An investigation into the potential of glacial flour as a novel soil treatment for crops

Abstract

There is an urgent need to address future global food production, enhancing crop
yields to meet demands whilst ensuring nutritional value. However, increasing agricultural
sustainability and resilience has become challenging due to climate warming. One potential
method of improving soil fertility is the use of crushed rock, however this practice is limited
by production costs. Glaciers act as natural ‘sediment factories’ known to finely crush
underlying bedrock to fine particulates that are exported downstream in annual meltwaters.
Only recently has the potential of glacial flour as an alternative to crushed rock for farming
been considered a possibility. A global overview of glacial flour nutrient and trace element
content from eleven geologically different glaciers was evaluated, highlighting the
geochemical composition with the greatest agricultural potential. Two contrasting glacial
flours, Chhota Shigri, Northwest Hindu Kush Himalaya (mixed bedrock granitic-gneiss with
minor sedimentary bands) and Sólheimajökull glacier, Southwest Iceland (igneous mafic
volcanic basalts) were investigated as potential soil fertility treatments for leguminous crops,
soybeans (Glycine max. var Black jet). Himalaya and Icelandic glacial flour increased crop
yields 85 % and 135 % above the control, whilst improved plant health, legume N-fixation
capacity and nutritional value. Nutritional value of the soybeans is determined by trace
element availability, which in turn is driven by the underlying geology beneath the glacier.
Glacial flour enriched soybeans in beneficial dietary nutrients (calcium, iron and zinc) which
suggests potential application as a micronutrient treatment to target soil micronutrient
depletion. However, it is also demonstrated that glacial flours which contain toxic trace
elements, such as Chhota Shigri flour containing arsenic, can result in toxic bioaccumulation
in crops. Overall, the results indicate that glacial flour has potential to act as a novel soil
treatment and micronutrient fertiliser but requires geochemically screening to avoid toxic
elements.

Date of Award	6 Dec 2022
Original language	English
Awarding Institution	University of Bristol
Supervisor	Alistair Hetherington (Supervisor), Jemma L Wadham (Supervisor) & Rory J Bingham (Supervisor)