Abstract:
The objectives of this study were to evaluate the e
ffects of nitrogen fertigation
frequency on lint yield, lint properties, chlorophy
ll content (SPAD readings), and the
photosynthesis rate (PR) of cotton. This study was
carried out in the Southeastern
Anatolia Region of Turkey in 2011 and 2012 with dri
p-irrigated cotton. The maximum
lint yield (1,856 kg ha
-1
) was obtained with one lateral for every two rows
and the
application of equal doses every two irrigation cyc
les (10 days). Fertigation frequency of
every two irrigation cycles (10 days) increased (P
≤
0.05) the fiber strength (32.3 g tex
-1
),
the fiber elongation (6.5%
), and the fiber length (28.9 mm). The SPAD reading
s ranged
from 40.1 to 54.9, depending on the treatment and e
xperimental year. There was no
significant difference (P
≤
0.05) among the SPAD readings. The PR ranged from
35.9 to
74.7 μmol m-
2
s
-1
, and there was no significant difference between t
he treatments. One
possible reason for the lack of difference in PR, o
r SPAD, was that there was no
difference in the total amount of nitrogen applied
in the different treatments. The PR
measured in cotton leaves may also change depending
on the environmental conditions
during measurement, prevailing ecological condition
s, age, and location of the leaf on a
plant.
Keywords:
Cotton, Chlorophyll (SPAD), Drip irrigation, Nitro
gen, Photosynthesis rate.
