Calag Archive

Three-dimensional model of fruit location on half an orange tree aids University studies of fruit removal problems aimed at total harvest mechanization,

March 1965
Volume 19, Number 3

Research articles

Research on: Mechanization of citrus harvesting

by C. E. Schertz, G. K. Brown

Abstract

This article briefly describes the various areas of research presently underway, by University of California and U. S. Department of Agriculture, aimed specifically toward total citrus harvest mechanization. The article considers: (1) the phases of work being performed, (2) the relationships of the phases to the overall objective, and (3) the coordination of the work among the research disciplines. It also points out that at the present stage of research, the total mechanization of California citrus harvesting is not imminent.

Soil Compaction Effects on Oxygen Diffusion Rates and Plant Growth

by R. W. Rickman, J. Letey, L. H. Stolzy

Abstract

Aeration conditions, as measured by the platinum microelectrode technique, were less favorable in compacted soil layers than conditions known to limit root growth in noncompacted soil. However, reduced root penetration and top growth of tomatoes grown above these compacted layers could not be blamed upon either the high physical resistance to root penetration or poor aeration, individually, because both factors were simultaneously present in the compacted soil layers.

Sprays for Aphid Control Increase Sugar Beet Yields in Davis Tests

by F. J. Hills, W. H. Lange, R. S. Loomis, H. L. Hall, J. L. Reed

Abstract

For the third consecutive year, sprays for aphid control applied to sugar beets planted at Davis, decreased yellows virus infection and substantially increased root production. Three sprays applied to beets planted in March, April or May, 1964, resulted in yield increases of 6, 9 and 5 tons per acre respectively.

A-Progress-Report…: Weed control in tomatoes

by A. H. Lange, F. M. Ashton, V. H. Schweers, H. B. Collins, H. Agamalian, A. F. Van Maren, R. C. King, H. L. Hall

Abstract

tomatoes are grown on more acreage in California than any other vegetable crop. Weed control costs amounted to $4.24 million, with additional losses from weeds estimated at $10.28 million -for a total cost of $14.5 million annually to tomato growers in California, according to the 1964. report of the Statewide Weed Control Committee of the State Chamber of Commerce. Current costs of weeding tomatoes are estimated at $27 per acre. These costs may increase : (1) if mechanical harvesting requires a longer period of weed control; and (2) if the labor for hand weeding becomes more scarce with the end of the bracero program.

Cabbage Looper: A principal pest of agricultural crops in California

by H. H. Shorey, R. L. Hale

Abstract

The cabbage looper causes economic losses to growers of a large variety of vegetable and field crops in California. The damage results principally from the caterpillars feeding on foliage. Studies of the biology of the cabbage looper, which are summarized in this article, are one segment of an intensive program underway to understand this pest and to develop better control methods.

Composition and Feeding Value of Almond Hulls and Hull-Shell Meal

by M. Velasco, C. Schoner, G. P. Lofgreen

Abstract

More than $1,000,000 worth of almond hulls have been marketed annually by California almond growers in recent years. This by-product of the almond industry is used mainly by livestock producers in beef cattle feeding operations. New methods of processing almonds have resulted in a feed by-product now consisting of almond hull and shell mixtures. Studies reported in this article indicate that hull-shell meal supplies little or no protein and is also a poor source of phosphorus and fat. However, the hull-shell mixtures are high in nitrogen-free extract, sugars and potassium. The money value of Nonpareil variety almond hull-shell meal containing an average of 18% fiber is about 58% that of barley.

Bark Grafting Grapevines: At high and low levels

by C. J. Alley

Abstract

High-level bark grafting of grapevines was shown to be preferable to low-level grafting (in tests at Davis) throughout the season.

Research articles