No abstract

The aim of integrated weed management (IWM) is to use of a combination of different practices to maintain weed densities at manageable levels. A field experiment was conducted at Agricultural College, Tehran of University, in Karaj city [2005][2006] by planting wheat, to investigate the response of planting methods and tank mixed herbicides. The experiment was laid out using a split plot arrangement, in randomized complete block design with three replications. Methods of planting were assigned to the main plots; while tank mixed herbicdes were kept in the sub-plots. The subplot size measured 4.5 × 4.5 m 2 . Row to row distance was kept at 30 cm. Data were recorded on weed density m -2 , plant height (cm), spike length (cm), Number of spikes m -2 , Number of grains spike -1 , 1000 grain weight (g), biological yield (kg ha -1 ), and grain yield (kg ha -1 ). The data for individual traits were subjected to the ANOVA technique and significant means were separated by the LSD test. The analysis of the data showed that methods of sowing were statistically significant for plant height, No. of grains spike -1 , 1000-grain weight and biological yield. The herbicides were statistically significant for all the parameters investigated except No. of grains spike -1 , while the interaction of methods of planting with herbicides could not reach the level of significance in any of the traits examined. Among the methods of planting, line sowing was the best followed by line + broadcast sowing. The herbicide mixtures controlled mixed stands of broadleaf and grassy weeds to the tune of 65 to 74% with a consequent increase in grain yield from 58-107%. Buctril-M + Topik 15 WP, 2,4-D + Puma Super 75 EW and Topik 15 WP were segregated as the top scoring applications by increasing yield to the extent of 107, 104 and 101 %, respectively over the weedy check.

Azadirachta indica, or Neem Tree, is an evergreen tree native to Southeast Asia. All parts of the tree have been used medicinally for centuries. The allelopathic potential of extracts of Azadirachta indica L., which is one of the most dominant weeds in tropical regions of South-west Asia, was investigated under laboratory conditions. The n-hexanesoluble, acetone-soluble and water-soluble fractions obtained from the acetone extract of A. indica shoots inhibited the germination and the growth of roots and shoots of six test plant species. The inhibitory activity of the water-soluble fraction was greatest, followed by that of the n-hexane-soluble and acetone-soluble fractions in all bioassays. Significant reductions in the germination and growth of the roots and hypocotyls were observed as the extract concentration increased. The concentration-dependent responses of the test plants to the fractions suggested that all three fractions might contain allelochemicals, but that the greatest potential was in the water-soluble fraction. These Vol. 1, No. 1 International Journal of Biology 72results indicate that A. indica may produce potent allelochemicals, which should be investigated further in the laboratory and the field.

The research is financed by University of Tehran (Sponsoring information) AabstractAn experiment was laid out to study the effect of different weed management practices and row spacings on the yield and yield components of wheat variety Karaj-2 during 2005Karaj-2 during -2006 at Agronomy Research Farm, University College of Agricultural and Natural Resource, University of Tehran. Wheat was sown at row spacing of 20, 30 and 40 cm, while herbicides applied were broad spectrum 2,4-D butyl Ester: 72 EC + Isoproturon 75 WP @ 865 ml and 865 g ha-1 respectively, broad leaf Buctril M 40 EC @ 1.25 liter ha-1 and a weedy check (no herbicide). Row spacing significantly affected all parameters. Minimum weeds density m-2 and maximum spikelets spike-1, grain yield, harvest index and net income were found in 20 cm row spacing. While number of grains spike-1 were highest in 30 cm row spacing. Among herbicides, minimum weeds density m -2 and maximum spikelets spike , grain yield, harvest index and net income were found in plots treated with broad-spectrum herbicide followed by Buctril-M 40 and the weedy check, respectively. It is concluded that maximum grain yield and net income can be obtained using broad spectrum (grasses + broad leaved) herbicides and narrow row spacing.