نتایج جستجو برای: depth soil 0045

تعداد نتایج: 333360  

2014
Bei-xiao Shi Cheng-feng Zheng Jin-kun Wu

Engineering problems shunned previously rise to the surface gradually with the activities of reforming the natural world in depth, the problem of expansive soil crack under the changing environment becoming a control factor of expansive soil slope stability. The problem of expansive soil crack has gradually become a research hotspot, elaborates the occurrence and development of cracks from the ...

2010
Whendee L. Silver Rebecca Ryals Valerie Eviner

Rangeland ecosystems cover approximately one-third of the land area in the United States and half of the land area of California. This large land area, coupled with the propensity of grasses to allocate a considerable proportion of their photosynthate belowground, leads to high soil carbon (C) sequestration potential. Annual grasslands typical of the Mediterranean climates of the western United...

2016
Yuanxin Liu Wenwu Zhao Lixin Wang Xiao Zhang Stefani Daryanto Xuening Fang Eric J. Jokela

Soil moisture scarcity has become the major limiting factor of vegetation restoration in the Loess Plateau of China. The aim of this study is: (i) to compare the spatial distribution of deep (up to 5 m) soil moisture content (SMC) beneath the introduced shrub Caragana korshinskii Kom. under different precipitation zones in the Loess Plateau and (ii) to investigate the impacts of environmental f...

Journal: :TheScientificWorldJournal 2007
Yvonne A Wood Mark Fenn Thomas Meixner Peter J Shouse Joan Breiner Edith Allen Laosheng Wu

We report the rapid acidification of forest soils in the San Bernardino Mountains of southern California. After 30 years, soil to a depth of 25 cm has decreased from a pH (measured in 0.01 M CaCl2) of 4.8 to 3.1. At the 50-cm depth, it has changed from a pH of 4.8 to 4.2. We attribute this rapid change in soil reactivity to very high rates of anthropogenic atmospheric nitrogen (N) added to the ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2017
Ying Fan Gonzalo Miguez-Macho Esteban G Jobbágy Robert B Jackson Carlos Otero-Casal

Plant rooting depth affects ecosystem resilience to environmental stress such as drought. Deep roots connect deep soil/groundwater to the atmosphere, thus influencing the hydrologic cycle and climate. Deep roots enhance bedrock weathering, thus regulating the long-term carbon cycle. However, we know little about how deep roots go and why. Here, we present a global synthesis of 2,200 root observ...

اسحاقی راد , جواد, متاجی, اسداله, واحدی, علی اصغر,

Soil organic carbon pool plays an important role in the global C cycle and climate change mitigation. Therefore, improving our understanding of some factors such as plant biodiversity that can affect forest soil C storage is fundamentally important for anticipating changes. This study was carried out in the mixed-beech forests of Glandrood located in Noor using a systematic network of points in...

Journal: :مهندسی زراعی 0

in order to study the effects of sugar cane harvest machinery traffic on bulk density and cone index variation, a survey was conducted in 10 farms of deabel khozaiee sugarcane agro-industrial company, ahvaz, in 2006. in this experiment, two types of harvesters including wheel half track and tire wheels with 14 tons of weight, versus two types of tractor and basket transporters, with 10 and 18 t...

1997
J. Gan

Methyl bromide (CH,Br) is currently the most widely used soil fumigant, and its emission into the atmosphere after application reportedly contributes to ozone depletion in the stratosphere. Irreversible degradation and partially reversible sorption reactions affect the quantity of this fumigant reaching the soil surface and escaping into the atmosphere. Incubation studies in closed headspace vi...

2006
W. K. Jung

Spatial variability in soil properties has long been observed within uniformly managed fields. Understanding the spatial characteristics of soil properties would be helpful in understanding soil–landscape relationships and in the development of site-specific management. The primary objective of this research was to quantify the spatial characteristics of claypan soil properties for a 4-ha agric...

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