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The adverse effects of wind—chilling of dairy cows, poultry, and other livestock during cold weather, soil erosion and air pollution, scarring of citrus fruits such as lemons, and on fire control—are often economic factors in California agriculture.

Fertilizer trials and field studies in 1957, 1958, and 1959 indicated that the soil in some cotton fields in the San Joaquin Valley was deficient in available potassium, and the application of potassium fertilizers significantly increased cotton yields. Where available soil potassium is in low supply, cotton plants show distinctive visible deficiency symptoms.

The orange tortrix on apples in California usually has been controlled satisfactorily by the use of TDE in the codling moth schedule of treatments. However, the recent increase in cases of codling moth resistance to TDE—and to DDT—has caused some growers to change to other insecticides, although little is known about the effectiveness of the substitute compounds against orange tortrix.

Herbicide sprays that could control 80%-90% of the weeds in celery fields would reduce costly hand labor.

Chemical weed control methods now under development promise substantial savings in the million dollar weed bill of the growers of transplanted celery in California. The general method of weed control in the coastal counties is still cultivation and hand weeding.

Vegetatively propagated clones of tissues from citrus fruits in cultures are being used to study the factors controlling fruit growth and development. Light, aeration, temperature, and nutritional factors can be adjusted individually for study of their effects on each kind of tissue.