Soil pH, exchangeable aluminium and legume yield responses to deep-placed lime at Omarama Station

The passive moment of lime down the soil profile in dryland is slow so a machine was developed to directly inject lime into soil, and was tested it at Omarama Station. Pelleted lime was injected at simultaneous depths of 5-10 cm and 20-25 cm below the soil surface at rates of 0 (control), 500, 1000, and 2000 kg/ha and these treatments were compared with 1000 kg/ha of surface-applied pelleted lime. The growth of lucerne, ‘Russell’ lupins and festulolium was recorded over 3 years. The deep-placed lime increased soil pH and reduced Al levels at soil depths of 25 and 30 cm, whereas for the surface-applied lime this was only the case in the top 7.5 cm of the soil. The deep-placed lime increased the growth of lucerne in the second and third years of the experiment. The lucerne was out-yielded by ‘Russell’ lupins in each year, which were unaffected by the application of lime.