OCR Text |
Show Updating fertilizer labels would aid in understanding contents wrw 2J . . ,T. pre? are afraid it will look as and many people in lizer trade. 11,5 k A complete fertife I 6-10-4 to indicate the sTll and K20 under th70u'V:rll antee could be labeled 1 I N ;PParndPKtely r and K content v' users recognize this -dual labels can be 2 !) the fertilizer bags jf ers are afraid it will look as though they have lowered the analyses on their fertilizers if they should change to simply indicating the P and K. Yet, that is a realistic change urged urg-ed by professional agronomists, soils scientists, state chemists its "oxide," ntrate (No,), instead in-stead of nitrogen (N), ammonium ammon-ium nitrate (33 N) would have a guarantee of about 145, and anhydrous ammonia (82 N) would have a guarantee guar-antee of 360. Some fertilizer manufactur- P205. The present guarantee exaggerates the amount of phosphorus and potassium in the fertilizer, making phospor-us phospor-us appear 2.3 times as large as it really is and potassium 1.2 times larger than it is. If nitrogen were guaranteed as by Paul D. Christensen Utah State University Extension Soil Specialist The label is expected to be your key to knowing the content con-tent of your fertilizer. Fertilizer Fertiliz-er manufacturers are required by state law to indicate the amount and analysis of each fertilizer included in a mixture. The guaranteed analysis must show in this order the minimum percentages of total nitrogen (N), available phosphoric phos-phoric acid (P2Os), and essential essen-tial plant nutrients must be shown after the essential primary pri-mary nutrients: nitrogen, phosphorus phos-phorus and potassium. Actually, the terms available phosphate and available potash, though still required by law, don't really tell you what is contained in the fertilizer or what the crop will absorb. Since the guarantee is required to indicate phosphorus and potassium po-tassium as oxides, the chemist has to calculate the 'theoretical" 'theoreti-cal" content of P206 and K20. Single superphosphate contains con-tains about 9 phosphorus (P) and theoretically contains 20 P O.. Concentrated superphosphate superphos-phate has an analysis of about 20 phosphorus (P) with a theoretical content of 45 |