نتایج جستجو برای: soil nitrogen percent 006

تعداد نتایج: 382998  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
Zoe G Cardon John M Stark Patrick M Herron Jed A Rasmussen

Plant roots serve as conduits for water flow not only from soil to leaves but also from wetter to drier soil. This hydraulic redistribution through root systems occurs in soils worldwide and can enhance stomatal opening, transpiration, and plant carbon gain. For decades, upward hydraulic lift (HL) of deep water through roots into dry, litter-rich, surface soil also has been hypothesized to enha...

2017
Emad Ehtesham Per Bengtson

During the last decade there has been an ongoing controversy regarding the extent to which nitrogen fertilization can increase carbon sequestration and net ecosystem production in forest ecosystems. The debate is complicated by the fact that increased nitrogen availability caused by nitrogen deposition has coincided with increasing atmospheric carbon dioxide concentrations. The latter could fur...

2017
Guangyu Li Cifang Wu

Set-aside farmland can effectively improve the self-rehabilitation of arable soil. Long-term set-asides however cannot satisfy provisionment, therefore the use of short-term set-asides to restore cultivated soil is a better option. Few studies have compared short-term set-aside patterns, and the effects of set-asides on soil microbial community and enzyme enzymes. We analyzed the bacterial stru...

Journal: :تولید گیاهان زراعی 0
یعقوب حسینی استادیار مرکز تحقیقات کشاورزی و منابع طبیعی هرمزگان مهدی همایی استاد گروه خاکشناسی، دانشکده کشاورزی، دانشگاه تربیت مدرس صفورا اسدی کپورچال استادیار گروه علوم خاک، دانشکده علوم کشاورزی، دانشگاه گیلان

abstractbackground and objectives: in most saline and non-saline soils, nitrogen is the most restrictive nutrient for plant growth. in saline soils, interactive effects of salinity and soil fertility is very important from optimum production. nutrient imbalance is one of the problems with saline soils. in these circumstances, the fertilizer application may to increase osmotic effect of salt, th...

2005
Shiqiang Wan Dafeng Hui Linda Wallace Yiqi Luo

[1] This study was conducted to examine direct and indirect impacts of global warming on carbon processes in a tallgrass prairie in the U.S. Great Plains. Infrared radiators were used to simulate global warming, and clipping was used to mimic hay mowing. Experimental warming caused significant increases in green biomass in spring and autumn and total biomass in summer on most of the measuring d...

2017
Upendra M. Sainju

Nitrogen balance in agroecosystems provides a quantitative framework of N inputs and outputs and retention in the soil that examines the sustainability of agricultural productivity and soil and environmental quality. Nitrogen inputs include N additions from manures and fertilizers, atmospheric depositions including wet and dry depositions, irrigation water, and biological N fixation. Nitrogen o...

Journal: :Ecology 2012
Dario A Fornara David Tilman

Human-induced increases in nitrogen (N) deposition are common across many terrestrial ecosystems worldwide. Greater N availability not only reduces biological diversity, but also affects the biogeochemical coupling of carbon (C) and N cycles in soil ecosystems. Soils are the largest active terrestrial C pool and N deposition effects on soil C sequestration or release could have global importanc...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Samuel M Simkin Edith B Allen William D Bowman Christopher M Clark Jayne Belnap Matthew L Brooks Brian S Cade Scott L Collins Linda H Geiser Frank S Gilliam Sarah E Jovan Linda H Pardo Bethany K Schulz Carly J Stevens Katharine N Suding Heather L Throop Donald M Waller

Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We ...

Journal: :علوم گیاهان زراعی ایران 0
یحیی امام ارسلان ضیائی

water deficit and low nitrogen content of soil are the two major yield limiting factors in most maize (zea mays l.) producing areas. the objective of the current research was to evaluate the relationships between photosynthetic water and nitrogen use efficiency at different levels of soil moisture and nitrogen contents. a factorial experiment, based on completely randomized design with 3 replic...

2001
R. F. Wright C. Alewell J. M. Cullen C. D. Evans A. Marchetto F. Moldan A. Prechtel

Long-term records of nitrogen in deposition and streamwater were analysed at 30 sites covering major acid sensitive regions in Europe. Large regions of Europe have received high inputs of inorganic nitrogen for the past 20-30 years, with an approximate 20% decline in central and northern Europe during the late 1990s. Nitrate concentrations in streamwaters are related to the amount of N depositi...

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