A. Devincentis, S. Solis, S. Rice, D. Zaccaria, R. Snyder, M. Maskey, Anna Gomes, A. Gaudin, J. Mitchell
As fresh water supplies become more unreliable, variable and expensive, the water-related implications of sustainable agriculture practices such as cover cropping are drawing increasing attention from California's agricultural communities. However, the adoption of winter cover cropping remains limited among specialty crop growers who face uncertainty regarding the water use of this practice. To investigate how winter cover crops affect soil water and evapotranspiration on farm fields, we studied three systems that span climatic and farming conditions in California's Central Valley: processing tomato fields with cover crop, almond orchards with cover crop, and almond orchards with native vegetation. From 2016 to 2019, we collected soil moisture data (3 years of neutron hydroprobe and gravimetric tests at 10 field sites) and evapotranspiration measurements (2 years at two of 10 sites) in winter cover cropped and control (clean-cultivated, bare ground) plots during winter months. Generally, there were not significant differences in soil moisture between cover cropped and control fields throughout or at the end of the winter seasons, while evapo-transpirative losses due to winter cover crops were negligible relative to clean-cultivated soil. Our results suggest that winter cover crops in the Central Valley may break even in terms of actual consumptive water use. California growers of high-value specialty crops can likely adopt winter cover cropping without altering their irrigation plans and management practices.
{"title":"Impacts of winter cover cropping on soil moisture and evapotranspiration in California's specialty crop fields may be minimal during winter months","authors":"A. Devincentis, S. Solis, S. Rice, D. Zaccaria, R. Snyder, M. Maskey, Anna Gomes, A. Gaudin, J. Mitchell","doi":"10.3733/ca.2022a0001","DOIUrl":"https://doi.org/10.3733/ca.2022a0001","url":null,"abstract":"As fresh water supplies become more unreliable, variable and expensive, the water-related implications of sustainable agriculture practices such as cover cropping are drawing increasing attention from California's agricultural communities. However, the adoption of winter cover cropping remains limited among specialty crop growers who face uncertainty regarding the water use of this practice. To investigate how winter cover crops affect soil water and evapotranspiration on farm fields, we studied three systems that span climatic and farming conditions in California's Central Valley: processing tomato fields with cover crop, almond orchards with cover crop, and almond orchards with native vegetation. From 2016 to 2019, we collected soil moisture data (3 years of neutron hydroprobe and gravimetric tests at 10 field sites) and evapotranspiration measurements (2 years at two of 10 sites) in winter cover cropped and control (clean-cultivated, bare ground) plots during winter months. Generally, there were not significant differences in soil moisture between cover cropped and control fields throughout or at the end of the winter seasons, while evapo-transpirative losses due to winter cover crops were negligible relative to clean-cultivated soil. Our results suggest that winter cover crops in the Central Valley may break even in terms of actual consumptive water use. California growers of high-value specialty crops can likely adopt winter cover cropping without altering their irrigation plans and management practices.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69778343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The H-2A visa program allows farmers in the United States to be certified by the U.S. Department of Labor to recruit and employ guest workers, usually for a maximum of 10 months, when they are unable to find enough workers living in the United States (including U.S. citizens, other legally authorized workers, and workers not authorized to work in the United States). We analyzed U.S. and California H-2A job certification data to determine how the program is currently used and how a proposed H-2A wage freeze would likely affect future farm labor costs. Our analysis suggests that changes in the H-2A visa program would likely expand the program while reducing labor costs in California and elsewhere.
{"title":"Proposed changes to the H-2A program would affect labor costs in the United States and California","authors":"Philip Martin, Zachary Rutledge","doi":"10.3733/ca.2021a0020","DOIUrl":"https://doi.org/10.3733/ca.2021a0020","url":null,"abstract":"The H-2A visa program allows farmers in the United States to be certified by the U.S. Department of Labor to recruit and employ guest workers, usually for a maximum of 10 months, when they are unable to find enough workers living in the United States (including U.S. citizens, other legally authorized workers, and workers not authorized to work in the United States). We analyzed U.S. and California H-2A job certification data to determine how the program is currently used and how a proposed H-2A wage freeze would likely affect future farm labor costs. Our analysis suggests that changes in the H-2A visa program would likely expand the program while reducing labor costs in California and elsewhere.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43081839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Babin, Jazlyn Guerrero, Diego Rivera, Ashutosh Kumar Singh
California's wine grape growers will face increasing challenges under a changing climate as most production occurs near the boundaries of current varieties' climatic thresholds. As part of this study, we developed a method for transforming downscaled climate information from the publicly available Cal-Adapt database into useful and useable climate projections for vineyard managers and advisors in the Paso Robles American Viticultural Area. We shared vineyard-specific projections during interviews of 20 managers and advisors. Overall, interviewees expressed trust in the projections and found them helpful in reducing their psychological distance from climate change. The projections prompted consideration of strategies for managing future climate risk and planning adaptation, with the majority of adaptations associated with long-term decisions such as row orientation, variety selection, dry farming, crop diversification and relocation. Agri-climatic decision support tools such as the one prototyped here may prove especially helpful for incorporating climate adaptation into the long-term business planning and vineyard redevelopment decisions facing managers and advisors in the near future. This approach could be extended to other California wine grape regions or to other perennial crops with expected vulnerabilities to climate change.
{"title":"Vineyard-specific climate projections help growers manage risk and plan adaptation in the Paso Robles AVA","authors":"N. Babin, Jazlyn Guerrero, Diego Rivera, Ashutosh Kumar Singh","doi":"10.3733/ca.2021a0019","DOIUrl":"https://doi.org/10.3733/ca.2021a0019","url":null,"abstract":"California's wine grape growers will face increasing challenges under a changing climate as most production occurs near the boundaries of current varieties' climatic thresholds. As part of this study, we developed a method for transforming downscaled climate information from the publicly available Cal-Adapt database into useful and useable climate projections for vineyard managers and advisors in the Paso Robles American Viticultural Area. We shared vineyard-specific projections during interviews of 20 managers and advisors. Overall, interviewees expressed trust in the projections and found them helpful in reducing their psychological distance from climate change. The projections prompted consideration of strategies for managing future climate risk and planning adaptation, with the majority of adaptations associated with long-term decisions such as row orientation, variety selection, dry farming, crop diversification and relocation. Agri-climatic decision support tools such as the one prototyped here may prove especially helpful for incorporating climate adaptation into the long-term business planning and vineyard redevelopment decisions facing managers and advisors in the near future. This approach could be extended to other California wine grape regions or to other perennial crops with expected vulnerabilities to climate change.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48204179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lina Aoyama, J. Bartolome, Lucas C. R. Silva, W. Silver
Maintaining and enhancing soil organic carbon storage can mitigate climate change while promoting forage growth. California has adopted incentive programs to promote rangeland practices that build soil organic carbon. However, there is no standard framework for assessing the baseline level of soil organic carbon at the ranch scale. Here, we use the Ecological Site Description — a land-type classification system — to help ranch managers set priorities about where to implement practices to increase soil organic carbon. We measured baseline carbon stocks at 0 to 15 and 15 to 30 centimeters' depth across three ecological sites and two vegetation states (shrubland and grassland) at Tejon Ranch, California. We discovered increased levels of soil carbon at ecological sites in higher elevations, and more soil carbon in shrublands as compared to grasslands. Slope, elevation, and soil texture, as well as plant litter and shrub cover, were significant predictors of soil carbon. The Ecological Site Description framework can serve as an important tool to help range managers keep carbon in the soil and out of the atmosphere.
{"title":"Using Ecological Site Descriptions to make ranch-level decisions about where to manage for soil organic carbon","authors":"Lina Aoyama, J. Bartolome, Lucas C. R. Silva, W. Silver","doi":"10.3733/ca.2022a0007","DOIUrl":"https://doi.org/10.3733/ca.2022a0007","url":null,"abstract":"Maintaining and enhancing soil organic carbon storage can mitigate climate change while promoting forage growth. California has adopted incentive programs to promote rangeland practices that build soil organic carbon. However, there is no standard framework for assessing the baseline level of soil organic carbon at the ranch scale. Here, we use the Ecological Site Description — a land-type classification system — to help ranch managers set priorities about where to implement practices to increase soil organic carbon. We measured baseline carbon stocks at 0 to 15 and 15 to 30 centimeters' depth across three ecological sites and two vegetation states (shrubland and grassland) at Tejon Ranch, California. We discovered increased levels of soil carbon at ecological sites in higher elevations, and more soil carbon in shrublands as compared to grasslands. Slope, elevation, and soil texture, as well as plant litter and shrub cover, were significant predictors of soil carbon. The Ecological Site Description framework can serve as an important tool to help range managers keep carbon in the soil and out of the atmosphere.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69778410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Mitchell, A. Shrestha, L. Epstein, J. Dahlberg, T. Ghezzehei, S. Araya, B. Richter, S. Kaur, Peter Henry, D. Munk, Sarah E. Light, Monte Bottens, D. Zaccaria
To meet the requirements of California's Sustainable Groundwater Management Act, there is a critical need for crop production strategies with less reliance on irrigation from surface and groundwater sources. One strategy for improving agricultural water use efficiency is reducing tillage and maintaining residues on the soil surface. We evaluated high residue no-till versus standard tillage in the San Joaquin Valley with and without cover crops on the yields of two crops, garbanzo and sorghum, for 4 years. The no-till treatment had no primary or secondary tillage. Sorghum yields were similar in no-till and standard tillage systems while no-till garbanzo yields matched or exceeded those of standard tillage, depending on the year. Cover crops had no effect on crop yields. Soil cover was highest under the no-till with cover crop system, averaging 97% versus 5% for the standard tillage without cover crop system. Our results suggest that garbanzos and sorghum can be grown under no-till practices in the San Joaquin Valley without loss of yield.
{"title":"No-tillage sorghum and garbanzo yields match or exceed standard tillage yields","authors":"J. Mitchell, A. Shrestha, L. Epstein, J. Dahlberg, T. Ghezzehei, S. Araya, B. Richter, S. Kaur, Peter Henry, D. Munk, Sarah E. Light, Monte Bottens, D. Zaccaria","doi":"10.3733/ca.2021a0017","DOIUrl":"https://doi.org/10.3733/ca.2021a0017","url":null,"abstract":"To meet the requirements of California's Sustainable Groundwater Management Act, there is a critical need for crop production strategies with less reliance on irrigation from surface and groundwater sources. One strategy for improving agricultural water use efficiency is reducing tillage and maintaining residues on the soil surface. We evaluated high residue no-till versus standard tillage in the San Joaquin Valley with and without cover crops on the yields of two crops, garbanzo and sorghum, for 4 years. The no-till treatment had no primary or secondary tillage. Sorghum yields were similar in no-till and standard tillage systems while no-till garbanzo yields matched or exceeded those of standard tillage, depending on the year. Cover crops had no effect on crop yields. Soil cover was highest under the no-till with cover crop system, averaging 97% versus 5% for the standard tillage without cover crop system. Our results suggest that garbanzos and sorghum can be grown under no-till practices in the San Joaquin Valley without loss of yield.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47114564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The University of California 4-H Youth Development Program created the 4-H Water Wizards project in response to two related issues: the need for high-quality science education programming in afterschool settings, and the desire to foster a citizenry that understands and can make informed decisions about water. In collaboration with afterschool program staff, Sacramento County 4-H implemented the 12-week water education project for children in grades four through six. We evaluated the program over four years (2012–2016) utilizing a pretest-posttest study design and evaluation surveys from participants and program staff. Our findings indicate positive outcomes both for program staff who delivered the project and for the children who participated in the program. Afterschool program staff gained competence in delivering hands-on and inquiry-based science programming. Fourth- and fifth-grade students demonstrated small but significant knowledge gain about water. Students also demonstrated increased awareness about water issues and water conservation behavior. We discuss our findings for both groups and share our insights for promising practices when collaborating with afterschool providers, especially relating to the importance and challenge of science education in afterschool settings.
{"title":"4-H Water Wizards: Lessons Learned for Effective Afterschool Science Programming","authors":"M. Bird, Aarti Subramaniam","doi":"10.3733/ca.2022a0012","DOIUrl":"https://doi.org/10.3733/ca.2022a0012","url":null,"abstract":"The University of California 4-H Youth Development Program created the 4-H Water Wizards project in response to two related issues: the need for high-quality science education programming in afterschool settings, and the desire to foster a citizenry that understands and can make informed decisions about water. In collaboration with afterschool program staff, Sacramento County 4-H implemented the 12-week water education project for children in grades four through six. We evaluated the program over four years (2012–2016) utilizing a pretest-posttest study design and evaluation surveys from participants and program staff. Our findings indicate positive outcomes both for program staff who delivered the project and for the children who participated in the program. Afterschool program staff gained competence in delivering hands-on and inquiry-based science programming. Fourth- and fifth-grade students demonstrated small but significant knowledge gain about water. Students also demonstrated increased awareness about water issues and water conservation behavior. We discuss our findings for both groups and share our insights for promising practices when collaborating with afterschool providers, especially relating to the importance and challenge of science education in afterschool settings.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69778626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melissa T. Ibarra, C. Meehan, M. Daniels, W. Smith, Martin H. Smith
Disease outbreaks among visitors at venues where animals are exhibited, such as animal shows at county fairs or petting zoos, are national public health concerns. Zoonotic disease transmission at fairs can occur through a variety of pathways, including direct contact with livestock and indirect exposure through contact with animals' immediate surroundings. Handwashing can reduce pathogen transmission. The goal of this observational study was to determine rates of handwashing among county fair visitors and to learn whether signage and/or contact with animals were correlated with handwashing practice. The investigation was conducted at four county fairs located across two geographic regions of California. Observations occurred over the course of one summer. Results from our observations of fair visitors revealed a low overall prevalence (5%) of handwashing behavior. However, fair visitors who made contact with animals were more likely to wash their hands. Additionally, those individuals who walked through barns where handwashing signage was present were significantly more likely to wash their hands than those who visited barns without signage.
{"title":"Low prevalence of handwashing and importance of signage at California county fair animal exhibits","authors":"Melissa T. Ibarra, C. Meehan, M. Daniels, W. Smith, Martin H. Smith","doi":"10.3733/ca.2021a0015","DOIUrl":"https://doi.org/10.3733/ca.2021a0015","url":null,"abstract":"Disease outbreaks among visitors at venues where animals are exhibited, such as animal shows at county fairs or petting zoos, are national public health concerns. Zoonotic disease transmission at fairs can occur through a variety of pathways, including direct contact with livestock and indirect exposure through contact with animals' immediate surroundings. Handwashing can reduce pathogen transmission. The goal of this observational study was to determine rates of handwashing among county fair visitors and to learn whether signage and/or contact with animals were correlated with handwashing practice. The investigation was conducted at four county fairs located across two geographic regions of California. Observations occurred over the course of one summer. Results from our observations of fair visitors revealed a low overall prevalence (5%) of handwashing behavior. However, fair visitors who made contact with animals were more likely to wash their hands. Additionally, those individuals who walked through barns where handwashing signage was present were significantly more likely to wash their hands than those who visited barns without signage.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43210438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. A. Osipitan, B. Hanson, Y. Goldwasser, Matthew J. Fatino, M. Mesgaran
Branched broomrape (Phelipanche ramosa), a parasitic weed that was the focus of a $1.5 million eradication effort four decades ago in California, has recently re-emerged in tomato fields in several Central Valley counties. Processing tomatoes are important to the California agricultural economy; the state produced over 90% of the 12 million tons of tomatoes grown in the United States in 2018. Branched broomrape is listed as an “A” noxious weed by the California Department of Food and Agriculture (CDFA); discovery of broomrape in California tomato fields leads to quarantine and crop destruction without harvest, resulting in significant economic loss to growers. In countries where broomrape is common, yield reductions caused by this parasitic weed can range from moderate to 80%, depending upon the infestation level, host and environmental conditions. Developing a detailed understanding of the biology of this weed under local conditions is an important step towards developing effective management plans for California. In this review, we discuss branched broomrape in the context of California production systems, particularly of tomato. We also discuss the potential management practices that could help to prevent or reduce the impacts of branched broomrape in tomatoes and other host crops.
{"title":"The potential threat of branched broomrape for California processing tomato: A review","authors":"O. A. Osipitan, B. Hanson, Y. Goldwasser, Matthew J. Fatino, M. Mesgaran","doi":"10.3733/ca.2021a0012","DOIUrl":"https://doi.org/10.3733/ca.2021a0012","url":null,"abstract":"Branched broomrape (Phelipanche ramosa), a parasitic weed that was the focus of a $1.5 million eradication effort four decades ago in California, has recently re-emerged in tomato fields in several Central Valley counties. Processing tomatoes are important to the California agricultural economy; the state produced over 90% of the 12 million tons of tomatoes grown in the United States in 2018. Branched broomrape is listed as an “A” noxious weed by the California Department of Food and Agriculture (CDFA); discovery of broomrape in California tomato fields leads to quarantine and crop destruction without harvest, resulting in significant economic loss to growers. In countries where broomrape is common, yield reductions caused by this parasitic weed can range from moderate to 80%, depending upon the infestation level, host and environmental conditions. Developing a detailed understanding of the biology of this weed under local conditions is an important step towards developing effective management plans for California. In this review, we discuss branched broomrape in the context of California production systems, particularly of tomato. We also discuss the potential management practices that could help to prevent or reduce the impacts of branched broomrape in tomatoes and other host crops.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42362257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A critical component of water-resources management in the irrigated agriculture landscape, particularly those landscapes dependent on groundwater availability, is determining groundwater recharge rates from streams and other channels. In California, flows in many such channels are “controlled” by upstream reservoir releases to meet downstream urban, irrigation and environmental water requirements. Seepage volumes from these channels and how they might vary during controlled release periods is a key component of meeting downstream riparian and groundwater-pumping needs. Understanding annual seepage from streamflow channels is also important in developing water budgets as part of the management of groundwater resources under the Sustainable Groundwater Management Act (SGMA) in California. However, direct measurements of channel seepage rates are infrequent or unavailable, and these rates, or associated volumes, are most often only estimated. Here we describe direct point- and reach-scale field measurements of channel seepage rates in Lower Putah Creek (Solano County) and in distribution lateral channels of the Oakdale Irrigation District on the east side of the San Joaquin Valley (San Joaquin and Stanislaus counties). We measured overall average seepage rates of about 2 feet (610 mm) per day at both locations and determined how these rates varied spatially and temporally during the summer when channel flows are controlled for downstream requirements.
{"title":"Point- and reach-scale measurements are important for determining accurate seepage rates in controlled flow channels","authors":"M. Grismer","doi":"10.3733/ca.2021a0013","DOIUrl":"https://doi.org/10.3733/ca.2021a0013","url":null,"abstract":"A critical component of water-resources management in the irrigated agriculture landscape, particularly those landscapes dependent on groundwater availability, is determining groundwater recharge rates from streams and other channels. In California, flows in many such channels are “controlled” by upstream reservoir releases to meet downstream urban, irrigation and environmental water requirements. Seepage volumes from these channels and how they might vary during controlled release periods is a key component of meeting downstream riparian and groundwater-pumping needs. Understanding annual seepage from streamflow channels is also important in developing water budgets as part of the management of groundwater resources under the Sustainable Groundwater Management Act (SGMA) in California. However, direct measurements of channel seepage rates are infrequent or unavailable, and these rates, or associated volumes, are most often only estimated. Here we describe direct point- and reach-scale field measurements of channel seepage rates in Lower Putah Creek (Solano County) and in distribution lateral channels of the Oakdale Irrigation District on the east side of the San Joaquin Valley (San Joaquin and Stanislaus counties). We measured overall average seepage rates of about 2 feet (610 mm) per day at both locations and determined how these rates varied spatially and temporally during the summer when channel flows are controlled for downstream requirements.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46693474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The invasive annual grasses barb goatgrass (Aegilops triuncialis L.) and medusahead (Elymus caput-medusae L.) are widespread in western states and present management challenges on grasslands. To develop an integrated management strategy for these species, we treated sites in five pastures in Mendocino County, comparing combinations of intensive sheep grazing, glyphosate herbicide (low and high), and application timings (tillering, boot and heading stage). We found that grazing alone reduced barb goatgrass spikelet densities by 68% and the number of seeds per spikelet by 35%. Both rates of glyphosate application without grazing had similar effects on seed production. High and low glyphosate application at tillering resulted in almost complete control of both target species. Boot- and heading-stage applications reduced barb goatgrass density by 39% and 32%, respectively. Application at the boot stage also resulted in an 82% reduction in number of seeds per barb goatgrass spikelet. Our results suggest that intensive grazing may be a useful management strategy to reduce barb goatgrass and medusahead spikelet densities and barb goatgrass seed numbers, especially when integrated with a boot- or heading-stage glyphosate application.
{"title":"Integration of grazing and herbicide application improves management of barb goatgrass and medusahead in pasture and rangelands","authors":"T. M. Bean, Josh S Davy, Guy B. Kyser, E. Gornish","doi":"10.3733/CA.2021A0011","DOIUrl":"https://doi.org/10.3733/CA.2021A0011","url":null,"abstract":"The invasive annual grasses barb goatgrass (Aegilops triuncialis L.) and medusahead (Elymus caput-medusae L.) are widespread in western states and present management challenges on grasslands. To develop an integrated management strategy for these species, we treated sites in five pastures in Mendocino County, comparing combinations of intensive sheep grazing, glyphosate herbicide (low and high), and application timings (tillering, boot and heading stage). We found that grazing alone reduced barb goatgrass spikelet densities by 68% and the number of seeds per spikelet by 35%. Both rates of glyphosate application without grazing had similar effects on seed production. High and low glyphosate application at tillering resulted in almost complete control of both target species. Boot- and heading-stage applications reduced barb goatgrass density by 39% and 32%, respectively. Application at the boot stage also resulted in an 82% reduction in number of seeds per barb goatgrass spikelet. Our results suggest that intensive grazing may be a useful management strategy to reduce barb goatgrass and medusahead spikelet densities and barb goatgrass seed numbers, especially when integrated with a boot- or heading-stage glyphosate application.","PeriodicalId":9409,"journal":{"name":"California Agriculture","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42768020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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