The careful application of the principles of soil treatment discussed in the preceding chapters will leave the soil in good condition for sowing, either in the fall or spring. Nevertheless, though proper dry-farming insures a first-class seed-bed, the problem of sowing is one of the most difficult in the successful production of crops without irrigation. This is chiefly due to the difficulty of choosing, under somewhat rainless conditions, a time for sowing that will insure rapid and complete germination and the establishmcnt of a root system capable of producing good plants. In some respects fewer definite, reliable principles can.