Lime, phosphorus and sulphur response of French serradella (Ornithopus sativus) grown in an acid upland soil

Abstract

Soil acidity severely restricts legume persistence and growth in grazed upland agriculture in New Zealand. An alternative and potentially acid tolerant forage legume, French serradella (Ornithopus sativus), was examined in a climate controlled experiment. Plants were grown for 48 weeks in an acid (pHH20 4.9) upland soil and shoot yield measured every 8 weeks. Treatments were fully replicated combinations of lime (CaCO3; 0, 2, 4 or 8 t ha-1), phosphorus (P; 0, 50, 150 or 500 mg P L soil-1) plus various controls. Shoot yield varied significantly between lime treatments (P < 0.001), but were not strongly affected by P rate. Importantly, yields on the unlimed control treatments were 85% of maximum yield, suggesting that high yields are potentially achievable on even very acid soils. french serradella grew 16.9 g DM pot-1compared to 5.3 g DM pot-1 for the commonly grown reference species, subterranean clover (Trifolium subterraneum). French serradella showed significant potential as a new pasture legume suitable for acidic upland soils.