The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia.
The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia.
Environ Int. 2021 Jan;146:106245. doi: 10.1016/j.envint.2020.106245. Epub 2020 Nov 5.
We use soils to provide 98.8% of our food, but we must ensure that the pressure we place on soils to provide this food in the short-term does not inadvertently push the Earth into a less hospitable state in the long-term. Using the planetary boundaries framework, we show that soils are a master variable for regulating critical Earth-system processes. Indeed, of the seven Earth-systems that have been quantified, soils play a critical and substantial role in changing the Earth-systems in at least two, either directly or indirectly, as well as smaller contributions for a further three. For the biogeochemical flows Earth-system process, soils contribute 66% of the total anthropogenic change for nitrogen and 38% for phosphorus, whilst for the land-system change Earth-system process, soils indirectly contribute 80% of global anthropogenic change. Furthermore, perturbations of soils contribute directly to 21% of climate change, 25% to ocean acidification, and 25% to stratospheric ozone depletion. We argue that urgent interventions are required to greatly improve soil management, especially for those Earth-system processes where the planetary boundary has already been exceeded and where soils make an important contribution, with this being for biogeochemical flows (both nitrogen and phosphorus), for climate change, and for land-system change. Of particular importance, it is noted that the highly inefficient use of N fertilizers results in release of excess N into the broader environment, contributes to climate change, and results in release of ozone-depleting substances. Furthermore, the use of soils for agricultural production results not only in land-system change, but also in the loss (mineralization) of organic matter with a concomitant release of CO contributing to both climate change and ocean acidification. Thus, there is a need to markedly improve the efficiency of fertilizer applications and to intensify usage of our most fertile soils in order to allow the restoration of degraded soils and limit further areal expansion of agriculture. Understanding, and acting upon, the role of soils is critical in ensuring that planetary boundaries are not transgressed, with no other single variable playing such a strategic role across all of the planetary boundaries.
我们利用土壤为 98.8%的食物提供养分，但我们必须确保，我们在短期内对土壤施加的压力不会在长期内无意间将地球推向一个不太宜居的状态。利用行星边界框架，我们表明土壤是调节关键地球系统过程的主要变量。事实上，在已经量化的七个地球系统中，土壤在至少两个系统中直接或间接地发生变化，或者在另外三个系统中发挥较小的作用，对地球系统起着关键和实质性的作用。对于地球生物化学流动系统过程，土壤对人类引起的氮变化的贡献占 66%，对磷变化的贡献占 38%；而对于土地系统变化地球系统过程，土壤间接造成了全球人为变化的 80%。此外，土壤的干扰直接导致了 21%的气候变化、25%的海洋酸化和 25%的平流层臭氧消耗。我们认为，迫切需要进行干预，以极大地改善土壤管理，特别是对于那些已经超过行星边界且土壤做出重要贡献的地球系统过程，这些过程包括生物地球化学流动（氮和磷）、气候变化和土地系统变化。特别需要指出的是，氮肥的低效使用会导致过量的氮释放到更广泛的环境中，从而导致气候变化，并导致消耗臭氧物质的释放。此外，农业生产对土壤的利用不仅导致土地系统的变化，而且导致有机质的损失（矿化），同时释放出 CO，这既导致气候变化，又导致海洋酸化。因此，需要显著提高肥料的使用效率，并加强对最肥沃土壤的利用，以恢复退化的土壤并限制农业进一步扩张。理解并采取行动，了解土壤的作用对于确保不超过行星边界至关重要，因为没有其他单一变量在所有行星边界中发挥如此战略作用。
