Landowners are encouraged to get their soil tested and manure analysed this autumn to help build a farm-specific nutrient management plan and address any imbalances ahead of the spring. 

Autumn is a good time to take soil samples, with timing critical to the accuracy of the sample, explained experts during the latest Mole Valley Farmers' Podcast. 

Increasingly, farmers are looking to test their soil and manure to reduce artificial inputs, with NRM Laboratories reporting on the podcast a 40% increase in the number of manure samples being tested yearly. 

Lisa Hambly, Head of Grassland and Forage Agronomy at Mole Valley Farmers explained how a Nutrient Management Plan is essential to plan a farm's forage requirements and to help maximise their yields whilst reducing costs, with autumn a great time of year to sit down and conduct one. 

"Ask yourself if you know what your fields are yielding. If not, how do you know how much to feed the crop?" she said. 

"A Nutrient Management Plan isn't a bit of paper to sit on the shelf; this is an interactive tool where inputs/ cropping can easily be amended according to the changing requirements of the livestock diet. 

"What is put on the soil can also influence animal health," added Ms Hambly. "It's vital to link the soil to the animal and realise what you put on the soil and treat the soil with can make a difference to animal health, productivity, and profitability. 

"Likewise, what you feed your animals will also influence the quality of the FYM or slurry, which is why it's important to get it tested and input your farm numbers into the Nutrient Management Plan," she said. 

However, ensuring you are taking soil and manure samples at the correct time is essential for accurate results, explained Dr Sajjad Awan, Soil and Crop Nutrition Agronomist at NRM Laboratories. 

"Timing of sampling is critical. If you take a soil sample when it is too dry or wet, the results will be very different. The mineralisation of nutrients is low when the soil is dry, which can impact the available phosphorous in the soil. 

"Secondly, stick to taking samples when soil conditions are the same by recording when you took the samples and the conditions to gain a like-for-like comparison. Looking at trends over the long term will give you a good idea of which direction you are heading," he said. 

The type of soil test will also direct the sample that is needed. For example, if a farmer wants a soil carbon test, guidelines suggest a sample should be taken from 30cm deep, compared to 7.5-15cm deep for a standard soil test. Soil samples also shouldn't be collected following applications of slurry. 

Dr Awan encouraged farmers to work with experts like Mole Valley Farmers to use the results to make informed decisions. 

He said: "Make the best use of the test results. For instance, pH is the single most important factor for nutrient availability. The pH needs to be 6-6.5, which allows the maximum respiration rate of the soil microbes, meaning nutrient mineralisation will also be high when soil microbes are fully active. Our data has shown that the rate of respiration rests on the right pH. If this isn't right, there will be implications down the line." 

Likewise, when it comes to testing slurry, experts on the podcast advised taking samples as close as possible to the application date as the nutrients could be lost from the manure/slurry when stored for an extended period of time. 

Dr Awan added: "The mean value of total nitrogen from one tonne of cattle manure could range from £75 of N a tonne down to £3 of N a tonne. The value of the major nutrients applied could be worth £3,000 for every 20t of manure applied per ha or be as low as £100, which is why it's important to get it tested." 

Testing manure just before application will consider any dietary changes that can impact results. 

Dr Awan added: "Animals that are fed protein retain about 20-25%, and three-quarters are excreted, so if your feeding has changed, most likely the value of nutrients will have changed." 

Knowing what is happening in the soil and slurry will pinpoint areas for improvement, said Ms Hambly. 

"Having excess can be as bad as not having enough of one mineral. Excess minerals can also cause an antagonistic effect. If you don't measure, how can you manage? Potash in fields grazed by dairy herds can get very high, and as magnesium gets locked up when there are high potash levels, it's important to know what is going on." 

Mole Valley Farmers has a dedicated Nutrient Management Planning service for livestock farmers, which uses FACTS-qualified experts specialising in grassland and forage crops. More information can be found at www.moleonline.com   

To listen to the podcast, visit https://rss.com/podcasts/mvf/