calculation carbon.pdf

7/30/2019 calculation carbon.pdf

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Advanced CompostingDiscussion: Carbon toNitrogen Ratio Simplifed

CalculationsBy Omar Sadek


2/11

Carbon and Nitrogen - a quick review

Primary nutrients required by microorganisms orproper composting

CarbonNitrogenPhosphorus

PotassiumExcessive or insufcient quantities o Carbon orNitrogen greatly aects the composting process


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Carbon and Nitrogen - a quick review (cont)

Carbon: Provides energy and supports growth

Nitrogen: Provides protein and supportreproductionA balanced Carbon to Nitrogen (C:N) ratio o25:1 to 30:1 is ideal or an active compost pile

C:N ratios o as low as 20:1 or as high as 40:1also produce good quality fnished compost


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Carbon and Nitrogen - a quick review (cont)

I C:N < 20:1Excess Nitrogen will o-gas to theatmosphere as NH3 or N2O, resulting in anundesirable odor

I C:N > 40:1Decomposition rate (ie: composting process)slows downThis can be countered by reducing theparticle size


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C:N Ratio - Simplifed Calculations

Does not actor in Moisture Content o

eedstock materialDoes not actor in Degradability o thevarious eedstock materials

the ease in which the carbon compounds

in the individual material decomposesand utilized by the microorganisms


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Carbon to Nitrogen Ratio Simplifed Formula

[Carbon value

o material A] X

[Weight o

material A] )([Carbon value

o material B] X

[Weight o

material B] )( +...+___________________________________[Weight omaterial A] + [Weight omaterial B] +...


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Simplifed C:N Calc Example #1

10 lbs. Llama manure @ 20:1

10 lbs. Fresh leaves @ 40:1Thereore...([20] x [10]) + ([40] x [10])

[10] + [10]______________________ = 60020___ = 30:1


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Simplifed C:N Calc Example #2

10 lbs. Llama manure @ 20:1

10 lbs. Hardwood bark @ 220:1Thereore...([20] x [10]) + ([220] x [10])

[10] + [10]______________________ = 240020___ = 120:1Too much brown material added to mix!


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General Guidelines or Mixing Greens

and Browns or Acceptable C:N RatioFor browns < 60:1

Leaves, shrubs, corn stalks

For browns 60:1 to 120:1Pine Needles, straw, corncobsFor browns 120:1 to 180:1

Wheat, paper, newsprintFor browns 180:1 to 320:1

Hardwood bark, papertowelsFor browns 320:1 to >500:1Sotwood bark, cardboard,wood chips, sawdust

NOTE: I mixing more than 2 types o brown material, use the Compost Calculator!

=

= 1/2= 1/4

= 1/8= 1/16


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Practical Application ExampleVillage o Corrales Composting Facility

Starting Bin Dimensions: 10x8x5 = 14.8 cu ydEstimated kitchen scraps (greens) per week = Qty 10 55 galcontainers = 550 gals/wk = 2.7 cu yd = 4,300 lbsI we mixed w/ dried leaves (browns), wed need minimum o3000 lbs o leaves = 15 cu ydThereore, the starting bin would be too small; 14.8 cu yd vs.an estimated compost pile o 17.7 cu yd!I we mixed w/ 500 lbs o leaves and 200 lbs o wood chips,estimated compost pile would only be 6 cu yd!


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Questions???

Thanks or your attention!

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calculation carbon.pdf