THESE ARE the results of soil tests I mentioned in my July column. The tests were on one half of the paddock which was performing well, the other half which was much poorer, and a paddock right next door which belongs to a neighbour and has had no fertiliser or lime in
many years. There's nothing very striking about them, except for the comparison between my paddocks and the neighbour’s paddock. The neighbour’s result gives a clear example of a low Base Saturation and low Calcium levels corresponding with a low ph. Phosphate levels there are presumably as limiting to pasture growth as the acidity of the soil
(with associated Aluminium toxicity) and both would benefit
from being addressed. In our case, the pasture sampling (see page 36) emphasised the
nutrients the plants needed addressed, leading to our addition of Molybdenum, Salt and Sulphur to this
year's RPR application.
in particular. High-production dairy pastures require a lot more nutrients than a lightly-stocked block with older, mixed swards.
Good fungal life makes Phosphate much more available to your plants than it would be in a less lively soil. It is the long chains of mycorrhizal fungal cells whose enzymes break the bonds holding Phosphate deep in the soil aggregates and bring it back to their host plants. This means Phosphate which is fixed and not readily plant-available in many soils, becomes much more so where there is high biological activity. You may need much less phosphate than your fertiliser sales representative would like you to buy if you pay attention to overall soil health.
I've changed my thinking about soils and fertiliser while reading, thinking about and writing these columns over the past few months. It has been a process I'd like to continue and I welcome correspondence on anything I've raised which you would like to explore further.