Nine cuttings of ‘Alaskland’ red clover (Trifolium pratenseL.) grown in the greenhouse in a 24factorial experiment were made over a 2‐year period. Annual applications of two P and two K rates and sources in the presence and absence of additional C1 were made. The higher P rate did not increase clover yield, but did increase P percentage of and P uptake by the last five clippings only when K2SO4was used. Total C1 uptake was reduced by the higher P application. The higher K rate increased clover yield and P uptake. K source had no significant effect on clover yield. Uptake of C1 and C1 percentage were greater with KC1 than with K2SO4while total P uptake tended to be greater with K2SO4. Annual applications of 408 kg C1/ha depressed clover yield, P uptake and dry matter percentage, and increased C1 percentage and uptake. Available NO3‐N, P, and K in the soil were reduced by the nine clippings.