FarmOS
farmOS is a web-based application for farm management and planning. It is built on Drupal, which makes it modular, extensible, and secure. Openlayers is used for mapping and geodata manipulation.
Check the article “Installing FarmOS on Linux/Ubuntu Desktop” if you want to try the FarmOS software by your own. The source code is also available at github repo.
AgroSense
AgroSense is a free and open source farm management and decision making software. The source code is available at bitbucket & check the limetri website. You can also download the Windows & Linux executables of this software from website atdownloads page
OpenATK
Open Ag Toolkit ( OpenATK ) makes it easier to manage farms by improving the way farmers are able to collect and use information. written some simple, free, open-source mobile apps that sync across everyone on a farm through existing cloud services like Trello and Dropbox. You can find the source codes for these apps at github , also you can visit OpenATK website.