Researchers at the James Hutton Institute are working on a number of ways to tighten nutrient cycles.
This involves a combination of knowledge into how to reuse societies 'wastes' such as sewage effluent discharges as valuable nutrient resources, ways to make crop-soil systems smarter to maintain yields with declining inputs of chemical fertilisers, and how to minimise losses of nutrients from fields to waters via measures such as multifunctional buffer strips.
One aspect of this work is being explored by a soil phosphorus research group involving James Hutton Institute scientists with other UK and international colleagues. Our position paper on this work Recovering Phosphorus from Soil: A Root Solution? [1] was published in the journal Environmental Science and Technology 46, 1977–1978.
A conceptual model of the sizes, roles and accessibility of different soil phosphorus pools in relation to crop availability is shown above (figure 1).
Sizes of boxes and arrows depict the relative magnitudes of pools and pathways in P cycling. The average European fertiliser excess rate exceeding crop uptake is 12 kg P ha-1 year-1 and this excess P accumulates as stabilised inorganic orthophosphate and monoester P according to the following processes (numbered arrows).
We suggest that compensating for future declines in fertiliser P inputs without losing yields can be achieved by combining methods to increase agronomic P use efficiencies (in relation to letters).
Not one of these methods alone will be likely to succeed and a combined strategy is required.
Links:
[1] http://pubs.acs.org/doi/full/10.1021/es2044745
[2] https://www.hutton.ac.uk/sites/default/files/images/research/mcc/nutrient-cycle.jpg