Life Sciences Commons^™

Ec91-735 The Impact Of Nitrogen And Irrigation Management And Vadose Zone Conditions On Ground Water Contamination By Nitrate-Nitrogen, K.D. Frank, Darrell Watts, Andrew Christiansen, Edwin Penas

University of Nebraska-Lincoln Extension: Historical Materials

The single largest contaminant found in ground water samples taken throughout Nebraska is nitrate-nitrogen (nitrate-N). Much of it reaches the ground water as a "non-point source" contaminant leached out of the crop root zone.

Nitrate-N is essential to corn production. However, when leached from the crop root zone it can become a major source of ground water contamination. There are serious contamination problems in shallow aquifers beneath several river valleys in Nebraska. Increasing nitrate-N concentrations are beginning to appear in deeper aquifer.

G91-1010 Managing Corn And Sorghum Residues During The Ecofarming Fallow Period, Robert N. Klein, Gail A. Wicks

University of Nebraska-Lincoln Extension: Historical Materials

This NebGuide explains how to maintain an appropriate residue cover with ecofarming in the fallow period before winter wheat to reduce soil erosion and conserve soil moisture. Ecofarming is a system of controlling weeds and managing crop residues throughout a crop rotation with minimum use of tillage. This will reduce soil erosion and production costs while increasing weed control, water infiltration, moisture conservation and crop yields. In the winter wheat-ecofallow corn or grain sorghum-fallow rotation, corn or grain sorghum is no-till planted into winter wheat stubble in May. During the previous summer or fall the winter wheat stubble was treated …

Sterol Composition Of The Corn Root Lesion Nematode, Pratylenchus Agilis, And Corn Root Cultures, David J. Chitwood, William R. Lusby

Harold W. Manter Laboratory of Parasitology: Faculty and Staff Publications

Sterols from mixed stages of the com root lesion nematode, Pratylenchus agilis, and uninfected corn root cultures were analyzed by gas chromatography-mass spectrometry. Twenty-eight sterols were identified in P. agilis, including nine not previously detected in nematodes. The major sterols were 24-ethylcholest-22-enol, 24-ethylcholesta-5,22-dienol, 24-methy1cholestanol, 24-ethylcholestanol, isofucostanol, and 24-ethylcholesterol. The principal corn root sterols were 24-ethylcholesta-5,22-dienol, 24-methylcholesterol, 24-ethylcholesterol, isofucosterol, and cycloartenol. Therefore, the major metabolic transformation of sterols by P. agilis was saturation of the sterol nucleus. In addition, very small amounts of 4α-methylsterols were biosynthesized by P. agilis. The 4-methylation pathway is unique to nematodes and was …