Agriculture Reference
In-Depth Information
regions for different crops and cropping systems. A good research project involving experimenta-
tion should have appropriate planning to get meaningful results. The planning includes well-defined
objectives based on the priority of problems and to achieve these objectives, experimental method-
ology should be adequate. Statistical analysis and interpretation of experimental data are as impor-
tant as planning and executing the experiments. A detailed discussion regarding the basic principles
and methodology in conducting field experiments is given by Fageria (2007b).
3.7.2.1 Observation and Data Transformation in Field Experiments
As in the greenhouse experiments, in field experiments too, growth, yield, and yield components are
measured and data are transformed for statistical analysis. The following equations are used to trans-
form field experimental data for statistical analysis and presentation of results into technical articles.
In the field experiments, at the time of harvest, plant height and panicle density from a 1 m row
should be determined. A one meter row should also be harvested from each plot to determine the
straw dry weight. In addition, 10-20 panicles should be harvested from each plot to determine
spikelet sterility and 1000 grain weight in the case of cereals such as rice. Grain and straw yield
ha
−1
, panicle density m
−2
, spikelet sterility, 1000 grain weight and GHI can be determined by using
the following equations:
dryweight of strawm
−
rowinm
rowing
Strawyield
(
kg ha
−
1
)
=
× 10
spacing between
grainyield plot in g
area harvestedploti
−
1
Grainyield
(
kg ha
−
1
)
=
×
10
−
1
nnm
2
panicle numberm row
rowspacing in m
−
Panicledensity m
−
2
=
10
numberoffilledand unfilledspikelets in 10 panicles
× 100
numberof unfilledspikelets in
panicles
Spikelet sterility
(%) =
filledgrain weight in 10 panicles in g
number
Thousandgrain wt.g
()=
of filledgrain in 10 panicles
grainyield
grainplusstraw yield
Grainharvest indexGHI
(
) =
In addition to the determination of plant parameters, soil samples should also be taken from each
plot or treatment and the following soil chemical indices should be determined to evaluate fertilizer
treatment effects and correlate these soil indices with grain yield:
=
∑
CECcmolkg
(
−
1
)
(,
CaMgKHAl
,,,
)
c
where Ca, Mg, K, H, and Al are in cmol
c
kg
−1
, H + Al determined at pH 7.
∑
Ca Mg K
CECatpH
(,
,)
Base saturation
(%)
=
×
100
7
