Calag Archive

The recent development of coated fertilizers by industry offers a promising new tool to regulate the availability of minerals for the nutrition of plants. The new controlled-availability fertilizers cannot be expected to replace the liquid-fertilization techniques now widely used in the production part of the ornamentals industry. However, they will be useful in promoting the rapid start of seedlings and cuttings, as a supplement to liquid-fertilization programs, and for producing short-term crops. It is now possible for the pottedplant producer to incorporate enough fertilizer in his mix to grow a 3-month crop to maturity with no further fertilizer additions. Likewise, landscape contractors will benefit from the new materials, which will assure adequate nutrition to new plantings for a prolonged period. Longevity of nutrient supply and a high degree of safety from injury by excess application should be important for home-grounds maintenance. Another possible benefit is to minimize the large flushes of growth associated with the use of soluble nitrogen sources on turfgrass.

Spacing of plants affects both the total yield and the size of broccoli heads according to recent field tests. These results are important because the freezing industry generally prefers heads of smaller size than those shipped for fresh marketing. The tests indicate that the closer the spacing, the smaller the heads produced. Total yield increased to a maximum when spacing was reduced to 8 or 11 inches (depending on season and variety). Further decrease in the space between plants results in an abrupt reduction in yield.

It is much too early in the research program to even guess at how well the weevils imported last summer will work to eventually control puncture vine in California. But limited samples of seed pods and stems taken this fall have already indicated 30 to 50 per cent infestation on some plants at release sites in counties from San Joaquin to Riverside. Next year, if the weevils get off to a good start, it is expected that all interested counties can be supplied with initial stocks for wider distribution of the stem boring weevil, Microlarinus lypriformis, or the seed weevil, Microlarinus lareyniei. Both insects breed only on puncture vine.

The volume and species composition of herbage on a range are major factors governing its animal-carrying capacity—the number of animals of any given type that can be grazed on the range for a given period of time. Important differences in range herbage can be detected on small-scale aerial photographs, mainly on the basis of differences in photographic tone or color.

The occurrence of toxic levels of lithium in southern California citrus has been found to be more widespread than previously reported. Approximately 5 per cent of the total acreage shows symptoms of toxicity attributed at least in part to excess lithium. Some of the most severely affected acreages are on newly developed desert areas using locally developed well water with a high lithium content. A survey of the lithium content of irrigation waters of California is in progress.

Cobalt supplements in the form of “bullets” did not significantly improve sheep gains in a series of tests conducted in five northern California counties.