Extension Ag Update
January/February 2003
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Research

Identifying and Reducing Sources of Nitrates in Illinois Waters, C-FAR 97I-048-5-UIUC

Purpose and Goals

  1. To ascertain the effect of rate and time of N application on nitrate-N concentration and content in water from tile lines.
  2. To evaluate the effect of previous N management on current N needs.
  3. To evaluate the effect of previous N management on recovery of fertilizer N.
  4. To evaluate the effect of previous N management on fertilizer N transformations in soil.

Outcomes and Impact

Nitrate loss from tile lines was greater in years in which corn was grown than when soybean were grown. Nitrate loss was directly related to the rate of N used in the field, being highest on those fields that had substantially more N applied than recommended by the University of Illinois. This was true both in the years in which corn was grown as well as the years in which soybean were grown. Nitrate-N loss was greatest in years in which excess precipitation occurred and were very low in years of low rainfall (2000). Use of the recommended rate of N application resulted in minimal N loss from tile lines. Residual soil nitrate-N levels were generally highest on fields having a history of excessive rates of N application. The relationship between time of N application and N loss from tile lines was very low.

Rotational Grazing for Sheep, C-FAR 00I-002-3-WIU

Purpose and Goals

The purpose of this trial was to evaluate the advantages or disadvantages of rotational grazing for lambs and ewes. Lamb differences were evaluated on the basis of average daily gain during the grazing period, while ewe differences were evaluated on the basis of body condition scores. Based on the results of this trial, sheep producers will be better able to ascertain whether they should rotationally graze their pastures, or continuously graze the pasture as one large pasture.

Outcomes and Impact

This trial was conducted in two separate years, including a total of 60 lambs and 44 ewes. Two lambs died during the trial due to causes not related to the trial. Starting weight of the lambs was not significantly different between the rotationally grazed group and the continually grazed group. Lambs gained significantly faster when rotationally grazed rather than continuous grazed, with a difference of .08 pounds per day. In addition, when the continuous pasture was depleted, all lambs were turned in to the rotational pasture which was grazed for four additional weeks. In the ewe trial, there was no significant difference in body scores at the beginning of the trial. During the course of the grazing season, continuously grazed ewes dropped in average condition score by .159 scores, while the rotational group increased their average score by .432, which was a significant difference. When the continuous pasture was depleted, all ewes were grazed on the rotational pasture, which carried all of the ewes an additional four weeks.