Wasting food
Some vegetables cannot be sold, because they do not have a normed form, or the expiry date of some products is over, although they are still eatable. The Good Food in Germany does sell these groceries on a low-cost basis:
https://www.the-good-food.de

Querfeld in Berlin does the same offering a network of online order possibilities:
https://querfeld.bio





Urban Gardening
Incredible eadible is a network of towns, which aim at producing all the food they need locally. It leads to more social cohesion, strengthens the local food industry and shall also have educational aspects: 
https://www.incredibleedible.org.uk





Agriculture
Technology for Social Impact in Bangladesh provides services for soil testing and apps to improve soil and harvest management (fertilizer applications, best seed options,...):
https://tsi.com.bd

AgriShare is an App in order to connect farmers in Africa, who need farm ressources like tractors and who want to share ones:
https://www.agrishare.app

SEKEM in Egypt is a pioneer in organic agriculture and also active in education, labeling ("economyoflove") and research:
https://sekem.com/en/

Savethegrain is a German social business using their innovation "solar dryer" to dry the products of African farmers in order to make them more durable:
https://savethegrain.de/de/solardryer





Reforestation/ Restoring landscapes
The "Farmer Managed Natural Regeneration" method by Tony Rinaudo is one of the most effective ways to reforest dry soil (often used in Africa).
https://www.youtube.com/watch?v=ltyAaebpyTg

Greener.land is an online tool for landscape restoration:
https://www.greener.land

"Justdiggit" uses different approaches to restorate landscapes in Africa. For examples, holes are digged in order to reuse rainwater:
https://justdiggit.org




Nutrition for children
Grameen Danone produces fortified yogurt and biscuits in Bangladesh:
https://www.grameendanone.net




​Water 
http://sbi.ibk.me/6.html