Changing crop pattern can
add 16 percent yield
The Sunday Nation
Nairobi,
25 July 2010
Unlike most Kenyans, I was not brought in farming environment and
therefore, I was never bitten by the “farmer’s bug”. Still, I have
always wondered why crops are planted in rows and columns forming a
square grid. Is this the most efficient utilisation of land? Let’s find
out.
Suppose you have the standard “eighth of an acre” plot that measures
approximately 50feet-by-100ft and you want to grow, say, cabbages. As
explained several weeks ago, the actual surveyed measurements are
15m-by-30m.
Now, the recommended spacing for cabbages is about 50cm, thus the
eight-acre plot will take 30 plants along the width (15m divided by
50cm) and 60 along the length (30m divided by 50cm). This produces a
grid of squares with total of 1,800 cabbages (30 x 60).
In this pattern, each cabbage is surrounded by four others. Well, all
except the ones along the edges of the plot – these have three
neighbours. For this reason, the squire grid doesn’t utilise the
available space efficiently: but is there another way? Can we get a more
compact arrangement and still maintain the 50cm spacing? The answer is
yes.
We start by planting one line along the length of the plot with the
spacing of 50cm. That will be 60 cabbages as before. On the second line,
the cabbages are planted at positions that are adjacent to the midpoints
of those in the first row. This is done making sure that the spacing
between the all cabbages is 50cm.
That is, those on the first one line are 50cm from those on the second
one. Note that the two lines themselves will NOT be 50cm apart! The
second line in this staggered pattern will have 59 plants instead of 60.
The third row will be identical to the first one and so on. Clearly,
every odd numbered line will have 60 cabbages while the even ones will
have 59. We are losing one cabbage every two columns; so where is the
benefit?
This will be a triangular grid where each cabbage will have six nearest
neighbours. The big question is: will it fit more plants in the same
plot? To find out, we need to find out the distance between the rows.
Without going into too much detail (Pythagoras’ theorem and all), it
turns out that the rows of this triangular grid will be about 43cm apart
– instead of the 50cm of a square pattern.
Therefore we shall have 35 rows of cabbages on our plot – 18 with 60
plants each and 17 with 59. This makes a total of 2,083 plants.
Comparing this with the previous 1,800 of the square grid, we find that
it is 16 percent more.
The question then is whether 16 per cent higher yield is worth going into
the trouble of making a triangular grid instead of a square one. Well,
as I said in the opening, I do not have the farmer’s bug so I wouldn’t
know!
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