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United States Department of Agriculture

Agricultural Research Service

Title: Spatial and Temporal Correlations among Dryland Grain Yeild and Soil-Water Content in a Sloping Field

Authors
item Andales, Allan
item Ahuja, Lajpat
item Green, Timothy
item Erskine, Robert
item Peterson, Gary - COLORADO STATE UNIVERSITY

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 2003
Publication Date: November 1, 2003
Citation: Andales, A.A., Ahuja, L.R., Green, T.R., Erskine, R.H., Peterson, G. 2003. Spatial and temporal correlations among dryland grain yeild and soil-water content in a sloping field. Agronomy Abstracts. Amer. Soc. of Agronomy, Denver, CO. Nov. 2-6, 2003.

Interpretive Summary: Fourteen years of soil water content, corn [Zea mays (L.)] grain yield, and winter wheat [Triticum aestivum (L.)] grain yield data from a sloping dryland site in northeastern Colorado were analyzed to find spatial and temporal relationships among three slope positions (summit = 1, sideslope = 2, and toeslope = 3). The experiment included three rotations (wheat-fallow, wheat-corn-fallow, wheat-corn-millet-fallow) arranged in a randomized block design (2 reps). Analysis of variance in yield showed no significant differences (a = 0.05) among the three rotations at a given slope position. Significant differences were found between yield at positions 1 and 3, and positions 2 and 3, for both wheat and corn. Simple linear regression between wheat yield (averaged across plots at each slope position) at different positions (1 vs. 2, 1 vs. 3, and 2 vs. 3) gave generally high coefficients of determination (r2 ' 0.70). Similarly high r2 values were observed using the same analysis for corn yield and likewise for soil water content. A positive linear relationship was found between average slope length and average yield or soil available water (i.e., averaged across all years and all reps at each slope position). Overall, the results indicate that in certain portions of a sloping dryland field, yield or soil water content at one slope position may be estimated using measurements at another slope position.

Technical Abstract: Fourteen years of soil water content, corn [Zea mays (L.)] grain yield, and winter wheat [Triticum aestivum (L.)] grain yield data from a sloping dryland site in northeastern Colorado were analyzed to find spatial and temporal relationships among three slope positions (summit = 1, sideslope = 2, and toeslope = 3). The experiment included three rotations (wheat-fallow, wheat-corn-fallow, wheat-corn-millet-fallow) arranged in a randomized block design (2 reps). Analysis of variance in yield showed no significant differences (a = 0.05) among the three rotations at a given slope position. Significant differences were found between yield at positions 1 and 3, and positions 2 and 3, for both wheat and corn. Simple linear regression between wheat yield (averaged across plots at each slope position) at different positions (1 vs. 2, 1 vs. 3, and 2 vs. 3) gave generally high coefficients of determination (r2 ' 0.70). Similarly high r2 values were observed using the same analysis for corn yield and likewise for soil water content. A positive linear relationship was found between average slope length and average yield or soil available water (i.e., averaged across all years and all reps at each slope position). Overall, the results indicate that in certain portions of a sloping dryland field, yield or soil water content at one slope position may be estimated using measurements at another slope position.

Last Modified: 4/18/2014