The quest to improve nitrogen use efficiency and increase crop resilience has taken a leap forward on a drought-prone Somerset farm.
Soaring nitrogen fertiliser prices coupled with unpredictable crop uptake triggered a major rethink on plant nutrition in early 2022 for the Biss family, who grow 180ha of cereals and maize on drought-prone land at Middle Farm near Somerton.
Four years after the inquisition, bagged nitrogen bills are down, soils and plants are healthier and there has been no negative impact on crop yield or quality.
“It all started in early 2022 when fertiliser prices went through the roof,” says Patrick Biss. “Like most farmers we knew this would make life very difficult. Our wheats average around 8t/ha and, being tenants, margins were already tight.
“So we sat down with our agronomist to see what the alternatives might be and how they might work here.”
Matt, Patrick’s son, adds: “Our biggest problem in a dry spring is getting the fertiliser into the crop. We are usually OK to the end of March but after that prills can just sit on the soil surface.”
The farm’s soils are relatively shallow and brashy and have a high pH, often 8 or more. Agrovista’s Peter Waltham, the farm’s agronomist for eight years, says: “We were faced with a complex set of issues, not least the soil, that we had to take into account to improve nitrogen use efficiency (NUE) to help reduce bagged fertiliser inputs.”
Soil samples showed that soil health was, overall, relatively good. “Microbial respiration levels varied,” says Peter. “But the relatively good levels of soil organic matter suggested we could build microbial activity to deliver better NUE.”
Peter recommended using L-CBF Boost, a biostimulant from Agrovista’s Innovation range, on cereals. This molasses-based product contains humates and trace elements, providing a complex carbon food-source for microbes, particularly bacteria responsible for N mineralisation.
Over the past four years Matt has applied the product at 10 litres/ha with pre-emergence herbicide in the autumn, followed by a further 30-40 litres/ha usually at T0.
The resulting improvement in the soil microbe population has enabled a 15% reduction in applied nitrogen usage on wheat, from 220kg/ha to 187kg/ha. Similar percentage reductions have been achieved on winter barley.
“Yields and quality stayed the same, but we made significant savings on the fertiliser bill,” says Matt. “Boost had an effect soon after we started using it, particularly on crops that were starting to become stressed, which greened up pretty quickly.”
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The economics appear healthy. “Whatever we do it has to work financially,” says Patrick. “It’s hard to quantify, but nitrogen savings have more than offset the cost of the Boost. Yield and quality haven’t deteriorated, so I think we are in better place.”
The programme has since been tweaked with the addition of MZ28, a foliar-applied, controlled-release fertiliser. “It’s a highly efficient form of N,” says Peter. “We use just 35 litres/ha of MZ28 to replace the final 50kg N/ha split of bagged product.
“We don’t have to feed the soil to feed the crop, which further improves NUE. Reducing soil-applied N also helps maintain the carbon to nitrogen ratio, which is something we would actually like to raise, to promote a better balance between bacteria and fungi – this high-pH soil favours the former.”
With that in mind, Peter has recommended Sea2Soil, starting this spring. This liquid fertiliser contains fish hydrolysate, a by-product of the fish processing industry, that provides nitrogen, minerals, trace elements and amino acids, a rich energy source for beneficial fungi.
“Increasing the Ievels of arbuscular mycorrhizal fungi, which associate with crop roots, will improve uptake of major nutrients and trace elements – manganese deficiency is a major issue on this farm,” says Peter. “In turn this will produce healthier plants, aiding disease suppression and water regulation.”
The spring application will now consist of L-CBF Boost and Sea2Soil, both at 20 litres/ha.
Matt is looking forward to seeing what Sea2Soil can add. “Being an ex-dairy farm we have had access to plenty of organic matter and have always taken care of our soils.
“Since using Boost we have seen further improvement, we have some lovely soils to work with. You have to give any soil-enhancing product several years before deciding if it is worth it and we’ve only seen positives. Hopefully Sea2Soil will bring further benefits in the longer term – it feels like we are on a very worthwhile journey.”
SeaBoost – the ultimate soil biostimulant
Agrovista is introducing a co-formulated version of L-CBF Terra-Fed (L-CBF Boost minus nitrogen) and Sea2Soil this spring.
SeaBoost combines the powerful soil-conditioning effects of the two products, offering farmers the ultimate soil biostimulant in one package.
Peter says: “As well as the obvious benefits of speeding up and simplifying filling, SeaBoost provides a cost-effective, easy-to-use route for growers to help make tangible improvements to their soils in the longer term.”
Click here for further details on SeaBoost