1. AN AGRICULTURAL KIT OF SELECTIVELY AND UNIVERSELLY USABLE COMPONENTS FOR ASSEMBLING A SOIL WORKING IMPLEMENT HAVING SELECTED STRUCTURAL AND FUNCTIONAL CHARACTERISTICS, SAID KIT INCLUDING A BASIC FRAME ADAPTED FOR CONNECTION TO A TRACTOR, SAID FRAME HAVING AT LEAST ONE CROSS-MEMBER OF A POLYGONAL CROSS-SECTION, A TOOL CARRIER, A POLYGONAL SOCKET PROVIDED ON SAID TOOL CARRIER AND HAVING ONE OPEN SIDE, SAID SOCKET COMPLEMENTALLY EMBRACING SAID POLYGONAL CROSS-MEMBER OF SAID FRAME AND SAID OPEN SIDE OF THE SOCKET PERMITTING THE ASSOCIATED TOOL CARRIER TO BE QUICKLY DETACHED FROM AND ATTACHED TO SAID CROSS MEMBER, CAM-ACTUATED RELEASABLE LINKAGE MEANS FOR CLOSING THE OPEN SIDE OF SAID SOCKET WHEREBY TO LOCK THE SAME IN A PREDETERMINED FIXED POSITION ON SAID CROSS MEMBER, AND A SOIL WORKING TOOL REMOVABLY CONNECTED TO SAID TOOL CARRIER.