soil crusting has long been recog- nized as an obstacle to seedling emergence. This is particularly true with small-sized seed. Soil crusts will often result after a soil is wetted by rain or sprinkling and then dried. Seeds planted during the winter or spring months in much of California stand a very good chance of Ileinp rained on, allowing a crust to form above the seed before emergence. Overplanting the number of seeds required ih the customary way to assure an adequate stand of row crops under these conditions. However, mechanization of many row crops depends in part on planting the crop to a stand, or at least spacing the individual plants so they can lw mechanically thinned.

Cooperators in these trials also included R. Griffin, Extension Agricultural Engineering Technologist; W. Chancellor, Associate Agricultural Engineer; W. Flocker, Associate Olericulturist; M. B. Zahara, Associate Specialist in Vegetable Crops, University of California, Davis; and James Lugg, Bruce Church Company, Salinas.