Farming Monthly National March 2018 | Page 14

| Arable Don’t risk grassland yield and quality! Reliable evidence from the British Survey of Fertiliser Practice illustrates the continued and unsustainable decline in arable and grassland liming. he data emphasises a maintained reduction in liming, with the five year grassland average showing just 3% limed annually! Further robust data reported via the 2016 ‘PAAG’ survey show that more than 50% of 160,000 grassland soil samples were at or below pH 6.0! - this level of low pH will significantly impact on the utilisation of N, P and then K: Indications are that grasslands are becoming more acidic, and this will adversely affect sward composition, leading to decline in grassland yield and quality. Furthermore, nitrogen applications increase the natural rate of soil acidification, and cut herbage removes significantly larger quantities of calcium when compared to other crops. Managing soil pH closer to neutral will often improve forage magnesium content and support better K:Mg ratios that will in turn reduce the risk of hypomagnesaemia. Therefore, regular pH testing and corrective liming to > pH 6.5 will avoid consequential loss of yield and forage quality by maintaining soil pH at an appropriate level, such that other macro and micro nutrients are available to the growing crop. But, before buying lime, always T check the quality - preferably at least 45 NV and 40% or more passing the 150 micron sieve test are essential parameters. The Ag- lime Quality Standard was introduced in 2017 to give farmers greater confidence in the quality of lime – look for the standard! Beware! - hard stone greater than 1.3mm is rarely of any liming value, and ideally particles less than 0.6mm are the most reactive! LimeX is at least 85% passing 150 microns, and is at least 95% reactive, making it the ideal product for fast acting, but lasting 14 | Farming Monthly | March 2018 correction of pH and increases soil available calcium, and can be used in organic farming systems. The integral nutrient package within LimeX contributes to maintaining soil fertility by supplying valuable quantities of P2O5, MgO and SO3. LimeX is available via a network of local distributors for spring and summer applications. For more information on grassland liming advice please contact 0870 2402314, or visit: limex.co.uk Table 1: The effect of soil pH and fertiliser efficiency on mineral soil. www.farmingmonthly.co.uk