JIM CLARE / Nests of Guanay cormorants, (Phalacrocorax bougainvilliiorum) after breeding has finished, shows build-up of guano around the nest. The colonies are strictly protected and the guano will be harvested...

JIM CLARE / Nest of Guanay cormorants, (Phalacrocorax bougainvilliiorum), after breeding has finished, shows build-up of guano around the nest. The colonies are strictly protected and the guano will be harvested...

JIM CLARE / Nests of Guanay cormorants, (Phalacrocorax bougainvilliiorum), after breeding has finished, shows build-up of guano around the nest. The colonies are strictly protected and the guano will be harvested...

JIM CLARE / Nests of Guanay cormorants, (Phalacrocorax bougainvilliiorum), after breeding has finished, shows build-up of guano around the nest. The colonies are strictly protected and the guano will be harvested...

David Woodfall / Tractor spreading fertilizer on machair to improve it for agricultural production by crofters, North Uist, Scotland, UK, June.

David Woodfall / Nitrogen fertilzer in bags, ready for application to machair, coastal grazing habitat. Outer Hebrides. Scotland, UK, June.

David Woodfall / Manure, mixed with straw ready to spread on machair, sandy farmland. North Uist, Scotland, UK, June.

David Woodfall / Strips of cultivated Machair - bare sand with added seaweed to act as fertilizer.Uist, Outer Hebrides, Scotland, UK, June.

Ashley Cooper / Subsistence farming in the Annapurna Himalayas in Nepal. The terracing has been developed over centuries to farm this steep mountain land.

Ashley Cooper / Cow pat in a field.

Matthew Maran / Slurry from the Clinton Devon Estate's Home Farm dairy, stored in 20,000-cubic-metre slurry lagoon until it is needed for fertiliser on the farm. Devon, England, UK, May.

Matthew Maran / Farmer spreading slurry on organic dairy land. Slurry collected from the cattle herd is recycled as natural fertiliser, Devon, England, UK, July.