A marker may often be combined with the roller to good advantage, as in Fig. 113. Ropes are secured about the cylinder at proper intervals, and these mark the rows. Knots may be placed in the ropes to indicate the places where plants are to be set or seeds dropped. An extension of the same idea is seen in Fig. 114, which shows iron or wooden pegs that make holes in which very small plants may be set. An L-shaped rod projects at one side to mark the place of the next row.
In most cases the best and most expeditious method of marking out the garden is by the use of the garden line, which is secured to a reel (Fig. 96), but various other devices are often useful. For very small beds, drills or furrows may be made by a simple marking-stick (Fig. 115). A handy marker is shown in Fig. 116. A marker can be rigged to a wheel-barrow, as in Fig. 117. A rod is secured underneath the front truss, and from its end an adjustable trailer, B, is hung. The wheel of the barrow marks the row, and the trailer indicates the place of the next row, thereby keeping the rows parallel. A hand sled-marker is shown in Fig. 118, and a similar device may be secured to the frame of a sulky cultivator (Fig. 119) or other wheel tool. A good adjustable sled-marker is outlined in Fig. 120.
Two problems are involved in the fertilizing of the land: the direct addition of plant-food, and the improvement of the physical structure of the soil. The latter office is often the more important.
Lands that, on the one hand, are very hard and solid, with a tendency to bake, and, on the other, that are loose and leachy, are very greatly benefited by the addition of organic matter. When this organic matter—as animal and plant remains—decays and becomes thoroughly incorporated with the soil, it forms what is called humus. The addition of this humus makes the land mellow, friable, retentive of moisture, and promotes the general chemical activities of the soil. It also puts the soil in the best physical condition for the comfort and well-being of the plants. Very many of the lands that are said to be exhausted of plant-food still contain enough potash, phosphoric acid, and lime, and other fertilizing elements, to produce good crops; but they have been greatly injured in their physical condition by long-continued cropping, injudicious tillage, and the withholding of vegetable matter. A part of the marked results secured from the plowing under of clover is due to the incorporation of vegetable matter, wholly aside from the addition of fertilizing material; and this is emphatically true of clover because its deep-growing roots penetrate and break up the subsoil.