S.D. Codified Laws § 10-6-131
Before July first each year, the secretary of revenue shall annually provide each director the agricultural income value for each county as computed pursuant to § 10-6-127. The director shall annually determine the assessed value of agricultural land. The director may adjust the assessed value of agricultural land to the extent one or more of the following factors affect the productivity of the land:
The director shall document each adjustment by using data from sources reasonably related to the adjustment being made. In addition, the director may use data from comparable sales of agricultural land to document the adjustment concerning productivity for any of the factors listed in this section.
If the actual use of agricultural land varies from the land use category specified by soil classification standards, or if any factors listed in this section exist that affect the productivity of the land, the property owner may request an examination of the land by the director on a form prescribed by the department. The director shall determine whether to adjust the assessed value of the agricultural land pursuant to the factors listed in this section.
The director shall document all supporting evidence for the adjustment determination. The director shall provide any adjustment documentation to the department upon request. The director must keep the adjustment documentation in the director's office for the life of the adjustment.
For the purposes of this section, the term "shelterbelt" means field shelterbelts, farmstead windbreaks, wildlife tree plantings, living snow fences, and other tree plantings made specifically for conservation purposes, but excluding trees planted for ornamental or commercial purposes.
SDCL 10-6-131