Response of wheat cultivars with varying acid tolerances to liming of eastern Free State soils

The sustainable production of wheat can be affected by soil acidity in the eastern Free State, South Africa. Liming of soil to appropriate acidity levels is therefore regarded as an essential farming practice. In some instances, however, planting of acid-tolerant wheat cultivars is recommended as an interim management measure. Hence, we evaluated the response (grain yield, grain protein content and hectoliter mass) of wheat cultivars with poor (Karee or Limpopo), moderate (SST 224 or Gariep) and good (Tugela DN) acid tolerance on soils (8–33% clay) over a range of lime-induced pH (KCl) values (3.7–5.7) under field conditions spanning 4 to 5 years. In Year 2 no data was collected due to staff shortages. Across the pH ranges, grain yields of the most acid-tolerant cultivars exceeded those of the moderately acid-tolerant cultivars by 29–54%, and those of the poorly acid-tolerant cultivars by 36–62%. Due to climatic conditions, larger differences in grain protein content were observed between years rather than between treatment combinations. Hectoliter mass, although influenced by treatment combinations, exceeded the threshold value of 76 kg hL−1. The results, especially of grain yield, proved the usefulness of acid-tolerant wheat cultivars during the initial stages of liming programs, until acceptable levels of soil acidity are reached.