Four years of testing have shown that chemicals incorporated in the soil as pre-emergence treatments give satisfactory control of watergrass and many broad-leaved weeds in corn growing in the organic soils of the Sacramento-San Joaquin Delta. Eptam, Tillam, atrazine and Randox-T are all potentially useful chemicals. The method of incorporation in the soil and the amount of soil moisture available appear as important as the chemical selected. The least soluble materials are most handicapped by low soil moisture and inadequate mixing in the soil. The remaining task involves application equipment and fitting the use of these chemicals into the farming enterprise.