Tuesday, 8 November 2005
5

Long-Term Effects of Surface Applied Amendments in Reclamation of Sodic Soils.

Bruce L. Webb, Von D. Jolley, Micheal L. Lange, and Sheldon D. Nelson. Brigham Young University, 275 WIDB, Provo, UT 84602

This field study was conducted to compare the effectiveness of surface applied soil amendments in improving seedling emergence, infiltration rate, SAR, and crop yield. Eight treatments (three replicatins) consisted of an untreated control, high and low rates of sulfuric acid and gypsum, polyacrylamide (PAM), PAM plus gypsum and PAM plus [gypsum and calcium nitrate]. The treatments were surface applied prior to planting an alfalfa crop. High rates of application were calculated based on the amount of gypsum or sulfuric acid needed to reduce the SAR to approximately 5.0. Infiltration rate, SAR, and crop yield were measured over a five-year period. There was an immediate and similar impact with five of the treatments on seedling emergence of alfalfa (Medicago sativa L.). Only PAM and low sulfuric acid did not improve emergence. Surface applications of gypsum, sulfuric acid, PAM plus gypsum and PAM plus [gypsum and calcium nitrate] were equally effective in improving infiltration rates compared to the control within one year of application. These benefits disappeared by 2004. Only PAM failed to give any early benefit, but infiltration rates increased over time with PAM by 2004. Further study is needed to see if the trend continues. All surface applied amendments, except high gypsum, required two years to effect substantive differences in SAR compared to the control and the impacts continued through 2004. Further years of study are needed to determine if SAR values remain stable with these treatments. Most surface applied amendments improved crop yields in three of four years. The PAM treatment was the only treatment that produced just one year of yield increase in the four years harvested. Five years after initial application of treatments, barley (Hordeum vulgare L.) was planted, and yields were improved compared to the control with all but the PAM treatment.

Handout (.pdf format, 28665.0 kb)

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