Element
Pounds needed to
grow 1 bushel of corn Function Macronutrients
Nitrogen (N)
16Structural component of proteins, DNA, enzymes, etc. Phosphorus (P)
奥运会
法斗犬多少钱4Structural component of DNA; involved in energy conversion Potassium (K)
12Esntial for many chemical reactions in plants Sulfur (S)
8Structural component of some proteins Magnesium (Mg)
5Central component of chlorophyll Calcium (Ca)
5Influences permeability of cell membranes Micronutrients
toc理论
Iron (Fe)
0.2Structural component of a number of esntial enzymes Mangane (Mn)
0.03Involved in enzymes for respiration Boron (B)
0.006Required for protein synthesis Chlorine (Cl)
0.006Involved in carbohydrate metabolism Zinc (Zn)
Trace Component of enzyme for decomposition of carbonic acid Copper (Cu)burn是什么意思
Trace Component of enzymes for oxidation reactions Molybdenum (Mo)Trace
Component of enzyme that reduces nitrate to nitrite
粤语快歌
Prof. Shakhashiri
www.scifun Chemistry 103-1
AGRICULTURAL FERTILIZERS:
NITROGEN, POTASSIUM, AND PHOSPHORUS
Anyone who has grown a garden, maintained a lawn, or kept hou plants knows that it is necessary to apply a fertilizer to the soil to keep cultivated plants healthy. As they grow, plants extract nutrients they need from the soil. Unless the nutrients are replenished, plants will eventually cea to grow. In nature, nutrients are returned to the soil when plants die and decay. However, this does not occur with cultivated plants. Humans cultivate plants mainly for food, either for themlves or for livestock. When cultivated plants are harvested, the nutrients that the plants extracted from the soil are taken away. To keep the soil productive, it is necessary to replace the nutrients artificially. The kinds and amounts of nutrients that plants need have been determined and can be supplied by applying to the soil substances that contain the nutrients.
A plant contains a great number of chemical compounds. The major compound in all plants is water. The percent of the plant's weight that is water varies greatly from one kind of plant to another, from less than 20% to more than 90%. After the water is removed, the bulk of the dry plant material consists of carbohydrate compounds containing the elements carbon, hydrogen, and oxygen. Using the energy of sunlight in a process called photosynthesis, plants make carbohydrates in their leaves. The carbon and oxygen in carbohydrates come from carbon dioxide, which the plant absorbs from th
e air, and the hydrogen comes from water absorbed both through the roots and through the leaves. About 90% of the weight of carbohydrates is carbon and oxygen. Therefore, a plant obtains around 90% of its dry weight from the air.
Although carbohydrates account for most of the dry weight of a plant, the plant contains smaller amounts of other compounds that are necessary for its growth. Plants contain proteins, which are esntial in the chemical reactions of photosynthesis. Proteins contain the element nitrogen in addition to carbon, oxygen, and hydrogen.Some proteins contain sulfur as well. Plants also contain DNA, which carries the genetic information that controls how a plant grows. DNA contains the element phosphorus, in addition to nitrogen, carbon, oxygen, and hydrogen.
Total Nitrogen .......................................15%6.8% Ammoniacal Nitrogen 8.2% Urea Nitrogen Available Phosphoric Acid (P 2O 5)........................30%Soluble Potash (K 2O).................................15%Boron (B).........................................0.02%Copper (Cu).......................................0.05%0.05% Chelated Copper Iron (Fe)..........................................0.10%0.10% Chelated Iron Mangane (Mn) (Total)..............................0.05%0.05% Soluble Mangane Molybdenum (Mo).................................0.0005%Zinc (Zn)..........................................0.05%0.05% Chelated Zinc Po卡诺图
tential acidity equivalent to 1000 lbs. Calcium Carbonate per ton.Nitrogen from Ammonium Phosphates and Urea; Phosphoric Acid from Ammonium Phosphates; Potash from Muriate of Potash; Boron from Sodium Borate; Chelated Copper from Copper EDTA; Manga-ne from Mangane Sulphate; Molybdenum from Sodium
Molybdate; Chelated Zinc from Zinc EDTA; Chlorine max. available
14%.
GUARANTEED ANALYSIS 15-30-15Phosphorus is also significant in the storage and distribution of energy throughout the plant. Chlorophyll, the compound that makes plant leaves green and is central in photosynthesis, also contains the element magnesium.The fluids inside the plant's cells also contain other dissolved minerals which provide the proper environment for the many chemical reactions that occur in the fluid. Among the minerals are compounds of potassium and calcium.
Plants must obtain the elements esntial for their growth, other than carbon, oxygen, and hydrogen, from the soil. Thirteen elements esntial for plant growth have been identified, and the are listed in the table on the previous page. The esntial elements are called nutrients; tho needed in the greatest amount are called macronutrients whereas tho needed in lesr amounts are called micr
onutrients.
Among the macronutrients are nitrogen,
phosphorus, and potassium. The three elements
are tho most rapidly removed from the soil by
plants. Therefore, many commercial plant
fertilizers supply the three esntial elements.
The amount of each element is indicated by N-P-
玫瑰上的英格兰K numbers. The analysis information at right
(taken from a package of garden fertilizer) shows
an N-P-K rating of 15-30-15. The numbers
indicate the percent by weight of nitrogen,
diphosphorus pentoxide, and potassium oxide in
the fertilizer. The 15-30-15 rating indicates that
15% by weight of the fertilizer is nitrogen (N). It
also indicates that the weight of phosphorus in the
fertilizer is the same as it would be if the fertilizer
contained 30% diphosphorus pentoxide (P 2O 5).
The amount of potassium in the fertilizer is the
same as it would be if the fertilizer were 15%
potassium oxide (K 2O).The sources of nitrogen ud in fertilizers
给领导的一封信are many, including ammonia (NH 3), diammoni-
um phosphate ((NH 4)2HPO 4), ammonium nitrate
(NH 4NO 3), ammonium sulfate ((NH 4)2SO 4), calcium cyanamide (CaCN 2), calcium nitrate (Ca(NO 3)2), sodium nitrate (NaNO 3), and urea (N 2H 4CO). Phosphorus is generally supplied as a phosphate, such as diammonium phosphate ((NH 4)2HPO 4) or calcium dihydrogen phosphate (Ca(H 2PO 4)2). Potassium comes from potassium sulfate (K 2SO 4) or potassium chloride (KCl), which is also called muriate of potash.
The phosphorus content of a fertilizer is specified as the amount of P 2O 5 becau this is the anhydrous form of phosphoric acid. In this n it is the most concentrated form of phosphate, which is the form of phosphorus required by plants. The potassium content is designated in terms of K 2O, which is also called potash.Potash is a component of the residue left when plant materials are incinerated. The spreading of ashes on fields is an ancient method of replenishing potassium. Modern chemical fertilizers usually contain KCl instead, but the potassium content is still specified as the equivalent amount of potash. Potassium chloride is 52% by weight K.Potash is 83% potassium. Thus, KCl provides only about 2/3 as much potassium as the same weight of K 2O. Thus,if a fertilizer is 25% KCl by weight, its potassium rating, bad on potash, would be only 16.
