The high cost of fertilizer, combined with soaring fuel and labor costs, have led many growers in the Southeast to reevaluate how they sample soil to make management decisions.

Two options, zone sampling and grid sampling are currently used, but making the right choice as to which one, is important to the bottom line.

Zone sampling uses soils samples collected randomly from each zone. These samples are combined and analyzed to provide an average sample value for any unit. Unlike grid sampling, zone sampling is more subjective, allowing growers or crop advisors to divide a field into manageable zones.

Zone sampling is dependent on a grower’s ability to identify soil variability within a field.

Aerial or satellite photography, or higher tech systems like measuring soil electricity content, can be used to divide fields into management zones. The addition of yield monitors can add even more reliability to zone sampling data.

Grid sampling strategies are best used when a measure of non-mobile nutrients is the primary concern. Lack of movement in the soil restricts distribution and is less affected by topography and other fixed factors.

Other reasons to use grid sampling are when a measure of mobile nutrients is a major concern, or in areas where there is a history of manure use.

e-mail: rroberson@farmpress.com