Boosting pulse crop performance on acidic soils

Abstract

Key findings •• Acidic soil layers below 5 cm adversely affect root growth and architecture, nodulation, plant vigour, N2 fixation and yield potential of acid-sensitive pulses. •• Moderately (pHCa 4.6–5.0) and severely (pHCa <4.5) acidic layers in the 5–20 cm soil profile are not detected using soil samples collected over standard profile depths of 0–10 cm and 10–20 cm. •• Finer sampling at 5 cm intervals is recommended to detect pH stratification. •• The current standard industry practice of spreading lime with no incorporation and sowing with knife point press wheels or disc seeders confines the lime effect to the surface layers. •• Careful paddock selection and forward planning is required to correct pH stratification in the topsoil (0–10 cm). •• Lime application and incorporation with a full cultivation operation at least 6–12 months before sowing acid-sensitive species could be necessary. •• Appropriate lime rates should be used to ensure pHCa >5.5 in the entire top 10 cm layer. •• The effect of pH stratification on more acid-tolerant species, including canola, lucerne and cereals, should also be monitored.