Abstract: A drive apparatus has a first and second shaft rotatably mounted on the agricultural fertilizer implement. A drive wheel is fixed to the first shaft and an output wheel fixed to the second shaft. There are a plurality of wheels coupled to the first shaft and a plurality of wheels of varying sized fixed to the second shaft. A flexible connecting means is trained between a pair of selected wheels on the first and second shafts. A drive means rotates the drive wheel. A connecting means couples output wheel to the metering device. An engaging means is coupled to each of the plurality of wheels located on the first shaft coupling the selected wheel on the first shaft with the first shaft so that the wheel will rotate with the first shaft. There is also a control means that allows a user to selectively activate one of the engaging means located on the first shaft. When one of the engaging means is activated, one of the plurality of wheels is coupled to the first shaft and begins to rotate with the first shaft.

Abstract: An optical soil sensor for mobilized measurements of in-situ soil characteristics has a shank assembly, which creates a furrow in which a soil sample is exposed, and a window plate assembly including a window through which emitted and reflected light pass. The sensor window, formed of a hard and durable material, is positioned in intimate contact with the soil sample as the sensor moves across the ground or field and is continually scoured by the soil to greatly reduce or eliminate window buildup and contamination. The intimate contact between the window and soil also eliminates the sample distance or air gap through which light must pass, thereby reducing measurement distortion and error. The soil sensor provides a structural platform compatible with a wide variety of light sources, light detectors, signal conditioners, and other devices.