نتایج جستجو برای: must soil

تعداد نتایج: 487003  

2007
P. J. Steinle

Soil moisture is an important control over atmospheric evolution, since it controls the partition of incoming radiation into latent and sensible heating. To accurately model these land surface fluxes, atmospheric models must ultimately have accurate soil moisture fields. Yet soil moisture is typically initialised indirectly in Numerical Weather Prediction (NWP) models, frequently resulting in u...

2000
S. A. Billings D. D. Richter J. Yarie

In order to better predict soil sinks of methane, we need to examine soil methane ̄ux patterns and responses to altered soil moisture regimes. Estimates of the global atmospheric CH4 budget must also account for ̄uxes in the vast boreal region. We measured methane ̄uxes into the soil surface, methane concentrations, water content, and temperature in the soil pro®le in two interior Alaskan fores...

Fire can influence the stability of many natural habitats via changes in biological, chemical and physical properties of soil. The aim of the present study was to investigate the effects of fire on some chemical properties and nutrients availability in a rangeland soil. To perform this research, a fired area with a five-month history and a homogenized area close to it without fire were selected...

The use of wind turbines to generate electricity has increased in recent years. One of the most important parts of a wind turbine is the foundation, which should be designed accurately because it is influenced by difference forces. Soil cannot carry tension stress; thus, when a wind turbine foundation is applied eccentricity forces, a gap appears between the soil and foundation. The gap will ha...

2002
Richard T. Koenig

Determining when applications of nitrogen (N), sulfur (S), potassium (K) and phosphorus (P) fertilizer are needed is important to maintain alfalfa yield and quality. The Western U.S. is diverse in terms of climate, soil types, irrigation water need and availability, historical nutrient use and alfalfa production systems. Therefore, few generalizations hold regarding the timing and location of N...

Journal: :مهندسی سازه 0
ابوالفضل شمسائی سینا فرد مرادی نیا

pressurized injection operation means the pressurized injection of a liquid or solution into pore of a mass of soil or stone and/ or cavity between them and built structures. the injected mortar mustconstitute a soil and/ or jel- like matter inside the cavites, and/ or the operations of the injection must cause sedimentation of the solid matter suspending in these cavites. the primary purpose o...

Journal: :مهندسی عمران فردوسی 0
محمدحسین امین فر بهمن فرهمند آذر هادی صفری مرتضی بیکلریان

in practice, foundations are settled on the soft layers of soil, so the ground must be designed as well as the structure. wave propagation and hysteresis damping of soil layers may alter the seismic response of flexible-base design in comparison to controversial fixed-base. lots of uncertainties about this issue, necessitate most of seismic design standards including iranian standard no. 2800 t...

2003
Diego de la Rosa

Agricultural management systems have been historically adopted without recognizing consequences on soil conservation and environmental quality, and therefore significant decline in soil quality has occurred worldwide. Soil quality has been defined as “the capacity of a specific kind of soil to function with its surroundings, sustain plant and animal productivity, maintain or enhance soil, water...

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