[seedman]

Can any tell how long sulphate of ammonia and nitrate of soda last in the soil are they short term or long term thank you for any comments

[JayG]

They are both quick-acting and highly soluble so will quickly leach away (depending on your soil type and rainfall, of course.)

Both should be regarded as just high nitrogen feeds, but ammonium sulphate has an acidifying effect as well so it's handy for acid-loving plants (but not so good for other plants if your soil is already too acidic.)

[solway cropper]

Most chemical fertilizers are fast acting and quickly leached from the soil which is why many gardeners prefer organic ones.

It's also very easy to over fertilize with chemicals and cause more harm than good.

[Salmo]

Both of these are soluble and quick acting. One advantage is that they can be sprinkled on the surface as top dressing and will be washed down to the roots. You can notice plants greening up within about 10 days. They will be gone within a couple of months.

Phosphate and potash are less soluble and need to be worked into the seedbed before planting. If they are top dressed they need to be cutivated in to make them available. They can be applied in the Autumn and will still be there for the plants in the Spring. It is now common farming practice to apply phosphate and potash just once in a rotation but to apply nitrogen each year according to the needs of the crop being grown.

Potash is more soluble than phosphate and can be washed out of light sandy soils in a wet Winter.

If manure is spread on the surface many of the nutrients, especially nitrogen, are washed out over Winter and the only value is the organic matter as a soil conditioner. Manure heaps are best covered to preserve the nutrients. Nitrogen is in the form of urea and may also be lost to the air.