The influence of lime and phosphorus on crop production in northern Idaho

Soils in northern Idaho are rapidly becoming acidified as a consequence of heavy applications of ammonium‐based N fertilizers on cereal crops. The pH decline occurs primarily in the upper 30 cm of the soil profile. Liming with 4400 kg/ha resulted in 9 to 16% increase in cereal yields. A twenty percent increase in spring pea (Pisium sativum) yield was attributable to lime applications. Spring peas appeared to have a greater response to lime than cereals. This greater response may be due in part to increased numbers of Rhizobium leguminosarum found in the surface 15 cm of limed plots. Lime X P interactions were observed on spring pea and winter wheat yields (Triticum aestivum) in 1983 and 1984. The spring peas had a greater response to lime than wheat. Winter wheat, more tolerant to acid soil conditions, exhibited a greater response to P.