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ARS Home » Research » Publications at this Location » Publication #122892
Title: RELATIONSHIP BETWEEN SIX YEARS OF CORN YIELDS AND TERRAIN ATTRIBUTES

Author
item Kaspar, Thomas
item Colvin, Thomas
item Jaynes, Dan
item Karlen, Douglas
item James, David
item Meek, David
item PULIDO, D. - IOWA STATE UNIVERSITY
item BUTLER, H - IOWA STATE UNIVERSITY

Submitted to: Precision Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2002
Publication Date: 1/15/2003
Citation: KASPAR, T.C., COLVIN, T.S., JAYNES, D.B., KARLEN, D.L., JAMES, D.E., MEEK, D.W., PULIDO, D., BUTLER, H. RELATIONSHIP BETWEEN SIX YEARS OF CORN YIELDS AND TERRAIN ATTRIBUTES. PRECISION AGRICULTURE. 2003. V. 4. P. 87-101.

Interpretive Summary: Crop yield and soil properties are strongly related to landscape position. As a result, terrain information should be useful for interpreting yield maps and identifying reoccurring spatial patterns in agricultural fields. The objectives of our study were to examine the relationship between six years of corn yield data and basic terrain attributes and to develop a regression model to explain spatial variability of corn yield based on elevation, slope, and curvature for a 16 ha field in central Iowa. We found that in years of below normal rainfall corn yield was negatively related to elevation, slope, and curvature. In years with greater than normal rainfall, the relationship was not as strong and yield increased as relative elevation increased until elevation was high enough to avoid ponding and high water tables. The information will allow farmers to interpret yield maps of their fields that they have collected with combine yield monitors. By comparing yield maps, precipitation data, and terrain features they will be able to determine whether specific areas of their fields will exhibit reoccurring yield patterns. Knowing this, farmers should then be able to adjust inputs of fertilizers and agricultural chemicals to match expected yields for specific areas of fields and therefore increase profitability and reduce environmental impacts.

Technical Abstract: Crop yield and soil properties are strongly related to landscape position. As a result, terrain information should be useful for interpreting yield maps and identifying reoccurring spatial patterns in agricultural fields. The objectives of our study were to examine the relationship between six years of corn (Zea mays L.) yield data and basic terrain attributes and to develop a regression model to explain spatial variability of corn yield based on elevation, slope and curvature for a 16 ha field in central Iowa. Corn grain yield was measured in six crop years along eight transects using a combine equipped with a weigh tank. Soil surface elevation was measured at thousands of points using a kinematic global positioning system and elevation, slope and curvature were then determined using digital terrain analysis. Our data showed that in the four years with less than normal growing season precipitation there was a negative correlation between corn yield and elevation, slope and curvature. We hypothesized that in years of less than normal precipitation, higher and more sloping field positions would have less water infiltration, less water storage and lower yields. In the two years with greater than normal precipitation, yield was positively correlated with elevation and slope. In those years, yield was reduced in low and level field positions because of periods of standing water and high water tables. A multiple linear regression model based on elevation slope and curvature was developed that explained 78% of the spatial variability of corn yield in the four dry years.