Nutrient balance in the soil - Soil Essentials: Managing Your Farm's Primary Asset - page 19

Note . Soil pH is also a consequence of the cation balance, and this should be
adjusted if necessary to change the physical structure of the soil as well as its
chemical composition.
(2) Adjust pH levels
The pH can be adjusted by liming if pH is low, or adding acidifying agents if high,
within economic limits. Rather than just considering pH in isolation, it should also
be considered with cation balance and organic carbon. Balancing cations may well
change soil pH, at the same time changing the need for other action.
(3) Calculate nutrient ratios
Nutrient ratios should be calculated for calcium, magnesium, potassium, sodium
and the carbon/nitrogen ratio. Again, these ratios are aimed at obtaining ideal soil
conditions for soil macro- and micro-organisms and therefore for nutrient cycling
and for plant growth.
(4) Decide
Decide on where deficiencies or toxicities are.
(5) Calculate
Calculate how much fertiliser is needed to correct deficiencies and adjust ratios
based on the soil tests.
(6) Apply
Apply appropriate fertiliser with respect to economic limits.
This is not an easy job as it requires a good understanding of the effects of each
fertiliser considered, and requires time spent doing calculations. The advantages of
doing this job well will provide many benefits to the soil, and more particularly, to
the bank account at the end of the growing season.
Note . As soil is a dynamic living system, ideal ratios of nutrients will vary over
time and depend on the plants utilising the soil. There is no hard and fast rule that
can be applied all the time to a soil without taking seasonal variations into
account.