Sulphur and lime response of four adventive annual clovers grown in a New Zealand high country soil under glasshouse conditions

Abstract

Adventive annual clovers play a critical role in nitrogen (N) cycling and feed quality in extensive summer-dry hill country, where traditionally sown white and subterranean clovers often fail to persist. However, very little is known about the edaphic (e.g. soil fertility) requirements of these species. The growth response and nutrient uptake of four adventive annual clovers to applied sulphur (S) or lime, grown in a typical low-fertility South Island high country soil, were investigated under glasshouse conditions and compared with white and subterranean clovers as reference species. The annual species had yield responses of 12- 17% or were unresponsive to S applications. Trifolium repens and T. striatum responded to liming at low lime rates, while all other species had negative yield responses to liming. Maximum yields were generally in the order of T. subterraneum ≥ T. arvense > T. striatum ≥ T. dubium > T. glomeratum > T. repens. For lime treatments, yields were strongly driven by phosphorus (P) availability, linked to soil pH. The data indicate that the adventive annual clovers are better adapted to low soil fertility (low pH and S) conditions, which in turn may be an important factor contributing to their success under South Island high country field conditions.