Mineralization of 15NLabeled Dairy Manure Components in Several Soils

1
Mineralization of 15N-Labeled Dairy Manure
Components in Several Soils
P.R. Cusick, Department of Soil Science,
University of Wisconsin-Madison J.M. Powell,
USDA-ARS Dairy Forage Research Center, Madison,
WI R. F. Hensler, College of Natural Resources,
University of Wisconsin- Stevens Point K.A.
Kelling, Department of Soil Science, University
of Wisconsin-Madison
Introduction The rate and extent of manure N
mineralization in soil determines manure N
availability for crop uptake. In this study we
evaluated the N mineralization of dairy manure
components (feces, urine and bedding) in soils
under different environmental conditions. Soil
texture and other controls, such as moisture and
temperature, create environments where great
differences in manure N mineralization are
anticipated to occur. Understanding the
influence of these factors under field conditions
is crucial to better predicting the amount and
rate of how manure N becomes available to
agronomic crops. The objective of this incubation
study is to understand how soil type and
temperature effect N mineralization of individual
dairy manure components (feces, urine and
bedding) by use of unlabeled and 15N labeled
manure components. Materials and Methods A
laboratory incubation study was conducted in
which 15N-labeled or unlabeled feces, urine and
oat straw bedding were incubated in soil for 168
days. Manure amendments were applied at a rate
equivalent to 350 kg N ha-1 (36 derived from
feces, 42 from urine and 22 from bedding) into
incubation vessels (2L glass jars containing 250g
soil dry wt.). Treatment 1 15N-Labeled Feces,
Urine and Bedding at natural abundance. Treatment
2 15N-Labeled Urine, Feces and Bedding at
natural abundance. Treatment 3 15N-Labeled
Bedding, Feces and urine at natural
abundance. Treatment 4 15N-Labeled Feces, Urine
and Bedding. Treatment 5 Control, no
amendments. Triplicate vessels per manure
treatment plus controls were packed to natural
bulk density, kept at 60 water filled pore space
and incubated at 11, 18, or 25 C.  Vessels were
sampled at 0, 14, 21, 42, 84, and 168 days and
analyzed for mineralized N (NH4 and NO3-) and
15N abundance. Soil Series Texture
Description___________________ Symco Sandy
Loam Fine-loamy, mixed, mesic Aquollic
Hapludalfs Rosholt Sandy Loam Coarse-loamy,
mixed, superactive, frigid Haplic
Glossudalfs Catlin Silt Loam Fine-silty, mixed,
superactive, mesic Oxyaquic Argiudolls Loyal Silt
Loam Fine-loamy, mixed, superactive, frigid
Oxyaquic Glossudalfs Plano Silt
Loam Fine-silty, mixed, superactive, mesic Typic
Argiudolls Rozetta Silt Loam Fine-silty, mixed,
superactive, mesic Typic Hapludalfs

• Results and Discussion
• Day 14
• Manure N mineralization for most soils was higher
  at 11 and 18 ºC than at 25 ºC.
• Rozetta had the highest manure N mineralization,
  followed by Loyal, Symco and Plano. Rosholt and
  Catlin soils had the lowest. With the exception
  of the Catlin soils, it appears that soils with
  lower percent sand had more N mineralization than
  soils with higher percent sand.
• Day 21
• Loyal and Rosholt had the highest manure N
  mineralization followed by Plano and Symco.
  Catlin had the lowest manure N mineralization.
  With the exception of the Loyal soil, it appears
  that soils with higher percent sand had more N
  mineralization than soils with lower percent
  sand.
• Day 42
• Loyal had the highest manure N mineralization.
  All other soils were similar.
• Day 84
• Rosholt and Loyal had higher N mineralization
  than Catlin. Plano had the lowest N
  mineralization. It appears that soils with low
  initial CN ratios had higher manure N
  mineralization over soils with high initial CN
  ratios.
• Day 168
• Symco had the highest manure N mineralization and
  Loyal and Catlin had the lowest. Similar to day
  84, it appears that soils with low initial CN
  ratios had higher manure N mineralization over
  soils with high initial CN ratios.

• 15N- All Components
• Soil type did not have an effect on 15N
  mineralization when all components were labeled.
• Highest mineralized values were found at 11 and
  25 C.
• Average 15N mineralized over all soils and
  temperatures was 23. Average manure 15N
  mineralization by proportionally adding
  component averages equaled 32.
• Muñoz (2001) on the Plano soil, found 14 uptake
  of 15N in corn (Zea maize) averaged over 3 years
  of data. Only feces and urine were labeled in
  this trial.
• References
• Muñoz, G.R. 2001. Estimate of manure availability
  using 15N-labeled manure and other techniques.,
  University of Wisconsin, Madison.
• Acknowledgements The authors appreciated the
  diligent effort of Jennifer Hegge and Chris
  Fellner, University of Wisconsin- Stevens Point
  in the daily maintenance of this experiment.
• Funding Support for this project was provided by
  the UW Consortium for Agriculture and Natural
  Resources, the UW-Madison College of Agricultural
  and Life Sciences, and USDA-ARS and is gratefully
  acknowledged.

• Soil type had a significant effect on N
  mineralization of feces (p0.0001) and straw
  (p0.0093).
• Temperature had a significant effect on N
  mineralization of feces (p0.0001), straw
  (p0.0015), and all components (p0.0003).
• Soil type and temperature interacted to affect
  straw mineralization.
• 15N Feces
• Highest 15N mineralization was observed in Plano
  and Symco soils.
• Highest 15N mineralization was observed at 25 C
  for all soils.
• A field trial on the Plano soil (unpublished
  data), found 17 uptake of 15N labeled feces in
  corn (Zea maize). In good comparison, this
  incubation trial found 19 of 15N labeled feces
  to be mineralized.
• 15N Urine
• Soil type and temperature did not have a
  significant effect on 15N urine mineralization
  likely due to the rapid breakdown of most, if not
  all urine in the soil.
• Average 15N mineralization over all soils and
  temperatures is 55. A field trial on the Plano
  soil (unpublished data), found 31 uptake of 15N
  labeled urine in corn (Zea maize). Though urine
  nitrogen readily mineralizes, losses from this
  component may occur.
• 15N Straw
• Plano, Symco and Loyal soils had increasing 15N
  mineralization with increasing temperature. The
  Rosholt soil decreased 15N mineralization with
  increasing temperature. The Rozetta soil 15N
  mineralization remained stable for all
  temperatures.
• It should be noted that straw N mineralization
  was similar to fecal N mineralization, averaging
  17 and 15, respectively over all soils and
  temperatures.