Ammonia Volatilization Losses Following Irrigation of Liquid Swine Manure in Commercial Pine Plantations

Transcription

1 Mones, F. and J.P. Chasain Ammonia Volailizaion Losses Following Irrigaion of Liquid Swine Manure in Commercial Pine Planaions. In: R.T. Burnes (ed), Animal, Agriculural and Food Processing Wases IX : Proceedings of he Ninh Inernaional Symposium, Research Triangle Park, NC, Oc , ASAE, S. Joseph, MI, pp Ammonia Volailizaion Losses Following Irrigaion of Liquid Swine Manure in Commercial Pine Planaions Felipe Mones and John P. Chasain 1 ABSTRACT Ammonia volailizaion was measured afer land applicaion of liquid swine manure in a commercial pine fores in Souh Carolina. Three wind unnels were consruced and used o measure ammonia volailizaion afer applicaion. The fracion of ammonia los as percen of TAN applied was fied o he funcion Y a1 e K. The funcion represened he daa wih parameer a, he poenial volailizaion loss, and parameer K, a rae consan. The oal amoun of NH 3 -N los afer irrigaion of liquid swine manure varied from 0.38% o 3.6% of he TAN applied. The oal ammonia los was found o correlae significanly (R 2 = 0.950) wih he mass of TAN applied per m 2 per applicaion deph (g TAN/ m 2 -mm) and wih he oal solids conen of he manure. The average rae consan, K, for liquid swine manure applicaions wih mean air emperaure below 30 C was min -1. A mean air emperaures of 32 C, he rae consan increased o min -1 and was significanly differen from oher applicaion evens. Ammonia losses following irrigaion of liquid swine manure were on he same order of magniude as losses repored for oher land applicaion sudies in which he manure was immediaely incorporaed. Keywords: Ammonia volailizaion, nirogen losses, liquid swine manure, land applicaion, pine fores. INTRODUCTION Ammonia volailizaion affecs he amoun of nirogen available for crop ferilizaion modifying he agronomic value of manure as ferilizer and increasing he uncerainy of nurien managemen pracices. Ammonia volailizaion from applicaion of swine slurries can be 30% o 40% of he oal Kjeldhal nirogen (TKN) and up o 60% of he oal ammoniacal nirogen (TAN) applied (Pain e al and Lockyer e al. 1989). Volailizaion losses during applicaion are negligible; herefore mos of he loss occurs once he manure has been applied in he field (Pain e al. 1989; Mones and Chasain, 2000; and Mones, 2002) Ammonia volailizaion from manure is a complex process. In essence, i is he mass ransfer of NH 3 molecules from he manure soluion hrough he air-liquid inerface and hen o he amosphere hrough convecive mass ranspor. The process is affeced by he: ph of he manure and he soil in which i has been applied, equilibrium beween NH 3 and NH 4 + in he manure, emperaure of he environmen, wind velociy and airflow characerisics (Ni, 1999; and Mones, 2002). The complexiy of he process is furher increased when biochemical ransformaions such as mineralizaion and nirificaion are included. Managemen pracices such as he animal 1 Auhors are: Graduae suden and Associae Professor, Deparmen of Agriculural and Biological Engineering, Clemson, SC, USA. 1

2 wase handling sysem, applicaion rae and applicaion mehod also affec he volailizaion process (Mones, 2002). Few sudies have been conduced on land applicaion of animal manure in fores environmens and no sudy has evaluaed volailizaion losses from land applicaion in hese environmens. The objecives of his sudy were o measure ammonia volailizaion losses following irrigaion of liquid swine manure in a pine planaion, and o idenify he main facors affecing oal amoun of NH 3 los and he volailizaion rae. EXPERIMENTAL METHODS Ammonia volailizaion was measured on 12 occasions afer irrigaion of liquid swine manure in a commercial pine planaion near Manning, Souh Carolina. The rees were 10 years old a he beginning of he sudy and were machine-planed a a spacing of 1.8 m by 3 m (6 f by 10 f). Liquid manure was pumped from a lagoon serving a nearby finishing swine faciliy using 63.5 mm (2.5 in) schedule 40 PVC pipe and a 10.4 kw (14 hp) pump equipped wih a semi-open impeller. Large impac sprinklers wih 9.5 mm nozzles were used o apply he effluen a an operaing pressure of 179 kpa (26 psi). The sprinklers were posiioned o provide an overlap of more han 100%. Applicaion raes ranged from 67 kg PAN /ha (60 lb PAN / ac) o 134 kg PAN / ha (120 lb PAN / ac). These applicaion raes were defined by a parallel sudy on ree-growh response and waer qualiy impac. Deailed descripion of he projec sie, irrigaion sysem and fores characerisics are provided by Lucas e al. (1999). Liquid swine manure samples were colleced using eigh plasic conainers placed in he plo before he applicaion sared. A he end of each applicaion, conens of he conainers were mixed ino one represenaive sample, sored in a large plasic bole and mainained on ice for ranspor o he laboraory. Each of he large samples was screened o remove floaing debris and wo o hree well-mixed sub samples were drawn for nurien analysis. Each manure sample was analyzed o deermine ph, oal solids, oal Kjeldahl nirogen (TKN) and oal ammoniacal nirogen (TAN= NH 3 -N + NH 4 + -N) by he Agriculural Service Laboraory a Clemson Universiy. Ammonia volailizaion was measured using hree wind unnels designed and buil in he deparmen of Agriculural and Biological Engineering a Clemson Universiy. Inside each wind unnel, air flowed a L/min (50 3 CFM) over an applicaion area of 0.84 m 2 (9 f 2 ), carrying volailizing ammonia owards he unnel oule. Here air was mixed wih an elecric fan and sraighened by passing hrough a flow sraigher before ammonia concenraion was measured. Ammonia concenraion was measured using a Sensidyne-Gasec 800 model Deecion Pump/Reagen ube sysem. Reagen ubes wih sampling ranges of ppm 10% and ppm 10% were used; ammonia concenraion was read direcly in ppm using he deecion ube calibraed scale (Sensidyne Inc, 1990). Immediaely afer each manure applicaion ended, one wind unnel was carried o a locaion represenaive of he fores floor applicaion area. Once he wind unnel was in place, he fan was urned on, he saring ime was recorded and ammonia measuremens a he inle and oule were iniiaed. For he firs 30 minues afer applicaion, NH 3 concenraions a he inle and oule were recorded every 5 minues. The following hour ammonia concenraion was recorded every 10 minues, every 20 o 30 minues for he nex wo hours and every 1 or 2 hours hereafer unil NH 3 concenraion a he oule fell o 0.25 ppm. A his concenraion level i was deermined ha mos of he volailizaion loss had occurred. Sampling frequency afer he firs hree hours of measuremens depended on rae of change in NH 3 concenraion. 2

3 Concenraion measuremens a he inle were suspended afer ammonia concenraion fell below reagen ubes deecion limis. However, periodic inle concenraion measuremens were made o verify ha no deecable ammonia was presen in he inle air. Ambien air emperaure and relaive humidiy measuremens were recorded using a sling psychromeer (Bacharach, Inc.) hroughou he ammonia volailizaion experimen. The environmenal condiions presen during each volailizaion experimen as well as he TKN, TAN and TS of he irrigaed liquid swine manure are presened in Table 1. The ph of he swine lagoon effluen applied ranged from 7.8 o 8.2, wih a mean of 8.1 and sandard deviaion of Table 1. Ambien condiions during volailizaion measuremens, liquid swine manure applicaion raes, oal Kjeldhal nirogen (TKN), oal ammoniacal nirogen (TAN) and oal solids (TS) conen for each liquid swine manure applicaion. Volume applied (L/m 2 ) d Applicaion Even Dae Time a T b ( C) RH c (%) TKN (mg/l) TAN (mg/l) TS (%) SW1 3/21/00 12:55 PM SW2 3/21/00 8:44 AM SW3 3/21/00 9:58 AM SW4 7/5/00 4:50 PM SW5 7/6/00 10:44 AM SW6 7/5/00 3:45 PM SW7 11/7/00 2:15 PM SW8 11/7/00 12:20 PM SW9 11/7/00 10:20 AM SW10 3/19/01 3:24 PM SW11 3/19/01 2:20 PM SW12 3/19/01 4:32 PM a Time of day ha he wind unnel experimen began b Average air emperaure values for he applicaion even c Average relaive humidiy values for he applicaion even d L/m 2 is equivalen o applicaion deph in mm RESULTS Ammonia concenraion a he wind unnel oule reached is peak immediaely afer irrigaion and began decreasing wih ime. The rae of decrease was reduced as he concenraion approached zero. Ammonia concenraion a he wind unnel oule fell o levels below he deecion limi 3 o 5 hours afer applicaion of liquid swine manure. Ammonia concenraion in erms of mass per uni volume (mg NH 3 /m 3 ) can be calculaed from he concenraion in pars per million (volume basis) measured wih deecion ubes using he following applicaion of he ideal gas law a ideal pressure (Mones, 2002; Wark e al, 1988; Sensidyne Inc, 1990): NH 3 mg / m 3 NH 3 ppm MW NH T NH 3 ppm, (1) where, 3 NH = ammonia concenraion in mg/m 3 (m/v) 3 mg / m 3

4 ppm NH 3 = ammonia concenraion in pars per million, ml/m 3 (v/v) T = average emperaure during he experimens = K (20 C), 22.4 = volume of 1 Kmol a 0 C under 1 amospheric pressure (m 3 ), MW NH3 = molecular weigh of NH 3 = 17 kg-nh 3 / Kmol. I is necessary o know inle and oule NH 3 concenraion simulaneously o calculae he amoun of ammonia ha is being volailized wih respec o ime. Since i was impossible o measure inle and oule concenraions a exacly he same ime, linear inerpolaion was used o esimae inle concenraions ha mached oule concenraions in ime. The procedure used is illusraed using daa from one of he experimens in Figure 1. The average ammonia flux in he volailizaion area inside he wind unnel was calculaed by using he airflow rae in he wind unnel and he difference beween oule and inle NH 3 concenraion a a specific ime, as: where, J NH3 O NH 3 NH 3 I Q air A v, (2) J 3 = NH 3 mass flux a ime (mg NH 3 /m 2 s), NH I NH 3 = NH 3 concenraion in he inle air sream a ime (mg NH 3 /m 3 ), NH 3 = NH O 3 concenraion in he oule air sream a ime (mg NH 3 /m 3 ), Q air = airflow rae (0.024 m 3 / s), and A v = Area of volailizaion (0.36 m 2 ). The uncerainy in deermining he ammonia flux from he volailizaion area inside he wind unnel was calculaed o be 13 % of which he main componen was he measuremen error of NH 3 concenraion, 10 % (Mones, 2002). 4

5 NH 3 Concenraion (ppm) Applicaion Even No.SW11 Inle Inerpolaed value Oule Ne concenraion Elapsed Time (min) Figure 1. Sample daa showing he use of linear inerpolaion of inle NH 3 concenraion o mach oule measuremens in ime for volailizaion following liquid swine manure applicaion. Ne concenraion is he oule NH 3 concenraion minus he inerpolaed inle NH 3 concenraion Once mass flux was known, he amoun of ammonia los per uni area in a ime inerval was calculaed. The mass of ammonia los in a small ime inerval,, is approximaely equal o he average flux rae beween wo poins close in ime, muliplied by he ime difference beween hose poins. Thus, oal mass of ammonia los per square meer as a funcion of ime was calculaed as: where, M J NH J NH F J NH J 3 NH3 (3) M NH 3 = oal mass of NH 3 los per uni area (mg NH 3 /m 2 ),, NH = NH mass flux a ime and + (mg NH 3 /m 2 s), and F = ime duraion of he experimen (min). I is common pracice o repor he ammoniacal nirogen in manure as oal ammoniacal nirogen conen (TAN = NH 3 -N + NH 4 + -N). Therefore volailizaion losses were expressed as a percen of TAN applied. The cumulaive mass of NH 3 los in ime as percen of he TAN applied was calculaed as: NH 3L TAN M NH3 TAN ap 100, (4) 5

6 where, NH 3 L TAN = oal mass of NH3 los expressed as percen of TAN applied a ime, NH 3L = oal mass of NH 3 los per uni area (mg NH 3 /m 2 ) a ime, and TAN ap = mass of TAN applied per uni area (mg/m 2 ). Cumulaive NH 3 volailizaion daa ses were fied o he following funcion: Y a 1 e K. (5) The Marquad mehod of nonlinear regression procedures included in saisical analysis sofware (SAS insiue, 1990; Demeyer e al., 1995) was used fi he daa o equaion 5. In his funcion, Y is he oal volailizaion of ammonia expressed as percen of TAN applied a minues afer applicaion; a is he poenial volailizaion loss parameer; and K is a rae consan. The fied curves and daa for all liquid swine manure irrigaion experimens are shown in Figures 2 and 3. A summary of he nonlinear regression resuls and relevan saisics are given in Table 2. 6

7 NH 3 Los as % TAN applied Elapsed Time (min) SW1 SW2 SW3 SW4 SW5 SW6 Figure 2. Ammonia volailizaion loss as a funcion of ime expressed as percen of TAN applied (poins). Corresponding fied funcions for liquid swine manure applicaion evens SW1 hrough SW6 described in Table 1. NH 3 Los as % TAN applied Elapsed Time (min) SW7 SW8 SW9 SW10 SW11 SW12 Figure 3. Ammonia volailizaion loss as a funcion of ime expressed as percen of TAN applied (poins). Corresponding fied funcions for liquid swine manure applicaion evens SW7 hrough SW12 described in Table 1. 7

8 Table 2. Curve fiing resuls for volailizaion losses following irrigaion of liquid swine manure using he model given in equaion 6. Poenial Toal NH 3 Loss Parameer (a ± C.I) * Mean Square of Residuals (s 2 ) Applicaion Even Rae Consan (K ± C.I) * n R 2 ** Mean of Residuals SW ± ± SW ± ± SW ± ± SW ± ± SW ± ± SW ± ± SW ± ± SW ± ± SW ± ± SW ± ± SW ± ± SW ± ± *Approximae 95% confidence inerval (SAS Insiue 1990, Ryan 1997) **Nonlinear R 2 Fiing he daa ses o he menioned funcion resuls in he represenaion of he complee daa se by wo curve fiing parameers, eliminaes he need o esimae he volailizaion value a he beginning of he experimens and esimaes he oal volailizaion losses based on he whole daa se. As seen in Figures 4 and 5, he nonlinear funcion closely describes he daa. Good agreemen beween he funcion and he daa is also indicaed by high values of R 2, values of mean residuals very close o zero, and small values of mean square of residuals (Table 2). The parameer a varied from 0.46 o 4.4 for irrigaion of liquid swine manure. Therefore, 0.46 % and 4.4% of he TAN applied was los as NH 3. Nirogen represens 82 % of he molecular weigh of NH 3. Therefore he cumulaive NH 3 loss as percen of TAN applied is simply 0.82 a. Thus he amoun of NH 3 -N los ranged from 0.38% o 3.6% of TAN applied. These resuls are in agreemen wih oher volailizaion sudies in which manure was incorporaed immediaely afer applicaion (Malgeryd, 1998; Thompson e al. 1987; Hoff e al. 1981; Mones 2002). The amoun of NH 3 los, a, and he rae consan, K, were hypohesized o be influenced by he volume of manure applied, he amoun of TAN applied, he TS conen of he manure, manure ph, air emperaure, and relaive humidiy. The ph of he irrigaed manure was 8.1 wih a CV of 2.2%. Therefore, ph was no included in he analysis due o he small range of values. A correlaion analysis was performed o deermine if he variaion in a and K could be described as a funcion of he following variables: (1) volume of manure applied (V A, L/m 2 ), (2) mass of TAN applied per uni area (M TAN, g TAN/m 2 ), (3) oal solids (TS, %), (4) air emperaure (T AIR, C), (5) relaive humidiy (RH,%), and (6) mass of TAN applied per m 2 divided by applicaion deph (, g TAN/m 2 -mm). Significan correlaions were found beween a, and he independen variables TS and. The bes fi of he daa was provided by he following regression equaion: a 14.86TS (6) 8

9 The regression equaion for a had 8 degrees of freedom, an R 2 of 0.950, a sandard error of he y esimae (S y.x ) of and a mean CV of 16.7 %. The funcion was linear in TS and quadraic in. The variable represens he amoun of TAN applied per uni area relaive o he deph of liquid applicaion. Therefore, he oal NH 3 loss parameer can be prediced by he solids conen of he manure, he amoun on TAN applied, and he applicaion deph. The relaionship beween he rae consan K and variables V A, M TAN,, TS, T AIR and RH was sudied using correlaion analysis. The analysis idenified ha he only variable wih significan effec on he rae consan was mean air emperaure. Figure 4 shows he variaion in K wih respec o he average air emperaure during each applicaion even. The scaer of he daa suggesed ha here was a single rae consan for NH 3 volailizaion following irrigaion of swine manure wih mean air emperaure below 30 C and a differen value for applicaions ha occurred a 32 C. The mean K-value for emperaures below 30 C was min -1. The rae consan a 32 C was min -1. These wo rae consans were significanly differen a he 95 % confidence level. The rae consan value describes he dynamics of he volailizaion process. The inverse of he rae consan, ha is 1/K, is equal o he ime required for 63.2% of he volailizaion process o be compleed. Thus as he rae consan K increases, he ime required for he volailizaion process o be compleed decreases (Mones 2002). For he highes rae consan value in his experimen (K = min -1 a 32 C), only 30 min are required o complee 63.2 % of he oal volailizaion. If he rae consan is min -1 (less han 30 C), 80 min are required Rae Consan K (min -1 ) Temperaure C Figure 4. Rae consans for liquid swine manure. 9

10 CONCLUSIONS Nirogen volailizaion loss following irrigaion of liquid swine manure in a commercial pine planaion in Souh Carolina averaged 1.9 % of he TAN applied. Volailizaion loss ranged from 0.38% o 3.6% of he TAN applied and was explained by he oal solids conen of he liquid manure and he TAN applied per m 2 per mm applicaion deph. Temperaure and relaive humidiy were no imporan in deermining he oal volailizaion loss, alhough emperaures above 30 C showed a significan increase in he speed a which he process occurred. The resuls of his sudy are in agreemen wih oher volailizaion sudies in which manure was incorporaed immediaely afer applicaion. Acknowledgemens This work was funded by a gran from he Agriculural Produciviy and Profiabiliy Program as a par of he Clemson Universiy Public Service Allocaion. Addiional suppor was provided by Clemson Universiy Exension. REFERENCES 1. Demeyer, P., G. Hofman and O. Van Cleempu Fiing Ammonia Volailizaion Dynamics wih a Logisic Equaion. Soil Sci. Soc. Am. J. 59: Hoff, J. D., D.W. Nelson and A. L. Suon Ammonia Volailizaion from Liquid Swine Manure Applied o Cropland. J. Environ. Qual. 10 (1): Lockyer, D., B. F. Pain and J. V. Klarenbeek Ammonia Emissions from Cale, Pig and Poulry Wases Applied o Pasure. Environmenal Polluion 56: Lucas, W. D., J. P. Chasain and E. D. Dickens Waer Qualiy Impac of Using Swine Lagoon Effluen o Ferilize Loblolly Pine Planaions. Presened a he 1999 Annual Inernaional Meeing of ASAE. Paper No ASAE, 2950 Niles Rd., S. Joseph, MI Malgeryd J Technical Measures o Reduce Ammonia Losses afer spreading of Animal Manure. Nurien Cycling in Agroecosysems 51: Mones F., Ammonia volailizaion resuling from land applicaion of liquid swine manure and urkey lier in commercial pine planaions. Unpublished MS Thesis, Deparmen of Agriculural and Biological Engineering, Clemson Universiy. 7. Mones F. and J. P. Chasain, Ammonia volailizaion losses during irrigaion of liquid swine manure in commercial foresland and open field condiions. Presened a he 2000 ASAE Annual Inernaional Meeing. Paper No ASAE, 2950 Niles Rd., S. Joseph, MI Ni J., Mechanisic models of ammonia release from liquid manure: a review. J. Agric. Engng Res. (1999) 72, Pain, B. F., V. R. Philips, C. R. Clarkson and J. V. Klarenbeek Loss of Nirogen Through Volailizaion During and Following he Applicaion of Pig or Cale Slurry o Grassland. J. Sci. Food Agric., 47: Ryan, P Modern Regression Mehods. John Wiley & Sons. 11. SAS Insiue SAS/STAT User's guide. Version 6, Fourh Ediion, Volume 2. SAS Insiue. 12. Sensidyne Inc Sensidyne Gasec. Environmenal Analysis Technology Handbook. Firs Ediion. Sensidyne Inc. 13. Thompson, R. B., J. C. Ryden and D. R. Lockyer Fae of Nirogen in Cale Slurry Following Surface Applicaion or Injecion o Grassland. Journal of Soil Science, 38: Wark, K., C. F. Warner and W. T. Davis, Air Polluion: Is Origin and Conrol. Third ediion. Addison-Wesley. 10