Arable farmers mustensure their soils are working to maximum efficiency if they are to obtainoptimum performance from their crops, says Kevin Ashford, agronomist forSustainable Soil Management (SSM), the soil advisory division of The GlensideGroup.
While much of theirfocus will be on correcting physical damage done in the past two years, he saysthey also need to get a really accurate assessment of the soils chemical andproductive capacity before making plans something many of the soil testscurrently available fail to do.
The companyhighlighted the issue at Cereals 2013 by growing a set of six plots of wheat,with a central control plot being grown according to RB209 recommendations,based on the standard soil test provided to all exhibitors by the eventorganisers.
Before the event wecompleted one of our Albrecht Soil Surveys on our plot, which identified thatthe soil was calcium-dominated. Magnesium levels were lower than would beconsidered ideal, but what was there was tied up by the calcium and so notavailable to the plant.
On the rest of ourplots we responded to this by including some kieserite in the fertiliserregime, which successfully addressed this situation.
On these trialplots we applied the 250kgs of N recommended by the standard soil test theorganisers do on the site, but it generated just 27.30 tonnes/hectare ofbiomass in the wheat crop sampled just ahead of the event.
We adjusted ourstrategy in response to the Albrecht Soil Survey results, cutting the nitrogenapplied to 200kgsN/ha and adding Biagro Phos N to balance the soil and freeup the magnesium, and some Marraphite bio-stimulant, a combination that raisedthat figure to 32.20 t/ha
In cost terms thiswas broadly neutral, with the treatment costing around 48/ha, which was almostthe same as the saving on nitrogen.
But the crop treatedwith our regime had almost 5t/ha more biomass, which would be expected toproduce significantly greater yield, while utilising the fertilisers appliedmore efficiently a benefit in both business and environmental terms.
We would stressthat these were not replicated trial plots and that biomass does not alwaystranslate into yield. However, if we have increased biomass we will haveincreased the amount of sunlight and energy captured by the plants, and thuswill be returning more carbon to the soil.
This will helpbuild organic matter levels in the soil, and so help improve soil structure,microbial activity, nutrient cycling, and ultimately, the sustainability of thefarm itself.