Zaï

{{short description|Sahelian farming technique}}

{{Use dmy dates|date=February 2019}}

{{Expand Hungarian|Zaï|topic=sci|date=March 2023}}

File:Zaï farming technique (cropped).png

File:Zai in Batodi.webm, Niger]]

Zaï or tassa is a farming technique of digging pits in less permeable soil to catch water and concentrate compost.{{cite web |url=http://www.unep.or.jp/ietc/publications/techpublications/techpub-8a/zay.asp |title=Sourcebook of Alternative Technologies for Freshwater Augumentation in Africa |publisher=United Nations Environment Programme |access-date=11 December 2016 |archive-url=https://web.archive.org/web/20030326054244/http://www.unep.or.jp/ietc/publications/techpublications/techpub-8a/zay.asp |archive-date=26 March 2003}} The pits are between {{convert|15|and|50|cm|ft|sigfig=1}} across and around {{convert|5|to|15|cm|sigfig=1}} deep, spaced approximately {{convert|80|cm|ft|sigfig=1}} apart. The technique is traditionally used in western Sahel (Burkina Faso,{{cite web |title=Zai: Reversing Desertification – Soil International |url=https://soilinternational.com/zai/ |website=soilinternational.com |access-date=9 June 2024}} Niger, Mali) to restore degraded drylands and increase soil fertility.

Zaï holes were reintroduced since the 1980s by Yacouba Sawadogo, a farmer from Burkina Faso, who introduced the innovation of filling them with manure and compost to provide plant nutrients. The manure attracts termites, whose tunnels help further break up the soil. He also slightly increased the size of the holes over the traditional models. Zaï holes help by improving the yields of trees, sorghum, and millet by up to 500 percent.{{cite web |url=http://www.ifpri.org/publication/emergence-and-spreading-improved-traditional-soil-and-water-conservation-practice-burkin |title=The emergence and spreading of an improved traditional soil and water conservation practice in Burkina Faso |last1=Kaboré |first1=Daniel |last2=Reij |first2=Chris |year=2004 |publisher=International Food Policy Research Institute |archive-url=https://web.archive.org/web/20130108085325/http://www.ifpri.org/publication/emergence-and-spreading-improved-traditional-soil-and-water-conservation-practice-burkin |archive-date=8 January 2013 |url-status=dead}}

As an alternative to the zaï technique, some agricultural engineers suggest using a diking technique, especially in the case of very light soils.{{cite web |url=http://elib.suub.uni-bremen.de/edocs/00102919-1.pdf |title=Wasser ernten, Bäume schützen: Ernährungssicherung im Sahel |last1=Bass |first1=Hans-Heinrich |last2=von Freyhold |first2=Klaus |last3=Weisskoeppel |first3=Cordula |year=2013 |language=German |pages=46–48 |access-date=11 December 2016}}