Monday, November 13, 2006

Investigating the Correlation of Soil Properties Measured with Precision Agriculture Instruments in the Intermountain West.

Jay M. Payne, Utah State Univ, PO Box 1211, Logan, UT 84322, V. Philip Rasmussen, Western Regional SARE Program, Utah State Univ, 4865 Old Main Hill, Ag Science #305, Logan, UT 84322-4865, and Don Sleight, AgriNorthwest, AgriNorthwest, PO Box 2308, Tri Cities, WA 99302.

Recent efforts to increase sustainability of agricultural lands, through minimal tillage practices and new crop rotations, cause in situ measurements of soil properties to be more valuable to managers than ever before.  Early adopters of precision agriculture technologies in the Intermountain West often rely on the correlation trends between these highly technical instruments and soil test values developed in the Midwest and Southeast.  However, the soil properties and climate in the Intermountain West vastly differ than other regions that a study was needed to establish the same trends specific to the region. Precision agriculture instruments that measure electromagnetic conductivity and texture on the soil surface, as well as electrical conductivity, texture, penetration resistance, moisture content, color, and depth of horizons throughout the soil profile were used.  Next the data from each instrument were compared to each other and the control, conventional soil analysis, on plots of land across the Intermountain West.  Graphic and statistical results show these instruments effectively measure spatial distributions of electrical conductivity, pH, texture, penetration resistance, and depth of horizons.  The results also correlate well with color, clay content, soil organic matter, cation exchange capacity, and soil moisture.  Compaction was consistent with penetration resistance measurements but not with electrical conductivity measurements by either electromagnetic induction or the Werner array methods.  These results effectively establish meaningful trends between popular precision agriculture instruments and soil properties important to production agriculture.