid-winter vlues were ove the criticl vlue of 12 g N kg 21 for lololly pine (Allen, 1987; Colert nd Allen, 1996) nd well ove those reported for nutrient stressed sites (Gough et l., 24). The lck of nitrogen limittion is scried to inherent fertility, orgnic N inputs (i.e., fine root turnover) ssocited with thinning immeditely efore plot tretments, control of competing vegettion, nd reduced N demnd from the residul stnd fter thinning. Folir P, y contrst, ws consistently elow the criticl level of 1 g P kg 21 (Allen, 1987) t mid-winter for ll three yers in plots tht received no litter (Tle 1), reflecting the P deficient nture of these sites. Litter ppliction sustntilly incresed folir P concentrtion, douling it in mny cses. Phosphorus demnd ws pprently stisfied with the 4.6 Mg h 21 tretment, s the 18.6 Mg h 21 tretment resulted in no dditionl increse in P concentrtion over the 4.6 Mg h 21 tretment. Our findings with folir P re consistent with the widespred responses of lololly pine to P dditions on Ultisols of the upper Gulf Costl Plin (Allen, 199). Nutrient responses of the forest floor followed trends similr to those in the folige. Nitrogen nd P concentrtions were elevted y poultry litter ddition resulting in sustntilly elevted pools of N nd P in the forest floor (Fig. 5). In the first yer fter ppliction, N ws elevted y twofold nd P ws elevted more thn 2-fold with 18.6 Mg h 21 of litter compred with the control. As with folige, the C to N mss rtio ws less (pproximtely 3) t 18 Mg h 21 thn in the control (pproximtely 5) during the first two growing sesons (dt not shown). Forest floor N nd P pools returned to control levels y the end of the third growing seson (Fig. 5). This illustrtes the importnce of the litter lyer in forests s uffering mechnism for nutrient retention. In our cse, nerly 2 kg N h 21 nd 15 kg P h 21 were retined vi immoiliztion in the litter lyer during the first growing seson. This represents 25% of the N nd 5% of the P pplied in the poultry wste. Minerl soil ws nlyzed for totl N, totl C, nd C to N rtio for the sme months tht re reported for forest floor N nd P; however, no tretment effects were found. Totl N content ws pproximtely 1 g N kg 21 in the - to 8-cm lyer nd pproximtely.5 g N kg 21 in the 8- to 25-cm lyer. Cron content vried in similr proportions with pproximtely 2 g C kg 21 in the - to 8-cm lyer nd 1 g C kg 21 in the 8- to 25-cm lyer. The C to N rtio vried from 2 to 25, over oth depths, with no tretment effects.

10 846 J. ENVIRON. QUAL., VOL. 35, MAY JUNE Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. Bsl Are (m 2 h -1 ) Jn- Jul- Jn-1 Jul-1 Tree Growth Poultry litter incresed tree growth pprecily. During the yer in which litter ws pplied, stnding sl re incresed y out 5% (not significnt) for oth tretments compred with the control. During the second yer, tretment effects ecme significnt nd the size difference widened to out 2% (Fig. 6) nd remined t tht mrgin from the third through the fifth yers. Interestingly, height ws not ffected y litter ppliction ut did increse over time, from rnge of 6 to 7 m in the first yer to rnge of 9 to 13 m in the fifth yer (dt not shown). Our results were similr to those reported y Smuelson et l. (1999) for 18-yr-old lololly pine growing on similr soil in the djcent stte of Alm. After two growing sesons, they found tht stem dimeter increment t 1.3-m height incresed from 1.1 cm in control plots to 1.5 cm in plots treted with poultry litter tht supplied 24 kg N h 21 nd 1 kg P h 21. This is 4% increse in growth rte. We found 2-yr dimeter increment incresed from 1.15 cm in control plots to 1.76 cm in plots treted with poultry litter supplying 2 kg N h 21 nd 92 kg P h 21 (4.6 Mg litter h 21 ), which is 53% increse in growth rte over the sme time period. Stnding volume fter 4 yr in our study ws 76, 97, nd 16 m 3 h 21 in, 4.6, nd 18.6 Mg litter h 21 tretments, respectively (Roerts et l., 26). Jn-2 Jul-2 Dte Jn-3 Jul-3 Jn-4 Mg h Mg h Mg h -1 Fig. 6. Totl sl re (cross-sectionl re of ll trees) of lololly pine from plots treted with poultry litter. Plotted re the men vlues, y tretment, following the first five growing sesons fter litter ppliction. Similr letters (or no letters) mong the three tretments indicte no significnt tretment effects ccording to Tukey s test ( 5.5). Error rs indicte 6 one stndrd error of the men. Jul-4 Jn-5 CONCLUSIONS Lololly pine forests offer considerle potentil for the ppliction of poultry litter in the southestern United Sttes. Nutrients were contined nd pplied litter hd positive effects on tree growth. Nutrients in the 4.6 Mg h 21 tretment were lmost entirely contined. At the high ppliction rte (18.6 Mg h 21 ) nutrients were still contined remrkly well. Nitrte N in soil wter for this tretment exceeded 1 mg L 21 during the first two growing sesons fter ppliction; however, NO 3 ws elow 1 mg L 21 fter the second seson. The USEPA stndrd for drinking wter is 1 mg L 21 nd pplies to ground wter nd strem wter. This stndrd is not pplicle to soil wter from 5-cm depth ut the comprison illustrtes the success with which our system retined nitrte despite the ppliction of 18.6 Mg h 21 of poultry litter. In ddition, vegettion regrowth would normlly respond more rpidly thn the pine nd ccumulte the initil pulse of nutrient vilility (Jokel et l., 199). We repetedly controlled competing vegettion to evlute the nutrient removl potentil of the pine system; therefore, our conclusions concerning nutrient continment re conservtive. In reference to tree growth, litter pplictions of 2 kg N h 21 nd 92 kg P h 21 (4.6 Mg litter h 21 ) resulted in n pprecile growth stimultion. An increse of 2% in sl re will gretly increse the vlue of the stnd y shortening the rottion ge or incresing the volume hrvested, therey incresing the net worth of the stnd. These responses re comprle to wht we might expect from commercil ppliction of chemicl fertilizers. Despite the ovious economic enefits of fertilizing southern pine (Willims nd Frrish, 2), one study hs found tht socil rriers my e more importnt considertions to implementing this prctice thn economics (Lynch nd Tjden, 24). We will

11 FRIEND ET AL.: POULTRY LITTER APPLICATION TO LOBLOLLY PINE FORESTS 847 Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. continue to monitor the site to see if the 18.6 Mg h 21 tretment mintins its incresed growth for longer period thn the 4.6 Mg h 21 tretment. Overll, our results indicte tht poultry litter pplictions of pproximtely 5 dry Mg h 21 to mid-rottion lololly pine stnds will e esily contined y the ecosystem nd my result in significnt increses in tree growth. Previous work hs shown tht techniques exist for lnd pplying iosolids, including poultry litter, on n opertionl scle (Grey nd Henry, 22; Smuelson et l., 1999). The extent to which this prctice cn e repeted in susequent rottions is unknown; however, there is n undnce of forestlnd with no history of litter ppliction, nd single 4.6 Mg h 21 ppliction per rottion (pproximtely every 3 yr) would e consistent with current N fertiliztion prctices, though in excess of P needs (Allen, 1987). Our results with the higher rte (pproximtely 2 Mg h 21 ) suggest repeted pplictions of pproximtely 5 Mg h 21 over severl rottions would e sustinle; however, longterm studies of forest ppliction should e used to evlute the long-term sustinility of this prctice. Forest lnd provides vlule lterntive to psturelnds tht hve received repeted pplictions of litter nd re ecoming sturted with respect to N or P. ACKNOWLEDGMENTS Funding for this study ws provided y the Mississippi Agriculturl nd Forestry Experiment Sttion nd the Deprtment of Forestry, Forest nd Wildlife Reserch Center, Mississippi Stte University. This project ws prt of lrger effort led y Dr. F.T. Withers. Thnks re extended to E.J. Murphy II nd the Costl Plin Brnch Sttion for extensive help locting nd mintining the study site. D.M. Dennis conducted nd supervised much of the initil field work. J. Smith provided invlule ssistnce throughout the project. S.A. Pugh, USDA Forest Service, North Centrl Reserch Sttion (USDA-FS-NCRS), conducted the lnd cover lnd use nlysis nd prepred Fig. 1. Additionl support ws provided y the USDA-FS-NCRS Belowground Processes Reserch Work Unit (NC-4159). REFERENCES Allen, H.L Forest fertilizers: Nutrient mendment, stnd productivity, nd environmentl impct. J. For. 85: Allen, H.L Mnipulting lololly pine productivity with erly culturl tretment. p In S.P. Gessel et l. (ed.) Sustined Productivity of Forest Soils: Proc. 7th North Am. For. Soil. Conf. Univ. of British Columi, Vncouver, BC, Cnd. Binkley, D., H. Burnhm, nd H.L. Allen Wter qulity impcts of forest fertiliztion with nitrogen nd phosphorus. For. Ecol. Mnge. 121: Brockwy, D.G., nd D.H. 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12 848 J. ENVIRON. QUAL., VOL. 35, MAY JUNE 26 Reproduced from Journl of Environmentl Qulity. Pulished y ASA, CSSA, nd SSSA. All copyrights reserved. Yer-round soil nutrient dynmics from roiler litter ppliction to three ermudgrss cultivrs. Agron. J. 96: Smith, W., P. Miles, J. Visge, nd S. Pugh. 24. Forest resources of the United Sttes, 22. USDA For. Serv., North Centrl Res. Stn., St. Pul, MN. Tylor, J.R., M.A. Crdmone, nd W.J. Mitsch Bottomlnd hrdwood forests: Their functions nd vlues. p In J.G. Gosselink et l. (ed.) Ecologicl processes nd cumultive impcts illustrted y ottomlnd hrdwood wetlnd ecosystems. Lewis Pul., Chelse, MI. Torert, J.L., nd J.E. Johnson Estlishing Americn sycmore seedlings on lnd irrigted with pper mill sludge. New For. 7: Trn, T.S., nd R.R. Simrd Mehlich III-extrctle elements. p In M.R. Crter (ed.) Soil smpling nd methods of nlysis. Lewis Pul., Boc Rton, FL. USDA Soil survey of Newton County, Mississippi. USDA- NRCS, Wshington, DC. Vervoort, R.W., D.E. Rdcliffe, M.L. Crer, nd M. Ltimore Nutrient losses in surfce nd susurfce flow from psture pplied poultry litter nd composted poultry litter. Nutr. Cycling Agroecosyst. 5: Vitousek, P.M., S.W. Andriese, P.A. Mtson, L. Morris, nd R.L. Snford Effects of hrvest intensity, site preprtion, nd hericide use on soil nitrogen trnsformtions in young lololly pine plnttion. For. Ecol. Mnge. 49: Willims, C.M., J.C. Brker, nd J.T. Sims Mngement nd utiliztion of poultry wstes. Rev. Environ. Contm. Toxicol. 162: Willims, R.A., nd K.W. Frrish. 2. Response of lololly pine plnttions to lte-rottion fertiliztion nd hericide pplictions in north Louisin. South. J. Appl. For. 24: Young, M.J., J.E. Johnson, nd D.A. Thiel Effects of pper mill sludge nd weed control on competing vegettion nd growth of young red pine. New For. 7: