Yield gains in major U.S. field crops / Stephen Smith, Brian Diers, James Specht, and Brett Carver, editors. (OCLC #880168370)
A book containing multiple chapters may be considered a collection of separate works, with a whole-part or “contains” relationship. The rules for describing this relationship in RDA are in Chapter 25, Related Works. In general this can be recorded with a statement like:
Contains: Barley -- Cotton -- Cool-season forages.
As we are encoding the record in MARC, the “Contains:” phrase is not needed; it is specified by the first indicator of the 505. More details can be found in the LC-PCC PS for RDA 18.104.22.168.
Though recording this relationship is not required, I did not find doing so for this book burdensome, and the resulting statement was dense with helpful keywords:
505 0_ ǂa Barley -- Cotton -- Cool-season forages -- Lettuce and spinach -- Edible grain legumes -- Maize -- Peanut -- Potato -- Rangeland and warm-season forage grasses -- Rice -- Sorghum -- Soybean -- Sugarbeet -- Sugarcane -- Sunflower -- Wheat.