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PRODUCTION PAPER

Effect of Swine Slurry on Alfalfa Production and on Tissue and Soil Nutrient Concentration

^a UdL (Universitat de Lleida)—IRTA, Av. Rovira Roure, 191, 250198 Lleida, Spain
^b LAF (Laboratori d'Analisi i Fertilitat de Sòls), 25222 Sidamon, Spain
^c SIA, Diputación General de Aragón, Apartado 727, 50080 Zaragoza, Spain

^* Corresponding author (jaume.lloveras{at}irta.es).

Received for publication March 15, 2003.

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Alfalfa (Medicago sativa L.) may not be the most suitable crop to utilize all the manure nutrients, but it may be the best crop available, especially when the crop is dormant. The objective of this research was to investigate the effect of swine (Sus scrofa domesticus) slurry manure on alfalfa yield and the concentration of nutrients in soil. A 2-yr field experiment was initiated in 2001 on two soils: a Typic Xerofluvent and a Calcixerolic Xerochrept. Soil mineral elements were extracted with ammonium bicarbonate diethylenetriaminepentaacetic acid, and initial extractable P and K were 16.7 and 6 mg P kg^–1 and 152 and 103 mg K kg^–1 for the two soils, respectively. There were four treatments: annual winter applications of 25 and 50 m³ ha^–1 of swine slurry manure, annual fertilization of 32.75 kg P ha^–1 and 125 kg K ha^–1, and a no-manure or fertilizer control. Application of slurry manure in winter was not detrimental to the crop. Manure and fertilizer treatments increased alfalfa dry matter (DM) yield 37% on the low-fertility soil. There was no significant effect of manure or fertilizer on alfalfa DM yield on the Xerofluvent soil. Application of the slurry slightly increased the soil concentrations of P, Mg, Zn, and Fe in higher-fertility soils and copper in low-fertility soils. The 2-yr results suggest that the application of slurry in soils with low levels of trace elements, such as those used in the trials, does not produce a significant buildup of these elements that could lead to an environmental problem.

Abbreviations: AB-DTPA, ammonium bicarbonate-diethylenetriaminepentaacetic acid • DM, dry matter

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
LAND APPLICATION of animal wastes to enhance crop production is an agricultural practice that has been used for centuries. To better utilize the manure as a fertilizer, and to reduce the risks of pollution, studies have been conducted to evaluate its use, particularly in crops such as maize (Zea mays L.) that can enhance the value of N contained in the slurry (Hatfield, 1998). Farmers know that the application of manure to crops such as maize may be the most efficient way to utilize all the manure nutrients. However, many producers do not have sufficient area of maize for slurry applications at agronomic rates or following recommended best management practices, and they need other crops to apply the slurry (Kelling and Schmitt, 1996). Increasingly, regulatory pressure aimed at reducing environmental problems, the introduction of systematic nutrient management planning, and related concerns over ground and surface water pollution are causing swine and dairy producers to reconsider their management strategies (Bodet et al., 2001; Soil and Water Conserv. Soc., 1998; Danés et al., 1995).

In several alfalfa-producing areas, alfalfa and maize are important irrigated crops, and swine growing is one of the main animal production activities. Alfalfa has become an alternative crop although alfalfa fields may not be the best possible location for manure applications. As reported by Kelling and Schmitt (1996) in Wisconsin, topdress applications of manure on alfalfa are often made because of necessity rather than choice. These may be the only fields available at some times of the year and, on many farms, the best environmental alternative (Kelling and Schmitt, 1996).

Manure application on alfalfa has been considered a risky management practice by many because it may cause plant injury or stand reduction of the alfalfa due to the salts contained in the manure and physical damage to the crowns during application, mainly in the wheel-track areas (Kelling and Schmitt, 1996; Lory et al., 2000). Slurry manure may also increase DM yields due to an increase in the weeds. This may occur at least in the first cutting because weeds can take better advantage of the N of the slurry (Kelling and Schmitt, 1996). In a study conducted in Massachusetts, the application of dairy manure to alfalfa at the low rate (112 kg N ha^–1) had no significant effect on DM yields, N accumulation in herbage, and soil NO₃–N at the 0- to 30-cm depth. The authors concluded that dairy manure can be applied to established alfalfa without any adverse impact on herbage production or soil water (Daliparthy et al., 1994). In Southern Europe, preliminary studies comparing mineral fertilization with swine slurry on alfalfa did not suggest differences in the forage DM yield or detrimental effects of the slurry to the crop (Mangado and Ameztoy, 1997; Domingo and Bosch, 2001).

Traditional fertilizer recommendations have consistently stated that N fertilizers do not need to be applied on alfalfa fields (Hannaway and Shuler, 1993). Alfalfa typically meets its N need through symbiotic N fixation but will preferentially utilize mineral N if it is available (Allos and Bartholomew, 1955, 1959; McAuliffe et al., 1958). Research into the effects of manure on alfalfa has shown that manure is increasingly being applied to alfalfa because of alfalfa's ability to recycle nutrients and its potential to extract nutrients from a significant depth. For example, alfalfa can recover nitrates that have started moving downward in the soil due to its deeper rooting zone (Schmitt et al., 1991, Blumenthal et al., 1999). Publications from several countries stress the importance of the slurry manure as a supplier of P and K. Their equivalence is normally 1 to 0.85 compared with chemical fertilizers. Consequently, P and K furnished by the manure can replace part or all of these elements provided by traditional mineral fertilizers (Bodet et al., 2001; Lory et al., 2000).

There have been concerns regarding the increasing concentrations of Zn and Cu in soils where agricultural wastes have been applied (Coppenet et al., 1993). This potential buildup is due to the common nutritional practice within the swine industry of formulating swine diets with high levels of trace elements (Spears et al., 1998).

Alleviation of potential N problems on other fields and the benefit of the other nutrients in the manure could provide a sufficient economic and environmental justification for using manure on alfalfa fields (Schmitt et al., 1991).

In the Ebro Valley in Spain, manure applications to alfalfa would increase the land available for spreading, improving the N balance and thus lessening the potential of nitrate leaching. There is an opportunity in this region to apply manure in winter when the crop is dormant and precipitation is rare (Lloveras, 2001). However, few data are available on the effects of swine slurry on the alfalfa crop and on soil nutrient evolution.

This study evaluated the effects of moderate amounts of swine slurry manure on irrigated alfalfa production and on tissue and soil nutrient concentration.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
The experiments were conducted over two growing seasons, 2001 and 2002, in two irrigated fields seeded with ‘Aragón’ alfalfa in the second and third year of production in Alcolea de Cinca (Alcolea) and Villanueva de Sigena (Villanueva). The sites (41°43' N, 00°07' E) are about 10 km apart and are located in the Ebro Valley of Spain. Mean annual temperatures for the 2001 and 2002 growing seasons were 13.8 and 14.3°C, respectively. The plots were flood-irrigated every 15 to 20 d, receiving a total of about 800 mm of water. Annual rainfall was less than half of this amount (274.1 mm in 2001 and 377 mm in 2002),

The soil in Alcolea is a Typic Xerofluvent. It is a deep, calcareous soil (1.5 m), with a CaCO₃ equivalent of 370 g kg^–1, a basic pH of 8.2 (water), and an organic matter concentration of 17 g kg^–1. It has a silt loam texture (131 g kg^–1 of sand, 600 g kg^–1 of silt, and 269 g kg^–1 of clay) and is well drained, with a gravel layer of alluvial origin at about 1.5-m depth. From 30- to 60-cm depth, the soil has a sandy loam texture with a pH of 8.4 and a CaCO₃ equivalent of 250 g kg^–1. In Villanueva, the soil is a Calcixerolic Xerochrept. It has a clay loam texture (444 g kg^–1 of sand, 266 g kg^–1 of silt, and 290 g kg^–1 of clay) and is well drained with a petrocalcic layer at 65- to 75-cm depth. The soil analysis (0- to 30-cm depth) presented a pH of 8.2 (water), organic matter of 15 g kg^–1, and a CaCO₃ equivalent of 350 g kg^–1. From 30- to 60-cm depth, the soil has a sandy loam texture with a pH of 8.4 and a CaCO₃ equivalent of 400 g kg^–1. Neither soil is saline.

The statistical design was a randomized block with three replications. The elemental plot size was 50 by 14 m in Alcolea and 110 by 14 m in Villanueva. The plots had been leveled previous to the seeding of alfalfa. In each location, two rates of swine slurry, 25 and 50 m³ ha^–1, were applied annually at the end of January 2001 and 2002, when the crop was dormant, by a trained commercial applicator. These rates were considered low or moderate in the geographical area of the trials and are rates most commonly used in most crops. The slurry was spread, in one strip over each plot, over a width of 12 m, of which the central 6 m was used for forage yield and plant and soil mineral determinations.

The slurry treatments were compared with a control in which no slurry and no mineral fertilization were applied and with a fourth treatment with annual applications of 32.75 and 125 kg of P and K respectively, representing the average fertilizer applications in the area. The P and K fertilization treatment was not applied in 2001 in Alcolea.

Swine manure was obtained from a concrete pit of a neighboring farm. The average composition in N, P, and K in 2001 was 87, 23, and 55 g kg^–1, respectively, on an as is basis. In 2002, the composition was 55.9, 22.5, and 76.3 g kg^–1 N, P, and K, respectively.

Nitrogen in the fresh sample of pig slurry was analyzed by the Kjeldahl method (Nelson and Sommers, 1973), and the P and K contents were analyzed according to the European Commission BCR Reference Materials (Quevauviller et al., 1996). Dry matter contents of the slurry were 47 kg m^–3 in 2001 and 61 kg m^–3 in 2002. Trace elements of the slurry were not determined, but the average values of Cu and Zn contents of the farms of the area are 567 and 1200 mg kg^–1, respectively (LAF, 1999).

Forage yield was determined by harvesting six subsamples of 1 by 6 m from each plot, and their averages per plot were used for statistical analyses. Five cuttings were harvested each year at the mid- to full-flowering state, except for the first and the last cut of the year when the crop does not flower because of the photoperiod. The first harvest was in about mid-April and the last in late October, with a period of about 30 d between harvests.

Insect control was achieved by two to four sprays per year of 0.1 kg ha^–1 a.i. fenvalerate [cyano (3-phenoxyphenyl)methyl 4-cholo--(methylethyl)benzeacetate]. Weeds were controlled in the 2002 growing season by applying 1 kg ha^–1 a.i. hexazinone [3-cyclohexyl-6-dimethylamino-1-methyl-1,3,5-triazine-2,4 (1H,3H)-dione] in January. The proportions of alfalfa and weeds were evaluated from four subsamples of 300 g per plot and through separation of alfalfa and weeds in the laboratory.

Four wet samples of herbage of 500 g were collected from each plot at each harvest for moisture determination and subsequent chemical analysis. Samples were dried at 70°C, and DM yields were calculated on this basis. Ground (1-mm screen) plant tissue samples were analyzed for several nutrients. Total N was analyzed by the Kjeldahl method (Nelson and Sommers, 1973), and K, Ca, P, Mg, B, Cu, Fe, Mn, and Zn contents were analyzed by inductively coupled argon plasma spectrophotometry (Polyscan 61E, Thermo Jarrell-Ash Corp., Franklin, MA), after the calcinated plant ashes had been digested with nitric acid (Mills and Jones, 1996).

Ten soil cores were taken from the 0- to 30-cm soil depths of each plot before fertilization and end of the trials to determine the evolution of the soil fertility elements. Soil mineral elements were extracted using ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA) (Soltanpour, 1991) and determined by inductively coupled argon plasma spectrophotometry (Polyscan 61E, Thermo Jarrell-Ash Corp., Franklin, MA).

The results of each experiment were analyzed separately and were subjected to analysis of variance with the General Linear Model procedure of the Statistical Analysis System (SAS Inst., 1988). The two trials were analyzed separately because in Alcolea, one of the treatments, fertilization with P and K, was missing in 2001 and in the 2-yr total.

	RESULTS AND DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Forage Yields
The effects of swine slurry manure varied according to the location (Tables 1 and 2). Mean 2-yr total DM yield in Alcolea was 27.8 Mg ha^–1 whereas in Villanueva, it was 19.6 Mg ha^–1. Lower yields obtained in Villanueva could be partially due to problems in the irrigation system (less water than expected) during regrowth after the first harvest of 2001, contributing to low yields in the second harvest. However, total yields were similar for both years at this location.

The Villanueva results suggest the beneficial effects of the P and K on alfalfa, a crop that normally requires high levels of both elements (Lanyon and Griffith, 1988; Undersander et al., 1994). The similar effect of mineral P and K and the manure treatments shows the beneficial effects of swine slurry as a fertilizer for alfalfa and implied that the P and K content of the manure was its primary benefit to the Villanueva alfalfa crop.

In our trials, the amounts of swine slurry applied were not detrimental to the alfalfa DM yields in any year and location, in agreement with suggestions from preliminary reports (Mangado and Ameztoy, 1997; Domingo and Bosch, 2001). Research with higher amounts of liquid dairy manure, from 44 to 132 m³ ha^–1, also suggested that liquid dairy manure could be applied to alfalfa without any adverse effects on herbage yield or weed incidence and with no economic risk on productivity (Daliparthy et al., 1995).

In the experiments reported here, the wheel tracks of the applicators were observed in the plots for several weeks after the application. However, it was impossible to distinguish the wheel tracks from the rest of the field after the spring regrowth in any field or year.

In the first year of the experiment, in Alcolea (high-fertility soils), the proportion of the alfalfa in the herbage seemed to decrease, although not significantly, with the application of 25 and 50 m³ ha^–1 of slurry, going from 769 and 808 g kg^–1 of alfalfa, respectively, to 859 g kg^–1 with no slurry (Table 1). This suggested, as reported by others, that the N content of the slurry might favor weed growth and competition (Schmitt et al., 1991; Kelling and Schmitt, 1996). However, in the second growing season, when herbicide was applied in winter, the proportion of alfalfa in the subsequent spring regrowth increased. No differences were observed in weed proportion with the application of slurry in either year. The results suggest that the beneficial effect of the slurry was not due to a weed increase but to the fertilizer effects of the slurry, possibly P and K.

Plant Composition
Mineral concentration of alfalfa varied depending on the location. The weighted average concentrations of P, K, Cu, and Zn were higher in Alcolea than in Villanueva (Tables 1 and 2). In Villanueva, with a low soil concentration of P and K, the application of the slurry increased the alfalfa contents of P and K whereas there was no effect at Alcolea. The increase in plant concentration of P and K observed at Villanueva could be partially due to the lower initial soil extractable levels of these nutrients in this location compared with those found in Alcolea. Reports from other areas show that the plant responses were correlated with soil extractable quantities of P and K (James et al., 1995; Lanyon and Griffith, 1988). The average values of P and K of the whole-plant alfalfa, obtained in our experiments, are considered adequate in Alcolea, but they are at the critical levels for P and K in Villanueva according to the values summarized by Kelling and Matocha (1990). Nutrient sufficiency range is >3 g kg^–1 for P and from 14 to 30 g kg^–1 for K (Kelling and Matocha, 1990).

The application of the slurry increased the plant concentration of Cu, in both locations, whereas the concentration of Zn only increased in Villanueva (Tables 1 and 2). These results are in agreement with studies showing that the application of swine manure produces surpluses of Cu and Zn, leading to increases in soil and as a consequence plant concentrations of Cu and Zn (Chaussod et al., 1997; Coppenet et al., 1993).

Soil Nutrient Evolution and Balance of Nutrients
The initial and final soil mineral concentrations for each location are presented in Tables 3 and 4.

The balance of the K (Table 5) was negative for all treatments at both locations, showing that the amounts of swine manure applied were not sufficient to cover the needs of the alfalfa, whose average annual extractions ranged from 160.7 to 390 kg K ha^–1 in Villanueva and Alcolea, respectively. Consequently, lower final K soil concentrations were observed (Tables 3 and 4). However, the P needs, whose average annual extractions ranged from 23.0 to 44.7 kg P ha^–1 in Villanueva and Alcolea, respectively, were met by the application of 50 m³ ha^–1 of slurry. Consequently, the increase in soil P at the end of the trials at Alcolea, with the treatment of 50 m³ ha^–1, reflects the positive balance of this treatment (Table 3). At Villanueva, with lower soil fertility and lower DM yields, the nutrient balance for P was positive (Table 5), but it was not well reflected in the final P soil concentrations, possibly because, in this soil with high level of Ca, the P could be tied up (Sharpley, 2000).

The increase in Cu and Zn levels with the application of swine slurry has been reported to be of the order of 0.25 to 2 mg kg^–1 yr^–1 in soils of northwest France receiving annual applications of swine slurry of 50 m³ ha^–1 or higher for at least 15 yr (Bourrelier and Berthelin, 1998). In our study, the rates for Cu observed in Villanueva were at most, half of those reported in France, and there was no increase at Alcolea. One reason could be that in areas with long alfalfa growing seasons, such as those where experiments were conducted, and good forage yields, alfalfa can remove larger amounts of trace elements from soils (100 g ha^–1 yr^–1 of Cu and Zn) (Chang and Page, 2000).

The results of our experiments suggest that, with the moderate amounts of swine slurry applied, extractable levels of trace elements accumulate very slowly in alfalfa fields with high levels of CaCO₃, and alfalfa can be used as a crop to dispose of the slurry. These low rates of accumulation are not likely to interfere with agriculture.

Alfalfa can be a major sink for recycling (Undersander et al., 1994; Van Horn and Hall, 1997), with average annual extractions of 350 and 564 kg N ha^–1, in Villanueva and Alcolea, respectively.

The extractions of N were higher than the inputs (Table 5), showing a negative budget that went from 427 to 916.6 kg N ha^–1 for the treatments receiving N and consequently helping to reduce the possible N water pollution. It is known that the amount of N symbiotically fixed is inversely related to the amount of N available from other sources (Hannaway and Shuler, 1993). Alfalfa preferentially uses N from the soil and from applied sources such as manure and uses N fixation to meet any additional N need.

	CONCLUSIONS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Annual applications of up to 50 m³ ha^–1 of swine slurry were not detrimental to the alfalfa crop but increased DM yields by at least 36% in soils with low nutrient fertility levels (6 mg kg^–1 and 103 mg kg^–1 of AB-DTPA extractable P and K, respectively) compared with nonfertilized plots. In soils with better fertility (16.7 mg kg^–1 of extractable P and 152.5 mg kg^–1 of extractable K), the application of swine slurry did not decrease the DM compared with the untreated plots.

The application of slurry increased the soil concentrations of extractable Cu and Zn in one trial each. However, the results suggested that in soils with low levels of trace elements, a 2-yr application of swine slurry did not produce a significant buildup of these elements that could lead to an environmental problem.

	ACKNOWLEDGMENTS

 
We thank J.A. Betbesé, J.L. Millera, B. Bagá, J. Peñarroya, and Dra. Rosa Teira for their technical assistance. This research was financed by the AIFE (Asociación Interprofesional de Forrajes Españoles) (Spanish Association of Forage Producers).

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 

• Allos, H.F., and W.V. Bartholomew. 1955. Effect of available nitrogen on symbiotic fixation. Soil Sci. Soc. Am. Proc. 19:182–184.
• Allos, H.F., and W.V. Bartholomew. 1959. Replacement of symbiotic fixation by available nitrogen. Soil Sci. 87:61–65.
• Blumenthal, J.M., M.P. Russelle, and J.F.S. Lamb. 1999. Subsoil nitrate and bromide uptake by contrasting alfalfa entries. Agron. J. 91:269–275.[Abstract/Free Full Text]
• Bodet, J.M., S. Hacala, C. Aubert, and C. Texer. 2001. Fertilizer avec les engrais de ferme. Institut de l'Elevage, ITAVI, ITCF, and ITP, Paris.
• Bourrelier, P.H., and J. Berthelin. 1998. Contamination des sols par les éléments en traces: Les risques et leur gestion. Académie des Sciences. Rapport 42. Lavoisier Tec-Doc, Paris.
• Chang, A., and A. Page. 2000. Trace elements slowly accumulating, depleting in soils. Calif. Agric. 54:49–55.
• Chaussod, R., M. Lineres, M. Terce, and P. Chasin. 1997. Déchets urbains: impact sur la qualité des sols et des produits. p. 241–257. In G. Thevenet and P. Roiu (ed.) Qualité des sols et qualité des productions agricoles. Actes des Trosièmes Rencontres de la Fertilization Raisonnée et de l'Analyses de Terre, Blois, France. 18–20 Nov. 1997. Comifer, Blois, France.
• Coppenet, M., J. Golven, J.C. Simon, L. Le Corre, and M. Le Roy. 1993. Évolution chimique des sols en exploitation d'élevage intensif: Exemple du Finistère. Agronomie (Paris) 13:77–83.
• Daliparthy, J., S.J. Herbert, L.I. Moffitt, and P.L.M. Veneman. 1995. Herbage production, weed occurrence and economic risk from dairy manure applications to alfalfa. J. Prod. Agric. 8:495–501.
• Daliparthy, J., S.J. Herbert, and P.L.M. Veneman. 1994. Dairy manure applications to alfalfa: Crop response, soil nitrate, and nitrate in soil water. Agron. J. 86:927–933.[Abstract/Free Full Text]
• Danés, R., V. Molina, I. Prats, M. Alamos, J. Boixadera, and E. Torres. 1995. Manual de gestió dels purins i de la seva reutilització agrícola. Departament de Medi Ambient, Junta de Residus i Departament d'Agricultura, Ramadería i Pesca. Generalitat de Catalunya, Barcelona, Spain.
• Domingo, F., and A. Bosch. 2001. Uso de purín como fertilizante en una rotación de cultivos herbáceos en regadío. p. 261–277. In J. Boixadera and M.R. Teira (ed.) Aplicación agrícola de cultivos herbáceos. Universitat de Lleida, Lleida, Spain.
• Hannaway, D.B., and P.E. Shuler. 1993. Nitrogen fertilization in alfalfa production. J. Prod. Agric. 6:80–85.
• Hatfield, J.L. 1998. Manure as a soil enhancement tool: Taking proper nutrient credit on crop acres. p. 114–128. In Manure matters. Safe and effective ways to plan for use manure and its byproducts. Iowa Pork Producers Assoc., Ames.
• James, D.W., C.J. Hurst, and T.A. Tindall. 1995. Alfalfa cultivar response to phosphorus and potassium deficiency: Elemental composition of the herbage. J. Plant Nutr. 18(11):2447–2464.
• Kelling, K.A., and J.E. Matocha. 1990. Plant analysis as an aid in fertilizing forage crops. p. 603–643. In R.L. Westerman (ed.) Soil testing and plant analysis SSSA Book Ser. 3. SSSA, Madison, WI.
• Kelling, K.A., and M. Schmitt. 1996. Applying manure to alfalfa, how much and when. p. 92–102. In Proc. Natl. Alfalfa Symp., 26th, East Lansing, MI. 4–6 Mar. 1996.
• [LAF] Laboratori d'Anàlisis i Fertilitat de Sòls. 1999. Avaluació i aprofitament dels residus orgànics d'origen ramader en agricultura. Quaderns de Divulgació no. 5. LAF, Sidamon, Lleida, Spain.
• Lanyon, L.E., and W.K. Griffith. 1988. Nutrition and fertilizer use. p. 333–372. In A.A. Hanson, D.K. Barnes, and R.R. Hill (ed.) Alfalfa and alfalfa improvement. Agron. Monogr. 29. ASA, CSSA, and SSSA, Madison, WI.
• Lloveras, J. 2001. Alfalfa (Medicago sativa. L) management for irrigated Mediterranean conditions: The case of the Ebro Valley. Options Méditerranéennes, Série A: Séminaires Méditerranéens 45:115–126.
• Lory, J., R. Kallenbach, and C. Roberts. 2000. Managing manure on alfalfa hay. MU Guide G 4555. Univ. of Missouri–Columbia Ext. Serv., Columbia.
• Mangado, J.M., and J.M. Ameztoy. 1997. Abonado orgánico en alfalfa. Respuesta en producción y calidad a diferentes aportaciones. p. 347–357. In Reunión Científica de la SEEP, XXXVII, Sevilla, Spain. 5–9 May 1997. Junta de Andalucía, Consejeria de Agricultura, Sevilla, Spain.
• McAuliffe, C., D.S. Chamblee, H. Uribe-Arango, and W.W. Woodhouse, Jr. 1958. Influence of inorganic nitrogen on nitrogen fixation by legumes as revealed by ¹⁵N. Agron. J. 50:334–337.[Abstract/Free Full Text]
• Mills, H.A., and B. Jones. 1996. Preparation and analysis. p. 116–124. In Plant analysis handbook II. Micro Macro Publ., Jefferson City, MO.
• Nelson, D.W., and L.E. Sommers. 1973. Determination of total nitrogen in plant material. Agron. J. 65:109–112.[Abstract/Free Full Text]
• Quevauviller, Ph., H. Muntau, U. Fortunati, and K. Vercoutere. 1996. The certification of the total contents (mass fractions) of Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, and Zn and the aqua regia soluble contens (mass fractions) of Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn in a calcareous loam soil. European Commission BCR Reference Materials. EUR 16890.
• SAS Institute. 1988. Sas uses guide: Statistics. SAS Inst., Cary, NC.
• Schmitt, M.A., C.C. Sheaffer, and G.W. Randall. 1991. Utilization of liquid manure in alfalfa production. p. 30–37. In Proc. Natl. Alfalfa Symp., 21st, Rochester, MN. 14 Feb. 1991.
• Sharpley, A. 2000. Phosphorus availability. p. D-18–D-38. In M. Sumner (ed.) Handbook of soil science. CRC Press, Boca Raton, FL.
• Soil and Water Conservation Society. 1998. Manure management. In harmony with the environment and society. Soil and Water Conserv. Soc., West North Central Region, Ames, IA.
• Soltanpour, P.N. 1991. Determination of nutrient availability and elemental toxicity by AB-DTPA soil test and ICPS. Adv. Soil Sci. 16:165–191.
• Spears, J.W., B.A. Creech, W.L. Flowers, and G.M. Gill. 1998. Reducing zinc and copper in swine waste through dietary manipulations. p. 115–117. In Proc. Conf. Anim. Prod. Syst. and the Environ., Des Moines, IA. July 1998. Iowa State Univ., Ames.
• Undersander, D., N. Martin, D. Cosgrove, K. Kelling, M. Schmitt, J. Wedberg, R. Becker, C. Grau, J. Dool, and M. Rice. 1994. Alfalfa management guide. ASA, CSSA, and SSSA, Madison, WI.
• Van Horn, H.H., and M.B. Hall. 1997. Agricultural and environmental issues in the management of cattle manure. In J.E. Rechcigl and H.C. MacKinnun (ed.) Agricultural uses of by-products and wastes. ACS Symp. Ser. Am. Chem. Soc., Washington, DC.
• Virgili, J.M., A. Bosch, M. Perez, and J. Boixadera. 2001. Disponibilitat per a les plantes de Mn, Zn i Cd en sols de diferents sistemes agrícoles a Catalunya. p. 131–141. In A. Cortés and J. Boixadera (ed.) Sols contaminats. Dossiers Agraris ICEA, Barcelona, Spain.

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				J. F. S. Lamb, M. P. Russelle, and M. A. Schmitt Alfalfa and Reed Canarygrass Response to Midsummer Manure Application Crop Sci., September 23, 2005; 45(6): 2293 - 2300. [Abstract] [Full Text] [PDF]

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