Saturday, April 26, 2008

Pengiraan C / N Bahan Makanan

Table 3. Characteristics of common composting materials

Material

Nitrogen (dry weight) (%)

C:N (dry weight)

Moisture Content (%)

Bulk Density @Moisture Content (kg/m3)

Beef

- Feedlot with bedding

1.3

1.8

68

710

Dairy

- Solid manure handling

1.7

18

79

710

- Liquid slurry

2.40 - 3.60

16

88 – 92

990

- Solids separated from slurry

1.45

23

77

650

Pigs

- Liquid slurry

0.15 - 5.00

20

93 - 99

1000

- Solids separated from slurry

0.35 - 5.00

1.9

75 – 80

270 - 860

Poultry

- Broiler breeder layer

3.6

10

46

470

- Broiler litter

4.7

15

25

330

- Turkey litter

4.2

14

33

380

Horse Manure with Bedding

1.40 - 2.30

22 - 50

59 – 79

725 - 960

- with straw

1.5

27

67

-

- with shavings

0.9

65

72

-

Sheep Manure

1.30 - 3.09

13 – 20

60 – 75

-

Straw

- general straw

0.30 - 1.10

48 - 150

27-Apr

58 - 357

- oat straw

0.60 - 1.10

48 – 98

14

130 - 192

- wheat straw

0.30 - 0.50

100 - 150

10

135

- barley straw

0.75 - 0.78

-

18-Dec

-

Legume Grass Hay

1.80 - 3.60

15 – 19

10 – 30

-

Cardboard

0.1

563

8

154

Leaves 0.50

1.3

40 – 80

38

60 - 80

Paper

0.20 - 0.25

127 – 178

18 – 20

130

Sawdust

0.06 - 0.80

200 – 750

19 – 65

207 - 267

Woodwaste (Chips)

0.04 - 0.23

212 – 1313

15 – 40

264 - 368

Blending Sample Calculation


Appendix A1



Symbols



a

= total weight of ingredient a



b

= total weight of ingredient b



c

= total weight of ingredient c



M

= desired mix moisture content



Ma, Mb, Mc…

= moisture content of ingredients a, b, c



%Ca, %Cb, %Cc…

= % carbon of ingredients a, b, c… (on dry weight basis)



%Na, %Nb, %Nc…

= % nitrogen of ingredients a, b, c,… (on dry weight basis)



R

= desired C:N ratio of mix



Ra, Rb

= C:N ratio of ingredients a, b, c



.



Appendix A2



Formulas for Only Two Ingredients



Required amount of ingredient a per kg b



To obtain desired C:N ratio:

a = % Nb x (R-Rb) x (1-Mb)
.>..% Na (Ra-R) (1-Ma)



.



To obtain desired moisture content:

a = Mb-M
.>..M-Ma



.



Appendix A3



Formulas for a Mix of Materials



C:N ratio

= weight of C in ingredient a + weight of C in b + weight of C in c +…
.>...>..weight of N in a + weight of N in b + weight of N in c +…

= [%Ca x a x (1-Ma)] + [%Cb x b x (1-Mb)] + [%Cc x c x (1-Mc)]
> [%Na x a x (1-Ma)] + [%Nb x b x (1-Mb)] + [%Nc x c x (1-Mc)]



.



Moisture content

= weight of water in ingredient a + weight of water in b + weight of water in c + .

total weight of all ingredients

= (a x Ma) + (b x Mb) + (c x Mc) …
.>...>.>....a + b + c + ...0


Example

Assume a broiler breeder farm has manure to compost and that sawdust will be used as a bulking agent. How much sawdust and water needs to be added to the manure to have a good compost mix?

Step 1. Determine the approximate nitrogen, carbon, moisture, and bulk density from Table 3 in Chapter 2.

Material

Nitrogen (dry weight) (%)

C:N
(dry weight)

Moisture Content
(%)

Bulk Density @ Moisture Content(kg/m3)

Broiler Breeder Manure

3.60

10

46

470

Sawdust

0.06 - 0.80

200 - 750

19 - 65

207 - 267

Note: For a range of numbers, take the average if there has been no analysis performed.

Sawdust

0.43

475

42

237

. Step 2. Using the formula for two ingredients from Table 3, determine the amount of sawdust (a) needed for each kg of manure, (b) to give a desired C:N ratio (R) of 30.

Given:

b.
Ma.
Mb.
Ra.
Rb.
%Na.
%Nb.

= 1 kg of broiler breeder manure
= 0.20 (for this example 20% was selected)
= 0.46 (46% moisture content of manure )
= 500 (for this example C:N of 500 was selected)
= 10 (C:N ratio of manure)
= 0.1 (for this example 0.1% was selected)
= 3.6 (% nitrogen in manure)

Determine:

a (weight of sawdust needed) for the desired C:N ratio of R = 30
a = %Nb x (R-Rb) x (1-Mb)
.....%Na (Ra-R) (1-Ma)

(Appendix A2)

Calculation:

a = 3.6 x (30-10) x (1-0.46) = 1.0
.....0.1 (500-30) (1-0.20)

Answer:

For each kg of manure, add 1.0 kg of sawdust to obtain a C:N ratio of 30.












.

Step 3. Check the mix moisture content (M.C.) using the moisture content formula in Appendix A2.

Given:

a.
b.
Ma.
Mb.

= 1.0 kg weight of sawdust from Step 2
= 1.0 kg weight of manure
= 0.20 (for this example 20% was selected)
= 0.46 (46% moisture content of manure)

Determine:

M.C. (mix moisture content)
M.C. = (a x Ma) + (b x Mb)
..................a + b

(Appendix A3)

Calculation:

M.C. = (1 x 0.20) + (1 x 0.46) = 0.33 or 33 %
........................1 + 1

Answer:

This starting moisture content of 33% is too low, since ideal moisture content runs from 50 to 60%.

Step 4. Adjust moisture content to 55% using the two-ingredient formula from Appendix A2.

Given:

b.
M.
Ma.
Mb.

= 1 kg of manure/sawdust mix
= 0.55 (55% desired moisture content)
= 1.0 (100% moisture content of water)
= 0.33 (33% moisture content of manure/sawdust mix)

Determine:

‘a’ quantity of water required
a = Mb - M
......M - Ma

Calculation:

a = 0.33 - 0.55 = 0.49
......0.55 - 1.00

Answer:

Add 0.49 kg of water for every 1.0 kg of manure/sawdust mix.

. Step 5. Determine how much manure, sawdust and water to mix.

Given:

Tractor bucket volume = 2.0 m3
Manure bulk density = 470 kg/m3
Sawdust bulk density = 207 kg/m3

Determine:

Volume of manure, sawdust, and water

Calculation:

One bucket of manure weighs 2.0 m3 x 470 kg/m3 = 940 kg
Since an equal weight of manure and sawdust is wanted, add 940 kg of sawdust or 940 kg / 207 kg/m3 = 4.54 m3 of sawdust
This is equal to 4.54 m3 / 2.0 m3 per bucket = 2.27 buckets of sawdust
For each bucket of manure used, there will be a total manure/sawdust mix weighing
940 kg + 940 kg = 1840 kg
Similarly, for each bucket of manure used, add:
0.49 kg of water / kg of mix x 1840 kg = 902 kg of water (902 L of water)

Answer:

For each bucket of manure, add 2.27 buckets of sawdust and 902 litres of water.

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