2.3. Indices to measure the weed community structure
2.3.1. Weed density and dry weight
A quadrant sized 1 m by 1 m was placed in each plot randomly;
weeds sprawl inside the quadrant were considered for weed population
and biomass. All weeds inside a quadrant were uprooted
just after harvesting of baby corn, separated and counted specieswise
(weed species recorded during experimentations are listed in
Table 1). Subsequent to the weed count observation, the samples
were dried seperately in hot air oven at 65oC till it attains constant
weight to record weed dry weight.
2.3.2. Species diversity
Spcies diversity consists of two related components viz., species
richness (number of species present) and relative abundances of
different species or equitability. A diversity index is a mathematical
measure of species diversity in a community. Diversity indices
provide more information about community composition than
simply species richness. These indices reveal important information
about rarity and commonness of species in a community
[22].
2.3.3. Species richness
The species richness (S) is simply the number of species present
in an ecosystem/community [23]. This index is the oldest and simplest
measure of species diversity and makes no use of relative
abundances.
2.3.4. Shannon-Wiener index
The Shannon-Wiener index (H) is another index that is commonly
used to characterize species diversity in a community