How Regular Farm Soil and Manure Sampling Can Help Reduce Fertiliser Costs

Understanding what is already in the soil

Without up-to-date soil results, farmers may be making decisions based on old data, standard figures or assumptions. That can lead to nutrients being over-applied in some areas and under-applied in others. Both can cost money. Good soil sampling helps farmers make better decisions about:

• fertiliser use
• manure and slurry applications
• crop and grassland performance
• nutrient management planning
• compliance
• long-term soil health
• input costs

In simple terms, soil sampling helps answer one key question: What have I already got in the soil before I buy anything else in?

How often should soil be sampled?

Under the Farming Rules for Water, soil test results used for planning applications of organic manure or manufactured fertiliser must be no more than five years old. However, five years is a long time on a working farm.

Soil nutrient levels can change, especially where organic manures are being used, crops are being removed, or soil improvement work is taking place. For that reason, testing every three years is often better practice.

A three-year approach gives a more up-to-date picture and allows farmers to adjust nutrient plans sooner. This can be useful where a farm is trying to build soil indices, improve nutrient use, or make better use of organic materials.

Waiting five years may mean working with information that is technically still within the rules, but no longer accurate enough for the best business decisions.

Why more regular testing can save money

The cost-saving argument is simple. If soil results are out of date, the farm may not know what it really needs. That can lead to:

• buying fertiliser that is not required
• applying too much nutrient in some fields
• missing deficiencies in others
• underusing manure or slurry
• making plans based on historic conditions
• reducing crop or grassland performance

For example, a field may have built up more nutrients than expected through previous manure applications. If that is not picked up through sampling, fertiliser may still be applied unnecessarily.

Alternatively, a field may be lower than expected and not receiving enough nutrient to support the target yield. With fertiliser prices where they are, even small improvements in accuracy can make a meaningful difference across the farm.

Manure analysis and yield data matter too

Soil sampling shows what is in the soil. But if a farm is using slurry, farmyard manure or other organic materials, it is also important to know what those materials contain.

Standard nutrient values can be useful, but they are only averages. In practice, manure nutrient content can vary significantly depending on animal diet, bedding, storage time, storage conditions and dry matter content.

Testing manure or slurry gives a more accurate picture. It helps farmers decide how much nutrient is being applied and how much manufactured fertiliser may still be needed.

Accurate yield information is also important, especially for grassland and silage systems.

If a farm assumes a higher yield than it is actually achieving, it may apply fertiliser for a level of production the field cannot deliver.

That can lead to unnecessary cost.

Recording bale numbers, silage trailer loads, clamp quantities or harvested yield can help nutrient plans reflect what the field is actually producing.

Key takeaways for farmers

Soil sampling is not just a compliance task. It is a practical way to improve nutrient decisions, control costs and make better use of the resources already available on farms.

The main points are:

• Soil test results must be kept up to date.
• Testing every three years is often better practice than waiting five.
• Good sampling technique matters.
• Soil results show what nutrients are already available.
• Manure and slurry should be tested too.
• Better data can reduce unnecessary fertiliser spend.
• Better data can also reduce the risk of nutrients being lost to the environment via leaching.
• Nutrient planning should be based on evidence, not assumptions.

Final thoughts

Soil and manure sampling underpins good nutrient planning. It helps farmers understand what is in the soil, what the crop or grassland needs, and how much can be supplied from manure, slurry or existing reserves before buying in fertiliser.

With input costs remaining high, this information is more important than ever.

Talk to us today about our Soil and Manure Sampling Analysis service – and we’ll help you see where you can start making savings.

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