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Suggested Fertilizer Guidelines

39. AGVISE Laboratories offers three types of guidelines for phosphorus and potassium fertilization (Band, Broadcast and University). All fertilizer guidelines are reported in lbs/acre of P₂O₅ or K₂O. All fertilizer guidelines are based on research by universities and industry along with the experience of AGVISE's professional agronomic staff. A brief explanation of each of the three fertilizer guidelines is listed below:

Band P & K fertilizer guideline: The AGVISE band fertilizer guideline assumes that the P & K fertilizer is placed at least 2" away from the seed. If an excessive amount of fertilizer is placed directly with the seed, delayed emergence and stand loss may occur. The safe rate of fertilizer to place with the seed is determined by soil moisture status, row width, fertilizer material and crop sensitivity. Use local information from consultants and equipment manufacturers to determine safe rates of seed applied fertilizer.

At very low soil test levels the band fertilizer guidelines for P & K will slowly build the P or K soil test level to the medium level over a period of many years. When the P or K soil test is high, the band guideline is reduced to near zero with a small amount of starter P & K fertilizer suggested. If soil test levels are high initially and the band guideline is followed for many years, the soil test level will drop to the medium test range.

Band with Maintenance P & K fertilizer guideline: The AGVISE band with maintenance fertilizer guideline is the same as the band fertilizer guideline except when P & K soil test levels are medium or higher, the band with maintenance guideline is equal to crop removal levels of P & K.

University Broadcast fertilizer guideline: The University broadcast fertilizer guidelines are based on one set of guidelines provided by the University of Minnesota, North Dakota State University and South Dakota State University. At very low soil test levels the university broadcast guidelines for P & K will slowly build the test levels to the medium range over many years. When the P or K soil test levels are high, the university broadcast guideline is reduced to zero. Even when the university broadcast guidelines are zero, university agronomists would recommend using a small amount of starter fertilizer for most crops. The graph here shows the relationship between the band guideline, the band with maintenance and the university guidelines.

Broadcast P & K fertilizer guideline: The AGVISE broadcast fertilizer guidelines are based on a uniform fertilizer application which is then tilled in to the topsoil (except in the case of alfalfa). Seed safety is generally not a concern with broadcast fertilizer applications. At very low, low and medum soil test levels, the broadcast fertilizer guidelines will build the P or K soil test levels to the high range if followed over several years. When the soil test level for P & K are into the very high range, the broadcast guidelines are reduced to near zero and a small amount of starter P & K is suggested.

Broadcast with Maintenance P & K fertilizer guideline: The AGVISE broadcast with maintenance guidelines are the same as the broadcast fertilizer guidelines except at the high and very high P & K soil test levels. When the P & K soil test levels are at high and very high, the broadcast with maintenance guidelines are equal to crop removal. The chart here shows the relationship between the broadcast guidelines, broadcast with maintenance guidelines and crop removal.

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