نتایج جستجو برای: crop density
تعداد نتایج: 475095 فیلتر نتایج به سال:
No-till cropping is an option for growers needing to reduce soil erosion in the Palouse annual-cropped region of the Pacific Northwest, which is well suited for wheat production. A 6-yr field study was conducted to determine optimum levels of fertilizer and herbicide inputs in a no-till continuous wheat crop production system. Three levels of nitrogen (N) and two weed management levels (WML) we...
Weeds are a major obstacle to successful crop production in organic farming. Producers may be able to reduce inputs for weed management by designing rotations to disrupt population dynamics of weeds. Population-based management in conventional farming has reduced herbicide use by 50% because weed density declines in cropland across time. In this paper, we suggest a 9-year rotation comprised of ...
A general model of crop yield response to herbicide application is proposed. The model includes three components: the effect of herbicide dosage on weed density, the effect of surviving weed density on crop yield and the effect of herbicide directly on the crop. The model is used to estimate the response of wheat yield to application of diclofop-methyl to control ryegrass .(Lolium rigidum) in A...
Water management in cracked paddy soils is an important issue in rice cultivation. In order to study organic matter and zeolite effect and their interaction on moisture conditions and hydraulic and physical properties of paddy soils, the organic matter (rice straw) at four levels (0, 8, 16 and 24 tons per hectare), zeolite at four levels (0, 0.5, 1 and 1.5 percent ), and also moisture stages o...
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...
high-density planting system is one of the effective methods for improving production and profitability of tree orchards. in this research, the effects of four planting densities (1904, 2666, 3137 and 4800 tree/ha) on annual shoot growth, tree yield, physicochemical properties of fruit and leaf mineral contents of apple (malus domestica borkh cv ‘granny smith’treegrafted on m26 clonal rootstock...
Assemblages of macroalgae are believe to be among the most productive ecosystems in the world, yet difficulties in obtaining direct estimates of biomass and primary production have led to few macroalgal data sets from which the consequences of long-term change can be assessed. We evaluated the validity of using two easily measured population variables (frond density and plant density) to estima...
Stomata, the small opening in leaf connecting plant with atmosphere, play pivotal roles in global water and carbon cycles. Stomata regulate the two key important physiological functions viz. photosynthesis and transpiration and thus are crucial for performance of crop species in changing climatic conditions. Although environmental factors influence the density and size of stomata, the genetic c...
weed's behaviors differ in a multiweed-crop competition system compare to a mono weed-crop competition system. the present investigation was carried out in mashhad, iran, to study the effect of weeds, which emerged naturally in a multi species community along side with melon, on quantitative and qualitative characteristics of the crop during 2007. thirty five plots were selected randomly in a g...
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