WordNet

strike (the top part of a ball in golf, baseball, or pool) giving it a forward spin
the first half of an inning; while the visiting team is at bat; "a relief pitcher took over in the top of the fifth" (同)top of the inning
covering for a hole (especially a hole in the top of a container); "he removed the top of the carton"; "he couldnt get the top off of the bottle"; "put the cover back on the kettle" (同)cover
a conical childs plaything tapering to a steel point on which it can be made to spin; "he got a bright red top and string for his birthday" (同)whirligig, teetotum, spinning top
a garment (especially for women) that extends from the shoulders to the waist or hips; "he stared as she buttoned her top"
platform surrounding the head of a lower mast
the greatest possible intensity; "he screamed at the top of his lungs"
the highest or uppermost side of anything; "put your books on top of the desk"; "only the top side of the box was painted" (同)top side, upper side, upside
the upper part of anything; "the mower cuts off the tops of the grass"; "the title should be written at the top of the first page"
cut the top off; "top trees and bushes" (同)pinch
finish up or conclude; "They topped off their dinner with a cognac"; "top the evening with champagne" (同)top_off
provide with a top or finish the top (of a structure); "the towers were topped with conical roofs" (同)top_out
be at the top of or constitute the top or highest point; "A star tops the Christmas Tree"
reach or ascend the top of; "The hikers topped the mountain just before noon"
situated at the top or highest position; "the top shelf"
to a very great extent or degree; "the idea is so obvious"; "never been so happy"; "I love you so"; "my head aches so!"
(usually followed by `that'
in a manner that facilitates; "he observed the snakes so he could describe their behavior"; "he stooped down so he could pick up his hat"
in such a condition or manner, especially as expressed or implied; "Theyre happy and I hope they will remain so"; "so live your life that old age will bring no regrets"
in the same way; also; "I was offended and so was he"; "worked hard and so did she"
to a certain unspecified extent or degree; "I can only go so far with this student"; "can do only so much in a day"
the part of the earths surface consisting of humus and disintegrated rock (同)dirt
the act of soiling something (同)soilure, dirtying

PrepTutorEJDIC

〈C〉《the ~》(…の)『いちばん上の部分』,最先端,頂上 / 〈C〉《the ~》(…の)『最上面』,表面《+of+名》 / 《the ~》(…の)『最高位』,『首位』;上座《+of+名》 / 《the ~》(…の)『最高の程度』,頂点《+of+名》 / 〈C〉《the ~》(びんなどの)ふた,栓;(車の)屋根[カバー],ほろ《+of+名》 / 〈C〉《複数形で》(根菜の)葉の部分《+of+名》 / 〈C〉(上下の服の)上 / 《通例名詞の前にのみ用いて》 / 『最も高い』,いちばんの / 『最上位の』,第一位(一級)の / 最高程度の / …‘に'『おおい(ふた)を付ける』 / …の頂上にある,頂上をおおう / …‘の'頂上に達する,‘を'登りきる / …‘を'しのぐ,‘に'まさる / 〈野菜・果実など〉‘の'葉の部分を切る(刈り力む) / (ゴルフで)〈球〉‘の'上をたたく
こま
《様態の指示》『そういうふうに』,『そのように』・《補語に用いて》『そのようで』,そうで・《程度》『それほど』,そんなに・《強意として》《話》『非常に』,『とても』,たいへん・《前に述べたことの内容に対する同意を表して;「so+主語+[助]動詞」》『その通りで』,『本当に』,確かに,おっしゃるとおり・《肯定文を受けて;「so+[助]動詞+主語」の語順で》…『もまた』,『も同様に』・《as~, so…で》~と同じように…,(~のように)そのように・《目的を表して》…『するように』・《理由・結果を表して》『その結果』,それで・《文・節の頭に用いて》『それで』,だから・《驚き・賛成・嫌悪・疑いなどを表して》そうか,そうなんだ,どうかな,まさか・それでよし
=sol
《方向》(1)(到着の意を含めて)…『へ』,に,まで / 《状況の変化》…[のほう]へ;…に[なるまで],その結果…になる / 《適用範囲》(1)《動詞に伴って》『…に対して』,に,へ / (2)《形容詞[句]・[代]名倍に伴って》『…に対して』 / 《程度・範囲》『…[に至る]まで』 / 《時間の終り》『…まで』(till) / 《to one's+『名』の形で》(…が)『…したことに[は]』 / 《比較・対比・割合》『…と比べて』,より,に対して / 《一致・適合》『…に合わせて』,に合って,に応じて / 《目的・意図》『…のために』 / 《運命・境遇》『…に』 / 《所属・関係》『…へ』,に[対して] / 《付加・付着・固執》『…に』 / 《対立・対向》…に[対して] / いつもの状態(位置)に / 停止(閉鎖)の状態に / 活動状態に(へ),仕事に
《名詞的用法》『…すること』 / 《形容詞的用法》『…するための,すべき』 / 《副詞的用法》『…するために』,して,するとは,すれば / 《独立用法》 / 《文全体を修飾する慣用語句》…すれば,してみると,…だが / 短縮文
〈U〉(植物の成長に適する)『土』,土壌(どじょう) / 〈U〉(特殊な)土 / 〈U〉〈C〉《気取って》国,地方;《the~》土地,農地
〈衣服など〉‘を'汚す,きたくなくする / 《比喩(ひゆ)的に》〈名声など〉‘を'けがす / 〈衣服などが〉汚れる,きたなくなる / 汚れ,汚点,しみ / (人の)汚物

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/09/30 21:39:09」(JST)

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[Wiki en表示]

Surface runoff, also called nonpoint source pollution, from a farm field in Iowa during a rain storm.

Topsoil as well as farm fertilizers and other potential pollutants run off unprotected farm fields when heavy rains occur.

Topsoil is the upper, outermost layer of soil, usually the top 2 inches (5.1 cm) to 8 inches (20 cm). It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs.

Importance[edit]

Plants generally concentrate their roots in and obtain most of their nutrients from this layer. The actual depth of the topsoil layer can be measured as the depth from the surface to the first densely packed soil layer known as subsoil.

Classification[edit]

In soil classification systems, topsoil is known as the "A Horizon," therefore, it is the very top layer.^[1]

Evaluation[edit]

When starting a gardening project, it is very crucial to check whether or not the Soil is satisfactory. Following are the desired levels of Topsoil nutrients. ^[2]

Category	Desired Results
pH Level	5.8 to 6.2
Phosphorus (P-I)	Index of 50
Potassium (K-I)	Index of 50
Calcium (Ca%)	40-60% of Cation Exchange Capacity (CEC)
Magnesium (Mg%)	8-10% of CEC
Base saturation (BS%)	60-80% of CEC
Manganese (Mn-I)	Index > 25
Zinc (Zn-I)	Index > 25
Copper (Cu-I)	Index > 25

The two common types of Topsoil are Bulk and Bagged Topsoil. The following table illustrates major differences between the two. ^[3]

Topsoil Type	HM%^[4]	BS%	pH	P-I	K-I	Ca%	Mg%
Bulk	0.3	69	5.2	009	026	45	10
Bagged	0.7	78	5.8	166+	178	56	12.3

Commercial application[edit]

A variety of soil mixtures are sold commercially as topsoil, usually for use in improving gardens and lawns, e.g. container gardens, potting soil and peat. Another important yet not commonly known use for topsoil is for proper surface grading near residential buildings such as homes. "The ground around the home should slope down six inches for the first ten feet away from the home. This can often be done by adding topsoil (not sand or gravel)."

Erosion[edit]

A major environmental concern known as topsoil erosion occurs when the topsoil layer is blown or washed away. Without topsoil, little plant life is possible. The estimated annual costs of public and environmental health losses related to soil erosion exceed $45 billion.^[5] Conventional agriculture encourages the depletion of topsoil because the soil must be plowed and replanted each year. Sustainable techniques attempt to slow erosion through the use of cover crops in order to build organic matter in the soil. The United States alone loses almost 3 tons of topsoil per acre per year.^[6] This is of great ecological concern as one inch of topsoil can take 500 years to form naturally.^[7] On current trends, the world has about 60 years of topsoil left.^[8] However, farmer and engineer P. A. Yeomans developed a technique known as Keyline design, which has been proven to convert subsoil into topsoil much faster; Yeomans published a book about the technique in 1954.

References[edit]

^ U.S. Department of Agriculture (USDA), Soil Survey Division Staff (1993). "Soil Survey Manual." USDA Handbook 18. Chapter 3.
^ Topsoil . North Carolina Department of Agriculture(July, 1995).[1]
^ Topsoil . North Carolina Department of Agriculture(July, 1995).[2]
^ Percent humic matter is a measure of the portion of organic matter that has decomposed to form humic and fulvic acids. HM% represents the portion of organic matter that is chemically reactive. This value affects determinations of lime and herbicide rates. [3]
^ http://www.ce.cmu.edu/~gdrg/readings/2007/02/20/Pimental_EnvironmentalEnergeticAndEconomicComparisonsOfOrganicAndConventionalFarmingSystems.pdf
^ http://www.nrcs.usda.gov/technical/nri, "Summary Report, 2007 Natural Resources Inventory," Natural Resources Conservation Services, U. S. Department of Agriculture, December 2009, p. 97
^ James Smolka (May 01, 2001). "Eating Locally". Disover. Retrieved May 01, 2001.
^ "What If the World’s Soil Runs Out?".

The lowdown on topsoil: It's disappearing
Mann, C (2008). "Our Good Earth". National Geographic Magazine 214 (3): 80–107.

External links[edit]

USDA Electronic Field Office Technical Guide - Detailed soil conservation guides tailored to individual states/counties
UK British Topsoil Suppliers Association - Detailed soil information guides

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