Crop responses to subsoil manuring. II. Comparing surface and subsoil manuring in north-eastern Victoria from 2011 to 2012

摘要

An on-farm field-experiment was carried out in north-eastern Victoria in 2011 and 2012 to compare the agronomic effectiveness of surface and subsoil manuring on a Chromosol soil with a compacted clay subsoil. Surface manuring involved the surface application of 20 t poultry litter ha(-1), whereas subsoil manuring involved deep-banding of the same quantity of litter in 30-40-cm-deep rip-lines, spaced 80 cm apart. Treatments were applied at the start of the first cropping season. The objective of the study was to determine whether surface manuring might produce the large yield responses reported for subsoil manuring. Both manuring treatments increased yields of wheat (Triticum aestivum L.) by >2.3 t ha(-1) compared with the unamended control in 2011, when spring rainfall was close to the average. However, only subsoil manuring increased wheat yields in 2012, producing an extra 4.7 t ha(-1) above the control, in a year with a very dry spring. This yield response suggests that subsoil manuring would be more effective than surface manuring in the second year after treatment in years with a dry finish.