California Agriculture, December 1972
Volume 26, Number 12
Nutrient removal by Valencia orange fruit from citrus orchards in California
by C. K. Labanauskas , M. F. Handy
These data show that relatively small amounts of nutrients applied to the soil are removed by citrus fruit. The larger amounts of these nutrients tied up in plant parts, particularly those in the leaf tissue, are eventually returned to the soil. For the most part, phosphorus, calcium, magnesium, zinc, manganese, copper, and iron will be adsorbed by the soil particles and are not easily displaced from the soil. Conversely, these elements may not always be readily available to the plant. Availability of most of these cations to a plant is highly dependent upon soil hydrogen ion concentration. Nitrogen compounds, being water soluble, move readily in the soil and are quite easily leached out, usually in the form of nitrates, although in some instances leaching losses of ammonium have been reported. It is imperative that nutrients be applied only as needed, since larger applications may be considered as “soil-polluting,” and may find their way into underground water supplies used for human consumption.
Control of pythium root rot in carnations
by R. D. Raabe , J. H. Hurlimann
These tests showed that when Pythium vexans (isolated from carnation roots) was introduced into soil mixes, it reduced the top growth and yield of Red Sim carnations. No other symptoms were visible on the plants. Control measures using ethazol as a preplant at 50 ppm, diazoben as a preplant at 25 ppm, or diazoben as a drench at 100 ppm at weekly or biweekly intervals also gave control. The ethazol preplant and diazoben drenches at weekly or biweekly intervals may be slightly toxic. Additional experiments on control are in progress.
Lighting turkeys for off-season egg production
by Allen E. Woodard , Hans Abplanalp
Results from this study indicate that best turkey egg production is obtained from winter-hatched poults that are stimulated to lay at about 30 weeks of age following an exposure to 6 weeks of restricted light. Hens given stirnulatory light earlier (at 24 and 26 weeks of age) produced fewer and smaller eggs over a 20 week period of lay. These younger hens also tended to pause more frequently than older hens, and a greater percentage of the younger birds terminated egg production prematurely. It was of interest to note that approximately 54% of the hens in hatch 4 did not pause in lay at any time during the 20 weeks of lay, as compared with 77% of the hens in hatch 1. The incidence of pausing, irrespective of age of the hen, also appears to be concentrated in certain families within this study. The trait of broodiness has been greatly reduced in certain strains of chickens and small breeds of turkeys. Consequently similar genetic gains in decreased incidence of pausing can be anticipated in medium-to-large strains of turkeys. Thus increased rates of lay through improved genetic control of pausing may make it possible and economically profitable to supply light to hens before 30 weeks of age.
Adding formalin to milk helps in raising orphan lambs
by D. T. Torell
Abstract Not Available – First paragraph follows: Many newborn orphaned lambs die each year because ranchers cannot easily afford to take the time required to keep nursing equipment clean. As a result they often make no attempt to raise the orphaned lambs. Adding a bacteria-killing agent to the lambs' milk would eliminate the necessity of daily washing of equipment and would make orphan-lamb raising a more profitable operation. Formalin, a 37% solution of formaldehyde, has been used for many years as a bactericide and as a preservative, but it has never before been recommended for use in milk fed to lambs.
Chemically controlling root growth in containers
by Tok Furuta , Clay W. Jones , W. Humphrey , Tom Mock
Copper naphthenate, or copper sulfate, in a suitable carrier appears useful to eliminate growth of roots on the surface of the root ball of nursery plants in containers. Neither chemical presented a problem with soil ball integrity when transplanting, nor did they inhibit root growth following transplanting. While uptake was not determined, phytotoxicity due to excess copper uptake was not observed.
Rice straw… burning vs. incorporation
by W. A. Williams , M. D. Morse , J. E. Ruckman , F. P. Guerrero
Both burning and incorporating rice straw resulted in similar grain production and nitrogen economy for 8 years in a field planted annually to Colusa rice. There was no observable increase in disease or insect populations in any of the treatments.
Seed weevil released to control milk thistle
by R. B. Hawkes , L. A. Andres , P. H. Dunn
Abstract Not Available – First paragraph follows: Milk thistle, Silybum marianum (L.) Gaertn., is a widespread weed of increasing importance on range-land, ditch banks, highway and railroad right-of-ways, and wasteland in California. Although reported to be a biennial, it grows mainly as a winter annual, generally invading disturbed and overgrazed land. The plant reproduces only by seed.
editorial, news, letters & science briefs
New energy sources for agriculture
by Perry R. Stout