نتایج جستجو برای: weed infestation indices

تعداد نتایج: 103342  

Journal: :Bangladesh Journal of Agricultural Research 1970

2013
Mahbubur Rahman Brenna Blackwell Nilanjan Banerjee Dharmendra Saraswat

Weed infestation is a common problem in agriculture that adversely affects crop production. Given severe constraints on the budget of many landgrant universities due to the economic downturn, outreach services have taken a hit. To adapt to current economic climate without adversely affecting the quality of outreach program for weed management, we present a hierarchical system that uses image ca...

2002
J. BARROSO D. RUIZ C. FERNANDEZ-QUINTANILLA A. RIBEIRO B. DIAZ

The ability to manage weed infestations in a spatially precise manner will rely on the availability of efficient methods of mapping weed distributions. We have conducted a study designed to compare four different ground based methods for collecting georeferenced information on sterile wild oat infestation in a winter barley crop. Sampling was done at harvest time (when wild oat panicles are mos...

2000

June 23, 2000 Deciding whether a specific weed infestation is worth treating is usually based on a subjective evaluation of the potential impact of the infestation on crop yields. The two main criteria used are 1) the number of weeds present, and 2) the specific weeds present (foxtail, velvetleaf, etc.). Another factor that is just as important, if not more so, is the emergence date of the weed...

موحدی دهنوی‌, محسن, کیانی, ملیحه, یدوی, علیرضا ,

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...

Journal: :Revista de saude publica 2005
Vanêssa C G Morato Maria da Glória Teixeira Almério C Gomes Denise P Bergamaschi Maurício L Barreto

OBJECTIVE To assess infestation levels of Aedes aegypti using the oviposition trap (ovitrap) method and to compare these results with data obtained with the use of indices traditionally applied in public programs aimed at fighting this vector. METHODS Nine sentinel areas in Northeastern, Brazil, were assessed and infestation levels were measured for a nine-month period. Egg density and contai...

2014
P. Javier Herrera José Dorado Angela Ribeiro

An important objective in weed management is the discrimination between grasses (monocots) and broad-leaved weeds (dicots), because these two weed groups can be appropriately controlled by specific herbicides. In fact, efficiency is higher if selective treatment is performed for each type of infestation instead of using a broadcast herbicide on the whole surface. This work proposes a strategy w...

Journal: :Anais da Academia Brasileira de Ciencias 2014
Caio D Guzzo Leonardo B de Carvalho Paulo R F Giancotti Pedro L C A Alves Elaine C P Gonçalves José V F Martins

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...

2014
Leilei Tang Chuanpeng Cheng Kaiyuan Wan Ruhai Li Daozhong Wang Yong Tao Junfeng Pan Juan Xie Fang Chen

Weeding and fertilization are important farming practices. Integrated weed management should protect or improve the biodiversity of farmland weed communities for a better ecological environment with not only increased crop yield, but also reduced use of herbicides. This study hypothesized that appropriate fertilization would benefit both crop growth and the biodiversity of farmland weed communi...

2005
G. Drysdale

This paper analyses the potential and limitations of airborne remote sensing systems for detecting crop growth variability and weed infestation within paddocks at specified capture times. The detection of areas of crop growth variability can help farmers become aware of regions within their paddock where they may be experiencing above and below average yields due to changes in soil or managemen...

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