Preventing the growth of weeds and by checking losses by evaporation with a soil mulch.
TIME TO CULTIVATE
A seedling plant is easiest killed just as it has started into growth. The best time to kill a plant starting from an underground stem or a root is just as soon as it appears above the surface in active growth.
The best time to cultivate, then, to kill weeds is as soon as the weeds appear. At this time large numbers can be killed with the least of effort. Do not let them get to be a week or two old before getting after them.
In planting some crops the ground between the rows becomes trampled and compact. This results in active capillarity which brings water to the surface and it is lost by evaporation.
Every rainfall tends to beat the soil particles together and form a crust which enables the capillary water to climb to the surface and escape into the air. This loss by evaporation should be constantly watched for and the soil should be stirred and a mulch formed whenever it becomes compact or a crust is formed.
The proper time to cultivate, then, to save water is as soon as weeds appear or as soon as the surface of the soil becomes compact or crusted by trampling, by the beating of rain or from any other cause, whether the crop is up or not. The cultivation should start as soon after a rain as the soil is dry enough to work safely.
The surface soil should always be kept loose and open. The efficacy of the soil mulch depends on the thoroughness and frequency of the operation. It is particularly beneficial during long, dry periods. During such times it is not necessary to wait for a rain to compact the soil; keep the cultivators going, rain or no rain.
TOOLS FOR AFTER-CULTIVATION
The main objects of after-cultivation are to destroy weeds and to form a soil mulch for the purpose of controlling soil moisture. These ends are secured by shallow surface work. It is not necessary to go more than two or three inches deep. Deeper work will injure the roots of the crop. Therefore the proper tools for after-cultivation in the garden are the hoe and rake and for field work narrow-toothed harrows and cultivators or horse-hoes which stir the whole surface thoroughly to a moderate depth. These field tools are supplemented in some cases by the hand hoe, but over wide areas of country the hoe never enters the field.