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University
of Rhode Island GreenShare Factsheets
A
Guide to the Nutrient Value of Organic Materials
Many
home gardeners want to grow fruits and vegetables with organic
sources of fertilizer. Considering the many benefits of the addition
of organic materials, this subject warrants attention. Manure
and composted plant materials add organic matter, which aids
in moisture retention, helps reduce compaction and can buffer
extremes in pH. It also helps maintain the structure and nutrient
holding capacity of the soil. However,
the nutrient level of organic materials is lower, rate of release
is slower and levels of minerals may vary and are not balanced.
The information below will help you interpret differences in
nutrient content and relative availability of organic materials. Fruits
and vegetables often have high nitrogen demands, and it can be
difficult to provide sufficient nitrogen from an organic source
throughout the growing season of the crop. In addition, availability
of nitrogen late in the season can make perennial plants such
as raspberries and apples susceptible to winter injury. It is
a challenge to provide plants with a readily available organic
nitrogen source early in the growing season, yet have it less
available in late summer. Much
variability exists in the composition of similar organic materials.
For example, manure with straw will have a different nitrogen
composition than pure manure, and the rate of nitrogen release
may be slower because of the higher amount of carbon in the straw.
The table below lists the approximate composition of various
organic materials, and the nitrogen, potassium and phosphorus
that can be provided from them.
|
Composition
of Manure
(from Samples Reported in Knott's Handbook for Vegetable Growers)
|
| |
Moisture
(%) |
Nitrogen |
Phosphorus |
Potassium |
| Fresh
Manure with Bedding or Litter |
| Cattle |
86 |
11 |
4 |
10 |
| Duck |
61 |
22 |
29 |
10 |
| Goose |
67 |
22 |
11 |
10 |
| Hen |
73 |
22 |
22 |
10 |
| Hog |
87 |
11 |
6 |
9 |
| Horse |
80 |
13 |
5 |
13 |
| Sheep |
70 |
20 |
15 |
21 |
| Turkey |
74 |
26 |
14 |
10 |
| Dried
Commercial Products |
| Cattle |
10 |
42 |
42 |
61 |
| Hen |
13 |
31 |
31 |
40 |
| Hog |
10 |
45 |
45 |
20 |
| Rabbit |
16 |
26 |
26 |
32 |
| Sheep |
16 |
32 |
32 |
41 |
From:
Lorenz, Oscar A. and Donald N. Maynard, 1980
Knott's Handbook for Vegetable Growers. Second
edition, pg. 76 |
Guide
to the Mineral Nutrient Value of Organic Materials (%)
|
| Materials |
Nitrogen |
Phosphorus |
Potassium |
Relative
Nutrient Availablity |
| Bone
Meal (raw) |
2
to 6 |
15
to 27 |
0 |
Slow |
| Bone
Meal (steamed) |
0.7
to 4 |
10
to 34 |
0 |
Slow
Med. |
| Cocoa
Shell Meal |
2.5 |
1 |
2.5 |
Slow |
| Compost
(not fortified) |
1.5
to 3.5 |
0.5
to 1 |
1
to 2 |
Slow |
| Cotton
Seed meal (dry) |
6 |
2.5 |
1.7 |
Slow
Med. |
| Dried
Blood (dry) |
12 |
1.5 |
0.57 |
Med.
Rapid |
| Fish
Meal (dry) |
10 |
4 |
0 |
Slow |
| Manure
(fresh) |
|
|
|
|
|
Cattle
|
0.25 |
0.15 |
0.25 |
Medium |
|
Horse
|
0.3 |
0.15 |
0.25 |
Medium |
|
Sheep
|
0.6 |
0.33 |
0.75 |
Medium |
|
Swine
|
0.3 |
0.3 |
0.3 |
Medium |
|
Poultry
(50% water)
|
2 |
2 |
1 |
Med.
Rapid |
| Milogranite
(dry) |
5 |
2
to 5 |
2 |
Medium |
| Mushroom
Compost |
0.4
to 0.7 |
1 |
0.5
to 1.5 |
Slow |
| Peat
and Muck |
1.5
to 3 |
0.25
to 0.5 |
0.5
to 1 |
Very
Slow |
| Sawdust |
4 |
2 |
4 |
Very
Slow |
| Sewage
Sludge (digested) |
1
to 3 |
0.5
to 4 |
0
to 0.5 |
Slow |
| Urea |
42
to 45 |
0 |
0 |
Rapid |
Wood
Ashes
(may raise pH) |
0 |
1
to 2 |
3
to 7 |
Rapid |
Resource:
A Guide to the Nutrient Value of Organic Materials, Fact Sheet
#8, by Marcia Eames-Sheavly Extension Support Specialist, Department
of Fruit and Vegetable Science, Cornell University and Robert
Kozlowski and Joann Gruttadaurio, Senior Extension Associates,
Department of Floriculture and Ornamental Horticulture, Cornell
University, Spring 1993.
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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