Two factors limiting successful recruitment of planted blue oak (Quercus douglasii) seedlings are dry soils and animal damage. Many approaches have been used to mitigate these factors including several types of protective cages and alternative methods of weed control. This study examined how treeshelters, screen cages and varying intensities of weed removal affect the establishment and growth o...

This study concerns the detection and localization of weed patches in order to improve the knowledge on weed-crop competition. A remote control aircraft provided with a camera allowed to obtain low cost and repetitive information. Different processings were involved to detect weed patches using spatial then spectral methods. First, a shift of colorimetric base allowed to separate the soil and p...

Intercropped corn (Zeu mays L.) and soybean [Glycine mux (L.) Merr.] may produce more total yield per hectare than either grown separately, ie., land equivalent ratio (LER) >l. Low N fertility, limited moisture, and weed competition have each been reported to result in high land equivalent ratios. Thus it was hypothesized that intercropping advantages were greater under stress conditions. The o...

Evolutionary theory can be applied to improve agricultural yields and/or sustainability, an approach we call Evolutionary Agroecology. The basic idea is that plant breeding is unlikely to improve attributes already favored by millions of years of natural selection, whereas there may be unutilized potential in selecting for attributes that increase total crop yield but reduce plants' individual ...

Weed management is a major issue in organic farming systems. Although interseeding cover crops is one alternative to herbicides, cover crops often suppress not only weeds but also main crops. Therefore, using cover crops for weed control without adverse effects on main crop growth is important. To verify the effect of cover crops on competition between main crops, cover crops and weeds in snowy...

Weeds are a major constraint to the success of dry-seeded rice (DSR). The main means of managing these in a DSR system is through chemical weed control using herbicides. However, the use of herbicides alone may not be sustainable in the long term. Approaches that aim for high crop competitiveness therefore need to be exploited. One such approach is the use of high rice seeding rates. Experiment...

in order to study the effect of row spacing and plant density on quantity and quality yield of soybean in weed competitive condition, a field experiment was carried out at research farm of yasuj agricultural college in summer of 2011. experiment arrangement was split factorial base on randomized complete block design with three replication. the main factor included weed ( in two levels of contr...

Previously described weed competition models that use competition indices based on weed size relative to tree size (e.g., tree height divided by weed height) require models of weed growth and models of weed-free tree growth. A method is presented to model these using standard sigmoidal growth functions and to incorporate regular seasonal patterns of tree growth using Fourier series approximatio...