Features Fruit Production
Direction of crop rows maximizes access to sunlight

April 30, 2010 – Higher
demand for organically grown foods has farmers seeking new methods to increase
crop yields and reduce weeds without the use of chemicals.

April 30, 2010 – Higher
demand for organically grown foods has farmers seeking new methods to increase
crop yields and reduce weeds without the use of chemicals.

One very practical
solution uses a readily available resource and requires no additional costs or
time-consuming weeding and cultivating. It is, simply, maximizing the light of
the sun.

The March-April issue of
the journal Weed Science reports the results of four trials of crop orientation
conducted from 2002 to 2005 in Western Australia. Researchers compared the
effects of orienting rows of crops north to south or east to west to allow the
crops to increase their exposure to sunlight while decreasing access to light
for weeds.

Crops compete with weeds
for light. Situating the crop rows at a near right angle to the sunlight
direction can influence the light interception. Crops can create a canopy over
weed plants, giving the weeds more shade than sun, suppressing weed growth and
maximizing crop yield.

Grain crops of wheat,
barley, canola, field peas, and lupine were sown in both north-to-south and
east-to-west orientations in the Australian experiment. Wheat and barley crops
experienced significant yield increases when placed east to west rather than
north to south — a 24 per cent increase for wheat and a 26 per cent increase
for barley. Weed biomass was reduced by 51per cent and 37 per cent,
respectively, for these two crops.

The remaining three crops,
canola, field peas, and lupine, did not show a consistently significant
difference between the two orientations. The authors theorize that because
these are broadleaf crops and have a wider canopy structure than the cereal
crops, the row orientation provides less advantage.

Location determines which
direction crops should be planted for the best utilization of sunlight. The
Western Australian Wheat Belt ranges from 28 degrees to 33 degrees south in
latitude with a winter and spring growing season, making east-west crop
orientation the most advantageous. Near the equator, north-south orientation
would yield the best results, while latitudes up to 55 degrees would benefit
from north-south crops in the summer and east-west crops the rest of the year.
At latitudes above 65 degrees, east-west orientation would offer the best light
absorption throughout the year.

Full text of the article,
“Manipulating Crop Row Orientation to Suppress Weeds and Increase Crop Yield,”
Weed Science, Volume 58, Issue 2, March-April 2010, is available at
http://www2.allenpress.com/pdf/WEES_58.2_174-178.pdf.