According to manufacturers, growers are increasingly turning away from generic fertiliser blends and straights to more specialist products and bespoke mixtures tailored to specific field conditions.
The trend appears to be driven by a number of factors. Cost and efficiency are obviously of prime importance, but changes in fertiliser use also appear to be tied to the increasing use of precision farming techniques. In addition, as growers begin to embark on initiatives to reduce the carbon footprint of farming, the high greenhouse gas emissions associated with the production of traditional fertiliser products are also being addressed by manufacturers.
"It is precisely because we are aware that growers are becoming increasingly mindful of the effect on the environment and escalating cost of traditional bulk fertilisers that we are supporting them by providing precisely targeted nutritional inputs to replace traditional bulk nitrogen, phosphorus and potassium (NPK) treatments," says Ilex EnviroSciences marketing director Sue Spencer.
These products are typical of modern offerings, which are often designed to compliment a particular stage of crop growth or to supply macro-, secondary and micro-elements to commercially grown crops at reduced application rates.
"Many of our products work with the plant to maximise its uptake of naturally occurring nutrients," explains Spencer. "For example, Crop Rooter-P, P-K Plus or Stimplex encourage improved early root development, prevent or correct nutrient-related disorders and, most importantly, extend the shelf life of perishable crops such as leafy salads and soft fruits."
Crop Rooter-P is one product designed for application at a particular growth stage. Aimed at increasing initial root and shoot development, Spencer says it is proving effective in difficult growing seasons, particularly on crops suffering from physiological stress and disease pressure.
Another specialist product offering is the NovaTec range from Compo, which performs particularly well on salad crops such as lamb's lettuce and chard. While the NovaTec range is at heart a complex NPK fertiliser, it features a nitrification inhibitor known as DMPP that reduces nitrogen leaching while increasing the efficiency of the major nutrient.
DMPP is active from four to 10 weeks, depending on soil temperature and soil humidity, and during this time it delays the transformation of ammonium to nitrate, resulting in a profile of nitrogen availability more closely related to the plants' requirements.
Specialist products can help cope with uncertainty through the growing season or changing application windows. Fertiliser producer Yara head of agronomy Mark Tucker says that unpredictable weather patterns make the need for flexibility in crop nutrition programmes critical and that "Yara's portfolio of products means that if an application is missed an alternative product can be used at a later crop growth stage."
As part of this move to specialist products, organic lines and biological fertilisers are finding favour with growers, rather than only those involved in organic production. One example is Stimplex, a highly concentrated crop bio-stimulant derived from marine plant material, produced by Ilex.
"It contains high levels of natural cytokinins - a group of chemicals that play an important role in the production of plant enzymes and proteins," says Spencer. "Stimplex can therefore assist all phases of plant growth, from root formation to bud, stem and leaf development, particularly in crops suffering from temperature, water or salt stress."
Norwich-based PP Products is now marketing a new fertiliser concept from Germany called Lithovit. PP's Paul Corfield explains: "Based on a nutrient-rich source of calcium carbonate, the manufacturers are using a new technology that reduces the particle size down to a level that can easily enter the leaf through the stomata. Once inside the plant, the calcium is used to build stronger cell walls while the carbonate is broken down into carbon dioxide and oxygen."
The increased level of carbon dioxide in the leaf improves photosynthesis, helping plant growth and, in conjunction with the calcium, improving the plant's overall health and vitality. Corfield reports a successful season with a number of brassica growers last year and expects more farms will be using it this year.
Although not organic, calcium is at the heart of another specialist product from Ilex EnviroSciences. "InCa is based on the patented CaT (Calcium Transfer Technology) that mobilises calcium to areas of the plant where it is most needed," explains Spencer. "Practical benefits include increased calcium levels in the perishable parts of brassica and salad crops, resulting in improved cell wall integrity leading to prolonged shelf life and better resistance to potential damage during harvest and transport. Other benefits include a reduction in calcium related disorders such as internal browning and tip burn."
In most cases, precision farming is about helping growers to understand their field and crop at a micro level in order to achieve a lower cost of production per unit of marketable yield.
One well recognised tool is Yara's N Sensor ALS. "This is a tractor-mounted sensor that measures the crop's nitrogen status while on the move and makes an adjustment to the fertiliser being applied by means of an on-board computer," explains Tucker. "This can not only potentially reduce the grower's fertiliser usage, but also means the correct amount is being applied in each area. This fits in with Yara's commitment to environmental issues and the reduction of fertilisers' overall carbon footprint."
In turn, this move towards precise application and regular soil sampling is helping to drive the demand for crop-specific nutrients. Whether these take the form of solid and liquid macro-nutrients or foliar applied micro-nutrients, Tucker reports that the changes are "highlighting some important gaps in nutrient programmes".
Based on soil test data collated from Yara's laboratory facility in Pocklington, some 80 per cent of UK soils are deficient in boron. "This is where one of Yara's newer products NitraBor (a form of calcium nitrate plus boron) has been specifically used on brassica crops," he adds. "Independent trials have shown that NitraBor is one of the most effective products in helping to suppress club root where the synergy between calcium and boron works particularly well. The grower is getting boron into his crop while still benefitting from the calcium component."
Precision farming can also help growers to build up long-term soil fertility, and with the costs of inputs rising, targeted applications make sense. Long-term fertility is not something that growers should scrimp on, says Compo UK technical sales manager for Mike Butler: "Soil fertility is the farmers bank and most are committed to retaining it in top condition."
There are two approaches manufacturers are taking to help address the concerns of growers and their customers over the greenhouse gas emissions associated with fertiliser manufacture.
"We are particularly looking at the emissions from nitric oxide (NO) in the soil," says Butler. "We have been approached by several large food companies that are looking at their carbon footprint right back through the business to the start, examining what fertilisers are being used. The NovaTec range reduces gassing off and helps stop leaching of nitrogen into the environment. Being more efficient, it reduces applications and gives an extra yield associated with the energy cycle in the plants."
The recent launch of the Green House Gas Action Plan is likely to focus even more growers' attention on reducing the overall emissions associated with crop production and the role that fertiliser can play in achieving the industry's target of reducing emissions by three million tonnes of CO2 equivalent from 2018-2022 without compromising domestic production.
Larger manufacturers are looking at how they can reduce the emissions associated with fertiliser manufacture. "Over the past decade, Yara has developed and installed N20 (nitrous oxide) catalytic abatement technology in all its plants and this has reduced its emissions by 90 per cent," explains Tucker. "This, in conjunction with our field advice, means that applying Yara nitrate-based fertilisers such as Tropicote, Extran and Complex NPK can reduce growers' carbon footprint by 50 per cent."
Tucker believes that pressure from the supply chain to reduce the carbon footprint of vegetable production will be accompanied by the need to increase production as the global demand for food increases. "Yara has positioned itself to cope with this greater demand for crop nutrition products by increasing its own production capabilities and aligning itself with major raw material producers in strategic positions throughout the world," he says.