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Fluid Journal : Fluid Journal 1996-1998
Winter 1997 The practice of banding, stripping, or knifing fluid fertilizers has proved the superior method of application in almost all cases---especially in reduced-till operations---when compared with conventional broadcast methods. Research conducted over the years on banding, stripping, knifing of fluid fertilizers to produce high yields could fill more than one good-sized pickup. Trials on wheat, barley, corn, sorghum, soybeans, pastures---to name just a few crops---have been conducted to compare depths, band widths, and formulations. The trials are so numerous and varied that, owing to editorial space restrictions, only the more important implications of banding fluid fertilizers can be summarized. Reviewed will be the components of an all-encompassing strategy you can employ to overcome obstacles that often slice into profits of high-yield reduced-till farm operations. Stratification PROBLEM: In the Corn Belt, nutrients often are not distributed uniformly throughout the profile of many soils. Principal causes are several: Broadcasting. The most common reason for soil stratification is the practice of applying fertilizer on the surface, followed by shallow incorporation. Residue decay. Nutrients are also stratified because of decay of crop residues. Phosphorus, potassium, sulfur, and zinc thus tend to accumulate on the surface. Reduced tillage. Different tillage methods have contributed to stratification of nutrients when they are surface applied. Typical is an Iowa State University study. Note how phosphorus and potassium are more concentrated in the upper root zone and more deficient in the lower root zone in no-till, when compared to the other tillage methods (Table 1). Another good example of stratification is shown in Table 2. This western Iowa soil had been minimum tilled for approximately 14 years. Phosphorus, potassium, and sulfur had accumulated in the upper three inches. Because of stratification near the surface, these nutrients were not available to the crop in July and August when needed most. ANSWER: Stratification can be remedied by root zone banding fluid fertilizers, injecting them into the 3- to 12-inch soil profile where roots can proliferate. This can be accomplished during tilling, using chisel plows or field cultivators, or can be applied with knife machines and dual application units where ammonia and mixed liquids are applied simultaneously. This is a simple concept, yet a logical approach to correcting stratified soils. Soil sampling PROBLEM: Meaningful soil sampling is difficult in stratified soils, especially on eroded or heavily cropped fields, or on soils that have been minimum tilled. The standard 0 to 6-inch probe just doesn't give the true picture of root zone fertility level. For example, a potassium, sulfur, or zinc problem would not have been discovered on the test analysis in Table 2 if the soil had been sampled with a standard probe. Soil sampling technique must be modified to get a true picture. ANSWER: Meaningful sampling can be accomplished by using what we call the ABC system. Here the soil is divided into three zones. A soil analysis is made on each zone separately and listed as shown in Table 2. Complete analyses are usually made on zones A and B while only a nitrate analysis is made on zone C. Interpretation PROBLEM: Today's interpretations of soil tests are inadequate for high profit yields. As just noted, soils that are sampled with a standard 0 to 6-inch probe often provide misleading information and distort the soil test analysis. Stratification of phosphorus in the Sharpsburg soil (Figure 1) is quite serious, and an ordinary soil probe would not give true indications of the fertility level in the B or C root zones. The vertical dotted lines show the sufficiency level for a particular yield goal. Note how the 3- to 12-inch zone is below this sufficiency level in both phosphorus and potassium. Debates have taken place between Bill Lohry Fertility Management A Must For High-Profit Yields All-encompassing strategy must be developed and implemented to overcome obstacles that can drain profits from high-yielding reduced-till crops.
Fluid Journal 1993-1995
Fluid Journal 1999-2001