NOVELTY - Agricultural waste digester and biogas generation system (I) comprises: water vessel (14) containing water; buoyant digester assembly (12) placed within the water vessel and having cylindrical body, hollow interior (20), center axis (22), and many wheel segments within the interior of the digester assembly; gas conduit extending from the interior of the digester assembly to power generation device (16); water vessel containing water to support the weight of the entire digester assembly; and digester stabilizer assembly rotatably supporting the cylindrical body within the water vessel.    USE - The system is useful as agricultural waste digester for biogas generation.    ADVANTAGE - The system utilizes the force of trapped gas produced by the digester to further mechanically agitate the agricultural waste without additional energy added to the system such that the rising gas creates a mechanical force which induces agitation, thus the system is simple, effective, scalable and inexpensive.    DETAILED DESCRIPTION - Agricultural waste digester and biogas generation system (I) comprises: water vessel (14) containing water; buoyant digester assembly (12) placed within the water vessel and having cylindrical body, hollow interior (20), center axis (22), and many wheel segments within the interior of the digester assembly; gas conduit extending from the interior of the digester assembly to a power generation device (16); water vessel containing water to support the weight of the entire digester assembly; and digester stabilizer assembly rotatably supporting the cylindrical body within the water vessel such that a horizontal orientation of the cylindrical body and the center axis of the cylindrical body is maintained, where the wheel segments are fixedly attached to the cylindrical body such that the wheel segments extend radially within the interior of the cylindrical body and have an arcuate, contoured surface area that restricts biogas movement within the digester assembly and trap rising biogas under the segments such that an ascending force of the trapped biogas rotates the cylindrical body about the center axis of the cylindrical body and produces an induced agitation of agricultural waste. INDEPENDENT CLAIMS are also included for:    (1) generating biogas from agricultural waste comprising: providing the buoyant digester assembly; providing the gas conduit; providing water vessel containing heated water; placing the digester into the warmed water of the water vessel; supplying the interior of the digester with agricultural waste to generate biological gas; and operating the power generation device with biological gas generated by the digester assembly;    (2) an agricultural waste digester and biogas generation system comprising: water vessel containing water; the buoyant digester assembly, where the cylindrical body is enclosed at first end by a first cover having a hub and is enclosed at second end by a second cover having a hub; the gas conduit; bushing assembly included within the hub of the first cover rotatably supporting the gas conduit; and a pair of digester stabilizer assemblies, each rotatably supporting the first and second hubs of the cylindrical body within the water vessel such that a horizontal orientation of the cylindrical body and the center axis of the cylindrical body is maintained, where the wheel segments are fixedly attached to the cylindrical body such that the wheel segments extend radially within the interior of the cylindrical body and have an arcuate, contoured surface area that restricts biogas movement within the digester assembly and trap rising biogas under the segments such that an ascending force of the trapped biogas rotates the cylindrical body about the center axis of the cylindrical body and produces an induced agitation of agricultural waste; and    (3) an agricultural waste digester and biogas generation system (II) comprising: water vessel containing water; a digester assembly placed within the water vessel and having cylindrical body, hollow interior, center axis, and many wheel segments within the interior of the digester assembly; and the gas conduit, where the wheel segments are comprised of a series of segments, each having an arcuate, contoured surface area, and each extending within the interior of the cylindrical body from an outer edge fixedly attached to the cylindrical body to an inner edge extending freely within the hollow interior adjacent the center axis of the cylindrical body such that rising biogas is trapped under the wheel segments and an ascending force of the trapped biogas under the wheel segments rotates the cylindrical body about the center axis of the cylindrical body and produces an induced agitation of agricultural waste.    DESCRIPTION OF DRAWING(S) - The figure shows side cross sectional view of the digester assembly of the agricultural waste digester and biogas generation system.    Digester assembly (12)    Water vessel (14)    Power generation device (16)    Hollow interior of digester assembly (20)    Center axis of digester assembly (22)