All Issues

Many close-planted citrus groves have reached the stage where crowding has made it necessary to remove alternate trees. In some cases, the orchards are thinned by bulldozing trees to be removed. In other cases, they are thinned by cutting off the trunks of the trees a few inches above ground level. Sprouts from these cut stumps soon become a nuisance, and if left uncontrolled will produce considerable regrowth. Pruning stump sprouts is costly and results in the forcing of more buds so that the pruning soon has to be repeated.

Obtaining good commercial carrot stands in the San Joaquin Valley has often proven to be unpredictable and sometimes difficult. Carrots are becoming a major crop in this area and growers are using many mulching, irrigation and planting techniques in an effort to improve stands. During the last three years an increasing number of growers have used only large-sized seed in an attempt to guarantee stands. These studies at the U.C. West Side Field Station, Five Points, indicate that under most conditions small seed may be as good or better than large seed.

Applications of zinc, manganese, and copper compounds to alkaline California soils have not proven consistently effective in supplying these elements to citrus trees. However, commercially formulated compounds and mixtures containing zinc, manganese and copper in proper concentrations readily supply adequate amounts of these nutrients when used in foliar applications. Such sprays, in which precipitating agents are combined with ZnSO₄, MnSO₄ and CuSO₄, are relatively high in salts, but low in metallic ions in solution, as shown in tests reported here. Such sprays leave large amounts of residue on the leaves, and because of this undesirable effect, these studies were undertaken to develop safe, low-residue micronutrient sprays.

At Hopland during the 11 years of range improvement study, the total increase in ronch income through livestock use was $133.60 per acre. This value takes into account $57.09 per acre production value without improvement and treatment costs of $34.87. Thus, by reducing the woody plant component of the watershed and replacing it with herbage that livestock could use, the product values were increased fourfold. It should be noted that no fertilizer was applied in this improvement study —and that its use would probably have given a greater magnitude of production increase. It is also expected that this higher level of production can be sustained with a minimum of maintenance costs.

The economically optimum yield for INIA 66 wheat was obtained by using 150 lbs of nitrogen and 30 lbs of phosphorus per acre in these tests. Nitrogen had greater effect on yields than phosphorus, however, maximum yields were realized by using a combination of nitrogen and phosphorus as a fertilizer. Darker green color intensity was obtained with higher rates of fertilizer. Higher rates of phosphorus have a tendency to suppress the bushel weight. The highest net dollar return was obtained by using 150 lbs of nitrogen and 30 lbs of phosphorus per acre.

Broccoli is well adapted to the western San Joaquin Valley, and with careful selection of varieties, can be harvested every month except from mid-June to mid-September. The trials reported here were in response to an increased interest by freezing processors and produce handlers in broccoli production in the San Joaquin Valley.

The threat of pink bollworm and yield decline in the San Joaquin Valley have prompted investigations into more efficient production practices to permit growing the crop in less time. Higher plant populations planted in rows narrower than the conventional 38–40-inch row spacings have a potential for shortening the fruiting period, a requirement for reducing the time it takes to grow the crop. Preliminary studies indicate that varieties developed specifically for this system of production will be needed.