western-queensland-gardening-guide.pdf - South West NRM

Soil conditioners
Gypsum and sulphur
Gypsum (calcium sulphate) is a useful soil conditioner to offset the effects of salty bore
water. It is quite cheap if it can be obtained in 50 kg bags. Gypsum does two things:
the calcium substitutes for the sodium in the soil and in the plant, and it softens soil
containing sigruficant amounts of clay.
Sulphur is a powerful acidifier but has little effect on improving soil hardness.
Consequently, a combination of the two is useful to overcome the problems of
watering with bore water which is usually quite alkaline.
In garden beds the gypsum and sulphur should be dug into the soil for faster results.
For lawns this is not possible so watering is the only practical way to incorporate them
into the soil. If a problem has already developed, and the soil is very hard, this
treatment can be repeated two or three times during a summer season at monthly
intervals. Gypsum will take a while to soften the soil as it will be incorporated only
slowly into hard soil.
Organic matter
Adding manure or compost to soils will also help to prevent soil becoming hard. It
improves soil structure and fertility and helps in maintaining a suitable pH.
The most important nutrient required by lawns is nitrogen. Care should be taken with
nitrogenous fertiliser to apply the right amount--too much will damage the lawn.
Sulphate of ammonia is the best nitrogen fertiliser to use but urea and nitram are also
commonly used with bore water. The acidifying sulphur counteracts the effects of
bore water and the ammonia supplies the nitrogen.
Every two years, a mixed fertiliser such as Tropic or Q5 containing nitrogen, phosphate
and potassium should be used.
Fertilisers are often quite expensive when bought in small packets. Purchasing 20,40
or 50 kg bags is a much cheaper way of fertilising the lawn.