Calag Archive

The distance a pump must lift underground water to the surface is the most important single factor in the per acre-foot cost of irrigation pumping. Other physical factors in the cost complex—pump and well life, maintenance and repairs, changes in the water table and the total amount of water pumped per year—are influenced by the pump lift.

Wildfires are the biggest problem in the management of wildland resources in California.

Nutritional requirement studies of strawberry varieties Shasta and Lessen suggest that field behavior of strawberries in the major areas of California production is closer to the behavior of deciduous fruit trees than to annuals.

Pear tree decline has become one of the greatest problems of the California pear industry. Symptoms of the disorder include small, sparse, light green leaves, little or no shoot growth, early cessation of fruit growth, wilting, scorching, and death of leaves. The trees may quickly collapse and die or they may linger for an indefinite period.

Old Home pear—Pyruscommunis—rootstock can be propagated readily in commercial quantities by hardwood cuttings taken in the fall, treated with IBA—indolebutyric acid—and held under moist storage at 65°-70°F for about three weeks before planting. To take advantage of the Old Home blight-resistant properties, trees can be planted in place in the orchard and, after the trunk and primary scaffold branches are established, top-budded to Bartlett or other fruiting varieties.

Table beet seed crops are attacked regularly by the green peach aphid—Myzus persicae (Sulz.)—and by the bean aphid—Aphis fabae Scop. No definite knowledge about the kind and amount of damage to the seed crop caused by the aphids is available. Therefore growers usually apply aphicide sprays or dusts whenever the pests become obvious.

Gibberellin stimulates flowering of many plants, under appropriate conditions, but certain concentrations of gibberellin sprayed on branches of some stone-fruit trees at full bloom or at the beginning of pit-hardening retarded development of flower buds. At higher concentrations, vegetative buds as well as flower buds were inhibited. The year following the spray applications, those branches that had received the higher dosages were devoid of flowers or leaves except, in some cases at the tips of the long shoots, on regions which had apparently developed after gibberellin treatment. The terminal buds on the new growth were relatively immune to the adverse effects of gibberellin, while the lateral buds suffered such severe growth inhibition that recovery was impossible. That gibberellin did not inhibit growth in general was evidenced by the excessive length and diameter growth of stems and petioles while lateral bud growth was restricted. The higher the dosages, the more extreme the stem and petiole growth and greater the blocking of bud development.

Leaf and soil analyses are the best means of determining fertilizer needs for citrus orchards. On the basis of an initial orchard evaluation and preliminary leaf and soil analyses, current nutrient and salinity status can be assessed, and the grower can be advised whether his present fertilizer and soil management practices are right or wrong. Such analyses will tell him whether he is spending too much for nitrogen or not enough; whether he is applying fertilizers that are not needed; whether the levels of the minor elements should be built up or decreased; whether too much exchangeable sodium or potassium is building up in any part of the root zone; whether the soil is acid enough to require lime, or alkaline enough to require sulfur or gypsum, and whether to use acid- or alkaline-base nitrogen fertilizers.