Composted municipal biosolids were incorporated into a potting mix containing sphagnum peat and s... more Composted municipal biosolids were incorporated into a potting mix containing sphagnum peat and sand (1:1 by volume) at rates of 0%, 25%, and 50%, by volume. A second medium was prepared by mixing cow manure compost in the same basic mix at rates of 0%, 10%, and 25% by volume. Each mix was inoculated with P. cinnamomi colonized millet seed at a rate of 200/200 cc of compost-amended media. The potted plants were placed outdoors under nursery conditions 14 July 2003. One half of the plants were irrigated every day, except when natural precipitation occurred; the other half was watered once each week. Soil water potential of all treatments was measured daily with tensiometers. Plants were harvested on 18 Aug. and 21 Oct. 2003, when the experiment was terminated. Frequent rainfall during the period prior to the first harvest masked any impact that the irrigation treatments may have had on disease suppression. Even so, three compost treatments proved successful in suppressing disease act...
Composts vary in their ability to suppress disease activity when incorporated into growing media.... more Composts vary in their ability to suppress disease activity when incorporated into growing media. Bioassays that enable a reliable and quick assessment of compost's ability to suppress disease activity can save time, funds and space. A bioassay using Lupinu× `Russell Hybrid' seedlings was evaluated as a short-term test for gauging the ability of three composts to suppress activity of P. cinnamomi. Colonized millet seeds were prepared via the V-8 agar method. The colonized millet seed were incorporated into the potting media at 0, 50, 100, 200, and 400 colonized millet seed/200 cc of the media used. Three composts, including composted sewage sludge, brewer's waste and cow manure, were incorporated into the media (50% sand: 50% sphagnum peat, by volume) at rates of 0%, 10%, 25%, and 50%, by volume. The media, including the inoculated millet seed, were placed in small plastic pots (7.6-cm-diameter and 6.7 cm high), after which 10 Lupine seeds were sowed in each pot. Percent...
The Cornell Soil Health Test is a publicly available assessment of dynamic soil quality, which ha... more The Cornell Soil Health Test is a publicly available assessment of dynamic soil quality, which has been available to growers, researchers, and others since 2006. As a complement to the existing suite of biological, physical, and chemical indicators of soil quality, we have been exploring the addition of measurements of the soil protein pool, and the soil respiration rate, to the assessment. In addition to their promising utility as soil quality indicators, we have also been exploring the use of these measurements, as well as the other indicators in the assessment, for the prediction of nitrogen supply for crop production. Up-to-date results will be presented.
More efficient nitrogen management in maize production systems is essential, because of the well-... more More efficient nitrogen management in maize production systems is essential, because of the well-documented negative environmental impacts of N on water quality and greenhouse gas emissions. The web-based Adapt-N tool (http://adapt-n.cals.cornell.edu) was designed to improve maize N use efficiency by shrinking the uncertainty around the agronomic optimum N rate. It accounts for the dynamic, complex and locally-specific interactions among weather, soil and management that affect crop-available N in the soil and crop N uptake. Adapt-N uses near real-time high resolution climate data now available for the United State east of the 100th meridian, and field-specific management, soils, and crop information supplied by users via a user-friendly web-interface, as inputs for a dynamic simulation model (Precision Nitrogen Management model). The model simulates daily soil C and N transformations, soil water storage and transport, and uptake of water and N by the maize crop. The Adapt-N web-int...
Africa’s agricultural viability and food security depend heavily on the quality of its soils. Whi... more Africa’s agricultural viability and food security depend heavily on the quality of its soils. While approaches to measuring air and water quality are widely established, soil quality (SQ) assessment protocols are largely non-existent, especially for use in the tropics. The Cornell Soil Health Test (CSHT), developed for public soil testing, uses a set of inexpensive, agronomically meaningful, low-infrastructure-requiring indicators of SQ. We tested CSHT indicators for their ability to show known degradation trends over time and differences between management systems. We used a chronosequence including primary forest and 5-80 year old farms at the Kakamega and Nandi Forest Margins in Western Kenya. On each farm short- and long-term management systems were sampled: 1) kitchen-garden management, 2) continuous maize in low-input monoculture (control), and 3) short-term organic matter (OM) additions to maize. Physical (aggregate stability, available water capacity, and penetration resista...
In studies of erosion, runoff, and infiltration, high soil variability may demand many replicate ... more In studies of erosion, runoff, and infiltration, high soil variability may demand many replicate measurements and rapid, inexpensive methodology. We developed a drop‐forming rainfall simulator in which flow through long, coiled capillary drip tubes is controlled by an adjustable Mariotte‐type bubbling tube. These rain simulators are inexpensive, rugged, simple to operate, easily transported, and require minimal maintenance. Responses to pressure head and water temperature changes were determined for two simulators using tap water. Flow response to pressure head changes corresponded closely to that predicted by Poiseuille's Law. Response to increasing water temperatures was somewhat less than predicted, due to formation of bubbles in the capillary tubes. Simulators incorporating long, coiled capillary tubes can provide combinations of low flow rates and large drop sizes, or a desired range of flow rates when appropriate drip tube diameters, lengths, and numbers of tubes per unit ...
Journal of Irrigation and Drainage Engineering, 1995
The often rapid arrival of pesticides at the ground water has been explained by the concept of pr... more The often rapid arrival of pesticides at the ground water has been explained by the concept of preferential movement of water and solutes through the soil. To facilitate understanding of these transport processes, a drainage study was conducted by applying a nonadsorbed tracer ...
Composted municipal biosolids were incorporated into a potting mix containing sphagnum peat and s... more Composted municipal biosolids were incorporated into a potting mix containing sphagnum peat and sand (1:1 by volume) at rates of 0%, 25%, and 50%, by volume. A second medium was prepared by mixing cow manure compost in the same basic mix at rates of 0%, 10%, and 25% by volume. Each mix was inoculated with P. cinnamomi colonized millet seed at a rate of 200/200 cc of compost-amended media. The potted plants were placed outdoors under nursery conditions 14 July 2003. One half of the plants were irrigated every day, except when natural precipitation occurred; the other half was watered once each week. Soil water potential of all treatments was measured daily with tensiometers. Plants were harvested on 18 Aug. and 21 Oct. 2003, when the experiment was terminated. Frequent rainfall during the period prior to the first harvest masked any impact that the irrigation treatments may have had on disease suppression. Even so, three compost treatments proved successful in suppressing disease act...
Composts vary in their ability to suppress disease activity when incorporated into growing media.... more Composts vary in their ability to suppress disease activity when incorporated into growing media. Bioassays that enable a reliable and quick assessment of compost's ability to suppress disease activity can save time, funds and space. A bioassay using Lupinu× `Russell Hybrid' seedlings was evaluated as a short-term test for gauging the ability of three composts to suppress activity of P. cinnamomi. Colonized millet seeds were prepared via the V-8 agar method. The colonized millet seed were incorporated into the potting media at 0, 50, 100, 200, and 400 colonized millet seed/200 cc of the media used. Three composts, including composted sewage sludge, brewer's waste and cow manure, were incorporated into the media (50% sand: 50% sphagnum peat, by volume) at rates of 0%, 10%, 25%, and 50%, by volume. The media, including the inoculated millet seed, were placed in small plastic pots (7.6-cm-diameter and 6.7 cm high), after which 10 Lupine seeds were sowed in each pot. Percent...
The Cornell Soil Health Test is a publicly available assessment of dynamic soil quality, which ha... more The Cornell Soil Health Test is a publicly available assessment of dynamic soil quality, which has been available to growers, researchers, and others since 2006. As a complement to the existing suite of biological, physical, and chemical indicators of soil quality, we have been exploring the addition of measurements of the soil protein pool, and the soil respiration rate, to the assessment. In addition to their promising utility as soil quality indicators, we have also been exploring the use of these measurements, as well as the other indicators in the assessment, for the prediction of nitrogen supply for crop production. Up-to-date results will be presented.
More efficient nitrogen management in maize production systems is essential, because of the well-... more More efficient nitrogen management in maize production systems is essential, because of the well-documented negative environmental impacts of N on water quality and greenhouse gas emissions. The web-based Adapt-N tool (http://adapt-n.cals.cornell.edu) was designed to improve maize N use efficiency by shrinking the uncertainty around the agronomic optimum N rate. It accounts for the dynamic, complex and locally-specific interactions among weather, soil and management that affect crop-available N in the soil and crop N uptake. Adapt-N uses near real-time high resolution climate data now available for the United State east of the 100th meridian, and field-specific management, soils, and crop information supplied by users via a user-friendly web-interface, as inputs for a dynamic simulation model (Precision Nitrogen Management model). The model simulates daily soil C and N transformations, soil water storage and transport, and uptake of water and N by the maize crop. The Adapt-N web-int...
Africa’s agricultural viability and food security depend heavily on the quality of its soils. Whi... more Africa’s agricultural viability and food security depend heavily on the quality of its soils. While approaches to measuring air and water quality are widely established, soil quality (SQ) assessment protocols are largely non-existent, especially for use in the tropics. The Cornell Soil Health Test (CSHT), developed for public soil testing, uses a set of inexpensive, agronomically meaningful, low-infrastructure-requiring indicators of SQ. We tested CSHT indicators for their ability to show known degradation trends over time and differences between management systems. We used a chronosequence including primary forest and 5-80 year old farms at the Kakamega and Nandi Forest Margins in Western Kenya. On each farm short- and long-term management systems were sampled: 1) kitchen-garden management, 2) continuous maize in low-input monoculture (control), and 3) short-term organic matter (OM) additions to maize. Physical (aggregate stability, available water capacity, and penetration resista...
In studies of erosion, runoff, and infiltration, high soil variability may demand many replicate ... more In studies of erosion, runoff, and infiltration, high soil variability may demand many replicate measurements and rapid, inexpensive methodology. We developed a drop‐forming rainfall simulator in which flow through long, coiled capillary drip tubes is controlled by an adjustable Mariotte‐type bubbling tube. These rain simulators are inexpensive, rugged, simple to operate, easily transported, and require minimal maintenance. Responses to pressure head and water temperature changes were determined for two simulators using tap water. Flow response to pressure head changes corresponded closely to that predicted by Poiseuille's Law. Response to increasing water temperatures was somewhat less than predicted, due to formation of bubbles in the capillary tubes. Simulators incorporating long, coiled capillary tubes can provide combinations of low flow rates and large drop sizes, or a desired range of flow rates when appropriate drip tube diameters, lengths, and numbers of tubes per unit ...
Journal of Irrigation and Drainage Engineering, 1995
The often rapid arrival of pesticides at the ground water has been explained by the concept of pr... more The often rapid arrival of pesticides at the ground water has been explained by the concept of preferential movement of water and solutes through the soil. To facilitate understanding of these transport processes, a drainage study was conducted by applying a nonadsorbed tracer ...
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