Thermal and electric weeders

Thermal Weeder

Flame weeders briefly expose weeds to a propane or butane flame at 800-1000 C Ascard, 1995a , which disrupts cell membranes and leads to rapid dehydration Ellwanger, Bingham amp Chapell, 1973 Ellwanger et al., 1973 . A bank of burners can flame a wide area to kill weeds before crop planting or crop emergence, or to defoliate plants prior to harvest Tawczynski, 1990 . Shielding such machines to contain the heat increases their efficiency. Irrigation a few days before planting ensures that the...

Population dynamics of annual weeds in ridge tillage

Weed Population Dynamics

The effect of ridge tillage on weeds is distinctive from other types of tillage in that seeds do not move randomly relative to the crop row. In ridge tillage sometimes referred to as till-plant a crop is planted on ridges formed the previous growing season Figure 4.8 . During planting, the surface of the ridge is scraped into the inter-row valleys. Seeds that were shed onto the ridge the previous season are thus moved to the valleys where seedlings can be destroyed by inter-row cultivation....

Weed management objectives

From the standpoint of crop protection, weed management has three principal objectives (1) Weed density should be reduced to tolerable levels. Experimental studies with a range of species indicate that the relationship between crop yield loss and weed density can be described by a rectangular hyperbola (Cousens, 1985 Weaver, Smits & Tan, 1987 Norris, 1992 Blackshaw, 1993 Knezevic, Weise & Swanton, 1994 Chikoye,Weise & Swanton, 1995).The specific parameters of this relationship change...

Cultivator guidance systems

Cultivation is an exacting task that is often tiring for the tractor operator. It causes crop loss if not done carefully. These problems are multiplied when using tools that have to travel at a precise position relative to the crop row. Consequently, some rear-mounted implements are designed to be steered by a rider Geier amp Vogtmann, 1987 Melander, 1997 , but this is a laborintensive solution. Fortunately, automation of implement and tractor guidance is advancing rapidly. The simplest...

Nearrow tools vegetable knives disk hillers spyders basket weeders and brush weeders

Basket Weeder Cultivator

Several tools have been invented to cultivate 5 to 12 cm from the crop. To avoid root damage, typical working depth for near-row tools is shallow 2 to 5 cm. Furthermore, when working close to the crop, soil must flow either parallel with, or away from, the row to avoid burying small crop plants. Basket weeders and brush weeders can work closer to the row than disk hillers and spyders because their rotation is parallel to the row and thus the leading edge is no closer to the row than is the...