Investigating the effect of different forage corn production on yield, weed amount and herbicide requirement

ABSTRACT: The present study was conducted to determine the effects of different tillage,crop residue and weed control systems on weed amount and dry mass, herbicide energy requirement index (HERI), plant height and wet forage corn yield ( var. single cross 7040) at Zarghan agricultural research station, Fars province, located at southeast of Iran in summer 2004. Experimental treatments were included crop residual management (with and without residual), weed control (chemical and mechanical control) and seed bed preparation including moldboard plow plus two times heavy disk (M+2D), chisel plow plus two times heavy disk (C+2D) and two times heavy disk (D+D). The results showed that all treatments had no significant effect on wet forage corn yield. Seed bed treatments had significant effect on herbicide energy requirement index (HERI). The (M+2D) had the lowest HERI, due to lowest dependency on energy intensive chemical input. Crop residual management treatments had no significant effects on amount and dry mass of weeds, HERI, plant height and as well as wet forage corn yield. In comparison with mechanical weed control, chemical weed control resulted in lower amount and weed dry matter and higher plant height. This study revealed that yield criterion for decision making on forage corn production systems isn’t enough and criteria such as weed amount, expenditure, energy and so on should be considered as well.