نتایج جستجو برای: weed performance
تعداد نتایج: 1060520 فیلتر نتایج به سال:
Rubber tree production is reduced by weeds that compete for environmental resources; therefore, the timing and duration of weed control influences weed interference. The objectives of this study were to evaluate the growth of rubber tree (Hevea brasiliensis) plants, to determine the critical period for weed control, and to evaluate the growth recovery of rubber trees that coexisted with weeds f...
A Research Committee was established by the Weed Science Society of America to outline the direction of weed science research during the next decade. Weeds adversely affect humans in both agricultural and nonagricultural environments. It is the opinion of the research committee that weed science will be advantageously positioned for the future if research focuses on research decision processes,...
Host range expansion in insect herbivores is often thought to be mediated by several factors, principal among them are secondary plant metabolites. In weed biological control, the host range of a prospective agent is one of the most important considerations in its implementation. Extensive host testing tests seek to determine the behavioral acceptance and nutritional value of different test pla...
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...
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...
field studies were conducted at lorestan, kermanshah and golestan provinces in 2006 to separately evaluation of clethodim herbicide for weedy grass control in soybean. all experiments were designed as randomized complete blocks with four replicates. treatments included: clethodim at 0.6, 0.8, 1, and 1.2 l/ha; cycloxydim at 3 l/ha; haloxyfop-r-methyl at 0.75 l/ha; quizalofop-p-ethyl at 2 l/ha; a...
Unmanned aerial vehicles (UAVs) combined with different spectral range sensors are an emerging technology for providing early weed maps for optimizing herbicide applications. Considering that weeds, at very early phenological stages, are similar spectrally and in appearance, three major components are relevant: spatial resolution, type of sensor and classification algorithm. Resampling is a tec...
In conventional cropping systems, removal of weed population extensively relies on the application of chemical herbicides. However, this practice should be minimized because of the adverse effects of herbicide applications on environment, human health, and other living organisms. In this context, if the distribution of broadleaf and grass weeds could be sensed locally with a machine vision syst...
A field experiment was conducted for two consecutive years (2003 and 2004) to study the effect of row spacing (75, 65 and 55cm) and different weed competition durations (0, 15,30,45,60 days after emergence and throughout the growth period) on weeds density and biomass and growth and yield of maize. Reducing row spacing significantly suppressed the weed density and biomass. The maximum reduction...
Manure composting has gained increased acceptance by the beef cattle (Bos taurus) feedlot industry in southern Alberta, Canada. Unlike fresh manure, compost is often promoted as being "weed-free." Studies were conducted with five weed species in 1997 and thirteen in 1999 to examine the effect of feedlot manure composting on weed seed viability. Weed seeds were buried in open-air compost windrow...
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