Engineering Commons^™

Efficacy Of Four Soil Treatments Against Fusarium Oxysporum F. Sp. Vasinfectum Race 4 On Cotton, R. S. Bennet, D. W. Spurgeon, William R. Detar, J. S. Gerik, R. B. Hutmacher, B. D. Hanson

William R DeTar

Fusarium wilt, caused by race 4 of Fusarium oxysporum f. sp. vasinfectum, is a critically important disease problem in California cotton (Pima, Gossypium barbadense; Upland, G. hirsutum). Because few cultivars with resistance to race 4 are available, alternative management strategies for this disease are needed. Four soil treatments (50:50 methyl-bromide + chloropicrin as a positive control; 60:40 chloropicrin + 1,3-dichloropropene; 6 weeks of solarization; and metam-sodium) were evaluated for efficacy against race 4 in a naturally infested, heavy clay soil. Treatments were evaluated based on plant mortality, height, number of mainstem nodes, vascular discoloration ratings, and soil counts of F. …

Crop Coefficients And Water Use For Cowpea In The San Joaquin Valley Of California, William R. Detar

William R DeTar

To improve irrigation planning and management, a modified soil water balance method was used to determine the crop coefficients and water use for cowpea (Vigna unguiculata (L.) Walp.) in an area with a semi-arid climate. A sandy 0.8-ha field was irrigated with a subsurface drip irrigation system, and the soil moisture was closely monitored for two full seasons. The procedure used was one developed for cotton by DeTar [DeTar, W.R., 2004. Using a subsurface drip irrigation system to measure crop water use. Irrig. Sci. 23, 111–122]. Using a test and validate procedure, we first developed a double sigmoidal model to …

Yield And Growth Characteristics For Cotton Under Various Irrigation Regimes On Sandy Soil, William R. Detar

William R DeTar

Over-watering cotton wastes a valuable and scarce resource; it can also lead to rank growth, nutrient leaching, and contaminated groundwater. Since under-watering can decrease yields, the question becomes one of finding the optimum application regime. An irrigation experiment was set up to apply water at six different application rates, ranging from 33% to 144% of normal, with hopes of identifying the regime that produces maximum yield. Two cultivars, Acala Maxxa and Acala PhytoGen-72 (Gossypium hirsutum L.), were planted on sandy soil and irrigated daily with a highly efficient subsurface drip irrigation system for four seasons. The results showed that on …

Detection Of Soil Properties With Airborne Hyperspectral Measurements Of Bare Fields, William R. Detar, J. H. Chesson, J. V. Penner, J. C. Ojala

William R DeTar

ABSTRACT. Remote sensing with aircraft‐based sensors can provide the fine resolution required for site‐specific farming. The within‐field spatial distribution of some soil properties was found by using multiple linear regression to select the best combinations of wave bands, taken from among a full set of 60 narrow bands in the wavelength range of 429 to 1010 nm. The resulting regression equations made it possible to calculate the value of the soil property at every pixel, with a spatial resolution of 1.2 m. Both surface and subsurface samples of soil were taken from the center of each of 321 equal‐sized grids …

Airborne Remote Sensing Used To Estimate Percent Canopy Cover, And To Extract Canopy Temperature From Scene Temperature In Cotton, William R. Detar, J. V. Penner

William R DeTar

The goal of this research was to separate the soil and plant temperatures and create an image map of plant water stress. Data from hyperspectral imagery (HSI) and thermal infrared (TIR) sensors were collected using an airborne platform over three seasons, involving three different varieties of Acala cotton, four different fields, and a total of ten flights. The first step was to measure the percent canopy cover, which ranged from 30% to 100%. Using linear multiple regression, percent canopy cover, measured manually in the field, was found to be closely related to several new vegetation indices, taken from among 60 …

Drip System Used To Measure Water Use By Cowpea (Vigna Unguiculata), William R. Detar, Howard A. Funk, Blake M. Sanden

William R DeTar

Water use was calculated by multiplying a crop coefficient by a reference evapotranspiration (ET). We used evaporation from a USDA Class A evaporation pan as a reference ET, and we also used the more standard CIMIS (California Irrigation Management Information System) value of ETo, which is available on-line. World-wide, a more common reference ET is the Penman-Monteith equation.

Airborn Remote Sensing To Detect Plant Water Stress In Full Canopy Cotton, William R. Detar, J. V. Penner, H. A. Funk

William R DeTar

ABSTRACT. The potential for monitoring plant water stress in full-canopy cotton using airborne remote sensing was examined in this study. Remote sensing data, using hyperspectral (HSI), multispectral (MSI), and thermal infrared (TIR) sensors, were collected over two seasons on two varieties of Acala cotton and two experimental fields, with a total of nine flights, all with 100% canopy cover. The spatial resolution of the remote sensing data used in the study was near 1.0 m. The TIR camera was used to detect the elevated canopy temperature that occurs when the plants are water stressed. The degree of stress, as measured …

Using A Subsurface Drip Irrigation System To Measure Crop Coefficients And Water Use Of Cowpea (Vigna Unguiculata), William R. Detar, Howard A. Funk

William R DeTar

This is a progress report for the first year of growing cowpea on a 1.8-acre experimental plot where a subsurface drip irrigation system is installed with dripperlines buried 10-11" below grade in each plant row. Row spacing is 30" and it is irrigated on a daily basis. The field is level in both directions and extra-large diameter tubing (7/8") was used so that pressures throughout the field are very uniform, with a distribution uniformity (DU) of 96%. The main goal was to find out how much water the cowpea uses. The water use is calculated by multiplying a crop coefficient …

Using A Subsurface Drip Irrigation System To Measure Crop Water Use, William R. Detar

William R DeTar

Procedures are presented for determining crop water use and crop coefficients for a row crop, using a neutron scattering probe with an efficient subsurface drip irrigation system. One procedure is called the slopeprojection method, and the other is called a covariance procedure. Field tests were conducted with full-season, narrow-row cotton (Gossypium hirsutum L.) on a well-drained, sandy soil in a semi-arid environment over a 5-year period. The goal was to improve automated irrigation scheduling, by relating evapotranspiration (ET) to growing degree days (GDD). The result, using a Penman-Monteith reference ET, was an average mid-season crop coefficient of 1.11, with a …

Comparison Of Drip And Sprinkler Irrigation Systems For Applying Metam Sodium And Managing Stem Rot On Potato, G. T. Browne, William R. Detar, Blake M. Sanden, Claude J. Phene

William R DeTar

Drip and sprinkler systems were compared for effectiveness as preplant metam sodium chemigation systems and conduciveness to late-season development of stem rot disease on potato. Sclerotia of Sclerotium rolfsii were used in a bioassay to test efficacy of metam sodium treatments. Drip application of metam sodium (532 liters/ha, 32.8% a.i.) through lines at 7 cm of depth in preformed beds (depths from bed top unless stated otherwise) killed all test sclerotia at 15-, 30-, or 46-cm depths. Drip application of the metam sodium through drip lines at 41 or 46 cm of depth resulted in 0 to 17 or 68 …

Determining Cotton Leaf Canopy Temperature Using Multispectral Remote Sensing, S. J. Maas, G. J. Fitzgerald, William R. Detar

William R DeTar

Previous studies at Shafter have demonstrated that differences in surface temperature associated with water stress can readily be observed in multispectral images of cotton (Gossypium hirsutum L.) fields. In 1999, remote sensing and field observations were made to develop a linear mixture modeling approach to extracting cotton leaf canopy temperature from measurements of surface temperature. In this approach, bare soil temperature within the field was found to be correlated with the amount of crop ground cover. With this information, the effects of incomplete ground cover could be accounted for in estimating the temperature of the cotton leaf canopy.

Drip Vs. Furrow Irrigation Of Cotton On Sandy Soil With 1/4 Mile Runs - Includes: Yield Monitoring, Remote Sensing, And Electronic Soil Survey, William R. Detar, S. J. Maas, G. J. Fitzgerald

William R DeTar

Subsurface drip irrigation was compared to furrow irrigation of cotton on 990-ft runs for 4 seasons on sandy soil. The first furrow irrigation after planting was difficult (as expected) and wasted a lot of water, up to 4 in. The drip system was less efficient than expected due to the startup time required. On the average for the season, the furrow system used 10.5 in. more water that the drip system, a difference which is very similar to results from published short-run (300 ft) tests. There was no difference in yield between the drip and furrow treatments. There were extreme …

Bulk Density Of A Sandy Loam: Traffic, Tillage, And Irrigation-Method Effects, Burl D. Meek, Eric A. Rechel, Lyle M. Carter, William R. Detar

William R DeTar

Modern crop production creates a cycle between soil compaction caused by traffic and alleviation of this condition by tillage or natural processes such as freezing and thawing. The objective of this study was to evaluate important management practices as they relate to changes in bulk density of a tilled sandy loam soil. Practices evaluated were irrigation method, time between tillage and traffic, tire pressure and wheel load of applied traffic, and controlled traffic. Relationships among bulk density, penetration resistance, and infiltration rate were determined. Experiments were conducted in the San Joaquin Valley of California, on a sandy loam soil (Entisol) …

Real-Time Irrigation Scheduling Of Cotton With An Automated Pan Evaporation System, Claude J. Phene, William R. Detar, David A. Clark

William R DeTar

High frequency irrigation control necessitates real-time

monitoring of soil water, plant water status or atmospheric

evaporative demand. The research objective was to

determine the suitability of real-time control of subsurface

drip irrigation using automated evaporation pan

measurements.

Hourly electronic measurement of water loss from an

evaporation pan was a critical feedback control element in

the irrigation scheduling of a high frequency subsurface

drip system (SDI) used to irrigate cotton. The water level

in the class "A" pan was monitored continuously using a

micrologger to measure the output of the electronic water

level sensor. The crop water needs were calculated by …

Infiltration Rate Of A Sandy Loam Soil: Effects Of Traffic, Tillage, And Plant Roots, Burl D. Meek, Eric A. Rechel, Lyle M. Carter, William R. Detar, A. L. Urie

William R DeTar

Settling and trafficking of a soil after tillage causes rapid changes in the soil physical condition until a new equilibrium is reached. In the soil studied, a Wasco (coarse-loamy, mixed, nonacid, thermic Typic Torriorthent) sandy loam, soil compaction reduces infiltration rates, which under grower conditions could result in inadequate infiltration of irrigation water to supply crop requirements. Our objective was to evaluate important management practices as they relate to changes in the infiltration rate of a sandy loam soil. Factors evaluated were traffic, tillage between crops, and the formation of channels by roots of perennial crops. Tillage between crops increased …

Alfalfa (Medicago Sativa L.) Water Use Efficiency As Affected By Harvest Traffic And Soil Compaction In A Sandy Loam Soil, Eric A. Rechel, William R. Detar, Burl D. Meek, Lyle M. Carter

William R DeTar

Traffic during alfalfa harvest operations can cause soil compaction and damage to newly growing stems. Root exploration for soil water and nutrients, forage growth dynamics, and final yield can all be affected. The objectives of this study were to determine the long-term effects of harvest traffic and soil compaction on water-use efficiency (WUE) of alfalfa grown in a Wasco sandy loam (coarse-loamy, mixed, nonacid, thermic Typic Torriorthents). Alfalfa was planted into tilled soil and managed with or without harvest traffic. Plants subjected to traffic during harvest had a significantly lower WUE two out of the three years studied compared to …

Alfalfa Yield As Affected By Harvest Traffic And Soil Compaction In A Sandy Loam Soil, Eric A. Rechel, Burl D. Meek, William R. Detar, Lyle M. Carter

William R DeTar

Harvesting alfalfa (Medicago saliva L.) results in plants being subjected to traffic at different times during the growth cycle with equipment having different wheel sizes and loads. The affect of this traffic could have important ramifications on yield. The objectives of this study were to determine the long-term effects of harvest traffic and soil compaction on alfalfa yield. In the first experiment, two conventional traffic systems were compared to alfalfa production with no traffic. A single traffic event, that covered 100% of the plot area 3 to 5 d after each swathing, compared to no traffic significantly decreased yield by …

Fine Root Development Of Alfalfa As Affected By Wheel Traffic, Eric A. Rechel, Burl D. Meek, William R. Detar, Lyle M. Carter

William R DeTar

Root development in alfalfa (Medicago satire L.) is dependent of many factors including the soil environment which is influenced by crop management procedures. Soil compaction, which is unavoidable under current management procedures, can have a detrimental effect on root development. The purpose of this field experiment was to compare the effects of controlled and conventional traffic management on alfalfa fine root growth in a Wasco sandy loam (coarseloamy, mixed, nonacid thermic Typic Torriorthent). No wheel traffic and traffic only before planting were compared to two conventional systems that varied in the amount of traffic applied during crop production. Twenty months …

Infiltration Rate As Affected By An Alfalfa And No-Till Cotton Cropping System, Burl D. Meek, William R. Detar, D. Rolph, Eric A. Rechel, Lyle M. Carter

William R DeTar

Previous studies measured a long-term increase in infiltration rate in a sandy loam soil with time when alfalfa (Medicago saliva L., cv. WL514) was grown. Cotton (Gossypium hirsutum L.) was directplanted into alfalfa to determine if the high infiltration rates measured under alfalfa culture could be maintained in cotton under either a till or no-till system. Treatments were no-till or tillage to the 0.15 - m depth just before the cotton was planted. Prior compaction levels created by harvest traffic applied to the alfalfa made the soil loose or compacted. Cotton was planted flat and irrigated as a basin. Infiltration …

Changes In Infiltration Under Alfalfa As Influenced By Time And Wheel Traffic, Burl D. Meek, Eric A. Rechel, Lyle M. Carter, William R. Detar

William R DeTar

Infiltration rates were measured for alfalfa, (Medicago saliva L., cv. WL514) subjected to treatments where wheel traffic was varied in terms of area covered and time of application on a Wasco sandy loam (coarse-loamy, mixed, nonacid thermic Xeric Torriorthent). Traffic treatments were (i) No-traffic, (ii) Preplant, MO Repeated, and (iv) traffic similar to what a grower would apply. Infiltration rates increased for all treatments, with increases being 240% for treatments without harvest traffic and 140% for treatments with harvest traffic Increases in infiltration were related to decreases in stand density. Slight packing (traffic) applied before the soil was flood-irrigated in …

Infiltration Function From Furrow Stream Advance, William R. Detar

William R DeTar

Average infiltration rates for large land areas can be quickly determined using a new procedure for obtaining the coefficients of the Kostiakov equation. By introducing the concept of the average opportunity time it is possible to plot the infiltration function directly from tabulated data. This modification of the volume-balance method is a staightforward one, which is easy to understand and learn.

Soil Compaction And Its Effect On Alfalfa In Zone Production Systems, Burl D. Meek, Eric A. Rechel, Lyle M. Carter, William R. Detar

William R DeTar

Alfalfa (Medicago sativa L.) was grown under two zone production systems (no harvest traffic) (i) preplan! compaction and (ii) no preplant compaction and compared to two systems where traffic was applied (i) to 100% of the area during each harvest and (ii) to lanes simulating the traffic a grower would apply during harvest. The experiment was done in a semiarid area under irrigation on a Wasco sandy loam (coarse-loamy, mixed, nonacid, thermic Xeric Torriorthent), which is easily compacted. Without traffic the soil settled to a bulk density of 1.6 to 1.70 Mg m~\ Traffic increased the bulk density to the …

Regrowth And Yield Of Alfalfa As Influenced By Wheel Traffic, Burl D. Meek, Lyle M. Carter, Richard H. Garber, Eric A. Rechel, William R. Detar

William R DeTar

Wheel traffic from equipment used to harvest alfalfa reduces yields because of crown damage and soil compaction. As much as 70% of the soil surface may receive wheel traffic during a single harvest.

Travel Time For Chemicals In An Irrigation System, William R. Detar

William R DeTar

When a chemical is injected into an irrigation system, the length of time it takes to reach the end of the longest path can have a large effect on the uniformity of distribution of the chemical in the field. In trickle irrigation systems, the time to travel this path is also the minimum time before the end of the cycle at which system maintenance chemicals should be injected. In the case where wastewater is being applied to land through an irrigation system or where an injected chemical would cause damage to the piping if it were to remain in the …

Trickle Irrigation Vs. No-Irrigation Of Five Horticultural Crops In Pennsylvania, William R. Detar, David F. Kibler, D. W. Grenoble, R. Daniels, R. H. Cole

William R DeTar

IN humid regions, the question of whether one should irrigate often overshadows problems such as selecting the proper system or scheduling procedure. To show whether it pays to irrigate by running irrigation experiments in the field is a long, expensive process. It would take perhaps five to ten years to determine significant relationships. The approach used in this project was to set up a computer model relating crop yields to weather data and moisture stress, and then verify the model at a few points using field experiments. This first report on the project includes only the field procedures and yields.

Modified Graphical Determination Of Submain Size, William R. Detar

William R DeTar

THE pressure distribution in a multiple-outlet tapered pipe descending a non-uniform slope was determined graphically by DeTar (1975). His procedure enabled one to select the proper pipe size and the location for changes in pipe size. A table of multipliers was a key element in the procedure. This new article presents a simplified method for obtaining these multipliers for a variety of pipe types and for any number of outlets. The procedure involves the use of the correction factor commonly used in sprinkler lateral design; a table of three correction factors is given.

Rate Of Intake And Stream Advance For Liquid Dairy Manure In Furrows, William R. Detar

William R DeTar

FIVE different concentrations of very dilute dairy manure were run down 18 furrows in a sandy loam soil at rates of 200, 400, and 600 mL/min. The resulting intake rates were related to the total solids concentration of the liquid manure and the permeability of the soil. An equation is presented that fits well all of the stream advance curves. An example design problem shows how to determine the proper length of furrow and the duration of each irrigation.

Trickle Irrigation In The Eastern United States, David R. Ross, C. W. Reynolds, R. A. Parsons, E. D. Markwardt, William R. Detar

William R DeTar

A cooperative extension manual by the Northeast Regional Agricultural Engineering Service. Trickle or drip irrigation is a method of slowly applying small amounts of water to part of the plant root zone. Water is applied on a frequent, often daily, basis to prevent moisture stress in the plant by maintaining favorable moisture conditions. With adequate soil moisture, 25% of the root system of a fruit tree can supply enough water to prevent moisture stress. Trickle irrigation has been installed mainly in areas that are arid and have high labor costs. The system works well with water that is highly saline …

Infiltration Of Liquid Dairy Manure Into Soil, William R. Detar

William R DeTar

BASIN infiltrometers and double-ring infiltrometers were used on the subsoil of four different soils to determine the infiltration rate of various concentrations of liquid dairy manure. Raw manure was diluted with water by ratios varying from 3:1 to 50:1. The liquid used for most of the tests did not contain the heavy fibers that tend to settle out immediately after mixing. Total solids, St, was the primary measure of concentration, and steady-state infiltration with water, Iw, was the indicator used for the type of soil. It was found that the infiltration rate was proportional to Iw^0.11st^-.67 at one week. All …

Graphic Determination Of Sub-Main Pipe Size For Solid-Set Sprinkler Irrigation On Steep, Non-Uniform Slopes, William R. Detar

William R DeTar

The selection of the proper pipe size for sub-mains on a solid-set sprinkler system can be a tedious operation for hillside systems, especially if the slopes are not uniform. A typical field situation is where a main across the upper end of the field feeds several sub-mains that descend a steep, irregular slope. These sub-mains feed short laterals that lead off to both sides at regular intervals. The system is fairly common for hillside groves of oranges or avocadoes, and is also used for orchards and vineyards on rolling land. The graphical method presented here is a simplified approach for …