نتایج جستجو برای: introduces than common weed species final height

تعداد نتایج: 3086812  

Journal: :Ecological solutions and evidence 2021

Semi-arid forests need cost-effective restoration strategies to address their severe degradation. Tree shelters are often used minimize abiotic and biotic stress during seedling establishment. We asked if early-successional weeds act as a natural shelter by facilitating native seedlings, contingent on stressors ecological strategy. conducted manipulative weed exclusion experiment at semi-arid s...

1999
J. H. Miller

Intensive vegetation management alters seedling growth and development in southcm pine plantations. Adequate light, moisture. and nutrients stimulate seedling stem growth and crown development. Thus rapid stem growth could deplete nutrient and energy resources required for aggressive rcot growth. Early root system expansion within the available rooting zone is critical because structural root g...

Journal: :Journal of virology 2007
J Matousek L Orctová J Ptácek J Patzak P Dedic G Steger D Riesner

Weed plants characteristic for potato and hop fields have not been considered in the past as potential hosts that could transmit and lead to spreading of potato spindle tuber (PSTVd) and hop stunt (HSVd) viroids, respectively. To gain insight into this problem, we biolistically inoculated these weed plants with viroid populations either as RNA or as cDNA. New potential viroid host species, coll...

1997

Seven C3 crop and three C3 weed species were grown from seed at 360 and at 700 cm3 m–3 carbon dioxide concentrations in a controlled environment chamber to compare dry mass, relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and photosynthetic acclimation at ambient and elevated carbon dioxide. The dry mass at the final harvest at elevated carbon dioxide relative to ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی 1392

flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...

Journal: :Journal of nematology 1988
E M Jordaan D De Waele

The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki we...

Journal: :پژوهش های حبوبات ایران 0
علیرضا کوچکی حسام الدین سلوکی ثنا کاربر

introduction weed infestation causes an extremely reduction of crops yield. on the other hand, increasing the diversity of crops in agro-ecosystems will change the biomass distribution of weeds community, thereby reducing the number and density of different weed species. weed management in the past few decades has been in conflict with ecological principles and sustainability of the production ...

2011
N. Sapkota

A study was carried out to determine the composition and predominance of weed species in wheat field in Khokana of Kathmandu valley as a representative sample of mountain ecosystem in Nepal. A total of 44 weed species representing 18 families were recorded. The most abundant species were Chenopodium album, Polygonum plebeium and Spergula arvensis. With the improved temperature after February, t...

2010
Regina S. Baucom Rodney Mauricio

Background: The herbicide RoundUp® became widely used in agriculture in the mid-1990s. Current populations of the crop weed Ipomoea purpurea exhibit both resistance and tolerance to RoundUp, which are two types of defence that have previously been shown to have a genetic basis in this weed species. Questions: Did the genetic basis of RoundUp defence antedate the introduction of RoundUp? If so, ...

2011
Rita S. L. Veiga Jan Jansa Emmanuel Frossard Marcel G. A. van der Heijden

BACKGROUND Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. METHODOLOGY/PRINCIPAL FINDINGS First, under c...

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