نتایج جستجو برای: weed biomass

تعداد نتایج: 73899  

1999
A. Bischoff

The regeneration of weed communities after cessation of fertilization and herbicide use was investigated on an arable field representative of the Central German Chernozem Region. As a result of high, but spatially heterogeneous input of farmyard manure and slurry until 1983, there were large differences in soil nitrogen supply within this ‘regeneration field’ during the investigation period (19...

Journal: :بوم شناسی کشاورزی 0
احمد زارع فیض آبادی حمید رضا رستم زاده

in order to study the weed populations in wheat, under different crop rotations an experiment was carried out at agricultural research station of jolgeh rokh, iran. during growing season this project was done in five years, based on randomized complete bloch design with three replications, on crop rotations included: wheat monoculture for the whole period (wwwww), wheat- wheat- wheat- canola- w...

Journal: :تولید گیاهان زراعی 0

in order to evaluate the effect of row space and weed management on weed population, chickpea yield and yield components, a factorial experiment based on rcbd with three replications was conducted at field research of agriculture college of lorestan university in cropping season of 2006-2007. in this research experimental factors were chickpea row spaces with four levels (15, 20, 30 and 40 cm w...

2015
Xiaoyan Ma Hanwen Wu Weili Jiang Yajie Ma Yan Ma Baohong Zhang

Redroot pigweed is one of the injurious agricultural weeds on a worldwide basis. Understanding of its interference impact in crop field will provide useful information for weed control programs. The effects of redroot pigweed on cotton at densities of 0, 0.125, 0.25, 0.5, 1, 2, 4, and 8 plants m(-1) of row were evaluated in field experiments conducted in 2013 and 2014 at Institute of Cotton Res...

2012
Dionisio Andújar Martin Weis Roland Gerhards

Site-specific weed management requires sensing of the actual weed infestation levels in agricultural fields to adapt the management accordingly. However, sophisticated sensor systems are not yet in wider practical use, since they are not easily available for the farmers and their handling as well as the management practice requires additional efforts. A new sensor-based weed detection method is...

Journal: :journal of agricultural science and technology 2010
h. filizadeh a. rezazadeh z. younessi

crop rotation is one of the essential practices in sustainable agricultural systems, be-cause of its effects on soil fertility and other benefits including a reduction in weed compe-tition. a field experiment was conducted at chaparsar rice research station, tonekabon, iran, from 2002 to 2003 to assess the influence of crop rotation, time of planting, and till-age depth on rice (oryza sativa l....

2003
J. W. van Groenigen E. G. Burns J. M. Eadie W. R. Horwath C. van Kessel

This study quantifies the agronomic benefits of foraging waterfowl in winter flooded rice fields in the Sacramento Valley of California (US). Fifteen winter flooded rice fields along a 105 km long transect, each with five pairs of waterfowl exclosures and control plots were used to measure residue decomposition in spring, and weed biomass and grain yield at harvest. Experimental exclusion of wa...

Journal: :Journal of integrative plant biology 2008
Hai-Yan Li Yun-Fei Yang

Green foxtail (Setaria viridis L.) is a common weed species in temperate regions. Research on the effect of delayed reproduction on the phenotypic plasticity and regularity of the vegetative and reproductive growth is of vital significance for understanding population regulation and control of the weed in the growing season. Green foxtail seeds were sown every 10 days from 25 June to 24 August ...

Journal: :Proceedings. Biological sciences 2007
J D Pidgeon M J May J N Perry G M Poppy

Currently, the UK has no procedure for the approval of novel agricultural practices that is based on environmental risk management principles. Here, we make a first application of the 'bow-tie' risk management approach in agriculture, for assessment of land use changes, in a case study of the introduction of genetically modified herbicide tolerant (GMHT) sugar beet. There are agronomic and econ...

2004
Lisa J. Samuelson Kurt Johnsen Tom Stokes Weinlang Lu

Intensive forestry may reduce net CO2 emission into atmosphere by storing carbon in living biomass, dead organic matter and soil, and durable wood products. Because quantification of belowground carbon dynamics is important for reliable estimation of the carbon sequestered by intensively managed plantations, we examined soil CO2 efflux (SCO2 ) in a 6-year-old loblolly pine (Pinus taeda L.) plan...

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