California Agriculture, January-February 1999
Volume 53, Number 1
Bay-Delta debate: Who will get the water?
peer-reviewed research articles
Saline water can be reused to irrigate sugarbeets, but sugar may be low
by Stephen Kaffka , Dong Daxue , Gary Peterson
Salt is currently being transported into the San Joaquin Valley via rivers and irrigation water at about three times the rate that it is being removed, endangering the productivity of agricultural land. As a possible salt-management solution, the San Joaquin Valley Drainage Implementation Program seeks to reuse saline water, such as tile drainage water or shallow well water, in crop production. Sugarbeet is a deep-rooted, salt-tolerant crop that can be used as part of a cyclic reuse program to reduce drainage-water volume and conserve high-quality water. Although sugarbeets grown with saline water produced adequate yields on test plots, sugar percentages declined because nitrogen also was present in the irrigation water source. For this reason, irrigating sugarbeets with alternative water sources is more complex, requiring accounting of nitrogen in reused water together with soil nitrogen to assure adequate crop quality.
Shot hole encourages almond drop, doesn't harm kernels
by Beth L. Teviotdale , Nancy Goodell , Dennis Harper
Severe spring outbreaks of shot hole disease are often accompanied by leaf fall and fruit drop. Although fruit are shed in response to defoliation, the direct effect of shot hole infection on developing fruit was not known. When fruit at various stages of development were inoculated with high concentrations of the shot hole pathogen, very young and midsized fruit fell, whereas older fruit were retained. Typical shot hole lesions developed on midsized fruit, and full-sized fruit became resistant to infection when embryo development began. Infection did not affect kernel weight, but caused a slight, economically unimportant reduction in kernel length.
Contaminants and injury induce inking on peaches and nectarines
by Carlos H. Crisosto , R. Scott Johnson , Kevin R. Day , Bob Beede , Harry Andris
After 3 years of study, we have demonstrated that physical injury combined with contamination cause skin discoloration, called inking, on peaches and nectarines. Abrasion damage releases anthocyanin/phenolic pigments, which are located in the skin cells, allowing the reaction of these pigments with the heavy-metal contaminants. We found that iron, copper and aluminum were the most deleterious contaminants of those studied in inducing inking on abraded fruit. Approximately 10 ppm iron was enough to induce inking at the physiological fruit pH (~3.5). This contamination can occur within 15 days before harvest, or during harvest or packing operations. Foliar-nutrient, fungicide and insecticide preharvest sprays may act as sources of contamination for inking development, depending on the preharvest application interval. To reduce inking incidence, we have developed safe preharvest application intervals that yield low inking incidence benomyl for iprodione (Rovral), triforine (Funginex), vinclozolin (Ronilan DF) (Benlate) and certain foliar nutrients containing heavy metals.
Farmers adopt new irrigation and fertilizer techniques: Changes could help growers maintain yields, protect water quality
by Joe Dillon , Susan Edinger-Marshall , John Letey
During January and February 1997, farmers in 42 California counties were surveyed about irrigation and nutrient management techniques for individual crops during the 1986 and 1996 growing years. More than 800 responses were analyzed to identify trends in these management areas and relate the rates of change. The responses indicate that the acreage irrigated with gravity systems decreased 11% over the 10-year period while the use of microirrigation systems increased 12%. Our assessment of the rate of change agrees with an analysis of previous irrigation surveys. The percentage of growers utilizing nitrogen management techniques such as fertigation, foliar applications, soil analysis and plant-tissue testing has increased in the last decade throughout much of the state and on most crop types. Farms that changed their irrigation systems adopted new nutrient management techniques at a more rapid rate than farms that did not change their irrigation system, showing that these two management spheres are intertwined. Despite the adoption of “more-efficient” nitrogen management techniques, in most cases (57%) farmers are applying the same amount of nitrogen fertilizer to their fields or even more nitrogen fertilizer (24%) than a decade ago.
Food preparation practices influence nutrition
by Estella West , Cathi Lamp , Amy Block Joy , Suzanne Murphy , Mark Hudes , Sybille Bunch , Joan Wright
How do low-income families' food preparation practices contribute to their nutrition? To answer this question, 97 families in the Expanded Food and Nutrition Education Program (EFNEP) were surveyed about their cooking methods and food purchasing practices. The survey revealed that more-adequately nourished families were more likely to prepare dishes from scratch, purchase more fruits and vegetables, and use a greater variety of cooking methods. Researchers also found that EFNEP families could benefit from learning food preparation skills that reduce fat in the diet, particularly learning new ways to prepare fruits and vegetables — foods that are naturally low in fat.
Farmworkers positive about their jobs, but suggest improvements
by Gregory Encina Billikopf
A study conducted in 1995 reveals farmworkers are generally content with their jobs. Seasonal and year-round workers in orchard, vineyard, vegetable, agronomic, dairy and livestock operations in the Northern San Joaquin Valley were interviewed. Workers were generally complimentary to both supervisors and farm employers. One worker summed it up best, when he explained that he loved the job but it would be perfect if it paid better. An important implication is that workers may not necessarily be looking for work outside of agriculture. The 265 survey participants did, however, suggest numerous changes that supervisors and farm employers can make to improve the working conditions of agricultural laborers. Their suggestions included treating workers with more respect, constructive criticism of job performance, reasonable work pace and complete job instructions.
Desert heat degrades quality of stored alfalfa hay
by Juan N. Guerrero , S. Sherwood Winans
To quantify the effects of summertime heat on baled alfalfa hay, we baled alfalfa in May 1993 in three areas of the irrigated Sonoran Desert and stored it for 20 weeks. At each site we subjected the bales to four different storage treatments: an air-conditioned room, unprotected in full sunlight, in full sunlight but covered with a plastic tarp, and under a roof. Temperatures of the bales stored in full sunlight, whether tarped or unprotected, often exceeded 120°F for extended periods of time. After 20 weeks, feed quality of the bales stored in full sunlight decreased more than the quality of the shaded bales and those kept in an air-conditioned room. Bales stored unprotected in full sunlight dried out excessively and became brittle. Protected from the scant summer rainfall, the tarp-covered bales did not bleach and were able to maintain moisture for a longer period of time. Among the three outdoor treatments, nutritive quality of alfalfa hay bales was best preserved by storage under a protective roof.
editorial, news, letters & science briefs
Strategic planning enters new phase
by W.R. Gomes
Safety award winners describe best practices
UC shores up research for CALFED: How do you slice the water pie?
Q & A: Devising a water strategy for the 21st century
by Henry J. Vaux