Fertilizer addiction: implications for sustainable agriculture

To meet increased demand for food spurred by a larger and richer population, FAO projects that global agricultural production in 2050 will be 60 percent
higher than in 2005/07. Most of this increase in production over the next 40 years is expected to derive from improved yields (FAO 2012).

This brief presents a model-based examination of short and long-term trade-offs between two alternate agricultural paradigms: industrial agriculture
dependent on agrochemicals, fuel-based mechanization and irrigation operations, etc.; and sustainable, low external input agriculture centered on preservation of soil organic matter (Pedercini, Zullich and Dianati 2014a, 2014b). The associated policy implications for long-term sustainability in agricultural yields, and food security, are huge.

Read the full brief below and share your comments.

1 thought on “Fertilizer addiction: implications for sustainable agriculture

  1. Maria Antip

    Dear all,
    I am writing on behalf of the International Fertilizer Industry Association (IFA) to address a few issues and inaccuracies regarding so-called “fertilizer addiction” in the GSDR Brief.
    First of all, I would like to thank the authors and The Millenium Institute for dedicating their attention to the important role of fertilizer and balanced fertilization within an integrated soil fertility management framework, given the population projections and the need to sharply yet sustainably increase agricultural productivity by 2050.
    One important point to clarify in our view is that the claims in the brief are based on a modelling exercise and not on actual measurements and data collection. Measurements based on scientific experiments all over the world show that soil organic matter (SOM) content can be maintained or increased with adequate and balanced use of mineral fertilizers.
    Various studies have shown that SOM changes with cultivation and fertilizer nitrogen (N) inputs; this is an issue that has become increasingly controversial. Normally, SOM decreases with cultivation where no N fertilization is practiced, but it may increase with application of N fertilizer. Potentially, fertilizer N application affects SOM via two mechanisms: (i) it may increase SOM by promoting plant growth and thereby increasing the amount of litter and root biomass added to soil compared with soil not receiving N, and (ii) it may accelerate SOM loss through decay or microbial transformation of litter (leaves, straw, manures, etc.) and indigenous forms of organic carbon (C) already in the soil (Recous et al., 1995).
    On the basis of the results of 45 long-term experiments ranging from 7 to 136 years in duration and mostly from temperate regions, Glendining and Powlson (1995) showed that long-term applications of N fertilizer increased total soil organic N compared with treatments receiving no fertilizer N at 84% of the sites studied.
    Another point that could be better emphasized in the brief is that the starting point of this modelling exercise is conditions of natural grassland, not cropland. Reaching a new soil organic matter equilibrium is expected following such significant land use changes.
    Out of the three scenarios considered in the brief, the third one is the most sound but the reference to “integrated” fertilization should also include N fertilizer. Scenario iii + N fertilizer, i.e. a scenario integrating organic and mineral nutrient sources over the long term following nutrient stewardship principles (http://www.ipni.net/4R) should have been considered by the author, this scenario being in our view the most sustainable one.
    The International Fertilizer Industry Association is open to providing further information about fertilizers and best management practices to any and all stakeholders and interested parties in this debate.


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