Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/2001
Publication Date: N/A
Technical Abstract: Despite attempts to isolate causes of spatial variation in yield using classical statistics, poor correlations have been obtained. Similarly, many geostatistical techniques have failed to explain sufficient yield variation to be useful for practical situations. Several avenues of research hypothesized that spatial variation in water relations, and thus water stress, should explain yield variation. Unfortunately, the methods available to measure physical properties of even the surface soil, much less lower soil layers, are labor-intensive and thus impractical for wide-scale use. A preliminary study using state-space analysis suggested that saturated hydraulic conductivity explained appreciable block-to-block variation in yield that was not explained by treatment effects. Therefore, crop yield for several years was examined for possible support of the water relations cause of variation. Parameters studied included elevation, depth hto clay, available water holding capacity, and electrical conductivity. Crop indicators included the long-term yield database and also canopy temperature and crop water stress index data obtained during a single season.