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Fluid Journal : Fluid Journal 1999-2001
1 Fluid Journal Fall 2001 Summary: Summary: Summary: Summary: Summary: Liquid sulfur (S) increased mean corn grain yields at the shoulders (severely eroded) and backslopes (mod- erately eroded) by at least 17 and 29 bu/A, respectively, when compared to control plots. In these experiments con- ducted in the year 2000, ammonium thiosulfate (ATS) was applied during planting at the rate of 25 lbs/A of S, along with the UAN application. Landscapes in southeastern South Dakota, southwestern Minnesota, north- western Iowa, and northeastern Ne- braska are gently to moderately rolling. Soils in the region were formed from loess deposited during post-glacial events. The shoulders and hilltops of these landscapes are often eroded and soil organic matter content is often lower. Soil pH is often higher from free CaCO3 in the exposed subsoil than pH in the footslopes. The predominant soil association in the region is the Moody- Nora-Crofton series. Corn and soybeans are grown in rota- tion on either no- or conventional-till. In the eroded areas, crop yields are de- pressed in relation to the footslope po- sitions and strong leaf striping (interveinal chlorosis) in corn has been observed at these locations. This leaf coloration pattern is similar to that ob- served for micronutrient metal (Fe or Mn) deficiencies. However, in previous studies ATS ameliorated the leaf strip- ing and increased grain yield, compared to controls. The need for supplemental S in these eroded areas was indicated. Generally, crop S requirements are supplied by the mineralization of soil organic matter and crop residues. It is suspected that levels of available SO4-S released during the growing season on eroded soils were inadequate because the soils had lower organic matter which, when mineralized, could not supply adequate S levels to meet the potential yield goal. No-till practices probably contributed to this condition Dr. Howard J. Woodard and Anthony Bly Corn Responds To Sulfur Fertilization On Eroded Soils Studies conducted in 2000 on no-till, rolling South Dakota landscape show yield variances on different slope positions. since organic matter mineralization generally is less under no-till than in conventionally tilled fields, and the SO4-S released would be less. The objective of our study was to de- termine how growth and yield param- eters of corn will be enhanced by S fer- tilization across various organic matter levels as determined by landscape posi- tion. Soil test Soil organic matter, extractable soil orthophosphate-P and soil Zn increased significantly as sampling position pro- gressed from the shoulder (severe ero- sion) to the footslope (no erosion). Ero- sion removed much of the topsoil and subsequently reduced favorable chemi- cal and physical soil properties on these slopes. There was a 1.2 percent organic matter mean decrease and a 1.0 pH unit mean increase as sampling progressed from the footslope to the shoulder. In- terestingly enough, the level of extract- able SO4-S was very high at the shoul- der landscape positions. Available SO4- S can react with free calcium carbonate and form gypsum, which may not solu- bilize to release SO4-S at the same rate as mineralization of organic matter. Some of this SO4-S is likely to be re- leased from the gypsum by the soil grinding procedure and/or extracted by lab procedure during soil testing that would not necessarily be available to the crop during the growing season. In Table 1. Summary of treatments for corn, Woodard and Bly, Garretson, SD, 2000. Parameters RatesNPK ------------------lbs/A--------------- ------ Control 01303010 ATS 251223010
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