Complete: Sugar beet response to additional applications of sulphur fertiliser and the identification of soil & cropping systems

Timescale: 2016 - 2019

Project Lead: Dr Simon Bowen

Project Sponsor: BBRO

Project Summary

Work on other arable crops such as OSR and cereals has shown that crops frequently respond to additional sulphur fertilisers, especially on lighter land where the risk of sulphur deficiency is greatest. The depletion of atmospheric deposition of sulphur is well documented. The decline is expected to fall from 8-20kg SO3/ha per year to around 5-10kgSO3/ha per year by 2020 and for sulphur deficiencies to become more common place. The uptake of sulphur by sugar beet is around 50-70kg/ha in average yielding beet crops and as much as 100kg/ha in higher yielding crops. BBRO trials undertaken between 2003-5 (Table 1) indicated some responses to sulphur but the responses were inconsistent and gave no clear data about how much sulphur to add. The incremental increase in beet yields since these series of trials along with further declining atmospheric deposition is considered to increase the likelihood of sulphur responses in sugar beet and potentially impacting on further yield progression in the future.

Main Objectives

The project will assess the response of beet crops to a range of sulphur application rates across a range of sites with contrasting soil types and cropping regimes. It will target soil types and regional weather trends (such as light textured soils with high winter rainfall >175mm) where the risk of sulphur deficiency is considered higher. The work will be undertaken crops with later harvest dates (post November) to target potentially higher yielding crops. The work will include an analysis of sulphur levels in plants to identify how any responses may relate to deficiency levels (previous work indicates this as >250ppm) A limited survey of sulphur levels in crops will be used to assist in identifying where responses may be most likely to occur. This information will be used in conjunction with sulphur deposition maps to further improved advice in this area.

Latest Report

2019 report

Outcomes / Key Message For Growers And Industry

Four sites were unidentified where there was potential for sulphur deficiencies. This included light sandy loam, thin Lincolnshire brash and sandy clay loam soil types. None of the sites had organic manures applied to them.

There were no effects of sulphur treatments on yield and sugar content measured in 2018 on either site.

Drought affected all the sites, resulting in range of canopy yellowing, necrosis and leaf senescence. It was not therefore possible to assess visual symptoms of sulphur deficiency and measure plant tissue sulphur levels.