Millions of hectares of arable land are lost each year because of land degradation and desertification, which have developed into serious worldwide environmental catastrophes. Global biodiversity and food security are seriously threatened by this ecological degradation, especially in desert areas where traditional replanting attempts are frequently rejected by harsh weather and hazardous terrain. The problem is particularly severe in the Kingdom of Saudi Arabia, where degradation currently affects more than 20 million hectares. It is imperative to transition from manual work to autonomous technological solutions that can function in situations that are frequently dangerous or inaccessible to humans in order to meet the ambitious restoration targets set by the Saudi Green Initiative (SGI). This research presents the design and development of "Terrix," an innovative autonomous planting robot engineered specifically for the complexities of unstructured desert landscapes. The system’s architecture is built upon three primary technological pillars. First,A durable 4-wheel rocker-suspension system ensures the mechanical stability required to traverse steep inclines and shifting sand dunes while maintaining the platform's equilibrium. Second, the research introduces a sophisticated GPS-independent localization framework. By utilizing a high-precision trilateration method, the robot achieves a sub-5cm level of accuracy, ensuring reliable navigation in remote areas where satellite signals may be inconsistent or unavailable. Lastly, the system has a Multi-Purpose Modular Extension System that turns the robot from a specialized seed-planter into a flexible ecological platform that can monitor soil health in real time and apply pesticides.F Field evaluations and experimental testing demonstrate that the Terrix system offers a 350% increase in planting productivity compared to conventional manual methods. Furthermore, the robot’s ability to maintain high precision under extreme heat and irregular topography underscores its potential for large-scale deployment. The findings suggest that integrating advanced robotic mobility with localized high-precision navigation provides a scalable and sustainable pathway for ecosystem restoration. Ultimately, the Terrix project serves as a technical blueprint for the future of environmental engineering, proving that autonomous systems can play a decisive role in combating climate change and reclaiming the world’s most vulnerable landscapes.