System (CIMIS) originated in 1982. Its purposes were to provide estimates of crop water requireme... more System (CIMIS) originated in 1982. Its purposes were to provide estimates of crop water requirements as influenced by real-time weather conditions and to ensure reasonable use of limited water supplies for farming. This study documents the effects of managing on-farm irrigation practices, with and without using ClMlS information, in a Kings County walnut orchard. In this example, increased water use, increased production, and increased profits were experienced as a result of implementing CIMIS information.
Management of Irrigation and Drainage Systems: Integrated Perspectives, 1993
Slow water penetration in irrigated soils is a complex problem of major importance in California&... more Slow water penetration in irrigated soils is a complex problem of major importance in California's $18 billion agricultural industry. The Kearney Foundation of Soil Science chose to work on this problem during its 1986-91 mission in order to fill gaps in research knowledge, develop improved diagnostic methods, explore innovative management options, and publish a manual that deals with managing soils with water penetration problems. The manual displayed at this conference, written by a team including professional writers, academic department members, and Cooperative Extension specialists and farm advisors, is designed to help the farmer, farm advisor, and consultant prevent, diagnose and solve problems of slow water penetration. It combines research information with the experience of California farmers, who have been coping with slow water penetration for a long time. Flow charts direct the reader, based on answers to key questions, to short sections that describe diagnostic methods and solutions to problems. An index provides another method to locate information, and a resource directory provides a list of experts on various aspects of water penetration problems.
An observational study was conducted in the northern Sacramento Valley in California, United Stat... more An observational study was conducted in the northern Sacramento Valley in California, United States to determine crop water use and crop coefficients of three adjacent young Nonpareil/Monterey almond orchards. Methods used to quantify evapotranspiration estimates of crop water use include (1) a soil water balance and (2) a land surface energy balance using eddy covariance. Three adjacent almond orchards that were planted in 2016, 2017, and 2018 were monitored from 2018 to 2020. Actual crop coefficients were determined using actual evapotranspiration estimates from each orchard and short grass reference evapotranspiration from the Gerber South California Irrigation Management Information System station. Results showed that crop water use and crop coefficients increased until the 4th year, indicating the need to closely consider tree development and orchard age as factors in irrigation scheduling of young almond trees. The results led to the conclusion that farmers should use developm...
This paper discusses the Central Valley Conditional Waiver for Discharges from Irrigated Lands (C... more This paper discusses the Central Valley Conditional Waiver for Discharges from Irrigated Lands (Conditional Waiver) that was adopted in 2003 and that is under consideration for renewal at the end of 2005. This paper will explore: how the Conditional Waiver came into affect in 2003; how the Conditional Waiver has progressed through 2005; future possibilities for the Conditional Waiver; and how the Conditional Waiver relates to alfalfa and forage crop production in the Central Valley both now and possibly into the future.
Delta); the San Joaquin Valley; coastal areas (the North, Central, and South Coasts); and the Sou... more Delta); the San Joaquin Valley; coastal areas (the North, Central, and South Coasts); and the Southern Desert (including irrigated southern desert areas) (fig. 1). The Intermountain Region includes the Tulelake Basin, where small grains are grown primarily as spring-sown crops, usually in rotation with alfalfa, onion, and potato. Oat may be rotated with barley as a control for root-knot nematode. In the remainder of the Intermountain Region, small grains are primarily rotation crops for alfalfa. Spring-sown barley and fall-sown winter wheat (primarily soft white wheat) are most common. Oat, barley, and wheat are grown for grain or forage; triticale is grown for grazing and hay production. Some rye is planted for seed production, forage, or as a winter cover crop. The Sacramento Valley produces a large share of California' s fall-sown hard red wheat, along with fall-sown hard white wheat, barley, oat, and triticale. Conditions range from shallow soils along the western, eastern, and northern margins of the valley (rainfed grain production areas) to the deep, highly organic soils of the Sacramento-San Joaquin Delta. On the valley floor irrigated small grains are grown in rotation with alfalfa, cotton, corn, rice, safflower, sugarbeet, sunflower, melons, and a wide range of vegetable crops. The San Joaquin Valley, like the Sacramento Valley, produces a large share of California' s fall-sown hard red wheat as well as hard white and durum wheat, barley, oat, and triticale. Most of the production is irrigated and grown in rotation with other field and vegetable crops including tomato, cotton, alfalfa, and others. Rainfed grain production occurs primarily in foothill areas along the east side of the valley. Coastal growing regions consist primarily of rainfed production systems. Conservation tillage is common in the central coastal region, where fall-sown spring barley is produced for feed. In areas of the central coast that produce high-value vegetable crops, rye grown as a green manure cover crop is an important rotation. In other locations, dry beans or alfalfa are rotated with small grains grown for grain or forage. Valleys in the Southern Desert Region are major producers of durum wheat for the pasta market. All durum acreage is irrigated; some feed barley and forage oat are grown. Some rainfed small grain is produced under conservation tillage (reduced-tillage) in the northern portion of the area. Irrigated small grain crops are rotated with lettuce, melons, alfalfa, sugarbeet, cotton, and other crops. SMALL gRAIN PRODuCTION AND uSE Wheat Although most of California' s wheat production is classified as fall-sown hard red spring wheat, other wheat classes (hard red winter, soft white winter, soft white spring, hard red spring, hard white, and durum) are also produced in California. Wheat is Figure 1. Primary production regions for small grains in California.
Can farmers use water more effectively? Two on-farm demonstrations compare irrigation methods Hig... more Can farmers use water more effectively? Two on-farm demonstrations compare irrigation methods High water tables and associated high salinity now hamper farm production across 400,000 acres of farmland in Fresno, Kings, Tulare and Kern Counties in the San Joaquin Valley. The two following reports describe farm demonstration projects undertaken to reduce drainwater volume while maintaining profitability. Performed at different sites under differing conditions, the projects yielded different results. An analysis of the combined results appears on page 1 1. (Ed.
SOUTH COAST INLAND PLAINS AND MOUNTAINS NORTH OF SAN FRANCISCO More sunlight and higher summer ET... more SOUTH COAST INLAND PLAINS AND MOUNTAINS NORTH OF SAN FRANCISCO More sunlight and higher summer ETo than zone 3. 5 NORTHERN INLAND VALLEYS Valleys north of San Francisco. 6 UPLAND CENTRAL COAST AND LOS ANGELES BASIN Higher-elevation coastal areas. 7 NORTHEASTERN PLAINS 8 INLAND SAN FRANCISCO BAY AREA Inland area near San Francisco with some marine influence. 9 SOUTH COAST MARINE-TO-DESERT TRANSITION Inland area between marine and desert climates. 10 NORTH CENTRAL PLATEAU AND CENTRAL COAST RANGE Cool, high-elevation areas with strong summer sunlight. This zone has limited climate data and the zone selection is somewhat subjective. 11 CENTRAL SIERRA NEVADA Sierra Nevada mountain valleys east of Sacramento with some influence from the delta breeze in summer. 12 EAST SIDE SACRAMENTO-SAN JOAQUIN VALLEY Low winter and high summer ETo with slightly lower ETo than zone 14. 13 NORTHERN SIERRA NEVADA Northern Sierra Nevada mountain valleys with less marine influence than zone 11. 14 MID-CENTRAL VALLEY, SOUTHERN SIERRA NEVADA, TEHACHAPI, AND HIGH DESERT MOUNTAINS High summer sunshine and wind in some locations. 15 NORTHERN AND SOUTHERN SAN JOAQUIN VALLEY Slightly lower winter ETo due to fog and slightly higher summer ETo than zones 12 and 14.
Low-Cost Methods of Measuring Diverted Water T he California State Water Resources Control Board ... more Low-Cost Methods of Measuring Diverted Water T he California State Water Resources Control Board requires that the amount of water diverted from the surface waters of the state be reported. For many years diverters were able to estimate the amount of water they diverted and report this estimate. Legislation passed in 2010 requires that the amount of water diverted be measured. Many water right owners are seeking to comply with this regulatory requirement. Other reasons to measure water could include the following: • to assure that the appropriate amount is diverted • to divide shared interest in water • to identify opportunities to save water for other uses This publication focuses on simple and inexpensive methods of measuring surface water to irrigate pastures and other lower-value crops where more advanced methods of measurement may not be as feasible. A simple method of estimating flow in open channels, along with installation and use of contracted rectangular and V-notch weirs, are discussed. Examples of how to apply the flow measurements are also provided. Basic Water Measurement in Open Channels (Float Method) The volume of water passing through a point on a stream per unit of time is used to measure stream flow. Two factors are required to determine volume (quantity) of water: cross-sectional area, generally in square feet (ft 2), and flow velocity, generally in feet per second (ft/sec). Flow is usually expressed in cubic feet per second (cfs).
SOUND CONCEPT OR MISCONCEPTION To many people, the Sacramento Valley appears as an expansive grou... more SOUND CONCEPT OR MISCONCEPTION To many people, the Sacramento Valley appears as an expansive groundwater basin filled with freshwater. It is also common to conceptualize the groundwater basin as an underground lake or a series of underground rivers that provide water to wells. Are these sound concepts or misconceptions? Recent interpretation of over 150 down-hole electrical resistivity logs from widely scattered locations throughout much of the northern Sacramento Valley has revealed that these simplistic concepts are incorrect. This pamphlet provides a glimpse of ongoing studies of the aquifer systems in the northern Sacramento Valley. The findings are preliminary and will likely improve as further information is gathered. Comprehensive reports of these studies should be available later in 2004.
Author(s): Forero, Larry; Satomi, Rick; Bali, Khaled; Zaccaria, Daniele; Fulton, Allan; Davy, Jos... more Author(s): Forero, Larry; Satomi, Rick; Bali, Khaled; Zaccaria, Daniele; Fulton, Allan; Davy, Josh | Abstract: Since stock ponds are not flat bottomed, the simplest way to monitor water volume is with a depth-capacity curve showing the total volume stored at various water levels throughout the season. You can use this publication to develop a pond curve, if one is not available for your stock water pond. You'll be walked through the steps needed to develop a pond curve - including data collection, instructions on using an ANR online app to develop your curve, how to determine volume.
Greater sustainability is one of the main goals of agricultural and natural resource policy in Ca... more Greater sustainability is one of the main goals of agricultural and natural resource policy in California and worldwide. "Diffusion networks," which consist mainly of connections among producers, local outreach and education agencies and agricultural organizations, provide critical pathways for achieving sustainability. We analyzed the role of diffusion networks in the context of agricultural water-quality management in the Sacramento River Valley. Data from a survey of more than 1,200 agricultural producers demonstrates the role of diffusion networks in increasing satisfaction with environmental policies, participation in water-quality management programs and the implementation of sustainable agricultural practices.
ratios captured relatively few moths (table 1). Analysis of the septa after this test showed that... more ratios captured relatively few moths (table 1). Analysis of the septa after this test showed that,after 19days,EZ:EEratiosinall septa had decreased to below the average figure of 89.2:10.8 found in the females. The ratios found in the lures indicate that, during the test, those with initial values of 98.5:1.5 and 90:lO EZ:EE were changing, mainly throughout the range found in the females, while the 80:20 lures would have been, at best, marginal at the beginning of the test and considerably below the values found in females during much of the test. Thus males in this area greatly preferred the percentages found in females native to this area. In San Diego, the 50:50 EZ:EE lures caught very few moths, while catches of the other treatments increased with increasing EZEE ratio (table 1). All seven single pair matings between low-ratio moths produced either all progeny in the 37 percent EZ range or progeny in both the 58 percent and 37 percent ranges (table 2). These results suggest that...
Abstract California’s weather is characterized by extreme droughts and floods. This has resulted ... more Abstract California’s weather is characterized by extreme droughts and floods. This has resulted in overdraft of groundwater aquifers as growers turn to this source of water for irrigation during droughts. California produces 99% of all walnuts in the US, walnut growers are under extreme pressure to optimize crop water use. Water use estimates at the field scale are crucial for growers to refine irrigation scheduling decisions. In this study, two single source remote sensing-based energy balance models (pySEBAL [python-based Surface Energy Balance Algorithm for Land] and SEBS [Surface Energy Balance System algorithm]) for estimating evapotranspiration (ETa) were evaluated against in-situ ETa measurements from surface renewal in two young walnut orchards in California’s Sacramento Valley. Strong correlations were obtained between the RS-based estimates and in-situ measurements for both pySEBAL and SEBS from 2017 to 2020, with R2 above 0.87, RMSE ranging from 0.79 to 1.05 mm, and NSE ranging from 0.79 to 0.88. SEBS out-performed pySEBAL on estimating time-series daily ETa for walnut at the field scale. During the mid-season characterized by high wind speed and high temperatures, pySEBAL and SEBS both underestimated ETa while the two models slightly overestimated ETa during the early growing season and post-harvest period. These results indicate the need for future research to focus on improving the performance of pySEBAL and SEBS when simulating time-series ETa under advection and sparse vegetation conditions, to provide more accurate ETa for both in-season and off-season irrigation water management. Comparisons of historical Kc and RS-based Kc were evaluated, and RS-based Kc matched better with the actual water use requirements of developing 2nd to 4th leaf young walnuts orchards. We observed substantial spatiotemporal variability of RS-based Kc in wo young walnut orchards at the CAPEX and Kauffman sites. For instance, Kc values for the north and south halves of the CAPEX orchard were above 1.2 and 0.9–1.1 respectively. Kc values for the north and south halves at the Kauffman site were in a range of 0.6–0.71 and 0.82–0.94 respectively. In other words, conventional irrigation management based on multiplying historical Kc and reference evapotranspiration is inadequate for site-specific walnut irrigation management due to spatial and temporal variability in Kc. ETa and Kc mapping from two single source models were similar in the spatial patterns and provided an overall visual characterization of the spatial variability in crop water use. Overall, RS-based ETa models using freely accessible satellite images and open-source algorithms could be used as an alternative to expensive in-situ measurements for enhancing site-specific young walnut irrigation management.
Garbanzo Bean (Chickpea) Production in California G arbanzo beans (chickpeas, Cicer arietinum) (f... more Garbanzo Bean (Chickpea) Production in California G arbanzo beans (chickpeas, Cicer arietinum) (fig. 1) are an annual grain legume, or "pulse crop, " that is used extensively for human consumption. In California, garbanzos are mostly grown for the canning industry as a high-end specialty product, including garnishes for salads. To meet this market demand, canning-quality garbanzo beans must be creamy colored, have a large, uniform seed size, and maintain firmness after canning with no seed splitting or skin peeling. There is also a market for the largeseeded, dry-packaged garbanzo beans. California's Mediterranean climate, with relatively warm, wet winters and hot, dry summers, provides ideal growing conditions for famers to meet this market demand. Most garbanzo beans grown around the world are smaller-seeded varieties that are often milled for flour or used for the increasingly popular hummus food spread.
The Journal of Horticultural Science and Biotechnology, 2006
Drought reduces photosynthesis in walnut (Juglans regia L.), but it is not known whether this is ... more Drought reduces photosynthesis in walnut (Juglans regia L.), but it is not known whether this is due mainly to the closure of stomata, or to possible effects on leaf biochemistry. In an attempt to answer this question we studied diurnal changes in the water status and gas exchange in droughted [50% crop evapotranspiration (ET c)] and fully irrigated (100% ET c) walnut trees, over 2 d. Stem water potential (⌿ s) ranged from-0.5 MPa in the morning to-1.2 MPa in the afternoon under drought, and from-0.1 MPa to-0.4 MPa under full watering. Net CO 2 assimilation (A max) ranged from 15 µmol CO 2 m-2 s-1 in the morning to 3 µmol CO 2 m-2 s-1 in the afternoon under drought, and from 25 µmol CO 2 m-2 s-1 in the morning to 10 µmol CO 2 mm-2 s-1 in the afternoon under full watering. At these times, stomatal conductance (g s) varied from 0.2 to 0.02 mol H 2 O m-2 s-1 and from 0.7 to 0.2 mol H 2 O m-2 s-1 , respectvely. Drought reduced the internal CO 2 concentration (C i) by about 55 µmol mol-1 on day-1, and by about 100 µmol mol-1 on day-2 and increased leaf temperature (T l) by about 2°-5°C. The reductions in g s and C i with drought suggest that lower photosynthesis was associated with stomatal closure. However, in each treatment, A max decreased during the day, while C i was stable, suggesting that photosynthesis was also reduced by a direct effect of heat on leaf biochemistry. Both A max and g s correlated with T l and with the leaf-to-air vapour pressure deficit (VPD l), but with different relationships for droughted and control trees. However, when stomatal limitations to photosynthesis were accounted for (i.e., based on the assumption that, under stomatal limitation, photosynthesis is proportional to C i , a single relationship between A max and T l described all the data (R 2 = 0.81). Thus, photosynthesis was limited by the closing of stomata under drought, and by a direct effect of heat on leaf biochemistry. These results suggest that hot and dry weather reduces photosynthesis and potential productivity in walnut in the absence of soil water deficit.
System (CIMIS) originated in 1982. Its purposes were to provide estimates of crop water requireme... more System (CIMIS) originated in 1982. Its purposes were to provide estimates of crop water requirements as influenced by real-time weather conditions and to ensure reasonable use of limited water supplies for farming. This study documents the effects of managing on-farm irrigation practices, with and without using ClMlS information, in a Kings County walnut orchard. In this example, increased water use, increased production, and increased profits were experienced as a result of implementing CIMIS information.
Management of Irrigation and Drainage Systems: Integrated Perspectives, 1993
Slow water penetration in irrigated soils is a complex problem of major importance in California&... more Slow water penetration in irrigated soils is a complex problem of major importance in California's $18 billion agricultural industry. The Kearney Foundation of Soil Science chose to work on this problem during its 1986-91 mission in order to fill gaps in research knowledge, develop improved diagnostic methods, explore innovative management options, and publish a manual that deals with managing soils with water penetration problems. The manual displayed at this conference, written by a team including professional writers, academic department members, and Cooperative Extension specialists and farm advisors, is designed to help the farmer, farm advisor, and consultant prevent, diagnose and solve problems of slow water penetration. It combines research information with the experience of California farmers, who have been coping with slow water penetration for a long time. Flow charts direct the reader, based on answers to key questions, to short sections that describe diagnostic methods and solutions to problems. An index provides another method to locate information, and a resource directory provides a list of experts on various aspects of water penetration problems.
An observational study was conducted in the northern Sacramento Valley in California, United Stat... more An observational study was conducted in the northern Sacramento Valley in California, United States to determine crop water use and crop coefficients of three adjacent young Nonpareil/Monterey almond orchards. Methods used to quantify evapotranspiration estimates of crop water use include (1) a soil water balance and (2) a land surface energy balance using eddy covariance. Three adjacent almond orchards that were planted in 2016, 2017, and 2018 were monitored from 2018 to 2020. Actual crop coefficients were determined using actual evapotranspiration estimates from each orchard and short grass reference evapotranspiration from the Gerber South California Irrigation Management Information System station. Results showed that crop water use and crop coefficients increased until the 4th year, indicating the need to closely consider tree development and orchard age as factors in irrigation scheduling of young almond trees. The results led to the conclusion that farmers should use developm...
This paper discusses the Central Valley Conditional Waiver for Discharges from Irrigated Lands (C... more This paper discusses the Central Valley Conditional Waiver for Discharges from Irrigated Lands (Conditional Waiver) that was adopted in 2003 and that is under consideration for renewal at the end of 2005. This paper will explore: how the Conditional Waiver came into affect in 2003; how the Conditional Waiver has progressed through 2005; future possibilities for the Conditional Waiver; and how the Conditional Waiver relates to alfalfa and forage crop production in the Central Valley both now and possibly into the future.
Delta); the San Joaquin Valley; coastal areas (the North, Central, and South Coasts); and the Sou... more Delta); the San Joaquin Valley; coastal areas (the North, Central, and South Coasts); and the Southern Desert (including irrigated southern desert areas) (fig. 1). The Intermountain Region includes the Tulelake Basin, where small grains are grown primarily as spring-sown crops, usually in rotation with alfalfa, onion, and potato. Oat may be rotated with barley as a control for root-knot nematode. In the remainder of the Intermountain Region, small grains are primarily rotation crops for alfalfa. Spring-sown barley and fall-sown winter wheat (primarily soft white wheat) are most common. Oat, barley, and wheat are grown for grain or forage; triticale is grown for grazing and hay production. Some rye is planted for seed production, forage, or as a winter cover crop. The Sacramento Valley produces a large share of California' s fall-sown hard red wheat, along with fall-sown hard white wheat, barley, oat, and triticale. Conditions range from shallow soils along the western, eastern, and northern margins of the valley (rainfed grain production areas) to the deep, highly organic soils of the Sacramento-San Joaquin Delta. On the valley floor irrigated small grains are grown in rotation with alfalfa, cotton, corn, rice, safflower, sugarbeet, sunflower, melons, and a wide range of vegetable crops. The San Joaquin Valley, like the Sacramento Valley, produces a large share of California' s fall-sown hard red wheat as well as hard white and durum wheat, barley, oat, and triticale. Most of the production is irrigated and grown in rotation with other field and vegetable crops including tomato, cotton, alfalfa, and others. Rainfed grain production occurs primarily in foothill areas along the east side of the valley. Coastal growing regions consist primarily of rainfed production systems. Conservation tillage is common in the central coastal region, where fall-sown spring barley is produced for feed. In areas of the central coast that produce high-value vegetable crops, rye grown as a green manure cover crop is an important rotation. In other locations, dry beans or alfalfa are rotated with small grains grown for grain or forage. Valleys in the Southern Desert Region are major producers of durum wheat for the pasta market. All durum acreage is irrigated; some feed barley and forage oat are grown. Some rainfed small grain is produced under conservation tillage (reduced-tillage) in the northern portion of the area. Irrigated small grain crops are rotated with lettuce, melons, alfalfa, sugarbeet, cotton, and other crops. SMALL gRAIN PRODuCTION AND uSE Wheat Although most of California' s wheat production is classified as fall-sown hard red spring wheat, other wheat classes (hard red winter, soft white winter, soft white spring, hard red spring, hard white, and durum) are also produced in California. Wheat is Figure 1. Primary production regions for small grains in California.
Can farmers use water more effectively? Two on-farm demonstrations compare irrigation methods Hig... more Can farmers use water more effectively? Two on-farm demonstrations compare irrigation methods High water tables and associated high salinity now hamper farm production across 400,000 acres of farmland in Fresno, Kings, Tulare and Kern Counties in the San Joaquin Valley. The two following reports describe farm demonstration projects undertaken to reduce drainwater volume while maintaining profitability. Performed at different sites under differing conditions, the projects yielded different results. An analysis of the combined results appears on page 1 1. (Ed.
SOUTH COAST INLAND PLAINS AND MOUNTAINS NORTH OF SAN FRANCISCO More sunlight and higher summer ET... more SOUTH COAST INLAND PLAINS AND MOUNTAINS NORTH OF SAN FRANCISCO More sunlight and higher summer ETo than zone 3. 5 NORTHERN INLAND VALLEYS Valleys north of San Francisco. 6 UPLAND CENTRAL COAST AND LOS ANGELES BASIN Higher-elevation coastal areas. 7 NORTHEASTERN PLAINS 8 INLAND SAN FRANCISCO BAY AREA Inland area near San Francisco with some marine influence. 9 SOUTH COAST MARINE-TO-DESERT TRANSITION Inland area between marine and desert climates. 10 NORTH CENTRAL PLATEAU AND CENTRAL COAST RANGE Cool, high-elevation areas with strong summer sunlight. This zone has limited climate data and the zone selection is somewhat subjective. 11 CENTRAL SIERRA NEVADA Sierra Nevada mountain valleys east of Sacramento with some influence from the delta breeze in summer. 12 EAST SIDE SACRAMENTO-SAN JOAQUIN VALLEY Low winter and high summer ETo with slightly lower ETo than zone 14. 13 NORTHERN SIERRA NEVADA Northern Sierra Nevada mountain valleys with less marine influence than zone 11. 14 MID-CENTRAL VALLEY, SOUTHERN SIERRA NEVADA, TEHACHAPI, AND HIGH DESERT MOUNTAINS High summer sunshine and wind in some locations. 15 NORTHERN AND SOUTHERN SAN JOAQUIN VALLEY Slightly lower winter ETo due to fog and slightly higher summer ETo than zones 12 and 14.
Low-Cost Methods of Measuring Diverted Water T he California State Water Resources Control Board ... more Low-Cost Methods of Measuring Diverted Water T he California State Water Resources Control Board requires that the amount of water diverted from the surface waters of the state be reported. For many years diverters were able to estimate the amount of water they diverted and report this estimate. Legislation passed in 2010 requires that the amount of water diverted be measured. Many water right owners are seeking to comply with this regulatory requirement. Other reasons to measure water could include the following: • to assure that the appropriate amount is diverted • to divide shared interest in water • to identify opportunities to save water for other uses This publication focuses on simple and inexpensive methods of measuring surface water to irrigate pastures and other lower-value crops where more advanced methods of measurement may not be as feasible. A simple method of estimating flow in open channels, along with installation and use of contracted rectangular and V-notch weirs, are discussed. Examples of how to apply the flow measurements are also provided. Basic Water Measurement in Open Channels (Float Method) The volume of water passing through a point on a stream per unit of time is used to measure stream flow. Two factors are required to determine volume (quantity) of water: cross-sectional area, generally in square feet (ft 2), and flow velocity, generally in feet per second (ft/sec). Flow is usually expressed in cubic feet per second (cfs).
SOUND CONCEPT OR MISCONCEPTION To many people, the Sacramento Valley appears as an expansive grou... more SOUND CONCEPT OR MISCONCEPTION To many people, the Sacramento Valley appears as an expansive groundwater basin filled with freshwater. It is also common to conceptualize the groundwater basin as an underground lake or a series of underground rivers that provide water to wells. Are these sound concepts or misconceptions? Recent interpretation of over 150 down-hole electrical resistivity logs from widely scattered locations throughout much of the northern Sacramento Valley has revealed that these simplistic concepts are incorrect. This pamphlet provides a glimpse of ongoing studies of the aquifer systems in the northern Sacramento Valley. The findings are preliminary and will likely improve as further information is gathered. Comprehensive reports of these studies should be available later in 2004.
Author(s): Forero, Larry; Satomi, Rick; Bali, Khaled; Zaccaria, Daniele; Fulton, Allan; Davy, Jos... more Author(s): Forero, Larry; Satomi, Rick; Bali, Khaled; Zaccaria, Daniele; Fulton, Allan; Davy, Josh | Abstract: Since stock ponds are not flat bottomed, the simplest way to monitor water volume is with a depth-capacity curve showing the total volume stored at various water levels throughout the season. You can use this publication to develop a pond curve, if one is not available for your stock water pond. You'll be walked through the steps needed to develop a pond curve - including data collection, instructions on using an ANR online app to develop your curve, how to determine volume.
Greater sustainability is one of the main goals of agricultural and natural resource policy in Ca... more Greater sustainability is one of the main goals of agricultural and natural resource policy in California and worldwide. "Diffusion networks," which consist mainly of connections among producers, local outreach and education agencies and agricultural organizations, provide critical pathways for achieving sustainability. We analyzed the role of diffusion networks in the context of agricultural water-quality management in the Sacramento River Valley. Data from a survey of more than 1,200 agricultural producers demonstrates the role of diffusion networks in increasing satisfaction with environmental policies, participation in water-quality management programs and the implementation of sustainable agricultural practices.
ratios captured relatively few moths (table 1). Analysis of the septa after this test showed that... more ratios captured relatively few moths (table 1). Analysis of the septa after this test showed that,after 19days,EZ:EEratiosinall septa had decreased to below the average figure of 89.2:10.8 found in the females. The ratios found in the lures indicate that, during the test, those with initial values of 98.5:1.5 and 90:lO EZ:EE were changing, mainly throughout the range found in the females, while the 80:20 lures would have been, at best, marginal at the beginning of the test and considerably below the values found in females during much of the test. Thus males in this area greatly preferred the percentages found in females native to this area. In San Diego, the 50:50 EZ:EE lures caught very few moths, while catches of the other treatments increased with increasing EZEE ratio (table 1). All seven single pair matings between low-ratio moths produced either all progeny in the 37 percent EZ range or progeny in both the 58 percent and 37 percent ranges (table 2). These results suggest that...
Abstract California’s weather is characterized by extreme droughts and floods. This has resulted ... more Abstract California’s weather is characterized by extreme droughts and floods. This has resulted in overdraft of groundwater aquifers as growers turn to this source of water for irrigation during droughts. California produces 99% of all walnuts in the US, walnut growers are under extreme pressure to optimize crop water use. Water use estimates at the field scale are crucial for growers to refine irrigation scheduling decisions. In this study, two single source remote sensing-based energy balance models (pySEBAL [python-based Surface Energy Balance Algorithm for Land] and SEBS [Surface Energy Balance System algorithm]) for estimating evapotranspiration (ETa) were evaluated against in-situ ETa measurements from surface renewal in two young walnut orchards in California’s Sacramento Valley. Strong correlations were obtained between the RS-based estimates and in-situ measurements for both pySEBAL and SEBS from 2017 to 2020, with R2 above 0.87, RMSE ranging from 0.79 to 1.05 mm, and NSE ranging from 0.79 to 0.88. SEBS out-performed pySEBAL on estimating time-series daily ETa for walnut at the field scale. During the mid-season characterized by high wind speed and high temperatures, pySEBAL and SEBS both underestimated ETa while the two models slightly overestimated ETa during the early growing season and post-harvest period. These results indicate the need for future research to focus on improving the performance of pySEBAL and SEBS when simulating time-series ETa under advection and sparse vegetation conditions, to provide more accurate ETa for both in-season and off-season irrigation water management. Comparisons of historical Kc and RS-based Kc were evaluated, and RS-based Kc matched better with the actual water use requirements of developing 2nd to 4th leaf young walnuts orchards. We observed substantial spatiotemporal variability of RS-based Kc in wo young walnut orchards at the CAPEX and Kauffman sites. For instance, Kc values for the north and south halves of the CAPEX orchard were above 1.2 and 0.9–1.1 respectively. Kc values for the north and south halves at the Kauffman site were in a range of 0.6–0.71 and 0.82–0.94 respectively. In other words, conventional irrigation management based on multiplying historical Kc and reference evapotranspiration is inadequate for site-specific walnut irrigation management due to spatial and temporal variability in Kc. ETa and Kc mapping from two single source models were similar in the spatial patterns and provided an overall visual characterization of the spatial variability in crop water use. Overall, RS-based ETa models using freely accessible satellite images and open-source algorithms could be used as an alternative to expensive in-situ measurements for enhancing site-specific young walnut irrigation management.
Garbanzo Bean (Chickpea) Production in California G arbanzo beans (chickpeas, Cicer arietinum) (f... more Garbanzo Bean (Chickpea) Production in California G arbanzo beans (chickpeas, Cicer arietinum) (fig. 1) are an annual grain legume, or "pulse crop, " that is used extensively for human consumption. In California, garbanzos are mostly grown for the canning industry as a high-end specialty product, including garnishes for salads. To meet this market demand, canning-quality garbanzo beans must be creamy colored, have a large, uniform seed size, and maintain firmness after canning with no seed splitting or skin peeling. There is also a market for the largeseeded, dry-packaged garbanzo beans. California's Mediterranean climate, with relatively warm, wet winters and hot, dry summers, provides ideal growing conditions for famers to meet this market demand. Most garbanzo beans grown around the world are smaller-seeded varieties that are often milled for flour or used for the increasingly popular hummus food spread.
The Journal of Horticultural Science and Biotechnology, 2006
Drought reduces photosynthesis in walnut (Juglans regia L.), but it is not known whether this is ... more Drought reduces photosynthesis in walnut (Juglans regia L.), but it is not known whether this is due mainly to the closure of stomata, or to possible effects on leaf biochemistry. In an attempt to answer this question we studied diurnal changes in the water status and gas exchange in droughted [50% crop evapotranspiration (ET c)] and fully irrigated (100% ET c) walnut trees, over 2 d. Stem water potential (⌿ s) ranged from-0.5 MPa in the morning to-1.2 MPa in the afternoon under drought, and from-0.1 MPa to-0.4 MPa under full watering. Net CO 2 assimilation (A max) ranged from 15 µmol CO 2 m-2 s-1 in the morning to 3 µmol CO 2 m-2 s-1 in the afternoon under drought, and from 25 µmol CO 2 m-2 s-1 in the morning to 10 µmol CO 2 mm-2 s-1 in the afternoon under full watering. At these times, stomatal conductance (g s) varied from 0.2 to 0.02 mol H 2 O m-2 s-1 and from 0.7 to 0.2 mol H 2 O m-2 s-1 , respectvely. Drought reduced the internal CO 2 concentration (C i) by about 55 µmol mol-1 on day-1, and by about 100 µmol mol-1 on day-2 and increased leaf temperature (T l) by about 2°-5°C. The reductions in g s and C i with drought suggest that lower photosynthesis was associated with stomatal closure. However, in each treatment, A max decreased during the day, while C i was stable, suggesting that photosynthesis was also reduced by a direct effect of heat on leaf biochemistry. Both A max and g s correlated with T l and with the leaf-to-air vapour pressure deficit (VPD l), but with different relationships for droughted and control trees. However, when stomatal limitations to photosynthesis were accounted for (i.e., based on the assumption that, under stomatal limitation, photosynthesis is proportional to C i , a single relationship between A max and T l described all the data (R 2 = 0.81). Thus, photosynthesis was limited by the closing of stomata under drought, and by a direct effect of heat on leaf biochemistry. These results suggest that hot and dry weather reduces photosynthesis and potential productivity in walnut in the absence of soil water deficit.
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Papers by Allan Fulton