Agriculture Reference
In-Depth Information
Table 2.6
Properties of polypots
Size (cm)
Gauge
Weight
(no./kg)
Volume
(ml)
Weight with
soil (kg)
Remarks
Micron
Standard wire
gauge (SWG)
7
×
20
25
50
1,450
312
0.44
For economy works
10
×
25
40
48
525
796
1.12
For thorny plants
12
×
30
50
47
290
1,375
1.925
Standard for all plants
20
×
40
80
44
80
5,095
7.133
For tall plants
a
2
b
/
a
×
b
c
5
M
/
abc
π
0.00135
v
v
: volume,
M
: million
Purchase and storage of polypots is simple. Market rates are fairly consistent
and storage period is long enough to make long-term planning easy. However, the
strength of polypots reduces with passage of time even if stored properly. Therefore,
first-in-first-out order should be followed and fat inventories should be avoided.
Quality of polypots can vary a great deal even for a given type of material. A
standard quality check procedure (Table
2.7
) includes checking transparency (only
for the virgin LDPE type), strength, and leakproofness. Transparency should be good
and uniform and should not show streaks. If a bag is filled with soil and dropped on
firm ground from waist height and does not tear, it can be said to have passed the
strength test. If a bag is filled with water and hung for 2 h and no leakage of water is
seen, it passes the test of being leakproof. Another desired property is that of ease of
opening. The sheets should not be tightly stuck at the open ends to avoid unnecessary
wastage of effort and time. To test this property, hold the open end upwards in one
hand from each side and rub it between hands up and down. As a result of crumpling,
the polypot should separate its two sheets and open out easily. Consistency in size,
sealing border, and gauge are other factors that can be checked for further assurance
of quality.
2.7
Filling the Polypots
Potting mix should be prepared with meticulous care and control. All manure should
be pulverised, sieved through a 2-mm gauze, and thoroughly mixed with the other
two components (i.e. clay and sand) to make a homogeneous mix of desired ratio.
Similarly, clay should be cleared of stones and clods should be broken or pul-
verised before using. Prepared potting mix should be stacked and checked for quality
control before use. It is also desirable to mix pesticide powder where pests are a
serious and regular problem.
If facilities and know-how is available, inoculation of the potting mix with
vesicular-arbuscular mycorrhizae (VAM) is an advantage. Addition of VAM in-
oculum, in a way, fortifies the potting mix. Mycorrhizal association improves
plant growth, enables better uptake of nutrients—especially phosphorus and
micronutrients—and improves resistance to drought and root diseases. Starter VAM
inoculum is procured from forest soil excavated from the rhizosphere (root zone)
Search WWH ::
Custom Search