THE EFFECT OF CALIFORNIA'S DROUGHT ON LANDSCAPE HORTICULTURE

Baumgardt, J.P. 1977. Nutrients. Grounds Maintenance 12(10): 44, 46, 49-50, 52. Green plants take some minerals from the soil, others from the air, and they manufacture still other chemical compounds internally, all for various metabolic processes. From a practical standpoint, a gardener can manipulate only soil chemicals, but in doing so he can encourage vigorous, healthy plant growth which makes optimum use of gaseous compounds taken in through the leaves and permits optimum internal metabolic processes. Many chemical elements enter plants through the roots; only a few are taken in through pores in the leaves. Chemical compounds always enter plant roots in solution. It follows that the availability of nutritional compounds in the soil depends on soil moisture. One group, elements which are fixed in plant cell development, or which are required in large amounts, are known as major nutrients; the second group, those used only in very small amounts, are called trace elements, minor nutrients, or micronutrients. For normal, vigorous growth plants need ample supplies of these substances. We determine what is available in the soil by soil tests and supply the lacking amounts. It is all very simple when approached from a sensible, scientific standpoint. Boardman, R.M. 1977. Biological control: pitting insects against insects. California Agriculture 31(10): 8-11. Biological control involves discovering, importing, and using the most effective natural enemies of pest insects or weeds that can be found. UC scientists estimate that the importation and release of biological control agents in California alone has saved producers and consumers of food and fiber about $300 million in the last half century. In this review, "biological control" (BC) refers to only one of the many nonchemical insect control methods on which UC scientists are working. BC is the importation, colonization, and spreading of natural enemies (usually from the "old country" where the pests originated) to reduce a pest's population density to a lower average than would otherwise occur.