First Principles of Soil FertilityOrange Judd, 1908 - 265 páginas |
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Página 21
... nitro- gen than this , but the amount rarely equals 3 per cent of the dry matter , or six - tenths of one per cent of the green plant . In spite of the small quantity of nitrogen in the crop it is the most important of all plant foods ...
... nitro- gen than this , but the amount rarely equals 3 per cent of the dry matter , or six - tenths of one per cent of the green plant . In spite of the small quantity of nitrogen in the crop it is the most important of all plant foods ...
Página 25
... nitro- gen . Other experimenters also arrived at the con- clusion that clover has the power of procuring nitrogen from some unknown source . Farmers had known for some time that wheat grown after clover does as well as when manured with ...
... nitro- gen . Other experimenters also arrived at the con- clusion that clover has the power of procuring nitrogen from some unknown source . Farmers had known for some time that wheat grown after clover does as well as when manured with ...
Página 41
... nitro- gen , phosphoric acid and potash in rather larger quan- What immense quantities of plant food this hill must contain , but who can tell how much of it is available to plants ? tities than the other elements , and that they exist ...
... nitro- gen , phosphoric acid and potash in rather larger quan- What immense quantities of plant food this hill must contain , but who can tell how much of it is available to plants ? tities than the other elements , and that they exist ...
Página 73
... nitro- Weeds are objectionable because they remove large quantities of water and available plant food which are needed by the crop gen was much higher , in the early plowed plots , and that the yield of corn was greater . All evidence ...
... nitro- Weeds are objectionable because they remove large quantities of water and available plant food which are needed by the crop gen was much higher , in the early plowed plots , and that the yield of corn was greater . All evidence ...
Página 93
... fallow , but the growing plants appropriate the nitrates almost as rapidly as formed , and hence prevent loss of nitro- gen in the drainage water . CHAPTER IX HUMUS AND GREEN MANURING Humus Necessary to Soil SUMMER FALLOWING 93.
... fallow , but the growing plants appropriate the nitrates almost as rapidly as formed , and hence prevent loss of nitro- gen in the drainage water . CHAPTER IX HUMUS AND GREEN MANURING Humus Necessary to Soil SUMMER FALLOWING 93.
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Términos y frases comunes
acid and potash acre agricultural ammonia amount of nitrogen amount of plant animals applied average bacteria barn barnyard manure bedding carbonic acid clay clover commercial fertilizers complete fertilizers composition compounds condition corn crop decay deep stall denitrification drainage dry matter elements of plant Experiment Station fact farm farmer feeding fertilizing constituents fertilizing materials fertilizing value field grain green manuring ground grown hot fermentation humus important inches increase ingredients kainite land leaching legumes leguminous lime liquid excrement loss of nitrogen lysimeters manure produced materials ments method mineral matter mixed moisture necessary nitrate of soda nitrification nitrifying bacteria nitro nitrogen nure obtained organic matter oxygen phoric acid phos phosphate phosphoric acid plant food plant growth plots plowed pounds practically present rains ration removed rock roots rotation shown soil soil contains soluble substances sufficient sulphate superphosphate supply surface tillage tion urine wheat yield
Pasajes populares
Página 187 - The production possible from a definite amount of plant -food can be secured only when the conditions are such as to permit its proper solution, distribution and retention by the soil. The fact that fertilizers may now be easily secured, and the ease of application, have encouraged a careless use, rather than a thoughtful expenditure, of an equivalent amount of money or energy in the proper preparation of the soil.
Página 221 - Furthermore, the mineral elements are relatively cheap, while the nitrogen is relatively expensive, and thus that the economical use of this expensive element, nitrogen, is dependent to a large degree upon the abundance of the mineral elements In the soil. It is therefore advocated that for all crops and for all soils that are in a good state of cultivation, a reasonable excess of phosphoric acid and potash...
Página 241 - One will seek to know what the different forms of plant-food are, what they do, from what sources they can be obtained, and how he can use them to best advantage. He will become to some extent an investigator, and will, of necessity, take a deeper interest in his work.
Página 225 - When such crops as corn, cabbage, grass, potatoes, etc., have a luxuriant, healthful growth, an abundance of potash in the soil is indicated ; also, when fleshy fruits of fine flavor and texture can be successfully grown. (e). When a soil produces good, early maturing crops of grain, with plump and heavy kernels, phosphoric acid will not generally be found deficient in the soil. Such general indications may often be most helpful, and crops should be studied carefully with these facts in mind.