Calag Archive

Orange yields were maintained and packout appeared to be improved over a four-year period following maintenance hedging and topping (done before excessive crowding occurred) in a mature Valencia citrus grove.

The training of young orange trees in close-spaced hedgerow plantings to allow easier picking, and use of harvesting aids such as movable scaffolds and platforms—or possible machine harvesting—is being considered and tested by many citrus growers. The two reports included here involve many aspects of the topping and hedging operations involved and the effects on trees, fruit quality, and yields. One article discusses results of experiments with both topping and hedging to prevent crowding of mature citrus trees in the Ventura area, and the other discusses yield effects from annual sidewall trimming of trees in an Orange County plot. These are progress reports of continuing research by both Experimental Station and Extension Service researchers toward cost reduction and eventual mechanization in citrus harvesting.

White-flowered alfalfa plants vary widely in attractiveness to honeybees, according to this study under open pollination conditions at University of California, Davis. Several instances of plant preference were noted, but in general, plants having the most bee activity showed the greatest amount of cross pollination. When a strain of honeybees is developed with a distinct preference for alfalfa, it would appear to be advantageous to have parental lines equal in as many of the attractiveness characteristics as possible, to insure increased alfalfa seed production.

Prune russet scab, sometimes called lacy scab, was reduced to an insignificant level in the 1967 season by one application of a fungicidal spray during the full bloom period. Both Captan and Phygon (dichlone) proved successful and may be used by prune-growers. Difolatan (folcid), another chemical used in these tests, is not registered for use on prunes and should not be applied to prune trees.

Since 1962 the slip plow has been used extensively to improve drainage of perched water tables in Imperial Valley. This implement is a modified soil chisel with a flat plate 8 to 12 inches wide attached to its back from the chisel point to the aboveground portion. The upper section has a V-shaped flare to push loose soil away from the slit opened by the plow. Slits from a depth of 4 to 6 feet are common.

Animal Husbandry practices in the production of fat lambs in the Imperial Valley of California are quite different from those in the remainder of the state. Shipment of feeder lambs into the Imperial Valley begins early in September and is usually completed by the end of October. The lambs are grazed inside temporary fencing on alfalfa and barley stubble pastures. Pastures of 80 acres are usually used, and a band of 1,500 to 2,000 lambs is grazed for 1 to 2 weeks, after which the lambs are driven or trucked to another pasture. Dry hay is occasionally fed as supplemental feed. Most shearing is done by the middle of December, and most of the lambs are marketed directly from pasture by the first of March. In view of these husbandry practices, different patterns in the host-parasite relationship might be expected between sheep and their gastrointestinal nematode (roundworm) parasites in the Imperial Valley than in other regions of the state.

Field tests in 1966 and 1967 have confirmed initial reports from the Rice Experiment Station, Biggs, that chemical control of submersed aquatic weeds frequently results in substantial increases in rice yield. Promising materials for this purpose are TD294, Hydrothal 191, and chloroxuron. Injury to the seedling rice was the least when these chemicals were applied about 35 days after flooding and seeding. More work is needed to determine precisely how long riceland-treated water must be held to control the submersed weeds most effectively while also eliminating any possible hazard to wildlife, including fish. It should also be determined whether the yield increases result from decreased weed competition or from fertilization provided by the killed submersed weeds (which soon decay, releasing the organically bound plant nutrients).

The following conclusions were obtained from these experimental results and observations of commercial fertilizer applications on Glenn and Tehama County rangeland: (1) Economical feed can be produced by fertilization with sulfur alone, or combined with nitrogen or phosphorus, on bur clover ranges in Glenn and Tehama Counties. (2) Palatability of green and dry feed is increased with fertilization. (3) Nitrogen stimulates early grass growth principally in the year of application. (4) Sulfur stimulates bur clover growth over a period of three to seven years, depending upon the amount, source and seasons. (5) During “clover years” bloat hazard may be increased by sulfur fertilization. (6) If bur clover is not present for any reason—soil type, growing season, or grazing management—there is little or no response to sulfur. (7) Coarse elemental sulfur is not readily available to plants for several years whereas fine elemental sulfur and sulfate sulfur fertilizers are effective the first season. (8) An effective legume stand must be established on some soils before fertilization with sulfur or phosphorus is economical.

Wildfires in Chaparral Occur with amazing regularity and consume a tremendous amount of fuel. Published figures indicate that the average fire in chamise consumes between 15 and 25 tons of fuel. However, only temporary changes in vegetation occur as a result of the fire; the resprouting habit of most chaparral species insures that there will be abundant fuel for the next fire. The relatively small changes in vegetation consist primarily of dramatic but short-duration increases in annual species.