COMPLIANCE INFO_FILE 1 2003-2006

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Agriculture, Foo6 ► Contact u� � ► and Rural Develop mentSearch Albena - Government Home Find Staff Calculators Directories I General Store I Links ( Programs &Services Micronutrient Requirements of Crops Send to . Friend Download pdf-166K Sources of micronutrients I Factors affecting micronutrient availability I Determining the need for micronutrients Micronutrient deficient areas I Deficiency symptoms I Soil testing I Tissue testing I Vsin test strips I Micronutrient fertilizers Conclusions Crops require 16 essential elements to grow properly. The elements include carbon (C), hydrogen(H)and oxygen(02), which are derived from air and water.Ail the remaining nutrients used by plants come from soil in the form of inorganic salts. Legumes are an exception because they can also fix nitrogen from the air. The macronutrients obtained from the soil include nitrogen (N), phosphorus(P), potassium (K), calcium (Ca), magnesium (Mg), and sulphur(S). The remaining essential elements needed by plants are known as micronutrients because plants use them in relatively small amounts. They include: boron (B), chlorine(CI), copper(Cu), iron (Fe) manganese(Mn), molybdenum (Mo)a . nd zinc(Zn). Carbon, hydrogen and oxygen comprise from 94.0 to 99.5 per cent of fresh plant tissue. The remaining nutrients, which come from the soil, make up the balance of the tissue. The term micronutrient refers to the relative quantity of a nutrient that is required for plant growth. It does not mean that they are less important to plants than other nutrients.Table 1 lists amounts of micronutrients removed from the soil by several crops. Plant growth and development may be retarded if any of these elements is lacking in the soil or is not adequately balanced with other nutrients. This fact sheet describes where potential micronutrient deficiencies may occur in Alberta, how to determine if a micronutrient is deficient and how to correct the deficiency. Sources of Micronutrients in Soils Inorganic micronutrients occur naturally in soil minerals. The parent material from which the soil developed and soil forming processes determine what the micronutrient content of the soil will be. As minerals break down during soil formation, micronutrients are gradually released in a form that is available to plants. Two sources of readily available micronutrients exist in soil: nutrients that are adsorbed onto soil colloids(very small soil particles)and nutrients that are in the form of salts dissolved in the soil solution. Organic matter is an important secondary source of some micronutrients. Most micronutrients are held tightly in complex organic compounds and may not be readily available to plants. However, they can be an important source of micronutrients when they are slowly released into a plant available form as organic matter decomposes. Table 1.Amounts of some micronutrients removed by good yields of various crops. Micronutients removed (kg/ha) Crops harvested and portion used for analysis Yield level Chlorine Boron Copper Iron an anese Zinc tlha (CI) (B) (Cu) M (Fe) (Mn) (Zn) Alfalfa -hay 1.3 ©F 0.10 <0.1 0.20 0.70 0.70 F-B-a-ri-ev-jj grain 4.0 ® 0.10 <0.1 0.30 0.10 0.10 -straw 0.01 0.70 0.10 Corn -gF0.70 <0.1 0.20 0.10 r 0.20 -st07o6-1F-<-o-.1 1.0 1.70 0.30 Oats -grain F1-00]1 0.20 0.10 -straw FT 0-, 0.20 0.40 Peas -vines&pods 07o7--JF-<-o-.1--T0-7-011 0.50 0.10 Potatoes -white, tubers 40 27 0.07 <0.1 F659-61 1 0.20 0.10 Wheat 11 -grain 4.0 © 0.06 <0.1 0.50 0.20 0.20 -straw � 2� 0.02 <0.1 0.20 11 0.30 0.10 Data compiled from several sources.