National Commodity Crop Productivity Index (NCCPI) – Development.

The National Commodity Crop Productivity Index (NCCPI) model is a national soil interpretation that is generated from the National Soil Information System (NASIS).  Using data stored in NASIS, NCCPI arrays soils according to their inherent capacity to produce dryland (nonirrigated) commodity crops.  Most of the NCCPI criteria relate directly to the ability of soil properties, landscape features, and climate factors to foster crop growth.  A few criteria relate to factors that can limit use of the land (e.g., surface boulders).  All criteria used in the index affect crop culture and production and are referred to as factors affecting inherent productivity which is considered nearly invariant over time.  Temporary fluctuations in productivity through good or bad management and year-to-year variations in weather are not addressed.  More permanent changes in soil properties that cause significant changes in productivity can affect a soil's NCCPI rating when current NASIS information is used.  Extreme erosion, compaction, undesirable sediment deposition during flooding and salinization are examples that affect NCCPI.  The Conservation Reserve Program (CRP) of USDA provided one stimulus to develop the NCCPI.  The inherent capacity of soil to produce commodity crops is one factor needed to adjust average rental payments.  A soil model that is consistent across political boundaries and over time is required for this and many other uses.  Crop varieties, management scenarios, and yields vary from place to place and over time, reflecting choices made by farmers and ranchers. Excepting the extreme circumstances mentioned above,  inherent soil quality or inherent soil productivity varies little over time or from place to place for a specific soil identified by the National Cooperative Soil Survey.  NCCPI presently deals only with nonirrigated farm crops but it is envisioned that at a later date it will be expanded to include irrigated farm crops, rangeland, and forestland productivity.