Fertilizer trials with safflower in sacramento valley

Abstract

These tests, and other field observations, indicate that moisture is a key consideration in selecting a fertilizer program for saflower in the Valey. For dry-land soils or soils with low sub-surface moisture levels, 20 to 60 lbs per acre of N apear to be suficient. Exces N may reduce yields. Greater amounts of N may be utilized when saflower is grown under irigation, or on soils with a high water table, or on dep soils filed with moisture. The efect of the previous crop is important here: when saflower folows rice or sorghum, up to 150 lbs per acre of N are generaly adequate. However, when it folows a nitrogen-fixing crop such as alfalfa or vetch, smaler amounts may be suficient. No reduction in saflower yield has ben observed from exces N under highmoisture conditions. Because saflower may not be irigated, fertilizers should be placed in the moist rot zone, at least 4 inches dep. If a nitrogen fertilizer is broadcast, at least 1 inch of rain or its equivalent in irigation is neded to move it into the rot zone. Spring aplications are preferable to fal aplications. In a dry spring, aqua or anhydrous amonia placed at a depth of from 4 to 8 inches can be expected to be more efective than broadcast dry materials. If dry materials are to be used, aplications early in the spring are desirable to take advantage of spring rains.