Assessment of Corn Densities on Ecological Indices of Weed Species

Document Type : Research Article

Authors

• Gh Mahmoudi
• A Ghanbari
• A Mohammadabadi

10.22067/gsc.v9i4.13276

Abstract

Diversity, dominance, and stability of weeds are the most important ecological properties in agricultural
systems, which influenced by management factors such as crop density, abundantly. This experiment was
conducted in 2009 at Ferdowsi University of Mashhad Research Field. The experimental design was interval
mapping with four levels of corn densities (5, 6, 7 and 9 plant.m-2) and four levels of weed control (full-control,
without control, broad-leaves control and grasses control). Weed sampling was done at 3 stages included
beginning and end of critical period weed control and harvesting time. The results showed that the effect of plant
density on species diversity was significant; some how the amount of Shanon and Simpson Indices were lowest
in the 9 plant.m-2 (0.39 and 0.45, respectively) and greatest in 5 plant.m-2 (0.84). The results also showed that the
maximum amount of dominance index was observed in 9 plant.m-2, that was seen in Echinochloa crus- galli and
Convulvulus arvensis at the beginning of growing season, then in Solanum nigrum and Amaranthus retroflexus
in the end of growing season. The amount of community dominance index in 9 plant.m-2 was higher than other
densities, and it decreased with decline of densities. based on the results of present experiment the linear
relationship between plant species and area was found. The calculated amount of Alpha and Beta diversities. in a
θ and β scales based on coefficients of this relationship were 0.534 (four species per unit area) and 0.29 (two
species per unit area), respectively. In conclusion the result of this experiment pointed that the weeds diversity
decreased with increasing of corn density, weed diversity decreased and therefore, having appropriate plant
density is very efficient for sustainable weed management.

Keywords

• Species diversity
• Shanon Index
• Simpson index
• Margalef index
• Dominance
• St

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