# Onions!

**URL:** <https://community.pix4d.com/t/onions/34008>\
**Category:** Agriculture\
**Created:** [August 14, 2025, 3:37pm UTC](https://community.pix4d.com/t/onions/34008 "2025-08-14T15:37:03Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![chris\_davies](https://avatars.discourse-cdn.com/v4/letter/c/f19dbf/32.png) [@chris\_davies](https://community.pix4d.com/u/chris_davies)\
**Post date:** [August 14, 2025, 3:37pm UTC](https://community.pix4d.com/t/onions/34008/1 "2025-08-14T15:37:03Z")

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We’ve got a field that has onions. NDVI isn’t very helpful because there is a lot of soil and not so much crop. I’ve been researching and there is an index called SAVI (Soil Adjusted Vegetation Index) which disregards the soil in the calculations. I can’t see this as an option in Pix4D Fields, has anyone got any suggestions?

Many thanks  
Chris

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**Author:** ![Jose.Arnaudo](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/jose.arnaudo/32/5966_2.png) [@Jose.Arnaudo](https://community.pix4d.com/u/Jose.Arnaudo)\
**Post date:** [August 18, 2025, 9:25am UTC](https://community.pix4d.com/t/onions/34008/2 "2025-08-18T09:25:06Z")

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Hi, Osavi formula is (1+0.16)\*((nir-red)/(nir+red+0.16)) you can insert it by visiting “Create custom index”

 ![image](https://global.discourse-cdn.com/pix4d/original/2X/1/134fc9c92368ffa8b245232efb0fd6fb75a44187.png)

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**Author:** ![chris\_davies](https://avatars.discourse-cdn.com/v4/letter/c/f19dbf/32.png) [@chris\_davies](https://community.pix4d.com/u/chris_davies)\
**Post date:** [August 21, 2025, 9:43am UTC](https://community.pix4d.com/t/onions/34008/3 "2025-08-21T09:43:13Z")

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Amazing! Thank you so much. I’ll try that out now,

Many thanks, Chris