Agriculture Reference
In-Depth Information
Lbs per Acre to Lbs per 1000 ft
2
One acre is 43 560 ft
2
. There are 43.56 x 1000 ft
2
sections in an acre.
To convert
lbs/acre into lbs/1000 ft
2
,
we
divide lbs/acre by 43.56:
Sulfur needed: 138 lbs / 43.56 = 3.168 lbs, rounded off to two decimals, 3.17
lbs/1000 ft
2
.
Working With Volume: Cubic Meters and Cubic Yards
To amend the minerals in potting soil, container growing mixes, raised beds or
compost piles, one needs to know the weight per cubic volume of the dry soil or
growing media.
If one is working with
mineral soil
in the
pounds/acre system
, it's safe enough to
assume that
an acre of soil 6 inches deep
will weigh
2 million pounds
.
2 000 000 lbs / 43 560 sq ft = 45.91 lbs per square foot. Two 6 inch deep 1 square
foot sections would be 1
cubic foot
which would weigh about 92 lbs, and there
would be
43 560 / 2 =
21 780 cubic feet in the top 6” of an acre of soil.
Acubic yard is 3 ft x 3 ft x 3 ft = 27 cubic feet.
21 780 ft
3
/ 27 =
806.67 cubic yards in the top 6” of an acre of soil
; close
enough to 800 cubic yards.
For
mineral
soils,
if we know
how many lbs
/acre of a mineral or amendment we
need, we can
divide lbs/acre by 800
to find out
how many lbs/cubic yard
we
need:
We need 600 lbs/acre of Calcium.
600 lbs per acre / 800 yds
3
per acre = 0.75 lbs Ca / yard
3
.
For a
mineral soil
in the
kilogram/hectare system
, we are working with 10 000
square meters of soil ~15 cm deep that weighs 2 million kg.
100 centimeters = 1
meter.
15 cm is 0.15 meters.. To calculate the number of cubic meters in 1 hectare
to a depth of 15 cm we multiply
10 000 m x 0.15 =
1500 cubic meters per hectare
to a depth of 0.15 m.
If we know
how many kg
of an element or amendment is
needed per hectare, in
a mineral soil,
we can
divide by 1500
to see how many
kg
the soil needs
per
cubic meter:
We need 600 kg/ha of Calcium
600 kg / 1500 = 0.4 kg per cubic meter
