نتایج جستجو برای: soil type

تعداد نتایج: 1509264  

2004
Jeffrey P. Walker Garry R. Willgoose Jetse D. Kalma

A number of automated techniques for point measurement of soil moisture content have been developed to an operational level over the past few decades. While each of those techniques have been individually evaluated by the thermogravimetric (oven drying and weighing) method, typically under laboratory conditions, there have been few studies which have made a direct comparison between the various...

Conservative agriculture is considered as an alternative to tackle the need for increased agricultural production based on sustainable agriculture activities with the aim of increasing production and product stability along with preserving the environment. Tillage is one of the most important factors affecting soil structure. Selection of appropriate tillage systems varies according to the cond...

2016
Christian Folberth Rastislav Skalský Elena Moltchanova Juraj Balkovič Ligia B. Azevedo Michael Obersteiner Marijn van der Velde

Global gridded crop models (GGCMs) are increasingly used for agro-environmental assessments and estimates of climate change impacts on food production. Recently, the influence of climate data and weather variability on GGCM outcomes has come under detailed scrutiny, unlike the influence of soil data. Here we compare yield variability caused by the soil type selected for GGCM simulations to weat...

2008
C. Hahn

The knowledge of soil type and soil texture is crucial for environmental monitoring purpose and risk assessment. Unfortunately, their mapping using classical techniques is time consuming and costly. We present here a way to estimate soil types based on limited field observations and remote sensing data. Due to the fact that the relation between the soil types and the considered attributes that ...

Journal: :The New phytologist 2013
Stephanie S Porter

Although adaptive plant population divergence across contrasting soil conditions is often driven by abiotic soil factors, natural enemies may also contribute. Cryptic matching to the native soil color is a form of defensive camouflage that seeds can use to avoid detection by seed predators. The legume Acmispon wrangelianus occurs across a variety of gray-green serpentine soils and brown nonserp...

2016
Haichuan Cao Ruirui Chen Libing Wang Lanlan Jiang Fen Yang Shixue Zheng Gejiao Wang Xiangui Lin

Considering the extensive functional redundancy in microbial communities and great difficulty in elucidating it based on taxonomic structure, studies on the biogeography of soil microbial activity at large spatial scale are as important as microbial community structure. Eighty-four soil samples were collected across a region from south to north China (about 1,000 km) to address the questions if...

2014
Susanne Schreiter Guo-Chun Ding Holger Heuer Günter Neumann Martin Sandmann Rita Grosch Siegfried Kropf Kornelia Smalla

The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for 10 years ...

2007
J. P. Walker R. Panciera R. Young E. J. Kim

Reliable soil moisture measurements over large areas are much needed for both hydrologic modelling and remote sensing applications. For collecting such data, portable electronic sensors offer a practical alternative to gravimetric measurements. The conversion of the measured electrical output to soil moisture is nonetheless a non trivial task as it depends on soil type and temperature. In this ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران 1370

حوضه آبخیز سدمخزنی شهید پارسا در جنوب شرقی شهرستان فردوس استان خراسان واق گردیده است . بااحداث این سد علاوه برآبیاری اراضی موجود، 700 هکتار از اراضی جدید پایین دست به زیر کشت می روند. عمده ترین معضل موجود در رابطه با حوضه آبخیز، وجود بار رسوب فراوان و تجمع آن در پشت مخزن سد می باشد. لذابه علت عدم وجود اطلاعات کافی از وضعیت فرسایش خاک در حوضه آبخیز، دراین رساله بررسی و مطالعه فرسایش پذیری خاک ان...

1999

Grazing cattle on forest plantations in the interior of British Columbia is a common practice. Soil compaction can occur following cattle use, although this may vary with stocking rate, vegetation type and age, soil type, soil water content, and climate. Several studies have shown that increased soil compaction can have a negative impact on growth of young tree seedlings and on productivity in ...

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