Novel carbon capture-based organo-mineral fertilisers show comparable yields and impacts on soil health to mineral fertiliser across two cereal crop field trials in Eastern England

Abstract

Context: Whilst mineral fertiliser is required to meet nearly 50% of global crop demand, its production is energy intensive and contributes close to 2% of the global emissions of greenhouse gases.

Objective: The aim of this study is to evaluate the efficacy of a novel fertiliser to meet crop demand and its impacts on soil health. This novel fertiliser incorporates point source carbon dioxide captured into organic matter balanced with mineral fertiliser. It is hypothesised that this carbon capture-based organo-mineral fertiliser (CCOMF) will mineralise and release nutrients adequate to meet demand of cereal crops.

Methods: Two field trials were conducted to evaluate the performance of CCOMF on winter wheat and winter barley. Each field trial compared three concentrations of CCOMF (5% N, 10% N, and 15% N) to a conventional mineral fertiliser treatment and an unfertilised control. Each fertiliser treatment was applied at the recommended application rate for the crops (270 kg/ha N and 180 kg/ha N, for winter wheat and winter barley, respectively). Each field trial included three additional application rates for each fertiliser treatment of 50% less, 50% more, and double the recommended rate in order to obtain a yield response curve. This totalled 160 experimental plots (2 field sites, 5 fertiliser treatments, 4 doses, with 4 replicates). All treatments were organised into a randomised block design with 4 replicates in both sites. The impact of the fertilisers on yield, soil nutrients, and root development were established by comparing baseline soil analysis and root measurements taken before the first application of fertiliser to samples taken at harvest.

Results: The results showed that the CCOMFs produced winter wheat and winter barley yields (7.49 ± 0.74 t/ha and 5.85 ± 0.29 t/ha, respectively for the 10% N) comparable to those produced following mineral fertilisers (7.40 ± 0.50 t/ha and 5.35 ± 0.16 t/ha, respectively). There was no significant fertiliser impact on soil organic carbon, microbial biomass, or pH. In terms of nutrients, there was also no significant difference in residual concentrations. There was also no significant difference in root development between the treatments.

Conclusion: This study showed that CCOMFs are a promising alternative to conventional mineral fertilisers as they produce comparable yields with no additional negative impacts in the short term.

Implications: This study is the first of its kind in a field context showing feasibility of using carbon capture technology to formulate sustainable fertilisers adopting a circular economy approach.