Greenhouse gas (GHG) emissions are fueling global climate change, with methane and nitrous oxide ... more Greenhouse gas (GHG) emissions are fueling global climate change, with methane and nitrous oxide being the primary agricultural gases emitted. It has been shown that N 2 O emissions correlate to moisture content fluctuations; however, emissions from agricultural fields in the semiarid regions of the Southwest where rewetting events occur regularly are not well established. The scope of this study was to quantify GHG emissions in correlation to soil moisture fluctuations and fertilizer application. The study was conducted continuously in two pecan [Carya illinoinensis (Wangenh.) K. Koch] orchards between Aug. 2010 and Aug. 2011 on a sandy loam soil (La Mancha) and a silty clay loam soil (Leyendecker), both under normal management practices. The small chamber technique was used to measure GHGs. Emissions varied greatly throughout the year. The largest flux of CO 2 at La Mancha and Leyendecker both occurred during a drying event immediately following an irrigation event: 84,642.49 mg • m L2 • h L1 and 30,338.24 mg • m L2 • h L1 , respectively. The net CH 4 flux at Leyendecker and La Mancha was close to zero with the largest emissions occurring during wetting events. Results showed that N 2 O emissions were maintained near the baseline except for the few days following an irrigation event. The largest emission peak at La Mancha occurred after irrigation and nitrogen application: 322.06 mg • m L2 • h L1. The largest emission peaks of 26.37 and 1.13 mg • m L2 • h L1 at Leyendecker and La Mancha, respectively, occurred after irrigation, nitrogen application, and tillage. Nitrogen application was the driving factor affecting N 2 O emissions at La Mancha, whereas soil moisture content was the driving factor at Leyendecker. Emission factors (EFs) at La Mancha and Leyendecker were 0.49% and 0.05%, respectively. A thorough accounting of GHG emissions is necessary for budgeting and identifying mitigation policy.
Piflon-juniper woodlands occupy more than four mil lion ha or 14% of the land base in New Mexico.... more Piflon-juniper woodlands occupy more than four mil lion ha or 14% of the land base in New Mexico. The ma jority of land (42%) is managed by the federal govern ment. The remainder is either privately (29%), Indian, (18%) or state owned (12%). Approximately 62% of the piilon-juniper woodland is considered accessible and suit able for forestry and agriculture use. The current annual production of the woodland is about $29 and ornamental products is more than $3,600JhaIyr or more than $8 bU lionlyr. Clearly, the potential value is unattainable. How ever, a reasooable target of $60 million/yr is achievable through better management and utilization. Allpiilon-juniper land units do not have the same pr0 duction capacity, and they are not equally accessible for product harvest. Furthermore, market demands for speci I I fic products such as fuelwood or ornamentals, vary i among regions. Consequently, the actual value of all \ plant products obtained from New Mexico's piilon " juniper woodlands is well below potential. However, the (~ value could be increased substantially if more productive woodlands were intensively managed. At present. land managers generally do not have enough information to optimize benefits from more than one product. An absence of critical knowledge in some cases permits over-exploitation of a product. Future use depends on interdisciplinary teams developing technol ogy to manage this valuable, diverse resource better.
Greenhouse gas (GHG) emissions are fueling global climate change, with methane and nitrous oxide ... more Greenhouse gas (GHG) emissions are fueling global climate change, with methane and nitrous oxide being the primary agricultural gases emitted. It has been shown that N 2 O emissions correlate to moisture content fluctuations; however, emissions from agricultural fields in the semiarid regions of the Southwest where rewetting events occur regularly are not well established. The scope of this study was to quantify GHG emissions in correlation to soil moisture fluctuations and fertilizer application. The study was conducted continuously in two pecan [Carya illinoinensis (Wangenh.) K. Koch] orchards between Aug. 2010 and Aug. 2011 on a sandy loam soil (La Mancha) and a silty clay loam soil (Leyendecker), both under normal management practices. The small chamber technique was used to measure GHGs. Emissions varied greatly throughout the year. The largest flux of CO 2 at La Mancha and Leyendecker both occurred during a drying event immediately following an irrigation event: 84,642.49 mg • m L2 • h L1 and 30,338.24 mg • m L2 • h L1 , respectively. The net CH 4 flux at Leyendecker and La Mancha was close to zero with the largest emissions occurring during wetting events. Results showed that N 2 O emissions were maintained near the baseline except for the few days following an irrigation event. The largest emission peak at La Mancha occurred after irrigation and nitrogen application: 322.06 mg • m L2 • h L1. The largest emission peaks of 26.37 and 1.13 mg • m L2 • h L1 at Leyendecker and La Mancha, respectively, occurred after irrigation, nitrogen application, and tillage. Nitrogen application was the driving factor affecting N 2 O emissions at La Mancha, whereas soil moisture content was the driving factor at Leyendecker. Emission factors (EFs) at La Mancha and Leyendecker were 0.49% and 0.05%, respectively. A thorough accounting of GHG emissions is necessary for budgeting and identifying mitigation policy.
Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant wo... more Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant woody biomass from hedge prunings with little economic value. Value-added uses could aid pecan growers, and one possible use is wood chips for potting substrates to lessen dependence on peatmoss, thereby aiding greenhouse growers. We evaluated vegetative growth and leaf nutrient responses of 'Carpino' garden chrysanthemum (Dendranthema 3grandiflorum) over a 60-day period. Plants were grown in five pecan wood chip substrate levels that substituted 0%, 25%, 50%, 75%, and 100% of peatmoss by volume. Three water soluble fertilizer (WSF) rates-N at 0, 200, or 400 mg • L L1 (0-N, 200-N, and 400-N, respectively)-were applied with each irrigation and to each of the wood substitution treatments. The WSF and wood substitution treatments interacted strongly. In the presence of wood, (25L100% substitution levels), increasing WSF to 400-N increased cumulative evapotranspiration (ET), crop height, total leaf number and area, total leaf and stem dry weight, and leaf N and P concentrations. However, with 0% wood substitution, 400LN provided little or no such enhancements. With 25% to 50% wood substitution, root dry weight increased by 61% to 91% from 0-N to 200-N, which may be an adaptive response to nutrient-limiting conditions at 200-N. Appearance of a white rot fungal species in and atop pecan wood-supplemented substrate supports the likelihood that microbial activity was, at least in part, responsible for the nutrient limitations. High WSF at 400-N in combination with 25% pecan wood substitution maintained adequate fertility and shoot growth that was comparable to the conventional peat-only substrate at 200-N. With low to moderate amounts of pecan wood, further adjustments to WSF rate and irrigation volume would support sustainable fertigation practices, reduce dependence on peatmoss by greenhouse industry, and provide a value-added recycling option for pecan growers.
Piflon-juniper woodlands occupy more than four mil lion ha or 14% of the land base in New Mexico.... more Piflon-juniper woodlands occupy more than four mil lion ha or 14% of the land base in New Mexico. The ma jority of land (42%) is managed by the federal govern ment. The remainder is either privately (29%), Indian, (18%) or state owned (12%). Approximately 62% of the piilon-juniper woodland is considered accessible and suit able for forestry and agriculture use. The current annual production of the woodland is about $29 and ornamental products is more than $3,600JhaIyr or more than $8 bU lionlyr. Clearly, the potential value is unattainable. How ever, a reasooable target of $60 million/yr is achievable through better management and utilization. Allpiilon-juniper land units do not have the same pr0 duction capacity, and they are not equally accessible for product harvest. Furthermore, market demands for speci I I fic products such as fuelwood or ornamentals, vary i among regions. Consequently, the actual value of all \ plant products obtained from New Mexico's piilon " juniper woodlands is well below potential. However, the (~ value could be increased substantially if more productive woodlands were intensively managed. At present. land managers generally do not have enough information to optimize benefits from more than one product. An absence of critical knowledge in some cases permits over-exploitation of a product. Future use depends on interdisciplinary teams developing technol ogy to manage this valuable, diverse resource better.
The environmental and natural resources deterioration in the arid and semiarid zones have motivat... more The environmental and natural resources deterioration in the arid and semiarid zones have motivated a great interest in arder to look for a transition toward the sustainable development. This ecological condition includes areas in the border region between Mexico and the United States. A common prevalent situation along the border region is the inadequate wastewater treatment and in sorne cases, the absences of these systems. In addition, the conventional wastewater treatment systems are very expensive in order to be installed and operated, not providing the important advantages for the ecological and socio-economic growth. The Ojinaga Agroforestry Project (PACO) is a.n alternative that could direct 'those necessities, since it seeks to integrate approaches of sustainable development. A main component of this study is the use and management of wastewater· and irrigation water for the commercial production of. wood for fiber. In this sense, an important element is the involvement of the border community of Ojinaga, Chihuahua, Mexico, in the decision making process through the Search Conference Methodology. The social community participates in planning, implementing and assessing th'e actions for its development, including ecological, social and economic aspects. The purpose is to reduce the environmental pollution and the pressure on the natural resources. At the same time, these measures help to use and manage wastewater and irrigation water aiming to improve their quality and the salted soil conditions and abandoned lands, and generate better economic opportunities and sources of employment for the people in this border region.
... Growth (cell enlargement, biomass) is impacted much more severely and at a much higher yleaf ... more ... Growth (cell enlargement, biomass) is impacted much more severely and at a much higher yleaf than photosynthesis. yleaf must approach -1.5 MPa before photosynthesis is reduced 50%. Growth, however, can be reduced ...
Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant wo... more Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant woody biomass from hedge prunings with little economic value. Value-added uses could aid pecan growers, and one possible use is wood chips for potting substrates to lessen dependence on peatmoss, thereby aiding greenhouse growers. We evaluated vegetative growth and leaf nutrient responses of 'Carpino' garden chrysanthemum (Dendranthema 3grandiflorum) over a 60-day period. Plants were grown in five pecan wood chip substrate levels that substituted 0%, 25%, 50%, 75%, and 100% of peatmoss by volume. Three water soluble fertilizer (WSF) rates-N at 0, 200, or 400 mg • L L1 (0-N, 200-N, and 400-N, respectively)-were applied with each irrigation and to each of the wood substitution treatments. The WSF and wood substitution treatments interacted strongly. In the presence of wood, (25L100% substitution levels), increasing WSF to 400-N increased cumulative evapotranspiration (ET), crop height, total leaf number and area, total leaf and stem dry weight, and leaf N and P concentrations. However, with 0% wood substitution, 400LN provided little or no such enhancements. With 25% to 50% wood substitution, root dry weight increased by 61% to 91% from 0-N to 200-N, which may be an adaptive response to nutrient-limiting conditions at 200-N. Appearance of a white rot fungal species in and atop pecan wood-supplemented substrate supports the likelihood that microbial activity was, at least in part, responsible for the nutrient limitations. High WSF at 400-N in combination with 25% pecan wood substitution maintained adequate fertility and shoot growth that was comparable to the conventional peat-only substrate at 200-N. With low to moderate amounts of pecan wood, further adjustments to WSF rate and irrigation volume would support sustainable fertigation practices, reduce dependence on peatmoss by greenhouse industry, and provide a value-added recycling option for pecan growers.
The environmental and natural resources deterioration in the arid and semiarid zones have motivat... more The environmental and natural resources deterioration in the arid and semiarid zones have motivated a great interest in arder to look for a transition toward the sustainable development. This ecological condition includes areas in the border region between Mexico and the United States. A common prevalent situation along the border region is the inadequate wastewater treatment and in sorne cases, the absences of these systems. In addition, the conventional wastewater treatment systems are very expensive in order to be installed and operated, not providing the important advantages for the ecological and socio-economic growth. The Ojinaga Agroforestry Project (PACO) is a.n alternative that could direct 'those necessities, since it seeks to integrate approaches of sustainable development. A main component of this study is the use and management of wastewater· and irrigation water for the commercial production of. wood for fiber. In this sense, an important element is the involvement of the border community of Ojinaga, Chihuahua, Mexico, in the decision making process through the Search Conference Methodology. The social community participates in planning, implementing and assessing th'e actions for its development, including ecological, social and economic aspects. The purpose is to reduce the environmental pollution and the pressure on the natural resources. At the same time, these measures help to use and manage wastewater and irrigation water aiming to improve their quality and the salted soil conditions and abandoned lands, and generate better economic opportunities and sources of employment for the people in this border region.
Journal of environmental horticulture, Jun 1, 2008
To direct, fund, promote and communicate horticultural research, which increases the quality and ... more To direct, fund, promote and communicate horticultural research, which increases the quality and value of ornamental plants, improves the productivity and profitability of the nursery and landscape industry, and protects and enhances the environment. The use of any trade name in this article does not imply an endorsement of the equipment, product or process named, nor any criticism of any similar products that are not mentioned.
... Growth (cell enlargement, biomass) is impacted much more severely and at a much higher yleaf ... more ... Growth (cell enlargement, biomass) is impacted much more severely and at a much higher yleaf than photosynthesis. yleaf must approach -1.5 MPa before photosynthesis is reduced 50%. Growth, however, can be reduced ...
The use and manipulation of the mycorrhizal symbiosis has enormous potential benefits in tree nur... more The use and manipulation of the mycorrhizal symbiosis has enormous potential benefits in tree nurseries and in artificial regeneration programmes. This paper discusses the role of a mycorrhizal inoculation programme in reforestation. Included in this discussion are type of inoculation and response of the host to inoculation. The direct impact of a mycorrhizal inoculation programme will depend upon the symbionts selected and, of course, site characteristics. Inoculation generally improves survival and growth following outplanting. However, this advantage may be a function of the larger seedling size resulting from inoculation rather than from transplanting fungal inoculum to the forested site. This paper also points out current problems and future directions of any inoculation programme.
Journal of environmental horticulture, Jun 1, 2008
To direct, fund, promote and communicate horticultural research, which increases the quality and ... more To direct, fund, promote and communicate horticultural research, which increases the quality and value of ornamental plants, improves the productivity and profitability of the nursery and landscape industry, and protects and enhances the environment. The use of any trade name in this article does not imply an endorsement of the equipment, product or process named, nor any criticism of any similar products that are not mentioned.
The use and manipulation of the mycorrhizal symbiosis has enormous potential benefits in tree nur... more The use and manipulation of the mycorrhizal symbiosis has enormous potential benefits in tree nurseries and in artificial regeneration programmes. This paper discusses the role of a mycorrhizal inoculation programme in reforestation. Included in this discussion are type of inoculation and response of the host to inoculation. The direct impact of a mycorrhizal inoculation programme will depend upon the symbionts selected and, of course, site characteristics. Inoculation generally improves survival and growth following outplanting. However, this advantage may be a function of the larger seedling size resulting from inoculation rather than from transplanting fungal inoculum to the forested site. This paper also points out current problems and future directions of any inoculation programme.
Greenhouse gas (GHG) emissions are fueling global climate change, with methane and nitrous oxide ... more Greenhouse gas (GHG) emissions are fueling global climate change, with methane and nitrous oxide being the primary agricultural gases emitted. It has been shown that N 2 O emissions correlate to moisture content fluctuations; however, emissions from agricultural fields in the semiarid regions of the Southwest where rewetting events occur regularly are not well established. The scope of this study was to quantify GHG emissions in correlation to soil moisture fluctuations and fertilizer application. The study was conducted continuously in two pecan [Carya illinoinensis (Wangenh.) K. Koch] orchards between Aug. 2010 and Aug. 2011 on a sandy loam soil (La Mancha) and a silty clay loam soil (Leyendecker), both under normal management practices. The small chamber technique was used to measure GHGs. Emissions varied greatly throughout the year. The largest flux of CO 2 at La Mancha and Leyendecker both occurred during a drying event immediately following an irrigation event: 84,642.49 mg • m L2 • h L1 and 30,338.24 mg • m L2 • h L1 , respectively. The net CH 4 flux at Leyendecker and La Mancha was close to zero with the largest emissions occurring during wetting events. Results showed that N 2 O emissions were maintained near the baseline except for the few days following an irrigation event. The largest emission peak at La Mancha occurred after irrigation and nitrogen application: 322.06 mg • m L2 • h L1. The largest emission peaks of 26.37 and 1.13 mg • m L2 • h L1 at Leyendecker and La Mancha, respectively, occurred after irrigation, nitrogen application, and tillage. Nitrogen application was the driving factor affecting N 2 O emissions at La Mancha, whereas soil moisture content was the driving factor at Leyendecker. Emission factors (EFs) at La Mancha and Leyendecker were 0.49% and 0.05%, respectively. A thorough accounting of GHG emissions is necessary for budgeting and identifying mitigation policy.
Piflon-juniper woodlands occupy more than four mil lion ha or 14% of the land base in New Mexico.... more Piflon-juniper woodlands occupy more than four mil lion ha or 14% of the land base in New Mexico. The ma jority of land (42%) is managed by the federal govern ment. The remainder is either privately (29%), Indian, (18%) or state owned (12%). Approximately 62% of the piilon-juniper woodland is considered accessible and suit able for forestry and agriculture use. The current annual production of the woodland is about $29 and ornamental products is more than $3,600JhaIyr or more than $8 bU lionlyr. Clearly, the potential value is unattainable. How ever, a reasooable target of $60 million/yr is achievable through better management and utilization. Allpiilon-juniper land units do not have the same pr0 duction capacity, and they are not equally accessible for product harvest. Furthermore, market demands for speci I I fic products such as fuelwood or ornamentals, vary i among regions. Consequently, the actual value of all \ plant products obtained from New Mexico's piilon " juniper woodlands is well below potential. However, the (~ value could be increased substantially if more productive woodlands were intensively managed. At present. land managers generally do not have enough information to optimize benefits from more than one product. An absence of critical knowledge in some cases permits over-exploitation of a product. Future use depends on interdisciplinary teams developing technol ogy to manage this valuable, diverse resource better.
Greenhouse gas (GHG) emissions are fueling global climate change, with methane and nitrous oxide ... more Greenhouse gas (GHG) emissions are fueling global climate change, with methane and nitrous oxide being the primary agricultural gases emitted. It has been shown that N 2 O emissions correlate to moisture content fluctuations; however, emissions from agricultural fields in the semiarid regions of the Southwest where rewetting events occur regularly are not well established. The scope of this study was to quantify GHG emissions in correlation to soil moisture fluctuations and fertilizer application. The study was conducted continuously in two pecan [Carya illinoinensis (Wangenh.) K. Koch] orchards between Aug. 2010 and Aug. 2011 on a sandy loam soil (La Mancha) and a silty clay loam soil (Leyendecker), both under normal management practices. The small chamber technique was used to measure GHGs. Emissions varied greatly throughout the year. The largest flux of CO 2 at La Mancha and Leyendecker both occurred during a drying event immediately following an irrigation event: 84,642.49 mg • m L2 • h L1 and 30,338.24 mg • m L2 • h L1 , respectively. The net CH 4 flux at Leyendecker and La Mancha was close to zero with the largest emissions occurring during wetting events. Results showed that N 2 O emissions were maintained near the baseline except for the few days following an irrigation event. The largest emission peak at La Mancha occurred after irrigation and nitrogen application: 322.06 mg • m L2 • h L1. The largest emission peaks of 26.37 and 1.13 mg • m L2 • h L1 at Leyendecker and La Mancha, respectively, occurred after irrigation, nitrogen application, and tillage. Nitrogen application was the driving factor affecting N 2 O emissions at La Mancha, whereas soil moisture content was the driving factor at Leyendecker. Emission factors (EFs) at La Mancha and Leyendecker were 0.49% and 0.05%, respectively. A thorough accounting of GHG emissions is necessary for budgeting and identifying mitigation policy.
Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant wo... more Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant woody biomass from hedge prunings with little economic value. Value-added uses could aid pecan growers, and one possible use is wood chips for potting substrates to lessen dependence on peatmoss, thereby aiding greenhouse growers. We evaluated vegetative growth and leaf nutrient responses of 'Carpino' garden chrysanthemum (Dendranthema 3grandiflorum) over a 60-day period. Plants were grown in five pecan wood chip substrate levels that substituted 0%, 25%, 50%, 75%, and 100% of peatmoss by volume. Three water soluble fertilizer (WSF) rates-N at 0, 200, or 400 mg • L L1 (0-N, 200-N, and 400-N, respectively)-were applied with each irrigation and to each of the wood substitution treatments. The WSF and wood substitution treatments interacted strongly. In the presence of wood, (25L100% substitution levels), increasing WSF to 400-N increased cumulative evapotranspiration (ET), crop height, total leaf number and area, total leaf and stem dry weight, and leaf N and P concentrations. However, with 0% wood substitution, 400LN provided little or no such enhancements. With 25% to 50% wood substitution, root dry weight increased by 61% to 91% from 0-N to 200-N, which may be an adaptive response to nutrient-limiting conditions at 200-N. Appearance of a white rot fungal species in and atop pecan wood-supplemented substrate supports the likelihood that microbial activity was, at least in part, responsible for the nutrient limitations. High WSF at 400-N in combination with 25% pecan wood substitution maintained adequate fertility and shoot growth that was comparable to the conventional peat-only substrate at 200-N. With low to moderate amounts of pecan wood, further adjustments to WSF rate and irrigation volume would support sustainable fertigation practices, reduce dependence on peatmoss by greenhouse industry, and provide a value-added recycling option for pecan growers.
Piflon-juniper woodlands occupy more than four mil lion ha or 14% of the land base in New Mexico.... more Piflon-juniper woodlands occupy more than four mil lion ha or 14% of the land base in New Mexico. The ma jority of land (42%) is managed by the federal govern ment. The remainder is either privately (29%), Indian, (18%) or state owned (12%). Approximately 62% of the piilon-juniper woodland is considered accessible and suit able for forestry and agriculture use. The current annual production of the woodland is about $29 and ornamental products is more than $3,600JhaIyr or more than $8 bU lionlyr. Clearly, the potential value is unattainable. How ever, a reasooable target of $60 million/yr is achievable through better management and utilization. Allpiilon-juniper land units do not have the same pr0 duction capacity, and they are not equally accessible for product harvest. Furthermore, market demands for speci I I fic products such as fuelwood or ornamentals, vary i among regions. Consequently, the actual value of all \ plant products obtained from New Mexico's piilon " juniper woodlands is well below potential. However, the (~ value could be increased substantially if more productive woodlands were intensively managed. At present. land managers generally do not have enough information to optimize benefits from more than one product. An absence of critical knowledge in some cases permits over-exploitation of a product. Future use depends on interdisciplinary teams developing technol ogy to manage this valuable, diverse resource better.
The environmental and natural resources deterioration in the arid and semiarid zones have motivat... more The environmental and natural resources deterioration in the arid and semiarid zones have motivated a great interest in arder to look for a transition toward the sustainable development. This ecological condition includes areas in the border region between Mexico and the United States. A common prevalent situation along the border region is the inadequate wastewater treatment and in sorne cases, the absences of these systems. In addition, the conventional wastewater treatment systems are very expensive in order to be installed and operated, not providing the important advantages for the ecological and socio-economic growth. The Ojinaga Agroforestry Project (PACO) is a.n alternative that could direct 'those necessities, since it seeks to integrate approaches of sustainable development. A main component of this study is the use and management of wastewater· and irrigation water for the commercial production of. wood for fiber. In this sense, an important element is the involvement of the border community of Ojinaga, Chihuahua, Mexico, in the decision making process through the Search Conference Methodology. The social community participates in planning, implementing and assessing th'e actions for its development, including ecological, social and economic aspects. The purpose is to reduce the environmental pollution and the pressure on the natural resources. At the same time, these measures help to use and manage wastewater and irrigation water aiming to improve their quality and the salted soil conditions and abandoned lands, and generate better economic opportunities and sources of employment for the people in this border region.
... Growth (cell enlargement, biomass) is impacted much more severely and at a much higher yleaf ... more ... Growth (cell enlargement, biomass) is impacted much more severely and at a much higher yleaf than photosynthesis. yleaf must approach -1.5 MPa before photosynthesis is reduced 50%. Growth, however, can be reduced ...
Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant wo... more Commercial production of pecan [Carya illinoinensis (Wangenh.) K. Koch.] generates significant woody biomass from hedge prunings with little economic value. Value-added uses could aid pecan growers, and one possible use is wood chips for potting substrates to lessen dependence on peatmoss, thereby aiding greenhouse growers. We evaluated vegetative growth and leaf nutrient responses of 'Carpino' garden chrysanthemum (Dendranthema 3grandiflorum) over a 60-day period. Plants were grown in five pecan wood chip substrate levels that substituted 0%, 25%, 50%, 75%, and 100% of peatmoss by volume. Three water soluble fertilizer (WSF) rates-N at 0, 200, or 400 mg • L L1 (0-N, 200-N, and 400-N, respectively)-were applied with each irrigation and to each of the wood substitution treatments. The WSF and wood substitution treatments interacted strongly. In the presence of wood, (25L100% substitution levels), increasing WSF to 400-N increased cumulative evapotranspiration (ET), crop height, total leaf number and area, total leaf and stem dry weight, and leaf N and P concentrations. However, with 0% wood substitution, 400LN provided little or no such enhancements. With 25% to 50% wood substitution, root dry weight increased by 61% to 91% from 0-N to 200-N, which may be an adaptive response to nutrient-limiting conditions at 200-N. Appearance of a white rot fungal species in and atop pecan wood-supplemented substrate supports the likelihood that microbial activity was, at least in part, responsible for the nutrient limitations. High WSF at 400-N in combination with 25% pecan wood substitution maintained adequate fertility and shoot growth that was comparable to the conventional peat-only substrate at 200-N. With low to moderate amounts of pecan wood, further adjustments to WSF rate and irrigation volume would support sustainable fertigation practices, reduce dependence on peatmoss by greenhouse industry, and provide a value-added recycling option for pecan growers.
The environmental and natural resources deterioration in the arid and semiarid zones have motivat... more The environmental and natural resources deterioration in the arid and semiarid zones have motivated a great interest in arder to look for a transition toward the sustainable development. This ecological condition includes areas in the border region between Mexico and the United States. A common prevalent situation along the border region is the inadequate wastewater treatment and in sorne cases, the absences of these systems. In addition, the conventional wastewater treatment systems are very expensive in order to be installed and operated, not providing the important advantages for the ecological and socio-economic growth. The Ojinaga Agroforestry Project (PACO) is a.n alternative that could direct 'those necessities, since it seeks to integrate approaches of sustainable development. A main component of this study is the use and management of wastewater· and irrigation water for the commercial production of. wood for fiber. In this sense, an important element is the involvement of the border community of Ojinaga, Chihuahua, Mexico, in the decision making process through the Search Conference Methodology. The social community participates in planning, implementing and assessing th'e actions for its development, including ecological, social and economic aspects. The purpose is to reduce the environmental pollution and the pressure on the natural resources. At the same time, these measures help to use and manage wastewater and irrigation water aiming to improve their quality and the salted soil conditions and abandoned lands, and generate better economic opportunities and sources of employment for the people in this border region.
Journal of environmental horticulture, Jun 1, 2008
To direct, fund, promote and communicate horticultural research, which increases the quality and ... more To direct, fund, promote and communicate horticultural research, which increases the quality and value of ornamental plants, improves the productivity and profitability of the nursery and landscape industry, and protects and enhances the environment. The use of any trade name in this article does not imply an endorsement of the equipment, product or process named, nor any criticism of any similar products that are not mentioned.
... Growth (cell enlargement, biomass) is impacted much more severely and at a much higher yleaf ... more ... Growth (cell enlargement, biomass) is impacted much more severely and at a much higher yleaf than photosynthesis. yleaf must approach -1.5 MPa before photosynthesis is reduced 50%. Growth, however, can be reduced ...
The use and manipulation of the mycorrhizal symbiosis has enormous potential benefits in tree nur... more The use and manipulation of the mycorrhizal symbiosis has enormous potential benefits in tree nurseries and in artificial regeneration programmes. This paper discusses the role of a mycorrhizal inoculation programme in reforestation. Included in this discussion are type of inoculation and response of the host to inoculation. The direct impact of a mycorrhizal inoculation programme will depend upon the symbionts selected and, of course, site characteristics. Inoculation generally improves survival and growth following outplanting. However, this advantage may be a function of the larger seedling size resulting from inoculation rather than from transplanting fungal inoculum to the forested site. This paper also points out current problems and future directions of any inoculation programme.
Journal of environmental horticulture, Jun 1, 2008
To direct, fund, promote and communicate horticultural research, which increases the quality and ... more To direct, fund, promote and communicate horticultural research, which increases the quality and value of ornamental plants, improves the productivity and profitability of the nursery and landscape industry, and protects and enhances the environment. The use of any trade name in this article does not imply an endorsement of the equipment, product or process named, nor any criticism of any similar products that are not mentioned.
The use and manipulation of the mycorrhizal symbiosis has enormous potential benefits in tree nur... more The use and manipulation of the mycorrhizal symbiosis has enormous potential benefits in tree nurseries and in artificial regeneration programmes. This paper discusses the role of a mycorrhizal inoculation programme in reforestation. Included in this discussion are type of inoculation and response of the host to inoculation. The direct impact of a mycorrhizal inoculation programme will depend upon the symbionts selected and, of course, site characteristics. Inoculation generally improves survival and growth following outplanting. However, this advantage may be a function of the larger seedling size resulting from inoculation rather than from transplanting fungal inoculum to the forested site. This paper also points out current problems and future directions of any inoculation programme.
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Papers by John Mexal