Calag Archive

Studies on the sulfur requirements of subclover, Trifolium subterranean L., were initiated because of the importance of this species in the coastal counties of California where sulfur deficiencies in the soils are widespread. It has been discovered, for example, that many yield increases formerly attributed to phosphorus were actually due to the sulfur content of the phosphate carrier.

The only aphid that breeds on sugar beets in the Imperial Valley is the green peach aphid. This pest often builds up to high populations in late winter and early spring and reduces yields by feeding injury and by transmitting yellows viruses.

Lint yields of Acala 4–42 are highest (despite some lodging) when plants receive only adequate supplies of nitrogen and water, according to Palo Verde Valley tests reported here. When the nitrogen fertility level is adequate for maximum yields, excessive irrigations can produce such rank cotton with large amounts of boll rot that resulting yields are lower than those obtained under nitrogen deficiency conditions. Deltapine Smooth Leaf variety also grew more rank when given extra amounts of both water and nitrogen, but boll rot was not severe and yields were not depressed. Deltapine Smooth Leaf performed better than Acala 4–42 under all conditions tested and required less strict attention to irigation and nitrogen fertilizer for maximum lint yields than Acala 4–42.

Field applications of the fungicides captan or thiram, for control of Botrytis, fruit rot of strawberries, resulted in yield increases of 333 to 388 crates per acre of marketable fruit, in recent Monterey County tests. The fungicides also reduced the amount of fruit rot in storage by 22 to 34 per cent as compared with fruit from check plots.

Forage yields of Coastal Bermudagrass almost doubled following application of the first 400 pounds of nitrogen, as compared with unfertilized check plots, in recent trials at Imperial Valley Field Station. However, additional nitrogen up to 1,600 pounds per acre increased yields only slightly and production dropped off when 2,000 pounds of nitrogen was applied. Late application of nitrogen did not prolong the growing season into the late fall. Heavy applications of fertilizer did not cause an appreciable increase of salt in the soil nor excessive accumulation of nitrate nitrogen in the forage.