Calag Archive

MISSION VELDTGRASS Ehrharta calycina Sm., a new high-seed-yielding, non-shattering strain of perennial veldtgrass, with a general area of adaptation following the Mission Trail from San Diego to San Francisco, is now approved for certification in California. Foundation seed will be available next year through the Department of Agronomy, University of California, Davis, or the Soil Conservation Service District Seed Increase Program. Seed will not be available through commercial channels until 1965.

Soil stabilization for wind erosion control is now possible by using chemical sprays. More tests are needed to determine the optimum dilution and application rates but the amount of spray to apply depends basically upon whether the stabilized surface must bear foot traffic. The economic feasibility of such wind erosion control methods depends upon the potential of the soil needing stabilization.

WINTER PLANTINGS of strawberries account for about one half of the annual acreage in southern California. Early production (March and April) is as important as total production in this area. Both earliness and total production are closely associated with the growth of plants during the short days of the winter.

Field tests in western Fresno County have confirmed laboratory tests indicating that glass fiber filtering materials can be used to satisfactorily replace the sand filters which have been standard practice in drain tile installations, but which may be quite costly in some areas. No information is yet available on the life of glass fiber filters. It was hoped to obtain quantitative evaluation of the effectiveness of several types of glass fiber filters in comparison with sand filters, but comparisons were masked by extreme variation in the sodium status of the soil. Glass fiber filters generally filtered out more of the fines than did sand filters.

Since their introduction, sudangrass-sorghum hybrids have found some use as a silage crop. However, their principal use for forage will probably continue to be for pasture and green chop. Several dual purpose and intermediate height hybrids offer some lodging resistance. These types have been the only hybrid forage sorghums to gain widespread usage in California. Tall growing types of hybrid forage sorghums should be used with caution. The development of a hybrid forage sorghum type with high yield capacity and lodging resistance continues to be necessary before greater use of sorghum silage can be expected in most areas of California.

Climatic and weather conditions directly affect the necessity for mite treatment in citrus, the number of applications needed per year, the type of application required and the effectiveness of acaricides used. The property of acaricides to be translocated is less advantageous, even for foliage applications, when made during the cooler periods of the year. Seasonal changes of the host and the direct or indirect influence of weather on the mite and the host are essential factors determining mite control and treatment scheduling under California conditions.

Low temperature predrying appears to be a promising method of evaporating free moisture from tanoak lumber. The most important drying defects, surface checking and collapse, have been reduced below the level encountered in kiln drying by low temperature drying. Tanoak showed considerable variation in drying characteristics particularly between bright colored and dark colored lumber. Separate drying of these two categories should improve drying time and grade recovery. The early period of drying is the most critical and it is necessary to keep the relative humidity high and temperature low. As soon as stresses in the boards become reversed, the drying rate can be increased by stepping down the humidity. In addition to the normal shrinkage of cell walls, a study of shrinkage characteristics showed the occurrence of collapse also determined the dimensional changes of tanoak specimens dried to various moisture content levels. The change in dimensions became apparent when the wood was still above the fiber saturation point. A distinct difference in the shrinkage of bright colored sapwood and dark colored heartwood occurs. Shrinkage values measured on boards in these tests must not be considered standard information because method of sawing, amount of heartwood present, method of drying, and other variables affect the shrinkage of tanoak lumber. However, these tests offer a good indication of dimensional changes to be expected from such drying of gang sawn or slash sawn boards.