From the summary of the paper, to myself it appears its authors seem to have a view that the majority of farm waste isn't recycled and go so far as to include

From the summary of the paper, to myself it appears its authors seem to have a view that the majority of farm waste isn't recycled and go so far as to include grazing livestock in open fields, which as far as I know, most grazing livestock poop where they feed and yes sometimes the farmer /workers needs to use machinery (eg using harrows or a bar) to spread out any heavier accumulations. That aside, from its summary, the paper seems to miss implications of heavy metal loading [1] [2] [3] in human waste and the summary doesn't mention what level of treatment processing they had determined to recycle. Typical modern waste management employs breaking the waste down with bacteria and produces a significant amount of methane in the process and are left with biosolids. [4] Such biosolids are very valuable to a farmer not for the NPK nutrients but supplying carbon for soil improvement. Higher carbon soils seem to have better water holding capabilities [5][6] along with a much better soil microbiome which is beneficial for plant growth. [1] https://journal.gnest.org/system/files/2024-08/gnest_06247_final.pdf https://journal.gnest.org/system/files/2024-08/gnest_06247_f... [pdf] [2] https://set.adelaide.edu.au/fertiliser/system/files/media/documents/2020-01/pres-heavy-metals-in-agriculture-with-a-focus-on-cadmium-ecuador.pdf https://set.adelaide.edu.au/fertiliser/system/files/media/do... [pdf] [3] https://www.fao.org/fileadmin/user_upload/GSP/INSOP/INSOP_2meeting_june23/Presentations/Item_2_Cd_fertilizers_Saynes.pdf https://www.fao.org/fileadmin/user_upload/GSP/INSOP/INSOP_2m... [pdf] [4] https://modernfarmer.com/2014/07/stink-human-poop-fertilizer/ https://modernfarmer.com/2014/07/stink-human-poop-fertilizer... [5] https://www.abc.net.au/news/2018-07-07/sydney-waste-turned-biosolids-fertiliser-helps-nsw-drought-soil/9931664 https://www.abc.net.au/news/2018-07-07/sydney-waste-turned-b... [6] https://www.abc.net.au/news/rural/2022-03-19/farmers-fertilising-cotton-with-treated-human-sewage/100920292 https://www.abc.net.au/news/rural/2022-03-19/farmers-fertili...