All Issues

Control of soil-borne plant diseases by the “rigolen” method of plowing means the careful inversion of the surface soil (usually about the first foot) with soil from below. Knowing that crops generally produced less and less when grown repeatedly without rotation in the same soil, but not knowing why, an unknown farmer developed the rigolen or soil-inversion technique over a century ago to counter diminishing yields. Thus, rigolen plowing (spades were used in the early days) was developed before the causes of soil-borne plant diseases were known. Actually, rigolen plowing is a method for controlling soil-borne diseases by rotation—but the soil, not the crop, is rotated. This three-year study was conducted to determine whether the rigolen method would control soil-borne diseases today—and especially Verticillium wilt of cotton.

Many of the roots used for sweet potato slip production produce only a few shoots. This is because the end of the root is strongly dominant and can inhibit slip growth. Various chemical and physical methods have been tried to find a practical method to overcome this inhibition. None of the chemicals that showed promise has found extensive commercial use. Sectioning the sweet potatoes by cross-cutting overcomes part of the dominance expressed by the apical end of the root. However, each cut end has a distinct proximal dominance.

Johnsongrass, Sorghum halepense, is the most serious perennial weed control problem in California orchards. This fast-growing, warm-season weed propagates prolifically from seed and underground rhizomes. The fleshy underground stems provide the necessary overwintering mechanism by which this plant gets an early start in competing with crop plants, as well as other weeds. In established trees and in young, producing orchards, competition from Johnsongrass may reduce nutrients, moisture, and light. In a field test at the Kearney Field Station, Fresno County, Johnsongrass seedlings were controlled in the nursery row with various soil-persistent herbicides. MSMA is not currently registered (or recommended by University of California) for orchard use. Dalapon is not registered for use on walnuts or almonds.

A study of nine commercial vineyard pruning operations covering some 3600 acres in four counties has shown that the manpower requirement for pruning was reduced an average of 30% during the 1965–66 season, when the use of pneumatic pruning machines was compared with conventional hand-pruning methods. A dollar savings averaging about 15% of the cost of hand pruning was also achieved, even after an original investment in pruning equipment of $12.65 per acre.

It has been estimated that 100,000 tons of alfalfa were wafered in California in 1965. Each year for the past six years increased amounts of wafered alfalfa hay have been fed to dairy cattle. A new experimental wafering machine was tested in the summer of 1965. Windrowed alfalfa was picked up by the experimental wafering machine, sprayed with water, chopped, and channeled between two wheels. A smaller wheel with scalloped cutting portions operated inside a larger wheel to compress the hay into wafers about 1 × 3 × 3 inches in size.

Long-range studies on cotton bollworm were initiated to develop control recommendations relating damage potential to pest population density, environmental conditions, and the general economics of cotton production. Data from these preliminary studies indicate that the present criteria used in determining the economic threshold for cotton bollworm need to be re-evaluated. The data suggest that higher infestations of cotton bollworm may be tolerated than previously believed.

A meat index being developed at Davis is designed to rate beef calves at weaning for the meatiness of the carcasses they will produce later, after being fed out. The meat index is based on rump shape and the degree of visibility of a crease in the rump (see sketch) formed by the juncture of the semimembranosus and semitendinosus muscles. The visibility of the crease is scored (see table) from 1 to 4 while the animal is standing and again when it is moving. The shape of the rump is scored from 1 to 4 with a “rump gage” as shown in the photo. By moving the rump gage from close to the viewer's eye to full arm's length, some position can be found at which one of the outlines will best fit the animal's rump shape.