Yield responses of arable crops to liming - An evaluation of relationships between yields and soil pH from a long-term liming experiment.

J.E Holland,P.J White,K.W.T Goulding,M.J Glendining,S.P Mcgrath

doi:10.1016/j.eja.2019.02.016

Abstract

The management of optimal soil pH is fundamental to sustainable crop production. Understanding the lime requirement for arable crops has developed gradually over the last several decades. The aim of this study was to examine the yield-pH relationship for a range of arable crops to understand their response to liming, based on the Long-Term Liming experiments established in 1962 at Rothamsted Research, UK. The main treatments of four different rates of lime and, therefore, four distinctly different soil pH levels were maintained for 35 years at two sites (Rothamsted and Woburn). The pH ranged from 4.4 to 8.0. The lime response was tested on the following crops: spring barley, spring oats, spring beans, spring lupins, winter lupins, potatoes, linseed, winter oilseed rape, winter triticale and winter wheat. Relative yield (RY) was used for non-linear regression analysis to detect site, year and phosphorus (P) fertiliser effects on the relationship with pH. Liming had a highly significant positive effect on soil pH, but overall there was no consistent increase or decrease in soil extractable P (Olsen) or exchangeable K. There were significant site effects detected for RY for most crops which reflect differences in the two soil types. Spring oats and potatoes had very weak responses to lime within the pH range tested. For spring barley, winter triticale, winter wheat and winter oilseed rape significant effects of P fertiliser on the yield-pH relationship were found, although the nature of effects differed between crops and sites. Findings from the Long-Term Liming experiment are invaluable in improving the fundamental understanding on the yield-pH relationship for important arable crops and this has significant implications on selecting crops for rotations. The pH at 90% RY was calculated for selected crops and the beneficial effect of fertiliser P was detected in significantly reducing the critical pH value.

Highlights

At a global scale soils are increasingly being degraded and becoming marginal for agricultural production driven by e.g. salinization, erosion and acidification (FAO, 2015)
There were very few significant yield effects among the subplot treatments, this paper focuses upon the Rothamsted Application dates
Liming treatments had a highly significant effect (P < 0.001) on increasing soil pH at both sites in every year of the experiment except for the first year (1962) when pH was measured before the lime was applied (Fig. 1a, d)

Summary

Introduction

At a global scale soils are increasingly being degraded and becoming marginal for agricultural production driven by e.g. salinization, erosion and acidification (FAO, 2015). Changes to atmospheric nutrient inputs make estimating soil acidification difficult. The S deposition at the Woburn Farm, Bedfordshire, UK is < 5 kg−1 ha−1 year compared with 85 kg in 1970 (Goulding, 2015). The recent reduction in atmospheric acidic load in the UK has been significant, but uncertainty remains about other acidifying inputs and processes at finer scales. The removal of nutrients via harvested biomass or grain is an acidifying process (Goulding and Blake, 1998), increasing as yields increase. With all these challenges there is a need to understand the management of soil acidity better

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