Weeds are commonly assumed to induce yield loss because of resource competition. However, there is growing empirical evidence that the picture much more complex, fertilizer inputs, by modifying level resources and weeding removing some weed species, affect outcome crop-weed interaction. We assess how two important crop production inputs - nitrogen (N) fertilization weed-control a fundamental no...

Among agricultural pesticides, herbicides comprise the most employed group in agriculture. The main function of these chemicals is to control weeds, weed competition reduces produc‐ tivity, without significantly impacting crop yield. Weeds tend to compete with crops by extracting essential elements from the soil, water, intercepting light and CO2, interfering in the culture development and affe...

This paper explores the benefits of competition control treatments in establishing plantations now and into the next rotation, -More is known about the economic outcome of woody control treatments than about herbaceous. control; thus, the former are given the most attention. But the early growth benefits of herbaceous weed control treatments are also reviewed, with the appropriate application m...

The availability of orthophosphate (Pi) is a key determinant of crop productivity because its accessibility to plants is poor due to its conversion to unavailable forms. Weed's competition for this essential macronutrient further reduces its bio-availability. To compensate for the low Pi use efficiency and address the weed hazard, excess Pi fertilizers and herbicides are routinely applied, resu...

ABSTRACT-The critical period of weed control is a part of crop life cycle during which weeds must be kept weed-free to avoid yield losses due to competition. In order to evaluate the effect of deficit irrigation on critical period of redroot pigweed (Amaranthus retroflexus L.) in sunflower (Helianthus annuus L.), an experiment was carried out  as split plot ba...

Ever-increasing demand for water to irrigate crops, support aquaculture, provide domestic water needs and to protect natural aquatic and riparian habitats has necessitated research to reduce impacts from a parallel increase in invasive aquatic weeds. This paper reviews the past 4-5 years of research by USDA-ARS covering such areas as weed biology, ecology, physiology and management strategies, ...

to study the critical period of weeds competition with sugar beet and determine the duration that the crop can tolerate the weeds, a field experiment was carried out at esfahan agicultural research center, in kabotarabad-esfahan during 1999-2000.  the experiment conducted in rcb design with 14 treatments and four replications. the treatments included control throughout the growth season (as a c...

in order to evaluate the interference effect natural population weeds and plant density, an experiment with randomized complete block design in factorial arrangement with 4 replications was conducted in 2006 in a field experiment at ramin agricultural and natural resources university, khouzestan. treatments included two factor, plant density of corn at three levels (4, 7 and 10 plants m-2) and ...