Nursery Block Manufacturing Manual– For arid and desert areas –OYO Corporation
Japan International Forestry
Promotion and Cooperation CenterMarch 20191. What is “Nursery block”?
“Nursery block” is a soil block which consists of soil, compost and clay, which are
molded into a tubular shape by special equipment. The nursery block has a hole in themiddle in which soil is filled and seeds are sowed as a growth base for plant seedlings.
Seedlings which are grown in the block are called “nursery block seedlings”.

penetration hole
Photo 1

Photo 2

Nursery block

Nursery block seedlings

Features and effects of nursery blocks
1) Features by structure
The key feature of the nursery block is that the root system of the plant extends
straight and deep into the ground through the hole like a natural tree. As a result, thenursery block produces the following benefits.
(1) Planting forests to help protect the environment
In Japan with its steep topography, trees whose thick roots extend straight and deep
into the ground and whose lateral roots spread widely are planted, thus helping toprevent disasters. The wide-reaching lateral roots and net-like structure of entangling
with the root systems of adjacent trees help to suppress soil erosion; the planted forests
conserve the soil and water sources.
(2) Improvement of survival rate in arid areas
The surface of dry ground which has little vegetation and receives direct sunlight isextremely hot and dry. However, the temperature of the soil deep underground is stable
and retains more moisture than the ground surface. The nursery block encourages theroot system to extend deep into the ground where the roots can efficiently absorb
moisture in the soil, thus increasing the retention rate in arid areas.

12) Features of materials
Nursery blocks are an environmental-friendly product made of soil and organic
matter, and not petroleum products such as plastic and vinyl. Moreover, other than theequipment to manufacture the blocks, nursery blocks are a kind of greening material
which can be made from local materials, and so have the following advantages.
(1) Greening material that does not pollute the environment
Because nursery blocks are not made of materials that do not decompose in thenatural environment such as petroleum products, no garbage remains after planting,thus avoiding environment pollution. Moreover, recycled resources can be effectively
used by using river sediment as a soil or using garbage compost as organic matter.
(2) High potential for people thanks to ease of block preparation
Only equipment for manufacturing nursery blocks is needed, as the blocks are madeof only soil and organic matter, and so can be easily produced in developing countries
with few high-tech materials. For this reason, people in developing countries canproduce their own nursery blocks and continue greening activities.

Mechanism of plant root development
In the nursery block, the plant roots extend deep into the ground by the following
two mechanisms.
(1) Protection of taproot by air root cutting
In the nursery, seedlings in the nursery blocks grow on a steel net. When the taproot
reaches the bottom of the block and touches the air it temporarily stops growing. This
technology is called “air root pruning”, and is different from physically cutting theroots by scissors. The taproot that has stopped growing by air root pruning will growagain after planting, straight and deep into the ground.

2Nursery block
保育ブロックSeeds
種子Development
植栽後の of root systemafterplanting
根系の発達

Culture培土soil
金網
Net
Taproot that stopped
growing at the bottom

2～3か月育苗した
Nursery
block seedlings after
2 to3 months
保育ブロック苗(in China or Japan)

Taproot
直根Fig. 1 Growth of nursery block seedlings and development of root system(2) Promotion of root system development by high retention of water and fertilizer
As nursery blocks contain a large amount of clay, they effectively retain water andfertilizer. This feature provides nutrients and moisture intensively to the plant, protects
its growth during the early stage, and speeds up growth of the root system.

32. How to manufacture nursery blocks
The materials and method of manufacturing nursery blocks are explained below, assuming
the blocks will be used in dry and degraded areas overseas.
1) Materials
The four main materials used for manufacturing nursing blocks are: soil, organic matter,
clay, and chemical fertilizer.
(1) Soil
A local soil is used, such as farmland and grassland top (surface) soil.
The most suitable soil is an aggregate soil (so-called loamy soil, or clay loam soil) withhigh water retention and permeability. Choose a soil that has a highly developed
aggregate structure.
In overseas countries, pay attention to the pH and electrical conductivity (EC) of thesoil. The pH of mineral soil (dry soil with low organic matter) in a dry area is typically
pH 7.0 to 9.0.
It is possible to produce nursery blocks even using soil with a pH exceeding 9.0, butdue to the low solubility of essential trace elements such as iodine, iron, andmanganese, deficiencies of such elements may occur. In this case, consider using abasal fertilizer such as ammonium sulfate acidic fertilizer containing trace elements.
The appropriate EC value of dry soil is around 0.20–0.60 dSm−1. Avoid using soil with
an EC value exceeding 0.80 dSm−1 1).
(2) Organic matter
Use an organic matter containing 1–2 cm of fibrousmaterial. Using finely crushed organic matter may weaken
the nursing blocks and the large amount of air contained may
cause the blocks to collapse during the process of formation.
Such nursery blocks may also be poor in drainage.
Another organic matter is manure, which can easily bepurchased in arid areas. Because cattle are often kept instables, cow manure compost is comparatively easy to obtain.
Photo 3 Cow manure
In this case, it is also necessary to check the EC of the manure.
compostNote that unfermented compost contains livestock feces and bedding straw which aresources of manure, and so have very high EC values due to urine. In Japan, we use amanure with EC of less than 5 dSm−1 recommended by the Japan Central Union ofAgricultural Co-operatives2).
1) excerpted from “Salt-affected soils in Australia (P. Rengasamy 2016)”
2) Preferred reference for quality preservation of organic materials such as compost (Japan Central Unionof Agricultural Co-operatives, 1994)

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When using immature compost, regardless of the type of manure, care is required not
to inhibit plant growth during the fermentation process. In addition to cow manurecompost, there are also horse manure compost, peat moss and compost of mowed grass.
(3) Clay
When using soil with low clay content, clay should be added. In Japan, domestic soil
with high clay content is used. Clay is often used for making bricks and as a construction
material in arid lands, and so can be easily purchased from brick manufacturing factories
or construction sites.
Avoid using a material containing coarse sand (size that can be seen visually). If thematerial contains a lot of coarse sand, it will become trapped in the gaps of the nursery
block manufacturing equipment, making it difficult to produce the blocks.
(4) Compound fertilizers
As compounding fertilizers, it is recommended to use compound fertilizers containing
nitrogen (N), phosphate (P) and potassium (K), particularly those containing a large
amount of phosphoric acid which facilitates growth of the root system. Many soils in arid
land are strongly alkaline and the availability of trace elements such as iodine, iron, andmagnesium is low. For this reason, it is preferable to use a composite fertilizer containing
these trace elements.
2) Necessary equipment(1) List of equipment
The following equipment is needed tomanufacture nursery blocks:

handle (upper)
handle (lower)○ Nursery block manufacturing equipment○ Sieve○ Bucket○ Scoop○ Plywood plate○ Measuring cup○ Scalemolding cylinder

Fig. 2 Schematic diagram of nursery
block manufacturing equipment

5(2) Mechanism of nursery block manufacturing equipment
Figure 2 shows the structure of the nursery block manufacturing equipment. The green
handle and the steel plate in the cylindrical tube are interlocked. As material is filled in
the cylinder, the steel plate is pushed up, and the green handle also moves at the sametime. After packing the material into the cylinder, the green handle should be pushed
downward to mold (produce) the nursery block.

Photo 4 Nursery block manufacturing equipment Photo 5 Steel plate and handle after
pushing up
before packing materials

3) Manufacturing procedure
The method for manufacturing nursery blocks isshown below.
(1) Preparation
Sieve the soil, compost and clay, remove stones
and dirt, and loosen any lumps. The mesh size ofthe sieve used for soil and clay is approx. 0.5–1.5
cm, and that for compost is approx. 2.0–3.0 cm.
Photo 6 Soil sieving work☛ Note
You can sieve large quantities efficiently by using a wire mesh sieve with a wooden
frame and by tilting it at an angle.
(2) Mixing
Mix dry soil, compost, clay and chemical fertilizer
on a plywood plate. If the materials are notuniformly mixed, it will be difficult to pack theminto the nursery block manufacturing equipment, somix them well. According to the nursery block
patent1), soil should occupy 50–80% of the weight ofthe mixed material.
1) Patent No. 4660635: Greening method by using a nursery block

Photo 7 Material mixing6☛ Note
Mix the materials in the volume ratio of soil : organic matter = 1 : 1. If dried nursery
blocks break or hardly absorb water when submerged in water, change the proportionof soil and organic matter and/or add clay.
After mixing the dried ingredients, add waterand mix them well again. While rolling thematerial into dumpling shapes, add water until
the rolled hand becomes moist.
☛ NoteUsing a horizontally rotating mixer makes it
easy to mix the materials. When using a mixer,
Photo 8 Mixer
it is more convenient to choose one with the sloton the bottom. However, three-phase power is not available everywhere, so theworkplace should be carefully selected.
(3) Molding
Push the nursery block manufacturing
equipment into the mixed materials and fillthem into the equipment. While doing so, theiron plate inside the equipment will be pushed
upward and the upper handle will naturally rise.
Push the material with the equipment until thetube becomes full and the handle does notmove.
Photo 9 Molding process☛ NoteIf you slightly rotate the equipment while pushing, the material will easily enter theequipment.

7(4) Extrusion
Push the upper handle downward to extrude the material out from the equipment.

Photo 10 Extrusion of material(5) Drying
Place the extruded nursery blocks on theplywood plate and allow them to dry. If theblocks are used without drying, they may breakas the seedlings grow, so be sure to dry themcompletely.
Allow sufficient space between blocks tofacilitate drying.
Photo 11 Drying of nursery blocks

8Contact⦿ Question regarding nursery block

OYO Corporation
Global Environment Division
Natural Environment Department
43 Miyukigaoka, Tsukuba, Ibaraki 305-0841, Japan☎：+81-29-851-6958
Fax：+81-29-851-6552
⦿ For customers wishing to purchase nursery block manufacturing equipment:

Shin-Nihon Ryokka Co., Ltd.
2-1-18 Imaike, Chikusa-ku, Nagoya-shi, Aichi 464-0850, Japan☎：+81-52-732-2081
Fax：+81-52-741-4175*The patent for nursery blocks in Japan belongs to Mr. Yoshinari Yamadera.
Patent No. 4660635: Greening method by applying nursery block
Patent No. 4666833: Seed-bed, manufacturing method and sowing method
This manual is funded by Japan International ForestryPromotion and Cooperation Center (JIFPRO).

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