نتایج جستجو برای: weed densities
تعداد نتایج: 65127 فیلتر نتایج به سال:
The population effects of harvest depend on complex interactions between density dependence, seasonality, stage structure, and management timing. Here we present a periodic nonlinear matrix population model that incorporates seasonal density dependence with stage-selective and seasonally selective harvest. To this model, we apply newly developed perturbation analyses to determine how population...
In order to find the critical period of weed control, the best time of weed control beginning (i.e. herbicide application time), and the length of weed control period (i.e. herbicide persistency) in corn, field experiments were conducted in Bajgah and Kooshkak in Fars Province in 1995 using a randomized complete block design with 14 treatments and four replications. Treatments consisted of diff...
An experimental machine vision-based patch-sprayer was developed. This sprayer was primarily designed to do real-time weed density estimation and variable herbicide application rate control. However, the sprayer also had the capability to do high-resolution weed mapping if proper mapping techniques being integrated. Two weed mapping methods were developed. One is GPS signal-based off-line weed ...
Silage quality has great importance in animal feeding as much yield. Quality characteristics are generally evaluated over crude protein and digestibility, but parameters related to mineral, total fiber, sugar contents also important indicators of silage its nutritive value. Plant could affect these parameters, material, thereby, any environmental factors indirectly. Weeds one the main problems ...
Unsuitable planting and weed competition are the most important factors that greatly reduce the yield of bean. In order to study the effect of planting date on yield and yield components of three white bean cultivars in weed infest and weed free condition a factorial experiment with randomized complete block design and three replications was carried out at Semirom in 2009. The treatments were p...
The Farm Scale Evaluations of genetically modified herbicide-tolerant crops (GMHT) were conducted in the UK from 2000 to 2002 on beet (sugar and fodder), spring oilseed rape and forage maize. The management of the crops studied is described and compared with current conventional commercial practice. The distribution of field sites adequately represented the areas currently growing these crops, ...
BACKGROUND Enhanced atrazine degradation has been observed in agricultural soils from around the globe. Soils exhibiting enhanced atrazine degradation may be cross-adapted with other s-triazine herbicides, thereby reducing their control of sensitive weed species. The aims of this study were (1) to determine the field persistence of simazine in atrazine-adapted and non-adapted soils, (2) to comp...
Biological control is a crucial tool in the battle against biological invasions, but biocontrol agents can have a deleterious impact on native species. Recognition of risks associated with host shifting has increased the emphasis on host specificity of biocontrol agents for invasive weeds. However, recent studies indicate hostspecific biocontrol agents can also exhibit substantial nontarget eff...
The number and abundance of exotic weeds in native forest fragments are known to correlate with the distance to the nearest large town. This is of concern as land near lowland forest is increasingly being subdivided for housing throughout much of New Zealand. We quantified the relationship between settlements and exotic plants for the coastal forests in eastern Northland, New Zealand. Exotic pl...
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