Why use no-till on raised beds?
There are five soil management objectives that require the use of no-till crop establishment practices on raised beds. These are:
- To maximise the retention and build-up of the organic matter of roots and their associated soil organisms to stabilise weak or dispersible soil structure.
- To retain the large pores created by roots and their associated organisms to enhance rapid infiltration and aeration of the root zone.
- To retain the roots as ‘reinforcing rods’ to minimise or prevent subsidence of the raised beds in wet conditions.
- To minimise disturbance and ‘spray’ of soil during cultivation and seeding to avoid the need to re-shape beds to restore their original height and width.
- To aid the control of weeds by minimising inter-row soil disturbance (and germination).
Minimising soil disturbance at seeding is desirable, but there are good reasons to ensure some disturbance occurs around the seed placement zone. These reasons are:
- To control diseases like rhizoctonia bare patch, some of the septoria diseases, black spot in peas, ascochyta in faba beans and blackleg in canola.
- To incorporate root-active herbicides such as trifuralin.
- To mix fertiliser with soil close to the seed and minimise the risk of ‘fertiliser toxicity’ damage to germinating seeds.