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Homem BGC, Borges LPC, de Lima IBG, Guimarães BC, Spasiani PP, Ferreira IM, Meo-Filho P, Berndt A, Alves BJR, Urquiaga S, Boddey RM, Casagrande DR. Forage peanut legume as a strategy for improving beef production without increasing livestock greenhouse gas emissions. Animal 2024; 18:101158. [PMID: 38703756 DOI: 10.1016/j.animal.2024.101158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 05/06/2024] Open
Abstract
The transformation of pastures from a degraded state to sustainable productivity is a major challenge in tropical livestock production. Stoloniferous forage legumes such as Arachis pintoi (forage peanut) are one of the most promising alternatives for intensifying pasture-based beef livestock operations with reduced greenhouse gas (GHG) emissions. This 2-year study assessed beef cattle performance, nutrient intake and digestibility, and balance of GHG emissions in three pasture types (PT): (1) mixed Palisade grass - Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster (syn. Brachiaria brizantha Stapf cv. Marandu) and forage peanut (A. pintoi Krapov. & W.C. Greg. cv. BRS Mandobi) pastures (Mixed), (2) monoculture Palisade grass pastures with 150 kg of N/ha per year (Fertilised), and (3) monoculture Palisade grass without N fertiliser (Control). Continuous stocking with a variable stocking rate was used in a randomised complete block design, with four replicates per treatment. The average daily gain and carcass gain were not influenced by the PT (P = 0.439 and P = 0.100, respectively) and were, on average, 0.433 kg/animal per day and 83.4 kg/animal, respectively. Fertilised and Mixed pastures increased by 102 and 31.5%, respectively, the liveweight gain per area (kg/ha/yr) compared to the Control pasture (P < 0.001). The heifers in the Mixed pasture had lower CH4 emissions (g/animal per day; P = 0.009), achieving a reduction of 12.6 and 10.1% when compared to the Fertilised and Control pastures, respectively. Annual (N2O) emissions (g/animal) and per kg carcass weight gain were 59.8 and 63.1% lower, respectively, in the Mixed pasture compared to the Fertilised pasture (P < 0.001). Mixed pasture mitigated approximately 23% of kg CO2eq/kg of carcass when substituting 150 kg of N/ha per year via fertiliser. Mixed pastures with forage peanut are a promising solution to recover degraded tropical pastures by providing increased animal production with lower GHG emissions.
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Affiliation(s)
- B G C Homem
- Department of Animal Sciences, Federal University of Lavras, UFLA, Lavras, MG 37200-900, Brazil; Embrapa Agrobiologia, Rodovia BR-465, km 7, Seropédica 23897-970 RJ, Brazil
| | - L P C Borges
- Department of Animal Sciences, Federal University of Lavras, UFLA, Lavras, MG 37200-900, Brazil
| | - I B G de Lima
- Department of Animal Sciences, Federal University of Lavras, UFLA, Lavras, MG 37200-900, Brazil
| | - B C Guimarães
- Department of Animal Sciences, Federal University of Lavras, UFLA, Lavras, MG 37200-900, Brazil
| | - P P Spasiani
- Department of Animal Sciences, Federal University of Lavras, UFLA, Lavras, MG 37200-900, Brazil
| | - I M Ferreira
- Department of Animal Sciences, Federal University of Lavras, UFLA, Lavras, MG 37200-900, Brazil
| | - P Meo-Filho
- Embrapa Southeast Livestock, Rodovia Washington Luiz, km 234, Sao Carlos, SP 13560-970, Brazil
| | - A Berndt
- Embrapa Southeast Livestock, Rodovia Washington Luiz, km 234, Sao Carlos, SP 13560-970, Brazil
| | - B J R Alves
- Embrapa Agrobiologia, Rodovia BR-465, km 7, Seropédica 23897-970 RJ, Brazil
| | - S Urquiaga
- Embrapa Agrobiologia, Rodovia BR-465, km 7, Seropédica 23897-970 RJ, Brazil
| | - R M Boddey
- Department of Soil Science, Federal Rural University of Rio de Janeiro, Rodovia BR 465, km 7, Seropédica, RJ 23897-000, Brazil
| | - D R Casagrande
- Department of Animal Sciences, Federal University of Lavras, UFLA, Lavras, MG 37200-900, Brazil.
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de Kássia Gomes F, Homem BGC, Guimaraes BC, de Arruda Camargo Danes M, Broderick GA, Alves BJR, Boddey RM, Casagrande DR. Carbohydrates and protein digestive traits in beef cattle grazing fertilised or mixed tropical pasture. Arch Anim Nutr 2024; 78:60-77. [PMID: 38488818 DOI: 10.1080/1745039x.2024.2319936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 02/01/2024] [Indexed: 04/30/2024]
Abstract
This study was performed to investigate the nitrogen (N) and carbohydrate digestive traits of grazing heifers. The experiment was carried out at the Federal University of Lavras. The treatments were a Marandu palisadegrass (Urochloa brizantha [Syn, Brachiaria brizantha] Stapf. A. Rich. cv. Marandu) monoculture fertilised with 150 kg N/[ha ∙ year] (FP) or Marandu palisadegrass mixed pasture with forage peanut (MP). The pastures were grazed by six rumen-cannulated zebu heifers. A double cross-over design was used in four periods. Nutritive value, intake and apparent digestibility of forage, ruminal traits and kinetics and N balance were evaluated. Apparent total-tract digestibility of dry matter (DM) and neutral detergent fibre (NDF) were greater for FP than for MP. There was no effect in apparent total-tract digestibility of N. The estimated intestinal digestibility of nutrients was greater on MP than FP. Even though N intake and faecal N output were greater on MP than FP, there was no effect in urine N output. The N balance tended to be greater on MP than FP. The forage peanut, which contains condensed tannins, decreased ruminal fibre degradation, apparent digestibility and ruminal protein degradation, increased N flow from the rumen. Inclusion of forage peanut in the mixed pasture decreased the ruminal fibre degradability but increased N retention by the animals.
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Longhini VZ, Cardoso ADS, Berça AS, Boddey RM, Reis RA, Dubeux Junior JCB, Ruggieri AC. Nitrogen supply and rainfall affect ammonia emissions from dairy cattle excreta and urea applied on warm-climate pastures. J Environ Qual 2020; 49:1453-1466. [PMID: 33058171 DOI: 10.1002/jeq2.20167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
Cattle excreta and nitrogen (N) fertilizer deposited on tropical grasslands are important sources of ammonia (NH3 ) emission. We conducted three field trials (wet, intermediate, and dry conditions) to quantify NH3 emissions from urea fertilizer and simulated excretions of heifer urine and dung on warm-climate grasslands in Brazil. Heifer excreta were derived from pastures of palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster 'Marandu'] under three forms of N supply (without or with N fertilization [0 or 150 kg N ha-1 yr-1 ] or mixed with forage peanut [Arachis pintoi 'Amarillo']). Cumulative NH3 -N emissions across rainfall conditions were 7.6-16.6% (mean, 11.7%) for urine, 1.4-2.9% (mean, 2.0%) for dung, and 11.2-20.5% (mean, 14.8%) for urea. Ammonia loss from urine was significantly greater than from dung under all rainfall conditions. Emission from urine and dung differed from those when urea was applied on palisadegrass. There were greater NH3 emissions from urine in the wetter times of the year. Heifer excreta from N-fertilized pasture had greater NH3 emission than excreta from the grass-legume mixture and unfertilized palisadegrass. Urea applied on palisadegrass presented greater NH3 emissions in wet rainfall conditions compared with dry conditions but did not differ from intermediate conditions. Our study showed that N-fertilized systems increase N losses as NH3 emission from excreta, and emissions from urea fertilizer must be included in this system. Heifer excreta and urea fertilizer deposited on warm-climate grasslands increased the NH3 emissions mainly under wet conditions.
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Affiliation(s)
- Vanessa Zirondi Longhini
- Dep. of Animal Science, São Paulo State Univ., via de acesso Professor Paulo Donato Castellane, Jaboticabal, SP, 14884-900, Brazil
| | - Abmael da Silva Cardoso
- Dep. of Animal Science, São Paulo State Univ., via de acesso Professor Paulo Donato Castellane, Jaboticabal, SP, 14884-900, Brazil
| | - Andressa Scholz Berça
- Dep. of Animal Science, São Paulo State Univ., via de acesso Professor Paulo Donato Castellane, Jaboticabal, SP, 14884-900, Brazil
| | | | - Ricardo Andrade Reis
- Dep. of Animal Science, São Paulo State Univ., via de acesso Professor Paulo Donato Castellane, Jaboticabal, SP, 14884-900, Brazil
| | | | - Ana Cláudia Ruggieri
- Dep. of Animal Science, São Paulo State Univ., via de acesso Professor Paulo Donato Castellane, Jaboticabal, SP, 14884-900, Brazil
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Sarabia-Salgado L, Solorio-Sánchez F, Ramírez-Avilés L, Rodrigues Alves BJ, Ku-Vera J, Aguilar-Pérez C, Urquiaga S, Boddey RM. Increase in Milk Yield from Cows through Improvement of Forage Production Using the N 2-Fixing Legume Leucaena leucocephala in a Silvopastoral System. Animals (Basel) 2020; 10:ani10040734. [PMID: 32340205 PMCID: PMC7222761 DOI: 10.3390/ani10040734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/13/2020] [Accepted: 04/21/2020] [Indexed: 11/16/2022] Open
Abstract
Simple Summary In tropical livestock production, forage availability and quality are a serious constraint for milk and meat production. There is an urgent need to reduce the environmental impact of animal production while increasing productivity. The use of legume trees or shrubs associated with grasses effectively increased milk production and decreased the need to use nitrogen fertilizers by taking advantage of atmospheric nitrogen fixation. Abstract The objective was to evaluate milk production, N2-fixation and N transfer, forage yield and composition (under two cutting intervals) in a silvopastoral system (SPS) with Leucaena leucocephala-Megathyrsus maximus and M. maximus-monoculture (MMM) with crossbred cows in a completely randomized design. Forage yield in the SPS was 6490 and 6907 kg DM ha−1 for cutting intervals (CI) of 35 and 50 days. Forage yield for the MMM was 7284 and 10,843 kg DM ha−1, and forage crude protein (CP) was 29.0% and 26.1% for L. leucocephala, harvested at 35 and 50 days, respectively. CP for the associated M. maximus was 9.9% and 7.8% for CI 35 and 50 days, respectively, and for MMM was 7.4% and 8.4%, harvested at 35 and 50 days. Milk production was 4.7 kg cow−1 day−1 for cows grazing MMM and 7.4 kg cow−1 day−1 under SPS. Nitrogen fixation in L. leucocephala (%Ndfa) was estimated to be 89% and 95%, at 35 and 50 days, with an N2 transfer to the associated grass of 34.3% and 52.9%. SPS has the potential to fix and transfer important amounts of N2 to the associated grass, and increase forage CP content and milk production.
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Affiliation(s)
- Lucero Sarabia-Salgado
- Department of Soils, Federal Rural University of Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro 23897-000, Brazil
- Correspondence:
| | - Francisco Solorio-Sánchez
- Faculty of Veterinary Medicine and Animal Science, Autonomous University of Yucatán, Mérida, Yucatán 97315, Mexico; (F.S.-S.); (L.R.-A.); (J.K.-V.); (C.A.-P.)
| | - Luis Ramírez-Avilés
- Faculty of Veterinary Medicine and Animal Science, Autonomous University of Yucatán, Mérida, Yucatán 97315, Mexico; (F.S.-S.); (L.R.-A.); (J.K.-V.); (C.A.-P.)
| | - Bruno José Rodrigues Alves
- Embrapa Agrobiologia, Brazilian Corporation for Agricultural Research—National Centre for Agrobiology Research, Seropédica, Rio de Janeiro 23891-000, Brazil; (B.J.R.A.); (S.U.); (R.M.B.)
| | - Juan Ku-Vera
- Faculty of Veterinary Medicine and Animal Science, Autonomous University of Yucatán, Mérida, Yucatán 97315, Mexico; (F.S.-S.); (L.R.-A.); (J.K.-V.); (C.A.-P.)
| | - Carlos Aguilar-Pérez
- Faculty of Veterinary Medicine and Animal Science, Autonomous University of Yucatán, Mérida, Yucatán 97315, Mexico; (F.S.-S.); (L.R.-A.); (J.K.-V.); (C.A.-P.)
| | - Segundo Urquiaga
- Embrapa Agrobiologia, Brazilian Corporation for Agricultural Research—National Centre for Agrobiology Research, Seropédica, Rio de Janeiro 23891-000, Brazil; (B.J.R.A.); (S.U.); (R.M.B.)
| | - Robert Michael Boddey
- Embrapa Agrobiologia, Brazilian Corporation for Agricultural Research—National Centre for Agrobiology Research, Seropédica, Rio de Janeiro 23891-000, Brazil; (B.J.R.A.); (S.U.); (R.M.B.)
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Berça AS, Cardoso ADS, Longhini VZ, Tedeschi LO, Boddey RM, Berndt A, Reis RA, Ruggieri AC. Methane production and nitrogen balance of dairy heifers grazing palisade grass cv. Marandu alone or with forage peanut. J Anim Sci 2020; 97:4625-4634. [PMID: 31588955 DOI: 10.1093/jas/skz310] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 10/06/2019] [Indexed: 11/14/2022] Open
Abstract
Livestock production systems are an essential agribusiness activity in Brazil, but a critical challenge of Brazilian farmers is to maintain the equilibrium of the ecosystem, using herbage resources efficiently with a minimum impact on the environment. Nitrogen (N) fertilization and the inclusion of forage legumes into tropical grass pastures are management strategies which increase the productivity and nutritive value of pastures and may also affect methane (CH4) production by ruminants. The objective of this study was to examine the effects of either fertilizing palisade grass pastures with N or including the forage peanut (Arachis pintoi) into grass pastures on enteric CH4 emission, microbial protein production in the rumen via purine derivatives in the urine, and N balance. Twenty-one nonlactating crossbred dairy heifers were used in a completely randomized design with 3 treatments. The treatments consisted of pastures of palisade grass without N fertilization (control), fertilized with urea (fertilized), and palisade grass mixed with forage peanut (mixed). Seven animals (replications) were used to evaluate dry matter intake, digestibility, CH4 emission, urea, purine derivatives, and volume of urine, and N ingestion and excretion. Four paddocks (replications) were used to measure herbage mass; morphological, botanical, and chemical composition of herbage; and herbage allowance. The CH4 emissions were determined using the sulfur hexafluoride (SF6) tracer gas technique. The efficiency of N utilization (ENU) was calculated using the N balance data. Crude protein (CP) concentration of herbage increased with fertilization or legumes inclusion (P < 0.0001) while neutral detergent fiber (NDF) concentration decreased (P = 0.0355). The leaf allowance was higher in the fertilized treatment (P = 0.0294). Only uric acid excretion increased with N fertilization (P = 0.0204). The ENU was not affected by fertilized or mixed compared to control and averaged 55% (P = 0.8945). The enteric CH4 production was similar between treatments and averaged 129 g/d (P = 0.3989). We concluded that the changes in chemical composition of herbage provided by N fertilization or the inclusion of the legume showed no reduction in enteric CH4 emissions, but the ENU was more significant than previous studies with palisade grass, suggesting that different management strategies might alter the ENU under grazing conditions.
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Affiliation(s)
- Andressa S Berça
- Department of Animal Sciences, São Paulo State University, Jaboticabal, SP, Brazil
| | - Abmael Da S Cardoso
- Department of Animal Sciences, São Paulo State University, Jaboticabal, SP, Brazil
| | - Vanessa Z Longhini
- Department of Animal Sciences, São Paulo State University, Jaboticabal, SP, Brazil
| | - Luís O Tedeschi
- Department of Animal Science, Texas A&M University, College Station, TX
| | | | | | - Ricardo A Reis
- Department of Animal Sciences, São Paulo State University, Jaboticabal, SP, Brazil
| | - Ana Cláudia Ruggieri
- Department of Animal Sciences, São Paulo State University, Jaboticabal, SP, Brazil
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Cardoso ADS, Alves BJR, Urquiaga S, Boddey RM. Effect of volume of urine and mass of faeces on N2O and CH4 emissions of dairy-cow excreta in a tropical pasture. Anim Prod Sci 2018. [DOI: 10.1071/an15392] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We aimed to quantify nitrous oxide (N2O) and methane (CH4) emissions as a function of the addition of different quantities of bovine faeces and urine on soil under pasture. Two experiments were performed in randomised complete blocks with five replicates. In the first experiment, the emissions of CH4 and N2O were evaluated for 14 days after the addition of four amounts of faeces (0.0, 1.2, 1.8 and 2.4 kg of fresh faeces per plot), and in a second experiment, N2O emissions were evaluated for 43 days after addition of four volumes of urine (0.0, 1.0, 1.5 and 2.0 L). Urine and faeces came from crossbred (Fresian × Gir) dairy cows fed on pasture and concentrates. N2O emissions from faeces did not alter the emission factor (EF) according to the faeces weight (P = 0.73). N2O-N EF from faeces-N averaged 0.18% (±0.05) of total applied N. The volume of urine applied influenced N2O losses. The EF decreased linearly (P = 0.015) with increasing volumes of urine, being 4.9% (±0.75), 3.36% (±0.7) and 2.43% (±0.46) of N applied emitted as N2O for the 1.0, 1.5 and 2.0 L volumes of urine respectively. The EF from urine was significantly (P < 0.0001) higher than the EF from faeces. There was no change to the CH4 emissions per kilogram of excreta when the amount of faeces added was varied (P = 0.87). However, the CH4 emitted increased linearly with the amount of faeces (P = 0.02). The CH4 EF was estimated to be 0.95 (±0.38) kg/head.year.
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Chaer GM, Resende AS, Campello EFC, de Faria SM, Boddey RM. Nitrogen-fixing legume tree species for the reclamation of severely degraded lands in Brazil. Tree Physiol 2011; 31:139-149. [PMID: 21378065 DOI: 10.1093/treephys/tpq116] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The main challenges faced in the reclamation of severely degraded lands are in the management of the systems and finding plant species that will grow under the harsh conditions common in degraded soils. This is especially important in extremely adverse situations found in some substrates from mining activities or soils that have lost their upper horizons. Under these conditions, recolonization of the area by native vegetation through natural succession processes may be extremely limited. Once the main physical and chemical factors restrictive to plant growth are corrected or attenuated, the introduction of leguminous trees able to form symbioses with nodulating N₂-fixing bacteria and arbuscular mycorrhizal fungi constitutes an efficient strategy to accelerate soil reclamation and initiate natural succession. These symbioses give the legume species a superior capacity to grow quickly in poor substrates and to withstand the harsh conditions presented in degraded soils. In this article we describe several successful results in Brazil using N₂-fixing legume tree species for reclamation of areas degraded by soil erosion, construction and mining activities, emphasizing the potential of the technique to recover soil organic matter levels and restore ecosystem biodiversity and other environmental functions.
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Silva-Froufe LGD, Boddey RM, Reis VM. Quantification of natural populations of Gluconacetobacter diazotrophicus and Herbaspirillum spp. In sugar cane (Saccharum spp.) Using differente polyclonal antibodies. Braz J Microbiol 2009. [DOI: 10.1590/s1517-83822009000400018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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da Silva-Froufe LG, Boddey RM, Reis VM. Quantification of natural populations of Gluconacetobacter diazotrophicus and Herbaspirillum spp. In sugar cane (Saccharum spp.) Using differente polyclonal antibodies. Braz J Microbiol 2009; 40:866-78. [PMID: 24031435 PMCID: PMC3768561 DOI: 10.1590/s1517-838220090004000018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 03/21/2009] [Accepted: 05/15/2009] [Indexed: 11/22/2022] Open
Abstract
The species Gluconacetobacterdiazotrophicus, Herbaspirillum seropedicae and H. rubrisubalbicans are endophytic N2-fixing [diazotrophic] bacteria which colonise not only roots, but also the aerial tissue of sugar cane. However, the technique most commonly used to quantify the populations of these microbes in plants is by culturing serial dilutions of macerates of plant tissues in N free semi-solid media which are only semi-selective for the species/genera [the Most Probable Number (MPN) Technique] and each culture must be further subjected to several tests to identify the isolates at the species level. The use of species-specific polyclonal antibodies with the indirect ELISA (enzyme-linked immunosorbent assay) can be an alternative which is rapid and specific to quantify these populations of bacteria. This study was performed to investigate the viability of adapting the indirect ELISA technique to quantify individually the populations of these three species of diazotroph within the root and shoot tissues of sugarcane. The results showed that species-specific polyclonal antibodies could be obtained by purifying sera in protein-A columns which removed non-specific immuno-globulins. It was possible to quantify the three bacterial species in the Brazilian sugarcane variety SP 70-1143 in numbers above 105 cells per g fresh weight in roots, rhizomes and leaves. The numbers of the different bacterial species evaluated using the ELISA technique were found to be higher than when the same populations were evaluated using the MPN technique, reaching 1400 times greater for G. diazotrophicus and 225 times greater for Herbaspirillum spp. These results constitute the first quantification of Herbaspirillum using immunological techniques.
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Affiliation(s)
- Lúcia Gracinda da Silva-Froufe
- Departamento de Bioquímica e Biologia Molecular, Setor de Ciências Biológicas, Centro Politécnico, Universidade Federal do Paraná , Curitiba, PR , Brasil
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Ramos MG, Villatoro MA, Urquiaga S, Alves BJ, Boddey RM. Quantification of the contribution of biological nitrogen fixation to tropical green manure crops and the residual benefit to a subsequent maize crop using 15N-isotope techniques. J Biotechnol 2001; 91:105-15. [PMID: 11566383 DOI: 10.1016/s0168-1656(01)00335-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study the contribution of biological N2 fixation (BNF) to leguminous green manures was quantified in the field at different sites with different 15N methodologies. In the first experiment, conducted on a Terra Roxa soil in Cuba, the BNF contribution to three legumes (Crotalaria juncea, Mucuna aterrima and Canavalia ensiformis) was quantified by applying 15N-labelled ammonium sulphate to the soil. The second experiment was planted in a very low fertility sandy soil near Rio de Janeiro, and the 15N natural abundance technique was applied to quantify BNF in C. juncea, M. niveum and soybean. In both studies the advantages of using several non-N2-fixing reference plants was apparent and despite the much greater accumulation of the C. juncea in the experiment performed on the fertile soil of Cuba, the above ground contributions of BNF at both sites were similar (40-80 kg N x ha(-1)) and greater than for the other legumes. In a further experiment the possible contribution of root-derived N to the soil/plant system of two of the legumes was quantified using a 15N-leaf-labelling technique performed in pots. The results of this study suggested that total below-ground N could constitute as much as 39 to 49% of the total N accumulated by the legume crops.
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Affiliation(s)
- M G Ramos
- Instituto Nacional de Ciencias Agrícolas, Carretera de Tapaste-San José, Gaveta Postal No. 1, C.P. 32700, San José de Las Lajas, Havana, Cuba
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