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Short term intensive rotationalgrazing in native pasture: Effects on soil nitrate and extractable P     G. Sanjari, H. Gha...
Outline Introduction Currajong project  Location and climate  Grazing treatments  Soil analysis  Results        Soi...
Introduction   Livestock industry is of main sources    responsible for downstream water pollution
Introduction (continue)  Standards for the pollutants In water:• The maximum concentration of nitrate  allowed in drinking...
Introduction (continue)      Grazing behavior and animal waste      concern in native pastureGrazing animals:  • Recycle 7...
Introduction (continue)    Grazing practices affect soil health and    water qualityContinuous grazing (large paddock)  • ...
Currajong case studyShort term Intensive Rotational Grazing (SIRG)vs. yearlong Continuous Grazing (CG)Soil parameters:    ...
Currajong study (continue) Climate                                                       SepRainfall:                     ...
Currajong study (continue)Methods: Stocking properties                        Grazing                                     ...
Currajong study (continue) Methods: Soil analysisSoil Organic Carbon:Rapid wet oxidation (Walkley and Black)Soil Organic N...
Currajong study (continue)       Results: SOC & SON (treatments)                                   2001                 20...
Currajong study (continue)Results: SOC & SON (sub-treatments)                                   2001                   200...
Currajong study (continue)Results: Nitrate & Extractable P                                                      Ammonium c...
Currajong study (continue)   Results: Nitrate & Extractable P (continue)                                                  ...
Currajong study (continue)Results: Nitrate & Extractable P (Sheep camp effects)                                   100     ...
Currajong study (continue)Results: Nitrate & Extractable P (Sheep camp effects)                                  Nitrate  ...
Conclusion   Continuous grazing encourages animal aggregation to develop    camp sites with large deposits of animal wast...
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Short term intensive rotational grazing in native pasture: effects on soil nitrate and extractable P. Gholamreza Sanjari

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Presentation from the WCCA 2011 conference in Brisbane, Australia.

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Short term intensive rotational grazing in native pasture: effects on soil nitrate and extractable P. Gholamreza Sanjari

  1. 1. Short term intensive rotationalgrazing in native pasture: Effects on soil nitrate and extractable P G. Sanjari, H. Ghadiri, C. Ciesiolka Research Institute of Forests and Rangelands, Tehran, Iran School of Environmental studies, Griffith University, Australia Department of Natural Resources and Mines, QLD, Australia
  2. 2. Outline Introduction Currajong project  Location and climate  Grazing treatments  Soil analysis  Results  Soil Organic Carbon and Nitrogen  Soil nitrate and extractable P  Sheep camp results Conclusion
  3. 3. Introduction Livestock industry is of main sources responsible for downstream water pollution
  4. 4. Introduction (continue) Standards for the pollutants In water:• The maximum concentration of nitrate allowed in drinking water is 10 mg/L.• For aquatic life, nitrate level more than 4 mg/L considered as pollution problem• Biological growth can be stimulated when Dissolved reactive P (DRP) exceeds 0.01 mg/L In soil solutions:• Environmental concern arise when the nutrient level in soil profile exceed 160 kg/ha for nitrate and 330 kg/ha for available P
  5. 5. Introduction (continue) Grazing behavior and animal waste concern in native pastureGrazing animals: • Recycle 75 – 85% of forage they consume • Don’t graze pasture uniformly • Distribute deposits mainly around food and water troughs, under shades, along fence lines, etcOutcomes of a continual grazing: • Imbalanced distribution of nutrients • Nutrient depletion across paddocks • Low pasture productivity • Animal camp site development and environmental concern on water contamination Sheep Camp
  6. 6. Introduction (continue) Grazing practices affect soil health and water qualityContinuous grazing (large paddock) • Increasing runoff and soil loss and low productivity • Grazing animals are free to congregate • Encourages animal camp developmentRotational grazing (small paddocks) • Includes rest periods for pasture recovery after grazing operations • Better runoff and soil loss control • Discourages animal congregation • More balanced distribution of animal wastes
  7. 7. Currajong case studyShort term Intensive Rotational Grazing (SIRG)vs. yearlong Continuous Grazing (CG)Soil parameters: Q u e e n s la n d• Organic Carbon (SOC)• M u rra y D a rlin g B a s in Organic Nitrogen (SON)• Nitrate-Nitrogen Location: the data C u rra jo n g• Extractable P Property of Currajong Southeast Queensland
  8. 8. Currajong study (continue) Climate SepRainfall: Dry Season OctLong term annual: 645 mm 31% Wet season 69% Apr MarSoil:Up to 50 cm in depthBrown to dark clay loamVegetation:Open Eucalypt woodland withunderstorey of perennial grass speciesDominant species: Dichanthium sericem
  9. 9. Currajong study (continue)Methods: Stocking properties Grazing Grazing periods Rest periods SR DDH Treatments (days) (days) (dse/ha) dse.day/ha Short intensive rotational 14 9‡ (101 60)‡ 12.6 6‡ 3608 Continuous 365 0 1.6 0.2 3529 DDH- Number of dse days per hectare over the whole study period; ‡- Means 1SD; SR- Stocking rate 20 18 16 14Stocking rate DSE/H 12 10 8 6 4 2 0 1/01/00 1/05/00 1/09/00 1/01/01 1/05/01 1/09/01 1/01/02 1/05/02 1/09/02 1/01/03 1/05/03 1/09/03 1/01/04 1/05/04 1/09/04 1/01/05 1/05/05 1/09/05 1/01/06 1/05/06 Continuous grazing Short intensive rotational grazing
  10. 10. Currajong study (continue) Methods: Soil analysisSoil Organic Carbon:Rapid wet oxidation (Walkley and Black)Soil Organic Nitrogen:Semimicro Kjeldahl procedure (Bremner 1996)Nitrate and Ammonium:2 M KCL solution extraction (Bremner Keeney1966), auto analyzer (Lachat 2001)Extractable P0.5 M NaHCO3 Orthophosphate extraction(Colwell 1963), colorimetric procedure (Murphy and Riley 1962)
  11. 11. Currajong study (continue) Results: SOC & SON (treatments) 2001 2006 ns 2001 2006 30.0 ns 2.4 ns p<16 ns p<29SOC tonne/ha 27.5 SON tonne/h a 2.2 ns ns p<25 25.0 2.0 22.5 1.8 20.0 Not 1.6 Short intensive Continuous grazed Short intensive Continuous Not rotational grazing grazing rotational grazing grazing grazed
  12. 12. Currajong study (continue)Results: SOC & SON (sub-treatments) 2001 2006 2001 2006 3.0 ns 32.0 p<18 * p<10 ns ns 2.5 SON tonne/ha SOC tonne/ha ns ns 28.0 ns 2.0 ns 24.0 1.5 20.0 1.0 C1 C2 C3 C4 C1 C2 C3 C4 Short intensive Continuous Short intensive Continuous rotational grazing grazing rotational grazing grazing
  13. 13. Currajong study (continue)Results: Nitrate & Extractable P Ammonium concentration In grazing exclusion: 2001 4.56 mg/kg 6.0 2006 13.69 mg/kg 2001 2006 2001 20 2006 4.5 Kg/ha Kg/ha Extractable P 3.0 NO3-N 10 1.5 0.0 0 Short intensive Continuous Not Short intensive Continuous Notrotational grazing grazing grazed rotational grazing grazing grazed
  14. 14. Currajong study (continue) Results: Nitrate & Extractable P (continue) 3500 Herbage mass kg/ha 3000 Rotational grazing 2500Increase in herbage mass 2000 Continuous grazing 1500 1000 May 01 Feb 02 Mar 03 Mar 04 Feb 05 Feb 06 May 06 2000 Date of sam pling Short intensive rotational grazing 1600 Continuous grazingMass of residue kg/ha 1200 800 Increase in Residue 400 0 0 268 683 1047 1367 1737 1824 May 01 Days May 06
  15. 15. Currajong study (continue)Results: Nitrate & Extractable P (Sheep camp effects) 100 1000NO3 concentration (kg/ha in 0-10 cm) PO4 concentration (kg/ha in 0-10 cm) 10 100 NO3 2001 Sheep camp vegetation: 1 PO4 2001 10 Couch grass 0.1 PO4 2006 1 Agropyron repense (L.) P.Beauv NO3 2006 0.01 0.1 0 100 200 300 400 500 Distance from sheep camp (m)Couch grass regrowth: Herbage mass Rest period Kg/ha DM days 2650 26 3685 60
  16. 16. Currajong study (continue)Results: Nitrate & Extractable P (Sheep camp effects) Nitrate Phosphate Kg/ha Kg/haSoil analysis: 2001 126 222 2006 17.6 79.3 Thresholds 160 330Water analysis: Sampled on 22/01/06 Water analysis:Time (min) 6 15 25 34 Sampled in 2001NO3-N (Mg/L) 0.143 0.189 0.133 0.100 NO3-N 3.4 Mg/LDRP (Mg/L) 0.062 0.013 0.137 0.141 DRP 2.5 Mg/L
  17. 17. Conclusion Continuous grazing encourages animal aggregation to develop camp sites with large deposits of animal wastes raising alarm for downstream water contamination In the study area we found the above threat could be easily the case at regional scale with more camp site development under continuous grazing Short period Intensive Rotational Grazing (SIRG) in the native pasture, modified the aggregation behavior of animals, leading to a major decrease in soil nitrate and extractable P concentrations The rotational grazing provides an environmentally oriented pasture utilization giving a more forage production over continuous grazing

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