California Agriculture, September 1974
Volume 28, Number 9
Evaluating soil amendments for improvement of soil physical properties
by J. E. Warneke , S. J. Richards
All of the amendments tested lowered the bulk density and greatly improved the water flow rate through the soil mix, thereby reducing management problems. Wetting agents were found of value in management of soil mixes difficult to re-wet after being depleted of water. Water storage capacity of a soil mix was improved most by the addition of such water-absorbing materials as peat moss, redwood shavings, and vermiculite. Amendments that improved all soil properties, except water storage, included pumice and calcined clay. Only slight increases in water storage were obtained from use of larger wood chips, fir bark, or rice hulls. Evaluations of various amendments to several soils by two different laboratory and greenhouse methods showed agreement in results but the laboratory method required much more equipment. The greenhouse method could easily be used by anyone interested in evaluating his own soil, and amendments. The only equipment needed is a balance and several small tensiometers. The greenhouse method also allows evaluation of the plant grown to extract the water, for its response to the treatment. The laboratory method offers the possibility of evaluating many more mixes over a shorter period of time, however.
Improved Pistacia seed germination
by J. C. Crane , H. I. Forde
Scarification with sulphuric acid speeded up—and increased the percentage of Pistacia seeds germinating
Remote sensing in control of pink bollworm in cotton
by V. B. Coleman , C. W. Johnson , L. N. Lewis
Abstract Not Available – First paragraph follows: USING high altitude or space photography to identify crops has long been considered important for land use mapping, crop yield prediction, crop inventory, and disease identification and control. This study evaluates satellite imagery as an aid in controlling pink bollworm infestation through monitoring California's cotton production regulation program in the southern deserts. This was the initial and most obvious objective, but if further studies are successful, the potential of satellite monitoring programs for agriculture is unlimited.
Influence of rootstocks and inter stocks on the macro- and micro-nutrients in valencia orange leaves
by C. K. Labanauskas , W. P. Bitters
Abstract Not Available – First paragraph follows: THE NUTRITIONAL EFFECTS of the most commonly used citrus root-stocks have been extensively investigated. It is known that the citranges and trifoliate orange rootstocks produce the highest concentration of chloride in the leaves, and that sodium accumulation is higher in trees on mandarin rootstock than those on trifoliate orange hybrid rootstocks. But no information on inter-stock effects on nutrient concentrations in any citrus scion leaves has been obtained. This paper evaluates the effects of five trifoliate [Poncirus trifoliata (L.) Raf.] cultivare used as both rootstocks and interstocks on the accumulation of nutrients in ‘Valencia’ orange scion leaves. Five of the most commonly used trifoliate were selected for this study, since the literature indicated that trifoliate as a rootstock was not too tolerant to higher amounts of chloride and boron in the soils. Sweet orange Citrus sinensis (L. Osbeck) was used as a control rootstock.
Control of septoria leafspot of celery
by A. O. Paulus , H. Otto , J. Nelson , F. Shibuya
Benlate at 0.5 and 1.0 lb, Dyrene, Bravo and RH 3928 at 1.0 Ib and Mertect were significantly better than all other treatments in these tests for the control of Septoria leaf-spot of celery. Topsin M and Dithane M-45 provided intermediate control. RH 3928, Mertect, and Topsin M are not registered for use on celery at the present time and therefore cannot be recommended.
Suutter…a new late-maturing Barley
by C. W. Schaller , J. D. Prato , J. I. Chim
Abstract Not Available – First paragraph follows: LATE MATURITY AND DISEASE resistance are combined in Sutter, a new barley available to California producers. Named for the northern California county where its potential was first observed in field trials, the variety is highly tolerant to barley yellow dwarf and is moderately tolerant to the foliar diseases, net blotch, powdery mildew and scald.
Onion varieties, honeybee visitations, and seed yield
by Elmer C. Carlson
Onion seed plants, Allium cepa L., exhibited varietal differences regarding honeybee (Apis mellifera L.) visitation; incidence of pink root disease, Pyrenochaeta terrestris Hansen) Gorenz, Walker, and Larson; numbers of western flower thrips, Frankliniella occidentalis (Pergande) present; and seed yields. Results from an isolated onion planting showed that the male sterile, Code 2 hybrid, adjacent to a pollen-parent, was significantly more attractive to honeybees and produced significantly more seed than a second comparable hybrid.
Naa sprout inhibition shown in olives, pomegranates, prunes, plums, and walnuts
by J. H. Larue , G. S. Sibbett , M. S. Bailey , L. B. Fitch , J. T. Yeager , M. Gerdts
Application of an ethyl ester formulation of NAA to tree sprouts and suckers at rates of.5% to 1% solution resulted in. growth suppression on olives, pomegranates, prunes, plums and walnuts.
editorial, news, letters & science briefs
Food for thought
by J. B. Kendrick
Insectiveorous birds for forest insect control
Eggs help environmental research
The second in an agricultural research centennial series: Soil sciences, U.C. riverside… a brief history of research contributions
by Homer D. Chapman
“A hungry world: The challenge to agriculture”