received by the International Bureau on 03 July 2019 (03.07.2019)

1. A ground soil loosening device including an elongated tubular hub having a series of circumferenti§lly spaced apart blades extending all around said tubular hub, each blade in said series having an inner end affixed to said hub and extending along the length of said hub and projecting radially out from a perimeter of said hub, each of said blades having an outer portion continuously curving circumferentially in the same direction towards an outer portion of a next adjacent blade in said series, said blades formed from a resiliently deflectable material so that said outer portion of each of said blades is resiliently deflected radially inwardly by a seasonal increase of ground soil pressure exterted thereon when said device is buried in said ground soil to cause said outer portions of said blades to be moved radially inwardly and to thereafter move back radially out when said ground soil pressure decreases,

2. The ground soil loosening device according to claim 1 wherein said hub has a lengthwise slot extending through a tubular wall of said hub defining said perimeter thereof to allow said tubular wall of said hub to also be resiliently moved radially inwardly by an increase in ground soil pressure.

3. The ground soil loosening device according to claim 1 wherein said resiliently bendable material comprises polyethylene plastic.

4. The ground soil loosening device according to claim 1 wherein a cap is installed closing off said hub and blades of said device at a top end of said device.

5. The ground soil loosening device according to claim 2 wherein said blades axe thinner than said wall of said hub,

6. The ground soil loosening device according to claim 1 wherein said devices are approximately 43 cm long.

7. The ground soil loosening device according to claim 1 wherein there are a total of eighteen of said curved blades projecting from said perimeter of said hub,

8. A method of loosening compacted ground soil comprising installing a plurality of ground soil loosening devices according to claim 1 into ground soil to be loosened by forming an array of vertically extending holes formed in the ground soil to be loosened and inserting each of said devices in a respective hole and thereafter completely covering an upper end of each device.

9. The method of claim 8 wherein said array is in a grid form with said ground soil loosening devices arranged in rows.

10. The method according to claim 8 wherein said ground soil loosening devices are spaced apart a distance of approximately 51 cm.

11. The method according to claim 8 wherein each of said ground soil loosening devices are about 43 cm long.

12. The method according to claim 8 including providing a total of eighteen of said blades in each ground soil loosening device.

13. The method according to claim 8 including capping a top end of each ground soil loosening device.

14. The ground soil loosening device according to claim 1 wherein said outer portions of each blade extends circumferentially past said inner end of a next adjacent blade in said series of blades.