Legume yield and persistence when sown in grass and herb pasture mixes in Lees Valley, South Island High Country

Abstract

Four experiments were established to identify suitable companion species for legumes grown in the intermontane Basin of the Lees Valley, North Canterbury (400 m a.s.l.). This location experiences long cold winters, has soils of low pH and high aluminium, with low water holding capacity and severe summer soil moisture deficits. In Year 1, the ryegrass mixtures yielded 4550±290 kg DM/ha more (P<0.05) than the timothy mixtures (3440 kg DM/ha) and the dryland mixture total yield was 4370 kg. The average white clover yield of 1800±210 kg DM/ha was not different among all treatments and represented 43% of total DM, compared with only 8% for sub clover. Total yield in Year 2 was higher (P<0.05) in the dryland- and ryegrass-based mixtures (~4400±330 kg DM/ha) than timothy (2650 kg). White clover yield across the mixtures was 930±90 kg DM/ha and 29% of the total DM. Sub clover did not re-establish. White clover yields peaked in October-November of both years with growth rates of ~16 kg DM/ha/d. The start of the summer dry period, from late September onwards, resulted in a decline in white clover spring growth rates and lower yields. In the Caucasian-herbs experiment, yield in Years 1 and 2 were 2700±250 and 2830±230 kg DM/ha/yr respectively. In both years Caucasian clover yields were lower when grown in herb-based mixtures compared with a monoculture (Year 1: ~400 versus 1800±270 kg DM/ha, Year 2: 920 versus 1750±210 kg DM/ha). The herb content of the mixtures declined over time.