نتایج جستجو برای: canopy density
تعداد نتایج: 422904 فیلتر نتایج به سال:
There is increasing interest in evaluating the environmental effects on crop architectural traits and yield improvement. However, crop models describing the dynamic changes in canopy structure with environmental conditions and the complex interactions between canopy structure, light interception, and dry mass production are only gradually emerging. Using tomato (Solanum lycopersicum L.) as a mo...
Pathogens and other symbiotic fungi that infect above-ground plant parts commonly disperse as airborne spores. Here we present diel patterns of the density of airborne fungal spores in the canopy and understory of a tropical rain forest. Spores were 52-fold more abundant in the understory than in the canopy. Additionally, spores were 5to 35-fold more abundant at night than during the day, assoc...
Tropical pastures present multiple barriers to tree regeneration and restoration. Relict trees serve as "regeneration foci" because they ameliorate the soil microclimate and serve as safe spots for dispersers. Here, we describe another mechanism by which remnant trees may facilitate pasture regeneration: the presence of seed banks in the canopy soil that accumulates from decomposing epiphytes w...
We analyse spatial variability and different evolution patterns of snowpack in a mixed beech–fir stand in the central Pyrenees. Snow depth and density were surveyed weekly along six transects of contrasting forest cover during a complete accumulation and melting season; we also surveyed a sector unaffected by canopy cover. Forest density was measured using the sky view factor (SVF) obtained fro...
Light intensity intercepted by the soybean canopy during the reproductive period is an important environmental factor determining soybean yield components and grain yield. A 2-year field experiment was conducted to investigate the effects of light enrichment and its interaction with planting density on yield formation of soybean cultivars. Light enrichment increased seed yield per plant and yie...
The effects of small-scale disturbances (80 30-cm plots) of canopy and grazers on intertidal assemblages were investigated in this 4-year experiment on sheltered rocky shores on the Swedish west coast. Canopy disturbances due to ice scouring were mimicked by removal of adult plants of the seaweed Ascophyllum nodosum (L.) Le Joli. Density of the main epilithic grazing gastropods, Littorina spp.,...
Spiny and aromatic species in rangelands can play important role in the conservation of plant species in rangelands; however, few studies have been done on the role of these plants under different levels of livestock grazing. In this research, the facilitation effects of spiny (Astragalus chrysostachys Boiss) and aromatic (Artemisia kopetdaghensis (Poljakov) Y.R.Ling) shrubs were studied on sp...
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