How to Apply the Recommendations

When using SWEP soil tests, there are a few common mistakes people make and these notes are intended to help you avoid them. For more information, you should also read about The Mikhail System.

Some people say that the number of things required to meet our recommendations make them expensive, but it is important to realise why we make such recommendations and how to work with them. The first priority is to correct the Exchangeable Cation Balance as this will improve both soil structure and nutrient availability. This optimises the effectiveness of our nutrient recommendations; which are not intended to build fertility or give specific growth responses. Rather, they aim to provide balanced plant nutrition for all essential nutrients over the period of the growing season and for a specific Land use.

While BOTH cation and nutrient recommendations are necessary for a good results, the are not applied at the same time. In high rainfall areas (or with irrigation) 3 to 6 months is required after any application of Lime, Dolomite or Gypsum, before any nutrients are applied. In lower rainfall areas, longer periods may be needed. This prevents any risk of nutrient 'lock-up'.

If the soil pH (in water) is below 5.4 you should delay application of any trace elements until such time as the recommended applications of Lime &/or Dolomite have successfully increased the pH above this level.

If the soil pH (in water) is 7.5 or greater, apply any trace elements required as foliar sprays ONLY.

Using Gypsum:

When using Gypsum in low rainfall areas without irrigation, the required amount may need to be applied in smaller doses over a number of seasons. But remember – Gypsum should not be applied at all where there is a shallow, saline water table and no subsurface drainage. The risk here is that after excess Sodium or Magnesium is leached down to the watertable, capillary action may return them to the root zone – making the situation worse rather than better.

Lime Quality

With all materials you use, quality is very important, but with Lime and Dolomite it is paramount as these materials are essentially non-soluble and rely on reactions at the particle surface. For this reason, Lime and Dolomite must be BOTH chemically pure and with a fine particles size (to maximise the available surface area). If you want to adjust your recommended rates of Lime and Dolomite according to their quality, please Contact Us for assistance.

Soil Biology

On the Complete Soil Balance Analysis, the recommendations for Soil Biology are a bit different from the others. Their aim is to assist in the maintenance of a stable and diverse biological community on the soil. They will be most effective if your results show that BOTH Cation and nutrient Balances are 60% or more. If the Cation Balance is below this level, make this your first priority, rather than spending a lot of money on so-called 'biologicals'.

Nutrients and Fertiliser

Our recommendations are given in terms of the elemental nutrient requirement (in kilograms per hectare). This needs to be converted into fertiliser, however, you should not need to do this yourself. Think of our recommendations as being like a Doctor's prescription - whatever pharmacy you take it to and whatever brand of product they sell, you will always get what the Doctor specified. Our recommendations are the same.

Any good supplier should be able to convert them into appropriate fertiliser applications, using whatever products they have available. This means that you can use SWEP soil tests to get a good "Apples-for-Apples" comparison between different suppliers, products and prices.

If you want to know more about this, you can download our Fact Sheet on Converting Nutrients to Fertiliser.

Organic vs Chemical Fertiliser

Our nutrient recommendations also give you the ability to choose whether to use Organic or Chemical fertiliser, since the process of converting nutrients to fertiliser is the same, only the type of fertiliser is different.

If you require large amounts of a particular nutrient, it may not be practical to use an Organic type initially, but as soil balance and fertility improves, many people find that Organic fertilisers give the best result.

To read more on this topic, click the link opposite.

For more information on how we develop our recommendations, you should read about The Mikhail System.