Calag Archive

Dairy goats that eat poison oak do not transfer detectible amounts of the toxic principle, urushiol, to the milk or to the urine. Furthermore, this oily, toxic irritant is found in goat manure at less than 9% of its concentration in poison oak leaves. What does all this portend? That farmers using dairy goats to clear poison oak need not worry about contaminating the goats' milk with urushiol. More studies are underway.

A microcomputer program, ACRE, calculates the number of acres of field and row crops to plant, given a limited water supply. Inputs include crop water balance parameters and the anticipated supply of irrigation water. This program is useful for determining how many acres to plant when the goal is to avoid the kind of water stress that impairs marketable production of a crop.

To assess claims that water-sorbing polymers promote water conservation, a greenhouse experiment with container-grown marigolds was conducted to determine the effect of adding the polymers to soil mix. Plant growth and water retention in I- and 3-quart containers were not particularly affected, but in the 6-quart size, maximum water retention was significantly higher for the 4 lb/yd3 polymer treatment than for the other treatments, and the time from watering to wilt progressively increased from 6.1 to 7.4 days for the 0, 1, 2 and 4-lb/yd³ treatments. However, no water conservation occurred because evapotranspiration was not significantly affected by the polymer treatment.

Two debilitating grapevine diseases, fanleaf and yellow vein, are caused by nepoviruses. Once these viruses are established in vineyards along with their nematode vectors, they are extremely difficult to eradicate. Since the use of infected propagating wood can spread the diseases further, the development of rapid diagnostic procedures for these viruses is highly desirable. However, a 2-year study on the identity and incidence of nepovirus-infected grapevines in San Joaquin County vineyards indicates that sampling procedures and ELISA protocols will have to be improved before this virus assay can be used reliably in nursery certification programs.

Models developed on U.S. pistachio production simulate grower prices under scenarios of varying import levels and carryover stocks. Grower prices have significantly varied for 13 years, partly because of changes in import levels and domestic production. Bearing acreage has increased dramatically, and as nonbearing acreages mature, substantial growth in production is expected. In 1979, the fledgling U.S. pistachio industry produced 1,000 tons; in 1990, production was more than 58,000 tons. Anticipating future grower prices under alternative market scenarios is of interest, particularly as global political conditions change.

Potassium deficiency symptoms occur on Acala SJ-2 cotton when the soils, by test, are not deficient and when other crops grow well without additions of potassium. Field experiments in 1988, 1989 and 1990 resulted in significant lint yield increases when the soils were fumigated with methyl bromide and chloropicrin. Foliar potassium deficiency symptoms were drastically decreased without altering soil potassium levels.

Fertilizing avocado trees in smaller amounts more frequently can reduce nitrate leaching into the soil and thereby decrease contamination of ground wafer.

Topically applied 'Sevillano' olive pollen increased the percentage of normal fruit set and reduced incidence of worthless shotberry 'Manzanillo' olives. Applications were effective up to 90 feet from the pollen source.

Poa annua L. (annual bluegrass) is seen by researchers as both a troublesome' weed, especially on golf courses, and as an attractive turf. A wealth of genetic variations in the morphological, physiological and life history characters of this weedy species has been detected. Awareness of the genetic differences in growth habit and reproductive strategies between annual and perennial biotypes of P. annua can be helpful in managing it as turf, as well as in situations where it is treated as a weed.

Traditionally, little control is exerted over grazing on irrigated pasture. Today, however, with controlled grazing and feed budgeting, the pasture manager can use grazing stock to control forage levels, and forage levels can be used to control animal performance. Pasture budgeting can be applied to California's irrigated pastures when estimates of expected pasture growth are available, according to an ongoing study.

Dairy manure collected for 2 years from various sites in seven Central California dairies was found to contain viable weed seed. Weed seed Contamination Was most Severe when manure was taken from dry COW pens and liquid manure sedimentation handling facilities. Composting did not eliminate all viable weed seed.