An agricultural device includes a number of row units that each includes a seed furrow opener that creates a furrow in the soil for seed placement. Each row unit is mounted to a toolbar of the device by means of a four-bar linkage which allows each row unit to move vertically to adjust to the contour of the soil independently of the other row units on the same toolbar. The four-bar linkages include one or more springs which work to transfer weight from the toolbar to the row unit. An actuator varies the tension in the spring thereby adjusting the down or up force applied to the row unit.

An injection apparatus for treating soil adjacent a structure has a handle and a manifold head attached to the handle. The manifold head has at least one inlet and at least one internal passage in fluid communication with the at least one inlet. A high pressure nozzle is in fluid communication with the at least one internal passage in the manifold head and is adapted for emitting a discharge stream of pesticide for subsurface injection of the pesticide. A low pressure nozzle is provided for applying a pesticide to the surface. The manifold head has a substantially planar contact member having a contact surface for contact with the surface beneath which the pesticide is applied. The contact member has a first opening in the contact surface in fluid communication with the high pressure nozzle and a second opening in the contact surface in fluid communication with the low pressure nozzle.

An agricultural device includes a number of row units that each includes a seed furrow opener that creates a furrow in the soil for seed placement. Each row unit is mounted to a toolbar of the device by way of a four-bar linkage which allows each row unit to move vertically to adjust to the contour of the soil independently of the other row units on the same toolbar. The four-bar linkages include one or more springs which work to transfer weight from the toolbar to the row unit. An actuator varies the tension in the spring thereby adjusting the down or up force applied to the row unit.

Agricultural devices, row unit adjustment systems, and methods of adjusting a depth of a furrow are provided. In some aspects, an agricultural device is adapted to plant seeds and includes a frame, a furrow opener coupled to the frame and adapted to cut a furrow including a depth, a sensor adapted to sense a characteristic associated with planting seeds and generate a signal associated with the sensed characteristic, and a processing unit receiving the signal associated with the sensed characteristic. The depth of the furrow is adjustable based on the signal associated with the sensed characteristic. Such characteristic may be a characteristic of the soil, a force applied to the agricultural device, or a position of a portion of the agricultural device.