Calag Archive

Walnuts are California's leading deciduous tree crop. Walnut orchardists spend over one million dollars annually for weed control on an estimated 140,000 acres. In addition, losses due to weeds in the orchards were recently estimated at $2,720,000 annually.

The olive tree (Olea europaea L.) has very desirable characteristics for use as an ornamental. It has attractive, gray-green foliage, and develops a picturesque, gnarled trunk and branch system as the tree grows older. It is an evergreen with a willowy-type of shoot growth which makes a very pleasing appearance. The great disadvantage of the olive as a street, lawn, or patio tree is the production of fruits which drop over a long period of time during the winter and early spring months. These, of course, become a great nuisance, discoloring concrete walks, adhering to pedestrians' shoes, and attracting birds which consume some of the olives and further contribute to the litter.

The cypress bark moth is frequently found infesting cones and trunks of Monterey Cypress in central coastal California. Larval feeding on cones produces unsightly accumulations of frass, while trunk feeding results in the production of swellings and resin flow. Primary concern about the moth may lie in its relationship with a serious fungus disease on the cypress, according to these studies.

SUMMARY Among the soil amendments, peat has the advantages of promoting a very good top growth and dense root system, when properly irrigated to avoid poor aeration. It has the disadvantages of not being able to withstand compaction and can become excessively wet if proper irrigation practices are not followed. Lignified wood has the advantages of withstanding compaction, providing high infiltration rates, allowing good aeration, maintaining an extended supply of nitrogen under leaching conditions, and promoting a good root system under a high oxygen diffusion rate (ODR). It has the disadvantages of contributing to soil salinity, and apparently requires a higher ODR for maximum root growth. Calcined clay has the advantages of withstanding compaction, providing high infiltration rate and allowing for good aeration. Its disadvantage is that although it promotes deep roots, they are rather sparse with few roothairs. Better results were obtained with irrigation based upon tensiometer records than by irrigation according to a set calendar schedule. Advantages over the set program chosen for this experiment included a savings in water, improvement in soil aeration, and reduction in soil compact ability. One requirement in irrigating by tensiometer records is that excess water must be applied periodically to cause leaching, if salinity becomes too high. The wetting-agent treatment (at only 3 ppm), increased the infiltration rate of the unamended soil, reduced compactability of peat-amended soil, and also resulted in some other effects of minor significance. Other research in progress indicates that the relationships between wetting agents and plant growth are extremely complex, and no general conclusions are likely for some time.

Carnation growers utilize any of several bulky organic materials for amending greenhouse soils to improve aeration, drainage, and moisture retention. Redwood sawdust has been the standard material used in San Diego County. The trial reported here compared plant growth and flower production of carnations grown with two soil amendments—10 and 20% by volume of Redwood sawdust, and 10 and 20% by volume of processed lignin particles, replicated three times. They were conducted at Hillside Floral Company, Encinitas, and the amendents were incorporated in a Carlsbad sandy loam in raised benches prior to planting. The greenhouse soil had not been previously amended.

Recently a new family of frost protection devices has become available. Heaters are now being made from petroleum wax or coke and molded in various forms, such as candles, bricks or flat trays. Because these devices have a much lower heat output per unit than conventional heaters, and information about their protection ability is limited, preliminary tests were initiated to learn more about this type of heating.

Young dairy animals were grown in these tests on a free-choice, high energy, all-concentrate diet, over long periods of time, without roughage, and to date, without noticeable detrimental effects. There was no evidence of physiological disturbances due to overeating when any of the feeds were offered free choice. It appeared that the feeds must be pelleted to prevent sorting. There was no apparent abnormal behavior or delayed sexual development. All animals have been bred and are currently with calf. Certain portions of this work will be repeated and extended far verification of these preliminary conclusions. This program is on a continuing basis and further trials will also be carried out tom determine influences on lactation performance.