نتایج جستجو برای: weed density

تعداد نتایج: 420665  

2010
Irene Guerrero Patricia Martínez Manuel B. Morales Juan J. Oñate

Using a multimodel inference approach, the most relevant field-level and landscape context factors explaining the simultaneous variability of bird, carabid and weed species richness were identified and interpreted in a low-intensity cereal farming system in central Spain. Weed species richness was negatively influenced by sowing density, herbicides and surroundingmean field size. Carabid specie...

2012
Jesusa C. Beltran David J. Pannell Graeme J. Doole Benedict White

This paper describes a dynamic simulation model that allows for comprehensive assessment of integrated weed management programmes for the control of annual barnyardgrass (Echinochloa crus-galli complex) in Philippine rice farming systems. The main outputs of the model include weed seed and plant densities and seasonal and annualised profit over the simulated planning horizon. Results broadly in...

2013
Neelam Sharma Swati Sharma Suresh Kumar Robin Joshi

Wheat, a member of family Poaceae is one of the major food crops in the world. Globally, it occupies about 17% of the cropped land and contributes 35% of the staple food (Pingali 1999).Wheat constitutes one of the most abundant sources of energy and protein for the world population and its increased production is essential for food security (Chhokar et al. 2006). Severe competition from weeds i...

2017
Alexandra M Knight Wesley J Everman David L Jordan Ronnie W Heiniger T Jot Smyth

Adequate fertility combined with effective weed management is important in maximizing corn (Zea mays L.) grain yield. Corn uptake of nitrogen (N) is dependent upon many factors including weed species and density and the rate and formulation of applied N fertilizer. Understanding interactions among corn, applied N, and weeds is important in developing management strategies. Field studies were co...

2014
Ramon Albajes Belén Lumbierres Xavier Pons Jordi Comas

Genetically modified maize tolerant to broad-spectrum herbicides may greatly alter weed flora composition, abundance and therefore affect organisms of higher trophic levels, including herbivore and detritivore arthropods and their natural enemies. This three-year study measured the effects on arthropods of an intensive use of broad-spectrum herbicides in comparison with one application of conve...

Journal: :Annals of botany 2003
Sarah E Park Laurence R Benjamin Andrew R Watkinson

Many studies of plant competition have been directed towards understanding how plants respond to density in monocultures and how the presence of weeds affects yield in crops. In this Botanical Briefing, the development and current understanding of plant competition is reviewed, with particular emphasis being placed on the theory of plant competition and the development and application of mathem...

Journal: :New Zealand Journal of Experimental Agriculture 1978

Journal: :حفاظت گیاهان 0
معصومه نعمت پور نعمت اله پیردشتی محمد یعقوبی خانقاهی

a field experiment was conducted to investigate the spatial distribution of nutsedge (cyperus spp) during rice growing season using geostatic in 2011 at sari agricultural sciences and natural resources university. at the first field was divided into 36 grids (2.5×2.5 meter) after the final preparation. grid intersection points were determined and marked. all samples were taken from these points...

Journal: :علوم گیاهان زراعی ایران 0
یوسف غلام پور شمامی دانشجوی کارشناسی ارشد پردیس کشاورزی و منابع طبیعی دانشگاه تهران ناصر مجنون حسینی استاد پردیس کشاورزی و منابع طبیعی دانشگاه تهران حسن علیزاده استاد، پردیس کشاورزی و منابع طبیعی دانشگاه تهران

to determine the optimum weed management method and plant population density on chickpea yield, a split plot experiment based on rcbd with four replications was carried out at the university of tehran research farm (located in karaj) during 2010-2011. the main factor consisted of nine treatments including: 1. trifluralin pre-plant, 2. pendimethalin pre-plant, 3. complete weeding, 4. imazethapyr...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد 1375

این آزمایش با استفاده از طرح بلوکهای کامل تصادفی با 8 تیمار و در 3 تکرار با هدف اصلی تعیین دوره بحرانی رقابت علفهای هرز با سیب زمینی در مزرعه مرکز تحقیقات کشاورزی خراسان انجام شد. تیمارها شامل دو گروه 4 تایی بودند. در گروه تیمارهای (weed free) به مدتهای 3، 6، 9 و 12 هفته پس از سبزشدن سیب زمینی، مزرعه عاری از علفهای هرز نگه داشته شد و در گروه تیمارهای (weed infested) به مدتهای 3، 6، 9 و 12 هفته ...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید