نتایج جستجو برای: global hectare

تعداد نتایج: 450841  

2001
Ari Rabl Anil Markandya

By analyzing the decisions of policy makers and in addition public referenda, shadow prices for global warming (ca. 5 to 22 € per ton of CO2) and exceedance of critical loads for eutrophication and acidification (ca. 100 € per hectare of exceeded area and year with a range of 60 – 350 €/ha year) have been developed. These data are complementary to the valuation steps in ExternE, and can be used...

Journal: :Science 2003
Michelle A Walvoord Fred M Phillips David A Stonestrom R Dave Evans Peter C Hartsough Brent D Newman Robert G Striegl

A large reservoir of bioavailable nitrogen (up to approximately 10(4) kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of arid regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for wa...

2000
Mary Anne Sword James D. Haywood Dan Andries

h 1989, two levels each of stand density and fertilization were factorially established in an 8-year-old loblolly pine plantation on a P-deficient site. Levels of stand density were nonthinned at 2,732 trees per hectare and thinned at 721 trees per hectare. Fertilizer levels were none or application of 150 kilograms P plus 135 kilograms N per hectare. In 1994, stand basal areas of the nonthinne...

Journal: :پژوهش های تولید گیاهی 0
مجید عالیمقام دانشگاه علوم کشاورزی و منابع طبیعی گرگان افشین سلطانی دانشگاه علوم کشاورزی و منابع طبیعی گرگان ابراهیم زینلی دانشگاه علوم کشاورزی و منابع طبیعی گرگان

greenhouse gases emissions from burning fossil fuels and the effect of these gases on climate change is one of the most important ecological and political issues. in this study the energy consumption and greenhouse gas emissions from tillage and soybean planting were assessed in gorgan. this study is done on 13 soybean farms in 2012. information related to tillage and planting operations were p...

Journal: :Journal of animal science 2016
P A Beck C B Stewart M S Gadberry M Haque J Biermacher

Eight 4-ha mixed warm-season grass pastures in southwestern Arkansas (33°40'4″ N, 93°35'24″ W, and elevation 107 m) were stocked with either large mature size (571 kg [SD 55.2] BW) or small mature size (463 kg [SD 58.2] BW) spring-calving cows at 4 stocking rates (SR; 1, 1.5, 2, or 2.5 cow-calf pairs/ha) over 4 yr to test the effects of SR and mature body size on cow and calf performance and sy...

2011
Derek H. Lynch Rod MacRae Ralph C. Martin

About 130 studies were analyzed to compare farm-level energy use and global warming potential (GWP) of organic and conventional production sectors. Cross cutting issues such as tillage, compost, soil carbon sequestration and energy offsets were also reviewed. Finally, we contrasted E and GWP data from the wider food system. We concluded that the evidence strongly favours organic farming with re...

2014
Miroslava RAJČÁNIOVÁ

This paper discusses recent developments in the market for agricultural land in Slovakia related to the new law on land acquisition. The stated objective of this law is to protect agricultural land from non-agricultural use. We analyze landrelated data as reported by sellers in the newly established Registry of offers of agricultural land administered by the Ministry of Agriculture and Rural De...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2010
D Murdiyarso K Hergoualc'h L V Verchot

The upcoming global mechanism for reducing emissions from deforestation and forest degradation in developing countries should include and prioritize tropical peatlands. Forested tropical peatlands in Southeast Asia are rapidly being converted into production systems by introducing perennial crops for lucrative agribusiness, such as oil-palm and pulpwood plantations, causing large greenhouse gas...

Journal: :Journal of experimental botany 2011
Jianhua Zhang

China has to feed 20% of the global population with only about 5% of the planet's water resources and 7% of its arable land. With such limited natural conditions, however, China's grain production has increased from about 200 kg per capita in 1949 to about 400 kg in the early 1990s. Hunger as a social problem has largely disappeared after being prevalent in China for several thousand years with...

Journal: :Science 2006
David Tilman Jason Hill Clarence Lehman

Biofuels derived from low-input high-diversity (LIHD) mixtures of native grassland perennials can provide more usable energy, greater greenhouse gas reductions, and less agrichemical pollution per hectare than can corn grain ethanol or soybean biodiesel. High-diversity grasslands had increasingly higher bioenergy yields that were 238% greater than monoculture yields after a decade. LIHD biofuel...

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