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California Agriculture, Vol. 59, No.3

Collecting useful data streams to restore cold-water fisheries
Cover:  Monitoring of stream temperature and related factors is critical for protecting and restoring populations of salmonids and the other native fish that require cold-water and reproduce (see pages 149,153, 161). Likewise, the monitoring of flows into and out of irrigated pasture can help to mitigate environmental impacts (see page 168). Data collected at Lassen Creek (shown), in north-eastern Modoc County, demonstrates how shade from thick vegetative cover helps to maintain cool stream temperatures... Photo by Kenneth W. Tate .
July-September 2005
Volume 59, Number 3

Peer-reviewed research and review articles

Graphical analysis facilitates evaluation of stream-temperature monitoring data
by Kenneth W. Tate, David F. Lile, Donald L. Lancaster, Marni L. Porath, Julie A. Morrison, Yukako Sado
| Full text HTML  | PDF  
A case study shows how monitoring projects can display stream-temperature data, along with critical parameters such as canopy cover and stream flow.
Watershed groups, individuals, and land management and regulatory agencies are collecting stream-temperature data in order to understand, protect and enhance cold-water fisheries. While great quantities of data are being generated, its analysis and interpretation are often not adequate to identify stream reaches that are gaining or losing temperature, or to correlate temperature changes with factors such as vegetative canopy cover or stream-flow levels. We use a case study from the Lassen and Willow creek watersheds in northeastern Modoc County to demonstrate graphical methods for displaying, analyzing and interpreting stream-temperature data.
Statistical analysis of monitoring data aids in prediction of stream temperature
by Kenneth W. Tate, David F. Lile, Donald L. Lancaster, Marin L. Porath, Julie A. Morrison, Yukako Sado
| Full text HTML  | PDF  
Statistical analysis can make it easier to interpret and present the huge amounts of data collected in typical stream-temperature monitoring projects.
Declines in cold-water habitat and fisheries have generated stream-temperature monitoring efforts across Northern California and the western United States. We demonstrate a statistical analysis approach to facilitate the interpretation and application of these data sets to achieve monitoring objectives. Specifically, we used data collected from the Willow and Lassen creek watersheds in Modoc County to demonstrate a method for identifying and quantifying potential relationships between stream temperature and factors such as stream flow, canopy cover and air temperature. Our monitoring data clearly indicated that a combination of management practices to increase both in-stream flow and canopy cover can be expected to reduce stream temperature on the watersheds studied.
Monitoring helps reduce water-quality impacts in flood-irrigated pasture
by Kenneth W. Tate, Donald L. Lancaster, Julie A. Morrison, David F. Lile, Yukako Sado, Betsy Huang
| Full text HTML  | PDF  
Agricultural operators can improve water-quality by monitoring irrigation runoff and downstream waters, then managing irrigation accordingly.
Northern California has extensive areas of irrigated pasture, which provide critical summer forage for livestock. In many of these systems, water is diverted directly from a stream into ditches or pipes and transported to individual pastures, where it is applied as flood surface irrigation. Our case study of discharges from irrigated pastures on Willow and Lassen creeks in Modoc County illustrates an assessment and monitoring approach for land managers and natural-resources professionals working to resolve water-quality impairments related to agricultural discharges from similar systems. We report correlations between four indicator variables measured in the field and the variables determined in the laboratory, to evaluate the potential for employing a strategic combination of the two.
Soil sterilization and organic carbon, but not microbial inoculants, change microbial communities in replanted peach orchards
by Rebecca E. Drenovsky, Roger A. Duncan, Kate M. Scow
| Full text HTML  | PDF  
Commercial soil inoculants plus organic carbon improved soil composition no better than simple organic carbon alone; plastic mulch performed well compared with chemical fumigants.
Methyl bromide is highly effective in reducing soil pathogens. Although its use was to be phased out completely in the United States by Jan. 1, 2005, due to environmental concerns, a 1-year critical-use exemption will allow tree fruit growers to use the fumigant through the end of the year. To explore possible replacements for methyl bromide, we compared the effects of pre- and postplant treatments and amendments on soil microbial communities and tree vigor in a replanted peach orchard. Both soil sterilization treatments and organic carbon amendments changed the composition of microbial communities in the soil. High microbial biomass is generally considered beneficial to agricultural soils; we found that it was usually highest in soils that received the organic carbon amendment and lowest in those with soil sterilization. However, tree vigor was highest with the sterilization treatments. The effects of a microbial inoculants/organic carbon combination on microbial communities and plant vigor were no different from simply adding organic carbon.
Site-specific herbicide applications based on weed maps provide effective control
by Martina Koller, W. Thomas Lanini
| Full text HTML  | PDF  
Seedling and adult weeds were mapped by hand and incorporated into a variable-rate spraying scheme, for significant herbicide-use reductions.
More-effective weed control in agricultural fields can be achieved by utilizing information about the spatial distribution of the previous year's mature weeds. In our study, variable-rate herbicide applications based on weed infestation maps developed just before the previous year's harvest provided effective weed control. The results showed that when information about the spatial distribution of the previous year's weed seedlings or mature weeds was used, weed control was comparable to uniform, one-rate, herbicide applications, while the total amount of herbicide applied decreased. Herbicide use was reduced an estimated 39% for the seedling map and 24% for the mature map approach. However, incorporating the weed-seed redistribution from harvest to application time into the treatment maps could further improve weed control.
Drip irrigation can effectively apply boron to San Joaquin Valley vineyards
by William L. Peacock, L. Peter Christensen
| Full text HTML  | PDF  
The range between boron deficiency and toxicity is narrow; monitoring is critical to maintain productive vines.
Boron deficiency of grapevines occurs occasionally on the east side of the San Joaquin Valley. Its symptoms include shot berries, shoot-tip dieback and leaves with yellowish mottling between veins. Boron must be applied carefully because the range between deficiency and toxicity is narrow. Our research evaluated the safety and efficacy of boron fertigation of grapevines using drip irrigation. Applying boron annually at 1/3 pound per acre to a moderately deficient vineyard elevated tissue levels into the adequate range within 2 years. However, the amount of boron used in a fertigation maintenance program will vary with leaching potential. Blade samples should be routinely monitored following fertigation and fertilizer amounts adjusted accordingly to avoid boron toxicity or deficiency.
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California Agriculture, Vol. 59, No.3

Collecting useful data streams to restore cold-water fisheries
Cover:  Monitoring of stream temperature and related factors is critical for protecting and restoring populations of salmonids and the other native fish that require cold-water and reproduce (see pages 149,153, 161). Likewise, the monitoring of flows into and out of irrigated pasture can help to mitigate environmental impacts (see page 168). Data collected at Lassen Creek (shown), in north-eastern Modoc County, demonstrates how shade from thick vegetative cover helps to maintain cool stream temperatures... Photo by Kenneth W. Tate .
July-September 2005
Volume 59, Number 3

Peer-reviewed research and review articles

Graphical analysis facilitates evaluation of stream-temperature monitoring data
by Kenneth W. Tate, David F. Lile, Donald L. Lancaster, Marni L. Porath, Julie A. Morrison, Yukako Sado
| Full text HTML  | PDF  
A case study shows how monitoring projects can display stream-temperature data, along with critical parameters such as canopy cover and stream flow.
Watershed groups, individuals, and land management and regulatory agencies are collecting stream-temperature data in order to understand, protect and enhance cold-water fisheries. While great quantities of data are being generated, its analysis and interpretation are often not adequate to identify stream reaches that are gaining or losing temperature, or to correlate temperature changes with factors such as vegetative canopy cover or stream-flow levels. We use a case study from the Lassen and Willow creek watersheds in northeastern Modoc County to demonstrate graphical methods for displaying, analyzing and interpreting stream-temperature data.
Statistical analysis of monitoring data aids in prediction of stream temperature
by Kenneth W. Tate, David F. Lile, Donald L. Lancaster, Marin L. Porath, Julie A. Morrison, Yukako Sado
| Full text HTML  | PDF  
Statistical analysis can make it easier to interpret and present the huge amounts of data collected in typical stream-temperature monitoring projects.
Declines in cold-water habitat and fisheries have generated stream-temperature monitoring efforts across Northern California and the western United States. We demonstrate a statistical analysis approach to facilitate the interpretation and application of these data sets to achieve monitoring objectives. Specifically, we used data collected from the Willow and Lassen creek watersheds in Modoc County to demonstrate a method for identifying and quantifying potential relationships between stream temperature and factors such as stream flow, canopy cover and air temperature. Our monitoring data clearly indicated that a combination of management practices to increase both in-stream flow and canopy cover can be expected to reduce stream temperature on the watersheds studied.
Monitoring helps reduce water-quality impacts in flood-irrigated pasture
by Kenneth W. Tate, Donald L. Lancaster, Julie A. Morrison, David F. Lile, Yukako Sado, Betsy Huang
| Full text HTML  | PDF  
Agricultural operators can improve water-quality by monitoring irrigation runoff and downstream waters, then managing irrigation accordingly.
Northern California has extensive areas of irrigated pasture, which provide critical summer forage for livestock. In many of these systems, water is diverted directly from a stream into ditches or pipes and transported to individual pastures, where it is applied as flood surface irrigation. Our case study of discharges from irrigated pastures on Willow and Lassen creeks in Modoc County illustrates an assessment and monitoring approach for land managers and natural-resources professionals working to resolve water-quality impairments related to agricultural discharges from similar systems. We report correlations between four indicator variables measured in the field and the variables determined in the laboratory, to evaluate the potential for employing a strategic combination of the two.
Soil sterilization and organic carbon, but not microbial inoculants, change microbial communities in replanted peach orchards
by Rebecca E. Drenovsky, Roger A. Duncan, Kate M. Scow
| Full text HTML  | PDF  
Commercial soil inoculants plus organic carbon improved soil composition no better than simple organic carbon alone; plastic mulch performed well compared with chemical fumigants.
Methyl bromide is highly effective in reducing soil pathogens. Although its use was to be phased out completely in the United States by Jan. 1, 2005, due to environmental concerns, a 1-year critical-use exemption will allow tree fruit growers to use the fumigant through the end of the year. To explore possible replacements for methyl bromide, we compared the effects of pre- and postplant treatments and amendments on soil microbial communities and tree vigor in a replanted peach orchard. Both soil sterilization treatments and organic carbon amendments changed the composition of microbial communities in the soil. High microbial biomass is generally considered beneficial to agricultural soils; we found that it was usually highest in soils that received the organic carbon amendment and lowest in those with soil sterilization. However, tree vigor was highest with the sterilization treatments. The effects of a microbial inoculants/organic carbon combination on microbial communities and plant vigor were no different from simply adding organic carbon.
Site-specific herbicide applications based on weed maps provide effective control
by Martina Koller, W. Thomas Lanini
| Full text HTML  | PDF  
Seedling and adult weeds were mapped by hand and incorporated into a variable-rate spraying scheme, for significant herbicide-use reductions.
More-effective weed control in agricultural fields can be achieved by utilizing information about the spatial distribution of the previous year's mature weeds. In our study, variable-rate herbicide applications based on weed infestation maps developed just before the previous year's harvest provided effective weed control. The results showed that when information about the spatial distribution of the previous year's weed seedlings or mature weeds was used, weed control was comparable to uniform, one-rate, herbicide applications, while the total amount of herbicide applied decreased. Herbicide use was reduced an estimated 39% for the seedling map and 24% for the mature map approach. However, incorporating the weed-seed redistribution from harvest to application time into the treatment maps could further improve weed control.
Drip irrigation can effectively apply boron to San Joaquin Valley vineyards
by William L. Peacock, L. Peter Christensen
| Full text HTML  | PDF  
The range between boron deficiency and toxicity is narrow; monitoring is critical to maintain productive vines.
Boron deficiency of grapevines occurs occasionally on the east side of the San Joaquin Valley. Its symptoms include shot berries, shoot-tip dieback and leaves with yellowish mottling between veins. Boron must be applied carefully because the range between deficiency and toxicity is narrow. Our research evaluated the safety and efficacy of boron fertigation of grapevines using drip irrigation. Applying boron annually at 1/3 pound per acre to a moderately deficient vineyard elevated tissue levels into the adequate range within 2 years. However, the amount of boron used in a fertigation maintenance program will vary with leaching potential. Blade samples should be routinely monitored following fertigation and fertilizer amounts adjusted accordingly to avoid boron toxicity or deficiency.

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