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Fluid Journal : Fluid Journal 1999-2001
1 Fluid Journal Winter 2000 In past articles we have discussed the various ways that residue can increase soil quality, which in turn can provide the growing crop with many benefits such as increased water- holding capacity, increased water infiltration rate, and decreased compaction, to name a few. We have referred to the soil improvement program as MSP (maximizing soil productivity). In this article we'll delve more into the ABCs of MSP. What kind of fertilizer program do you need? What kind of tillage equipment? How deep do you till? How much will it cost? And most important, how long will it take? Why MSP? Many soils in the central Corn Belt are shallow. The dark soil rich in organic matter may be only 6 inches thick---about the length of a ballpoint pen (Figure 1). In dry spells, such shallow soil won't hold enough water. by FFF Review Putting MSP To Work It involves implementing the ABCs-- the basic fundamentals- -of a soil improve- ment program that will maximize your soil's productivity and increase yields. The probable result below this thin layer is compaction that will restrict root growth. Lack of aeration will rob soil of a healthy microbial environment. The antidote is MSP. Organic matter will be built and move deeply into the soil profile, making the soil ideal for extensive root proliferation. The soil will be able to support higher populations, resulting in higher yields. A study of 300-bu/A corn growers has shown one common thread: soils are deep, high in both nutrients and organic matter. How it works There are five critical steps to establishing MSP. Chop stalks. These stalks plus roots provide the residue that can be converted to organic matter. There is roughly 3.5 tons of residue for every 100 bushels harvested. Fertilize residue. We know that organic matter contains 5.3 percent nitrogen, 1.7 percent phosphate (as P2O5) and 0.7 percent sulfur (as S). Yet corn stalks and most residues are deficient in these nutrients. Applying fertilizer to the residue will restore the necessary nutrients and aid in the formation of organic matter. The amount to apply is determined by last year's yield (see Table I). Tops and roots left in the field after harvest are estimated. The lbs/A of 22-7-0-3 indicated adjusts the nutrients in the residues for maximum conversion to organic matter. You might call this product a "residue digester." Soil test. Nutrients in addition to 22- 7-0-3 should be applied according to soil test requirements and the removal of nutrients by harvested crops (Table 2). Till. Treated residue should next be tilled into the soil with a tool such as a twist shank chisel. The object is to move as much residue into the soil as possible and still leave enough on the surface for erosion control. A substantial portion of the fresh residue should be placed in the 3- to 4-inch zone because this is the zone where maximum biological activity occurs. In the years that follow, deeper and deeper tillage will move organic matter down into the 15- to 18-inch zone. This could take 8 to 10 years. Increase population. Plant population should be increased as yields increase. Nuts and bolts The proof is in the pudding. Let's Table 1. Pounds of nutrients to add to residue for MSP. Last year's Total residue Nutrients yield roots/tops Net residue* 22-7-0-3 lbs/A bu/A tons/A tons/A lbs/A NPS 140 5.0 3.3 330 732310 160 5.7 3.9 390 862712 180 6.5 4.6 460 101 32 14 200 7.1 5.2 520 114 36 16 220 7.8 5.8 580 128 41 17 240 8.6 6.4 640 141 46 19 260 9.1 6.9 690 152 48 21 280 9.9 7.7 770 169 54 23 300 10.7 8.3 830 183 58 25 320 11.4 8.9 890 196 62 27 * Some residue is left on the surface to control erosion, etc.
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