All Issues

The Delta, once considered a worthless swamp, has been transformed into an agricultural and recreational paradise by “men of determination.” Most of the old challenges have been met, but problems concerning the quantity and quality of its water require solutions.

The Delta's peatlands call for a unique subsurface irrigation system whereby river water is siphoned over levees and into unlined head ditches and small lateral ditches cut into the peat soil.

Crops grow well in the Delta's peat soils—but so do weeds. Growing crops that can compete successfully with weeds and withstand post-emergence herbicides is just one problem for farmers. Other problems: excessive soil moisture can delay spring planting, while surface dryness has created dust storms.

Study began in 1977 to discover how irrigation water and groundwater move through Delta soil and the implications of their movement on soil salinity.

Preliminary results of a recent study indicate that remote sensing will be useful in monitoring water quality in San Francisco Bay and the Delta—but there is a drawback: only the water's surface can be scanned.

Dangerous accumulation of salt in Delta soil can occur when leaching is not effective, so researchers are trying to determine the most effective—and inexpensive—ways to prevent accumulation and/or to remove it.

Sprinkler-irrigation and subirrigation treatments will be compared over the next three years to determine their effect on soil salinity and, consequently, the effect on corn production.

The fig wasp, established since about 1900 in California to assist in obtaining fruit set in Calimyrna figs, also transmits disease. U.C. researchers have been successful in standardizing the “caprification” process—the transferring by the fig wasp of pollen from the male caprifig to Calimyrna fruits—and in improving fungicides to eradicate disease.

Bacterization, the application of bacteria to soil and plant parts to promote growth and crop yield, was pioneered in the Soviet Union and now appears to be in the offing here, once methods for storing and applying have been improved.

The mold on spoiled bread, fruit and vegetables is not harmless; researchers are just beginning to realize that some produce potent toxins and carcinogens.