نتایج جستجو برای: weed density

تعداد نتایج: 420665  

Journal: :Eng. Appl. of AI 2009
Gláucia M. Bressan Vilma Alves de Oliveira Estevam R. Hruschka Maria do Carmo Nicoletti

This paper describes the modeling of a weed infestation risk inference system that implements a collaborative inference scheme based on rules extracted from two Bayesian network classifiers. The first Bayesian classifier infers a categorical variable value for the weed–crop competitiveness using as input categorical variables for the total density of weeds and corresponding proportions of narro...

Journal: :Pest management science 2012
Amit J Jhala Suduan Gao James S Gerik Ruijun Qin Bradley D Hanson

BACKGROUND Preplant fumigation with methyl bromide (MeBr) has been used for control of soilborne pests in high-value annual, perennial and nursery crops, but is being phased out. In 2007 and 2008, research trials were conducted to evaluate the effects of surface treatments and two application shanks on pest control with 1,3-dicloropropene (1,3-D) in perennial crop nurseries. RESULTS All 1,3-D...

2015
Judith A. Odhiambo Urszula Norton Dennis Ashilenje Emmanuel C. Omondi Jay B. Norton Jose Luis Gonzalez-Andujar

Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twic...

Journal: :حفاظت گیاهان 0
میثم زرگر حسین نجفی اسکندر زند فریبا میقانی

abstract a field experiment was conducted at iranian plant protection research farm in karaj during 2009 to evaluate the effects of diffrent planting patterns, times of mechanical control and herbicides application on weeds density and biomass in sugar beet farms. the experimental design was split–split plot based on randomized complete block design (rcbd) with four replications. planting patte...

2013

Smallholder farmers in southern Africa have reported on increased labour requirements for hoe weeding due to high weed infestations in conservation farming (CF) fields. However, CF proponents claim that weed pressure and labour requirements for weeding decrease within the first three years under the recommended CF practices. An observational study was carried out during the 2008/09 cropping sea...

Journal: :تولید گیاهان زراعی 0
محمد حشمت نیا دانش آموخته کارشناسی ارشد زراعت،دانشگاه آزاد اسلامی، واحد سبزوار، گروه زراعت و اصلاح نباتات، سبزوار، ایران محمد آرمین هیات علمی- دانشگاه آزاد اسلامی واحد سبزوار

chickpea (cicer arietinum) is the third most important pulse crop in the world, grown widely across asia and the middle east. weed is one of the main limiting factors in chickpea (cicer arietinum) production. several characteristics of chickpea (cicer arietinum), such as slow plant emergence, short plant height, and chickpea morphology allow weeds to compete effectively. to investigate the effe...

2016
H Metcalfe A E Milne R Webster R M Lark A J Murdoch J Storkey Lisa Rew

Weeds tend to aggregate in patches within fields, and there is evidence that this is partly owing to variation in soil properties. Because the processes driving soil heterogeneity operate at various scales, the strength of the relations between soil properties and weed density would also be expected to be scale-dependent. Quantifying these effects of scale on weed patch dynamics is essential to...

2014
M. Jiang X. P. Shen W. Gao M. X. Shen Q. G. Dai

We studied the heterogeneity of soil weed seed-bank in a rice-wheat rotation system after long-term application of different organic or non-organic fertilizers, and the effects of major nutrients on the characteristics of the weed seed-bank. The soil was sampled in the Taihu area after a 31-year long-term fertilization experiment. Weed seeds were identified and counted in the surface soil of 12...

2017
Morten Stigaard Laursen Rasmus Nyholm Jørgensen Mads Dyrmann Robert Poulsen

For the past three years, the Danish project, RoboWeedSupport, has sought to bridge the gap between the potential herbicide savings using a decision support system and the required weed inspections. In order to automate the weed inspections it is desired to generate a map of the weed species present within the field, to generate the map images must be captured with samples covering the field. T...

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