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In semi-arid regions, the adequacy of water supply is a prerequisite for production of food and fiber. Consequently, flow and retention of water in soils are keys to our understanding of processes that influence the efficient use of precipitation and ultimately production potential under dryland agriculture conditions. The objective of this study is to determine the influence of land use on infiltration and physical properties of the soil surface on adjacent pasture, cropland, and replanted grassland areas. Steady state infiltration rates over a range of tensions are being measured using a disk infiltrometer to characterize the hydraulic properties of the soil near the surface. Preliminary results of this research show that productive grasslands have higher saturated conductivities, lower unsaturated conductivities, and lower bulk densities than cropland. This indicates that the grassland soils can intercept more precipitation, reduce evaporative losses, and store water more deeply in the profile than cropland soils.
Robert C. Schwartz, Soil Scientist; Paul W. Unger, Soil Scientist; Steven R. Evett, Soil Scientist; USDA-ARS, Bushland, TX; and James Bauchert, Soil Scientist, USDA-NRCS, Dumas, TX
Problem: No-tillage is a drastic departure from conventional tillage, and there are concerns whether this type of farming can be maintained on dryland without developing problems that could adversely affect soil conditions and crop yields. Objectives: To determine the effect of long-term use of no-tillage on wheat and sorghum yields and on soil physical and chemical properties. Treatments: Winter wheat and grain sorghum have been grown in rotation under no-tillage conditions on three fields since 1979. Weeds and volunteer crop plants are controlled with herbicides. Soil water contents at planting and harvest and yields are determined for each crop. Soil conditions are determined periodically. Results: The average grain yield for wheat is about 2880 kg/ha (2570 lb/acre; 43 bu/acre) from 1985 through 1999. The wheat yielded up to 4700 kg/ha (4200 lb/acre; 70 bu/acre) in parts of the field in 1999. For grain sorghum, the average is about 4400 kg/ha. Yield for both crops are based on a 13.5% grain moisture content. The average yield for sorghum does not include results for 2 years when yield was not obtained. In 1990, sorghum was planted late (in July) because of early dry soil conditions and freezing weather in September killed the sorghum before grain filling had occurred. Sorghum was not planted because of the drought in 1998. Soil conditions have not been adversely affected by use of no-tillage when compared with soil conditions on other dryland field areas.
Paul W. Unger, Soil Scientist, USDA-ARS, Bushland, TX
Problem: Soil water storage and erosion control improve with increases in the amount of crop residues retained on the soil surface, but residue production by dryland crops such as winter wheat and grain sorghum often is low. If more residues could be `carried over' from one crop to the next and a `buildup' of residues could be obtained when these crops are grown in rotation, improved water conservation and erosion control should occur. Objectives: To determine if wheat and grain sorghum varieties differ with regard to amounts of residues carried over from one crop to the next when they are grown in a rotation in a no-tillage cropping system. Treatments: Five wheat varieties and five grain sorghum hybrids are `cross planted' in the study. Residue amounts remaining from each previous crop are determined at planting and harvest of each crop. Soil water contents and crop yields are determined also. Results: The study is still in progress and results are not yet available.
Paul W. Unger, Soil Scientist, USDA-ARS, Bushland, TX
Problem: Soil water storage and erosion control improve with increases in the amount of crop residues retained on the soil surface, but residue production by a dryland crop such as winter wheat often is low. Also, when wheat is harvested with a combine equipped with a cutter header, the straw that passes through the combine is spread on the soil surface where it decomposes quicker than the straw that remains standing. If more of the straw would remain standing until the next crop is planted, improved water conservation and erosion control should occur. Objectives: To compare the effects of header type (stripper or cutter) used for harvesting wheat on straw height and weight, soil water storage during fallow from wheat harvest until grain sorghum planting, weed control problems, and grain sorghum growth and yields. Treatments: Strips of wheat were harvested with a combine equipped with a stripper header or a cutter header (three strips with each type of header). Height and weight of standing straw and soil water contents are determined at wheat harvest and at grain sorghum planting (at the end of the fallow period). Effects of header type (straw on the surface) on weed control problems, etc. are noted and crop growth and yields are determined. Results: The study was started in 1999. Standing straw height is about 50 percent greater where wheat was harvested with the stripper header than with the cutter header. Other results are not yet available.
Paul W. Unger, Soil Scientist, USDA-ARS, Bushland, TX
Problem: Soil organic C content, recognized as an indicator of soil quality, declines with continued cropping when grasslands are converted to cropland. When croplands are planted to grass, it is generally assumed that soil C contents will increase, which would enhance C sequestration in the soil and improve soil quality. Some croplands in the region have been planted to grass under Conservation Reserve, Soil Bank, and Great Plains Programs. Land adjacent to such program lands has remained in crop production and/or in native grass. The effect of different management practices on soil C and related properties, however, is not well documented. Objectives: To determine effects of long- and short-term cropping practices and differently-managed grasslands on soil physical, chemical, and biological properties that are related to crop productivity, soil quality, production sustainability, and the environment. Procedure: Twelve widely separated sites in the High Plains (Panhandle) region of Texas where cropland, native grassland, and replanted grassland (Conservation Reserve Program [CRP]) areas are adjacent to each other were sampled to determine a number of soil properties, including texture, organic carbon content, aggregation, density, and water relations. Results: Soil bulk density means were similar at all sites, but increased with depth. Cone penetrometer resistances at 0-20 cm (0-8 inch) depths were least on cropland and greatest on native grass areas; they were variable at the 20-50 cm (8-20 inch) depth. The mean weight diameter (MWD) of water-stable aggregates at the 0-2 cm (0-0.8 inch) depth was lower (1.96 mm) (Note: 1 inch equals 25.4 mm) than at greater depths (all >2.39 mm). For the 0-30 cm (0-12 inch) depth, the mean MWD was lower on cropland (1.69 mm) than on CRP (3.03 mm) and native grass (3.28 mm) areas. Mean water stabilities of 1-2 mm aggregates differed, being 58.3% on cropland, 71.8% on CRP, and 80.9% on native grass areas. Converting native grass areas to cropland did not cause bulk density or penetration resistance problems. Some conditions were poorer on CRP than on native grass areas. Lower aggregate MWD and stability on cropland areas indicate a potential for lower water infiltration, which may hinder soil water conservation efforts.
Paul W. Unger, Soil Scientist; Steven R. Evett, Soil Scientist; R. Louis Baumhardt, Soil Scientist; and Robert C. Schwartz, Soil Scientist; Judy A. Tolk, Plant Physiologist; USDA-ARS, Bushland; Fred B. Pringle, Soil Scientist; USDA-NRCS, Amarillo; and Clay Robinson, Associate Professor, and B. A. Stewart, Distinguished Professor of Soil Science and Director, Dryland Agriculture Institute, WTAMU, Canyon, TX
Problem: Waste paper accounts for much of the material disposed of in landfills. Landfill space, however, is limited in many areas and some landfills are no longer available for waste paper disposal. Therefore, alternative means of disposal are needed. Applying waste paper to agricultural land is being considered. If applied to land, it must not result in a trashy appearance and it should provide benefits to land owners or operators. One such means is to use paper pellets, which are being used as a mulch for landscaping in some areas. Surface-applied paper pellets reduced soil water evaporation under laboratory conditions. Objective: A study was started in 1995 to determine whether surface-applied paper pellets would increase soil water storage under field conditions. Such application would increase the amount of organic materials on the surface, which should add to the benefits obtained from crop residues. It should also increase soil organic matter contents, which should improve soil conditions. Procedure: Paper pellets are applied after wheat harvest in a wheat-grain sorghum rotation study. Pellets are applied at rates of 0 (check treatment), 5000, 10000, or 15000 kg/ha (none and about 4460, 8930, and 13400 lb/acre) to no-tillage and sweep-tillage plots where wheat residues are retained on the soil surface or removed by raking. Effects of the pellets on soil water storage and on grain sorghum growth and yield are being determined. Results: The field study has been completed, but data have not yet been analyzed.
Paul W. Unger, Soil Scientist, USDA-ARS, Bushland, TX
Problem: The agricultural industry on the Texas High Plains generates $3.25 billion annually from livestock and the supporting feed grains and forage crop production. Much of the intensive crop production depends on irrigation from the declining Ogallala aquifer. Dryland crop production systems that integrate livestock grazing are needed to maintain continued success of the southern Great Plains agriculture industry. Objectives: This study was initiated to develop Best Management Practices (BMPs) for maintaining long-term productivity of an integrated livestock grazing and dryland Wheat-Sorghum-Fallow (WSF) cropping system. Approaches: The effects of cattle grazing on soil compaction, water conservation, and crop forage and grain yield will be determined for dryland WSF beginning with the 1999 wheat crop. Soil measurements include penetration resistance, density, and rain infiltration. Crop measurements include water use and the yield of grain and forage/residue. Cattle grazing density, grain-yield, residue-production, and soil properties will be mapped and cross-correlated. Results: Grain sorghum and early planted wheat for grazing could not be established in 1998 because of unusually dry conditions. While 1998 may have been unusually dry, preliminary results illustrate the risk and dependence of grazing livestock on growing season rainfall for dryland crops.
R. Louis Baumhardt, Soil Scientist, USDA-ARS; Steven R. Winter, Professor Agronomy and L. Wayne Greene, Professor Animal Science, TAES, Amarillo/Bushland, TX
Problem: The need for alternative dryland crops in the southern Great Plains results from declining water tables and irrigation, and from developing weed control problems where repeated chemical weed control methods have selected "resistant" weed populations. Information is needed on the adaptability and best management practices, BMPs, for growing cotton as an alternative dryland crop in this region. Some concerns affecting cotton production in this area, include: (i) the use of 2,4-D in neighboring fields, (ii) the limited growing season, and (iii) soil water availability. Objectives: Several studies are being conducted to evaluate: (i) variety tolerance and recovery after 2,4-D injury, (ii) the effect of cultural practices like row spacing and plant population on crop growth, and (iii) cotton growth as a function of climatic conditions for computer crop growth simulation modeling. Approaches: Plot areas were planted with cotton after the 10-day average soil temperature at the 6" depth was at least 60 F. Test populations vary from 60,000 to 90,000 plant/ac in row widths of 30, 20, and 15 inches. Varieties include DP-2156, ALL-Tex Quickie, AFD-2525, PM-145, PM-183, PM HS- 26. Results: The tests have been conducted during unusually dry and, so far in 1999, wet conditions, but crop growth has followed closely to established relationships between crop- stage and seasonal temperatures. The drought conditions of 1998 masked much of the crop population and row width effects on lint yield. Crop injury due to 2,4-D drift depressed yields 30 - 50% compared to unaffected cotton depending on the variety in 1998. While un-injured cotton lint yields were about 300 lbs/ac, the poor fiber quality (length~26/32) almost disqualified loan eligibility.
R. Louis Baumhardt, Soil Scientist, USDA-ARS, Bushland, TX
Problem: Common corn smut is a fungal infection that occurs with varying frequency, depending upon weather conditions. Corn smut can have adverse effects on corn yields, however, its effect on the feeding value of silage made from infected corn is not known. Objectives: These trials were conducted to determine the effects of common corn smut on the palatability and digestibility of corn silage. Treatments: The three treatments consisted of corn silage made with 0, 50, or 100% of the plants infested with common corn smut. Results: In a palatability trial, lambs preferred silage containing smut infested corn over non-infested corn. In both in vitro (lab-scale) and in vivo (in live sheep) digestion trials, digestibility decreased as the proportion of smut infested silage increased. This was probably because smut infested silage had higher fiber and crude protein content but lower non-structural carbohydrate content. These results indicate that corn smut does not adversely affect the palatability of corn silage; however, corn smut decreases the digestibility of corn silage. Thus, when formulating diets, the energy values of corn silage infested with common smut should be decreased compared to non-infested silage.
N. Andy Cole, Research Animal Scientist, USDA-ARS, and Charlie Rush, Professor, TAES, Bushland, TX
Problem: The feeding of livestock in confinement leads to concentration of feed nutrients into a relatively small geographic area. Significant quantities of excreted nitrogen (N), carbon (C), and sulfur (S) can be lost to the atmosphere. Nutrient volatilization from the feedlot surface and waste retention facilities can potentially be decreased by addition of amendments to the feedlot surface or to the waste water retention facility. Objectives: To determine the effects of several soil amendments on losses of ammonia from a mixture of cattle feces and urine using a laboratory-scale system. Treatments: The soil amendments tested included aluminum sulfate (alum), calcium chloride, a commercial urease inhibitor (N-(n-butyl) thiophosphoric triamide - NBPT: N-Conserve, IMC-Agrico, Bannockburn, IL), humates, and lime. Results: Additions of lime (2 tons/acre) increased ammonia production by 10X. Alum decreased ammonia production by 50 (1 ton/acre) to 98% (4 tons/acre). NBPT decreased ammonia emissions by approximately 65%, however, after 10 to 14 days, the inhibitor seemed to loose its effect. Calcium chloride (2 tons/acre) and humates (4 tons/acre) decreased ammonia production by 70%. Although several compounds decreased ammonia emissions, their costs are still probably prohibitive. These costs could be decreased by applying compounds only on pen locations with the greatest potential for ammonia losses. The costs may also be offset by charging for the increased fertilizer value (i.e., higher N content) of the manure collected.
N. Andy Cole, Research Animal Scientist, USDA-ARS, Bushland, TX, and David Parker, Assistant Professor, WTAMU, Canyon, TX
Nearly 7 million tons of manure are produced annually in feedlots in the panhandle region of Texas and Oklahoma and eastern New Mexico. Disposal of the large quantities of excreta produced by concentrated animal feeding operations (CAFOs) is achieved primarily by offsite land application of these wastes. Management guidelines for the land application of wastes needs to be developed in order to minimizes offsite and onsite environmental impacts. This requires an accurate assessment of manure and compost composition and rates of mineralization. Such research will permit the determination of optimal loading rates of these organic sources for crop production without impairing environmental quality. A long-term field study of the land application of stockpiled manure and compost were carried out to (i) quantify the mineralization of nutrients in waste amended soil and (ii) evaluate P surface and subsurface transport rates. Manure, compost, and inorganic fertilizers have been applied to level terraces since 1996 under a wheat-sorghum-fallow rotation with both stubble-mulch and no-tillage management. Manure and compost are applied once every third year coinciding with the sorghum phase at a rate equivalent to 150 kg N ha-1. In an alternative treatment, manure and compost are applied at a rate equivalent to 15 kg P ha-1 and urea is applied at a rate required to supplement the nitrogen requirements of the crop. Preliminary results in 1996 demonstrated that sorghum and winter wheat responded positively to applied nutrients from all sources. Water-soluble P was found to readily desorb from both compost and manure when incubated with soil from the study site (Torrertic Paleustoll). Rainfall simulation studies have also been carried out to evaluate the magnitude of surface transport of P from manure plots and the determination of the major forms of P in runoff water. This research will assist in the development of guidelines for addressing regulatory limits of P loading for soils in this region.
Robert Schwartz, Soil Scientist, USDA-ARS, Bushland, TX and Thanh H. Dao, Soil Scientist, USDA-ARS, Beltsville, MD
Objectives: 1). To determine the effects of various application rates of feedlot effluent on the forage value of sorghum and wheat. 2). To evaluate soil properties which may change due to the effluent application. Methodology: Plots will be laid out at the USDA-Agricultural Services Research Conservation and Production Laboratory located at Bushland, Texas. A two-year study will be conducted with consecutive crops of forage sorghum, winter wheat, and a crop rotation of forage sorghum followed by winter wheat. For each crop grown, there will be three treatments of application rates of collected feedlot effluent (0 acre-inch, 6 acre-inch, and 12 acre-inch). There will be three replications of each treatment. Effluent will be applied from the runoff holding pond at the 384 head TAES/ARS Experimental Feedlot at Bushland using flood irrigation. Procedures: Preliminary soil samples have already been obtained from the proposed plot area. These results, as well as the control plots, will help determine if any changes occur over time in the soil from the applications. The total plot area will be 195 ft by 235 ft. This computes to each plot being .01825 acres. There will be 3 blocks of plots, each containing 9 individual plots. Each block will have a singe crop at a time. One will be winter wheat, one will be forage sorghum, and one will be a continuous rotation of sorghum and wheat. A 20-ft road will separate each block from the others. Individual plots will be 15 ft wide by 53 ft long (see attached diagram). This size of plots is large enough to replicate actual practical field conditions. The effluent will be applied by flood irrigation. The plots will be leveled with a laser plane to assure equal application rates over the entire area. The research area has a 2% slope; therefore, the plots will be laid out by the contour of the area and leveled to assure equal application rates of effluent. Effluent will be applied through a 6" pipeline and a 225-gpm pump. All water will be either natural rainfall or applied from the storage pond, no other irrigations will be applied unless it is deemed necessary for plant survival. Effluent will be applied in three irrigations. Plots receiving 6 acre-inch of water will receive 2 inches at a time. Plots receiving 12 acre-inch will receive 4 inches at a time. Samples will be taken at the end of each growing season and sent to the Texas A&M Extension Soil, Water, and Plant testing lab in College Station for analysis. Samples will include soil samples taken at the end of each growing season, plant samples taken just before harvest, and effluent samples taken at the beginning, in the middle, and at the end of each irrigation. Growth rate (height of plants) of the plants will be measured at two-week intervals after plant emergence. Irrigations will occur at three to four week intervals depending on weather conditions. Expected Benefits: This study should demonstrate to producers an optimum rate of effluent to apply to crops typically grown in this area. It should also show feedlot managers a good way to utilize feedlot holding ponds in a beneficial manner. Concerns of phosphorus build-up in soils from feedlot runoff can also be addressed in this study by observing the effects of the various amounts of effluent applied. As regulations for CAFO's increase, studies of this nature should show producers how to utilize feedlot runoff as well as providing good data to regulatory agencies for further management practices.
M.B. Rhoades, Graduate Student; and D.B. Parker, Assistant Professor; WTAMU, Canyon, TX; J.M. Sweeten, Professor & Resident Director, TAES, Amarillo/Bushland, TX; L. Perino, Professor, WTAMU, Canyon, TX; and N.A. Cole, Animal Scientist, USDA-ARS, Bushland, TX
Problem: Fugitive feedyard dust is thought to increase acute bovine respiratory disease of market-stressed feeder calves and may have an adverse effect on weight gain. Fugitive dust in feedyards is also a nuisance factor to surrounding neighbors and towns. Agriculture practices that induce dust in the 2.5 micron (micro meter) size particles are of concern to Air Quality Regulators and human health. In fact if certain limits are exceeded fines can be made against the offending party. Objectives: Cattle and small ruminant models (sheep and goats) were chose to determine unknown parameters (body temperature, complete blood counts (CBC), inflammatory protein markers, rate of weight gain) when challenged with feedyard dust. Treatments and Results: High doses of endotoxin applied to market stressed feeder calves caused dust challenged calves without antibiotics to gain slower than their pen mates given dust and antibiotics; mature sheep challenged with high doses of endotoxin/dust exhibit maximum fever 8 hrs post challenge, and maximum CBC counts 20 hrs post challenge. Four month old goats challenged with endotoxin/dust exhibit maximum fever in 4-8 hrs and maximum CBC counts in 8 hrs. Additional Results: Two studies are in progress and results are not yet available.
Charles W. Purdy, Veterinary Microbiologist, USDA-ARS, Bushland, TX
Problem: Respiratory Bovine Coronavirus (RBCV) appears to be a new emerging virus disease which, heretofore has not been associated with acute BRDC. The virus is difficult to isolate and most State Veterinary Diagnostic Laboratories are not equipped to isolate the virus presently. Objectives: To determine of RBCV (in market stressed calves) induces acute BRDC similar to Infectious Bovine Herpes virus-1 (BHV-1) and Parainfluenze 3 virus (PI-3). Determine if the first outbreak encountered in 1997 was a fluke. Treatments: One- hundred-five calves were purchased in fall of 1997 from four auction markets in eastern Tennessee, processed in Order Buyer Barn (OBB) and shipped to Bushland, TX. One-hundred- twenty calves were purchased in fall of 1998 from three auction markets (one different from previous year) processed in an OBB and shipped to Bushland, TX. Results: In 1997, 86 of 105 calves nasally shed RBCV and 81 developed acute respiratory track disease, 10 calves died of pneumonia and RBCV was isolated from the lung tissue of 9 calves, by a novel virus isolation technique. These calves developed a typical primary antibody response to the virus. Either Pasteurella haemolytica or P. multocida were also isolated from the lung tissues of 10 calves. In 1998, 119 of 120 calves nasally shed RBCV and 16 calves died from pneumonia. Nine calves died within 1 to 3 days of arrival at the feedyard, lung tissue of all 9 were positive for RBCV. Pasteurella spp. were isolated from lung tissue of 14 to 16 calves. Clearly, RBCV infection represents an emerging virus-induced disease in the U.S. cattle population. Previously, RBCV infections were never suspected or found to be associated with BRDC.
Charles W. Purdy, Veterinary Microbiologist, USDA-ARS, Bushland, TX; Johannes Storz, Veterinary Microbiologist, Sch. Vet. Med., LSU, Baton Rouge, LA; Raymond W. Loan, Veterinary Microbiologist, CVM, College Station, TX; and Robert Briggs, Veterinary Microbiologist, USDA-ARS, Ames, IA
Electric tools, equipment, appliances, and conveniences are desired by many people to make life easier and improve production. For remote farms and ranches, islands, or Alaskan villages, electrical power is most often supplied by diesel generators. By adding wind turbines, the renewable wind energy at the remote site is substituted for part of the diesel fuel normally consumed by the generator sets. The search for the best technique and the most economic sizes and types of equipment used in the design of such a system is ongoing. The USDA - Agricultural Research Service is researching various system configurations, control strategies, and storage schemes to find the ones that provide reliable power of acceptable quality at the least cost over the life of a system. The specific items under investigation are penetration (rates wind power/consumer load), system configurations with and without storage, controls, bio-diesel generator fuels (soybean oil), resistive and inductive load concerns, power storage effects, and best storage methods and sizes. Additional investigation items have to do with reliability and maintainability of the system and it's components. The test system power generators include three CAT 3304 powered diesel generator sets (one 60 kW, 1,800 rpm and two 42 kW, 1,200 rpm), and AOC 15/50 wind turbine (50 kW) and Enertech 44/40 wind turbine (40 kW). Water pumps, lights, and a resistive load bank represent the "village" load. We do this work as part of an interagency agreement with the US Department of Energy.
Eric Eggleston, Mechanical Engineer, and R. Nolan Clark, Laboratory Director and Agricultural Engineer, USDA-ARS, Bushland, TX
Wind turbines that produce electricity are used with standard electric pumps and motors (submersible pumps with 3-phase motors). Flow rates vary from 10 gpm (38 liters/min) for a 1 kW wind turbine to 100 gpm (385 liters/min) for a 10 kW system at a pumping head of 100 ft (30 m) and a wind speed of 22 mph (10 m/s). A 1.5 kW (10 ft) wind turbine was used to replace a worn out 60 year old 10 ft Dempster mechanical windmill on a 300 ft well (240 ft static water level) here at Bushland. The piston pump, 2" steel drop pipe, and sucker rod of the mechanical system was replaced by a 3-phase 230 Volt 1.5 hp motor, 19-stage centrifugal pump, and 1" poly pipe of the wind-electric system. From October 97 to June 99 enough water was provided to satisfy the water requirements of 80 head of cattle. However, the low winds, high temperatures, and drought conditions we've experienced in July '98 required us to haul water for these cattle. If a rancher in this area decides to buy this wind-electric system, it is recommended that he either have a storage tank capable of supplying the cattle with water for 5 days, have a backup 4.5 kW 3-phase 230 Volt gasoline generator, or be prepared to haul water for the cattle in July/August. The 850 Watt (8 ft) wind-electric system can be used to replace a 8 ft mechanical windmill if a tower is used for the wind-electric system which is twice as high as that for the mechanical windmill. A completely new 850 Watt wind-electric system will cost about 20% less than a completely new mechanical windmill system.
R. Nolan Clark, Laboratory Director and Agricultural Engineer; Brian Vick, Mechanical Engineer; USDA-ARS, Bushland; and Shitao Ling, Research Technician, WTAMU-AEI, Canyon/Bushland, TX
Solar photovoltaic panels are used to produce DC electricity that is used directly to power electric pumps. Diaphragm pumps and DC electric motors are used to pump water from small systems (less than 400 Watts) and submersible pumps with AC electric motors are used on larger systems (greater than 500 W). An inverter is used to convert the DC output of photovoltaic panels to AC electricity to power the submersible motors on the larger systems. The DC diaphragm pumps have been pumping water for over 2.5 years now with an availability close to 100%. A rancher with a 100 ft well and 25 cattle to water, this is the best stand-alone renewable energy system to use. However, the lifetime of the diaphragm pump will significantly be shortened of the pumping depth is much deeper. The AC solar water pumping system has also been very reliable and for a rancher with 100 head of cattle and a 150 ft well, who has good solar resource but a poor wind resource, this is the best stand-alone renewable energy system to use.
R. Nolan Clark, Laboratory Director and Agricultural Engineer; Brian Vick, Mechanical Engineer; USDA-ARS, Bushland; and Shitao Ling, Research Technician, WTAMU-AEI, Canyon/Bushland, TX