Yield and nitrogen utilization by Lolium perenne and Trifolium repens on a limed stagnohumic‐gley soil in a pot experiment

In a pot experiment the pH of a hill peaty soil was adjusted to cover the range 3.8 to 6.8 with Ca(OH)₂. Yield and N content of the harvested plant material was greatest at pH 6.8 in pots sown with only Lolium perenne, and greatest at soil pH 6.1 in pots sown with Trifolium repens and L. perenne. T. repens established only at soil pH between 4·3 and 6·1. A small reduction in sward yield and a large and highly significant decrease in total N recovered by the harvested material, which occurred with increase in soil pH from 3·8 to 4·3, was attributed to a combination of increased N immobilization in the soil microbial biomass and to the poor performance of both sown and self‐propagating indigenous species around pH 4·3.