The quantity of wheat (Triticum aestivum L.) straw in the 0 to 7.6 cm depth of soil in wheat-fallow rotations was determined at Sidney, Montana, Akron, Colorado, North Platte, Nebraska, and Bushland, Texas. Rotation treatments varied between locations but included straw rates, dates of primary tillage, and straw burial times. Types of primary tillage were also studied with continuous wheat at Bushland, Texas.
Quantities of straw found mixed in the surface 7.6 cm of soil at the four Great Plains locations ranged from 1,300 to 7,480 kg/ha. The straw quantities found are influenced by duration of wheat-fallow rotation, date, and type of primary tillage and straw burial time but were not proportional to the rates of straw mulch used at the beginning of fallow. In a long-term study plots at Bushland, Texas, straw build-up was significantly greater with continuous wheat than with wheatfallow. Adding nitrogen fertilizer even at high rates did not influence the amount of straw found in soil at Sidney, Montana or North Platte, Nebraska.