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Table 4.Some common inorganic mIcMLutrient fertilizers. <br /> o <br /> Nutrient Fd1W IF %of nutrient <br /> in product <br /> Boron 1113orate 14-20 <br /> Borax 11 <br /> Copper Copper sulphate 1 25 <br /> Iron 111ron sulphate 19 <br /> Manganese Imanganese sulphate 26 <br /> Zinc Zinc sulphate 18-23 <br /> Boron <br /> Application of borate of borax can be either broadcast and incorporated or banded. Boron containing fertilizers should not <br /> come into contact with the seed at planting time. For permanent crops such as alfalfa, boron should be used as a <br /> topdressing. Soil application rates should not exceed 1.51b/ac on soils with a pH less than 6.5 to avoid boron toxicity <br /> problems. Foliar applications should not exceed 0.3lb/ac to avoid toxicity problems. For all types of applications, extreme <br /> care must a taken to apply the correct amount and to apply it uniformly to avoid toxicity problems. <br /> Copper <br /> Broadcast and incorporated rates of 3 to 7 Ib/ac of copper in the form of copper sulphate or copper oxide is recommended <br /> for deficient mineral soils. On organic soils, broadcast and incorporated rates of 10 to 15 Ib/ac are required. Soil application <br /> rates should be effective for up to 10 years. Chelated forms of copper are also very effective in the year of application but <br /> little is known about the residual effects in Alberta soils. Foliar application on mineral and organic soils is not as consistent <br /> but can be used after deficiency symptoms appear. Foliar applications are required annually and are most effective at the <br /> late tillering stage. If the deficiency is severe, two applications(mid-tillering and boot stage)are necessary. Foliar rates of <br /> between 0.1 to 0.3 lb/ac are recommended. <br /> Manganese <br /> Only limited information is available on manganese fertilization in Alberta.As a rule, broadcast applications are seldom <br /> effective. For cereals, a seed placed treatment of manganese sulphate should be most effective. Foliar application can also <br /> be used if deficiency symptoms develop during the growing season. <br /> Zinc <br /> For treatment of a zinc deficient soil where a sensitive crop such as beans or corn is grown, a band application of 2 to 5 Ib/ac <br /> of zinc sulphate or 0.5 to 1.0 Ib/ac of a chelated zinc is recommended. When zinc deficiencies are suspected early in the <br /> growing season, a foliar application of 0.5 lb/ac of zinc sulphate can be used. Severely, deficient beans may require two <br /> applications. On eroded soils a 5]b/ac broadcast and incorporated application of zinc sulphate can be tried. <br /> Conclusions <br /> The need for micronutrients in crop production have long been recognized in Alberta. Zinc deficiencies in irrigated beans in <br /> southern Alberta were detected in the early 1980s. Research by Alberta Agriculture and Agriculture Canada has clearly <br /> shown the need for copper fertilizer particularly for wheat grown on organic soils and on some Black and Grey-Black soils in <br /> central Alberta. One million acres may be copper deficient in central Alberta. Some suspected manganese deficiencies are <br /> presently being investigated. Continued research and testing is required to identify when various crops will give economic <br /> yield increases to additions of micronutrient fertilizers. <br /> It is important to keep the need for micronutrient fertilizers in perspective. Over-promotion of micronutrients has occurred on <br /> occasion. Some farmers have applied micronutrients in the hope of increasing crop yields even though there is little evidence <br /> to suggest a deficiency exists. <br /> Farmers who are concerned about micronutrient deficiencies are encouraged to investigate the need thoroughly and apply <br /> the nutrients in test strips if necessary. The test strip areas must be carefully marked out for comparison to areas where <br /> micronutrients were not used. Visual and qualitative comparisons should be made on these test strips. <br /> There is no question that micronutrient levels will gradually decline in soils over time as cropping continues. However, most <br /> Alberta soils are currently well supplied with micronutrients. Soils and crops in Alberta that require micronutrient fertilizers are <br /> the exception not the rule. Care must be taken to keep the need for micronutrient fertilizers in perspective and not to promote <br /> them beyond their true significance. <br /> Prepared by: <br /> Dr. Ross H. McKenzie, <br /> Soil Fertility Specialist, <br /> Soils Branch, Lethbridge <br />