Water in Plain Sight

This engaging and inspiring read is based on a number of case histories involving water innovators from around the world - people who are working with the water cycle to restore and enhance landscapes and maintain moisture in the soil. One of these is Allan Savory with his ideas on holistic management involving land stewardship and restoration. One of his key insights is that grassland and grazing animals have co-evolved, and a key element is plant litter keeping water in the soil so as to maintain not only the water, but also carbon and mineral cycles. As the author observes, 'when soil is left bare, water evaporates, carbon oxidises and microorganisms die. The ground becomes a hot plate and can no longer sustain life. Water runs off the land instead of sinking into it.' (p. 25) This represents water going sideways rather than up as evaporation, down into aquifers or being held in the soil (p. 42). The case studies in the book enable readers to realise not only the implications of an intensified water cycle and the benefits of slowing this down through vegetation and tree cover, but more generally the extent to which water influences climate.

All this makes one appreciate the importance of water infrastructure, and there is an extraordinary account of the importance of beavers in this respect as 'keystone ecosystem engineers' - unfortunately the numbers have decreased from 200 to 10 million, but scientists are now realising what an important role they play. As we know, irrigation plays a major role in farming today, yet it is also drawing down deep aquifers. Moreover, the minerals in this water are important and irrigation methods are associated with nitrate run-off. The author gives an encouraging example of David Johnson using compost low in salinity and rich in microbial life to produce not only a staggering plant growth, but also an astounding 70% of the carbon produced by the plants is sent back into the soil. Rather than compromising ecological integrity in order to feed the world - a depressingly frequent refrain - we learn that 'the synergies between plants and soil microbial communities in advanced, highly fertile soil allow for the capture of the equivalent of a year's anthropogenic CO2 emissions on less than 11% of the world's cropland.' This is a simple matter of allying with plant-soil-microbe dynamics to make the most of sunlight, water and nutrients, i.e. maximising photosynthesis. As many other thinkers are also arguing, we need much more integrated thinking with an overall goal not just of sustainability, but of restoration based on the insight that 'climate change, biodiversity loss and desertification are all facets of the same problem: that the world's carbon, water and energy cycles are out of whack.' (p. 217)