June 1970

Cover: Ponderosu Pine test plot in the Coast Range, Lake County, was thinned in 1952 and has shown no forest debris accumulation since then.

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California Agriculture, June 1970

Volume 24, Number 6

research articles

Rice introductions tested for use in California
by W. F. Lehman , M. L. Peterson , C. R. Adair , L. L. Davis , R. W. Haubrich
pp4-6, doi#10.3733/ca.v024n06p4
Abstract
Abstract Not Available – First paragraph follows: CALIFORNIA RICE GROWERS adopted an accelerated research program in 1969, based on recommendations of a rice industry committee. The basic objectives of the industry-sponsored program are to provide improved varieties, new production technology, and marketing information which will enable rice growers to remain competitive in domestic and world markets. The research program involves utilization of the expanded research facilities at the industry-owned and operated Rice Experiment Station at Biggs, plus the recently developed supplementary rice research resources of the University of California at Davis, and at the Imperial Valley Field Station, El Centre Research is already underway toward the development of better California varieties with fewer crop residue management problems.
Expanded Abstract | PDF

Debris accumulation in a ponderosa pine forest
by James K. Agee , Harold H. Biswell
pp6-7, doi#10.3733/ca.v024n06p6
Abstract
These results indicate that thinning, with subsequent slash removal, will diminish the rate of debris accumulation for at least 20 years—facilitating maintenance of low fire hazards, and easing the problems of multiple-use forest management.
Expanded Abstract | PDF

Progress report, 1969… whitewash trials in walnuts
by F. J. Perry , A. D. Rizzi
pp8-10, doi#10.3733/ca.v024n06p8
Abstract
Abstract Not Available – First paragraph follows: WHITEWASH SPRAYS were found beneficial to walnuts in studies conducted during the early 1960's. Sunburn injury to exposed nuts and limbs was reduced with applications of various types of whitewash sprays. Internal temperatures of exposed nuts averaged 2 to 3 degrees lower on whitewashed trees than the unsprayed checks, and there was a greater percentage of large sound nuts on sprayed trees than on unsprayed trees. Only slight differences in kernel color were reported in these early trials. A good whitewash cover on the trees was needed for results.
Expanded Abstract | PDF

Effects of nitrogen on nodulation and yield of irrigated soybeans
by R. M. Hoover , B. H. Beard
pp10-11, doi#10.3733/ca.v024n06p10
Abstract
A complex relationship exists between the soybean plant and symbiotic Rhizobium. The multiplication of the Rhizobium is dependent on the nitrogen fertility of the soil. On the other hand, the soybean plant can apparently use either nitrogen from the soil or that fixed by bacteria. However, a temporary shortage of nitrogen causing chlorosis did not affect yields in this study. When nitrogen became available later in the season the soybean plant was able to attain the same yield potential.
Expanded Abstract | PDF

Factors injecting effectiveness of two surfactants on water-repellent soils
by M. A. Mustafa , J. Letey
pp12-13, doi#10.3733/ca.v024n06p12
Abstract
Abstract Not Available – First paragraph follows: WATER-REPELLENT soils are characterized by two undesirable physical properties: low water infiltration rate, and high runoff. Such soils have been reported in many parts of the world under various conditions, however, one of California's real practical problems involves soil-water repellency occurring on burned water-sheds. A high percentage of the many acres (primarily in southern California) burned over by wildfires every year includes soils which repel water. The combination of removing protective vegetation, and inducing water repellency causes an extreme erosion hazard.
Expanded Abstract | PDF

Distribution of pear decline virus in California orchards
by J. F. Doyle , H. J. O'reilly , G. Nyland , B. Bearden , R. Bethell , C. Hemstreet , G. Morehead , S. Sibbett
pp14-15, doi#10.3733/ca.v024n06p14
Abstract
Pear decline virus is present in both healthy and weak appearing pear trees on all common rootstocks in commercial orchards in California. Vigorous condition of any tree probably results from true tolerance of the rootstock to the disease rather than the chance that it may have escaped infection. Research suggests a possible relationship between pear leaf curl and pear decline.
Expanded Abstract | PDF

editorial, news, letters & science briefs

EDITORIAL: Nutritional my speaking… were great producers, but poor communicators
by Jerry Lester
pp2, doi#10.3733/ca.v024n06p2
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General Information

Research previews
Editors
pp3, doi#10.3733/ca.v024n06p3a
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Pakmor and Calmart— two new disease-resistant tomatoes
Editors
pp3, doi#10.3733/ca.v024n06p3b
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