نتایج جستجو برای: seed rates
تعداد نتایج: 509200 فیلتر نتایج به سال:
PREMISE OF THE STUDY Mammalian herbivores, particularly white-tailed deer, can have a major impact on plant abundance and distribution. However, plants can tolerate herbivory by increasing seed production or seed quality. We used the monocarpic perennial Prenanthes roanensis to examine tolerance to mammalian herbivory through seed quality and modeled the effects of tolerance on population growt...
Many tropical pioneer species depend on the presence of highseeddensities inthesoil forsuccessful recruitment following canopy disturbance (Cheke et al. 1979, Dalling & Hubbell 2002, Guevara Sada & Gómez Pompa 1972, Whitmore 1983). However determinants of variation in the composition and abundance of soil seed banks remain poorly understood. Seed bank densities can be affected by rates of seed ...
In order to evaluate the impact of crop residues (zero, 25 and 50%) and nitrogen (zero, 125 and 250 kg ha) on weed seed bank and potato yield, two-years research was conducted as a split plot arranged in randomized complete block design in Rozveh Agriculture Research Station, Freidan-Esfahan. Numbers of weed species in seed bank, aboveground, and both seed bank and aboveground were 1, 2 and...
The two factors that determine plant migration rates - seed dispersal and population growth - are generally treated independently, despite the fact that many animals simultaneously enhance plant migration rate via seed dispersal, and decrease it via negative effects of herbivory on population growth. Using extensive empirical data, we modelled the antagonistic effects of seed dispersal and herb...
in order to evaluation of nitrogen fertilizer application and seed inoculation by azotobacter and azosprillium on yield, rate and grain filling period of corn sc-500 cultivar, a factorial experiment was conducted based on randomized complete block design with three replications in farm of agriculture and natural resource research center of azarbaijan-e- shargi province in 2011. the factors were...
first of all, in order to determine the high yielding rapeseed varieties, two field experiments were performed in 2006-2008 cropping seasons in agricultural and natural resources research center of markazi province, arak (34º 5´ n; 49º 42´ e, and 1775 m above sea level), iran. in this research, 15 winter rapeseed varieties were compared in a randomized complete block design with three replicati...
In order to determine the optimum rate of Vigna sun-hum seed sowing for rangeland rehabilitation in sandy soil of North Kordofan, Sudan, two trials were conducted separately under managed and unmanaged conditions at El-obeid Agricultural Research Farm in Sheikan locality of North Kordofan State in 2015 and 2016. Seed rates were 1, 2, 3, 4 and 5 Kg/feddan (4200m) and arranged by a Completely Ran...
Corvids (crows, jays, magpies and nutcrackers) are important dispersers of large-seeded plants. Studies on captive or supplemented birds suggest that they flexibly adjust their scatter-hoarding behaviour to the context of social dynamics and relative seed availability. Because many corvid-dispersed trees show high annual variation in seed production, context-dependent foraging can have strong e...
روانگرایی در ماسه های ریزدانه اشباع در هنگام زلزله، موجب خرابی سازه های زیادی در نقاط مختلف دنیا بوده است. از عوامل موثر در این پدیده می توان به تراکم خاک، دانه بندی خاک، عمق لایه مورد نظر و تنش های موثر همه جانبه، شدت و مدت زمان زمین لرزه و درصد عبوری از الک شماره 200 (مقدار ریزدانه و جنس آن) اشاره نمود. عالباً در روشهای رایج ارزیابی وقوع روانگرایی از خصوصیات درجای خاک، همانند نتایج آزمایش های ...
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