Weed Management In Maize (Zea Mays L.) Crop Using Allelopathy Of Sunflower (Helianthus Annuus L.) And Johnson Grass (Sorghum Halepense) Aquatic Extracts

Abstract

The impact of weeds on growth and yield of miaze has tremendously reduced per hectare yield due to their
competition with maize for water, nutrients and placement. Usually weeds in maize are controlled by either
manual weeding or by herbicide application, even in some areas the farmers let the weeds to grow freely with
this crop. Manual weed control is laborious and time consuming whereas, application of herbicide with higher
doses not only develops resistance in weeds but also degrades the environment. Therefore, this study was framed
with objectives to determine suitable allelochemical plant and its dose as well as form for weed management and
increasing maize yield. A series of field experiments were conducted at Student’s farm, Department of Agronomy,
Sindh Agriculture University Tandojam for weed management by using aquatic extracts as allelopathy of two
plants sunflower and Johnson grass. As illustrated in the analysis of variance, the results for maize traits were
found statistically significant (P<0.05) under various treatments. The treatments were weedy check, sunflower
aquatic extract at 20 L and 40 L ha-1
, Johnson grass aquatic extract at 20 L and 40 L ha-1
, sunflower aquatic extract
at 20 L with herbicide 1 L ha-1 and Johnson grass aquatic extract at 20 L with herbicide 1 L ha-1
, Johnson grass
aquatic extract at 20 L ha-1 with herbicide 1 L ha-1
, herbicide at 2 L ha-1 and interculturing twice. The application
of sunflower and Johnson grass aquatic extracts resulted for weed traits that minimum weed density (m2
), weed
fresh and dry biomass (g m2
) was recorded with Johnson grass aquatic extract at 20 L ha-1 with herbicide 1 L ha-1
at 1
st irrigation. The maximum stem girth (cm), cob length (cm), kernel weight (g cob-1
) and biological yield (kg ha1
) recorded with Johnson grass aquatic extract at 20 L ha-1 with herbicide 1 L ha-1 (1st irrigation). The treatment,
Johnson grass aquatic extract at 40 L ha-1 (1st irrigation) produced maximum plant height (cm), kernel rows cob-1
,
kernel cob-1
, kernel yield (kg ha-1
) and straw yield (kg ha-1
). It is concluded from the study that sunflower and Johnson
grass application on weed management and yield enhancement had high allelopathic potential in maize crop.
Therefore, aquatic extracts of sunflower and Johnson grass with lower dose of herbicide may be applied to control
weeds in maize crop for enhancement of growth and yield parameters to overcome the issues of food security
for human beings that is based on low input, high production.