College publications are given 2-part "pub numbers" that are used to identify them. The first part (the prefix) is a set of letters that indicates which series the document belongs to. A series is a grouping of documents that share similar content. The second part of the pub number is just a sequential number.
In descending order, by date published.
3/25/2024 (new)
Authors: Steve Higgins
The availability of abundant, clean water can be the most limiting factor for a grazing operation. Rainfall has been harvested for thousands of years to provide water for crops, humans, and livestock. A familiar example is a cistern adjacent to a barn or house. This old concept still offers opportunities and, with a little ingenuity, can be used to provide abundant, clean water for almost any situation and location.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.32 mb
Pages: 5
3/6/2024 (new)
Authors: Joshua Jackson, Karla Ladino
Sprayers are essential in agriculture, since they apply products that control weeds, pests, and diseases. In recent years, drone sprayers have gained popularity due to advantages associated with their flexibility in application timing, ability to operate without being constrained by ground conditions, and ease of deployment. Given the growing number of manufacturers and the wide range of available sizes, it can be challenging to select an optimally sized drone sprayer for a user's specific needs, as this decision carries significant economic implications.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.40 mb
Pages: 6
12/19/2023 (new)
Authors: Steve Higgins
Livestock must maintain a normal body temperature to optimize their production potential. Providing shade and protection from wind are two ways producers can aid in managing the impact of temperature-related stress on their livestock.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 4.66 mb
Pages: 7
12/5/2022 (new)
Authors: Tim Stombaugh
Nozzle tips are critical sprayer components for achieving accurate and uniform application of chemicals. Furthermore, nozzle tips are not cheap, especially when considering how many are required on a sprayer. As with any component on a machine, they will not last forever. So when should nozzle tips be replaced? It would be nice if there were a maximum number of sprayed acres or a fixed period of time after which the nozzle tips should be changed for new ones. Unfortunately, there are too many complicating factors to give such a simple answer. This document explains the causes of nozzle tip wear and some simple ways to tell when they should be replaced.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.37 mb
Pages: 4
11/29/2022 (new)
Authors: Gabriel Abdulai, Joshua Jackson, Karla Ladino, Tim Stombaugh
Similar to other agricultural equipment purchases, cost and potential for return on investment for drone sprayers must be carefully evaluated. General Considerations and Requirements for Drone Spraying (AEN-171) summarized what aspects should be evaluated prior to the purchase of a drone sprayer, or unmanned aerial systems (UAS) sprayer. These aspects include cost considerations, potential uses, certificates and licenses, equipment, utilities, software, insurance, maintenance and repairs, and time allocation.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.20 mb
Pages: 7
11/29/2022 (new)
Authors: Gabriel Abdulai, Joshua Jackson, Karla Ladino
The purchase of an unmanned aerial system (UAS) sprayer, also known as a drone sprayer, must be evaluated carefully. For farmers and sprayer service providers who are thinking about purchasing drone sprayers for their operations, this publication will summarize the potential uses, background information, certificates and licenses required, equipment needed, utilities used, software implemented, insurance needed, maintenance and repairs executed, cost metric utilized, time allocated, and application effectiveness considerations.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.02 mb
Pages: 9
9/13/2022 (new)
Authors: Steve Higgins, Lee Moser
Winter feeding of cattle is necessary in Kentucky, since forages are dormant from late fall to spring. To prevent damage to multiple pastures by the creation of mud from livestock and tractor traffic, producers traditionally select a small area to "sacrifice" for this task. However, poorly chosen sites for winter feeding can lead to the accumulation of mud and loss of productivity of livestock. This publication should be used as a tool to evaluate the suitability of winter-feeding sites and to provide solutions for correcting deficiencies.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.99 mb
Pages: 5
7/25/2022 (new)
Authors: Carmen Agouridis
Outdoor learning environments or classrooms are spaces where students can learn about the natural and human-created world while in an outdoor or natural setting. In these spaces, instructors can use engaging, interdisciplinary, hands-on curriculum to lead students through lessons and to encourage exploration. While often used for science and agricultural studies, outdoor classrooms are also useful for teaching mathematics, social studies, language arts, music, art, and practical living.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 5.73 mb
Pages: 12
3/11/2022 (new)
Authors: Steve Higgins
Having backyard chickens can be a fun, educational, and rewarding experience. There are many reasons why people keep backyard chickens, with availability of fresh, colored eggs, food security, and enjoying the birds as pets among them. However, for some, the goal is to obtain the rich manure that chickens produce to fertilize their garden. There is no better farmyard manure for the garden, as far as the nitrogen content, than poultry manure.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.16 mb
Pages: 6
3/9/2022 (new)
Authors: Matt Adams, Daniel Carpenter, Morgan Hayes
Off grid solar systems are often considered on farms and small acreages in locations where power is difficult or expensive to run. These locations typically do not have huge power requirements; the land owners just wish to have lights in a barn, a fence charger, or to run a small motor or power tool. Off grid solar systems provide an opportunity to have power without the expense of an electric service. Before purchasing an off grid solar system, it is important to have an idea of what electrical items the system will be used to operate, and to understand the components that make up the solar panel system (batteries, fuses, controllers, and inverters).
Departments: Biosystems and Agricultural Engineering, Hardin County, Larue County
Series: Agricultural Engineering (AEN series)
Size: 1.88 mb
Pages: 4
12/17/2021 (new)
Authors: Steve Higgins
The energy expended by a large animal traveling on a slope can be tremendous. To compensate, grazing animals create trails, which run parallel to a slope. These trails allow animals to graze the upper slope, while standing on flat ground, which provides energy and grazing efficiencies.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.30 mb
Pages: 2
11/4/2021 (new)
Authors: Steve Higgins
Many farms contain buildings that were productive long ago but contribute little to the farming operation today. A good example is a tobacco barn on a farm that no longer grows the crop. However, the application of land use planning concepts allows these barns to be repurposed or reprogrammed to significantly contribute to the farming operation. Once repurposed, these old barns can reduce labor, waste, time, and money while improving efficiency and profits.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.00 mb
Pages: 4
9/29/2021 (new)
Authors: James Ash, Steve Higgins
Interest in suburban-urban poultry keeping continues to increase. The main reasons for keeping poultry are for eggs and meat, and to address food sustainability or security issues. Poultry are also enjoyed as pets, for ornamental purposes, and providing enjoyment. Poultry can contribute to pest control and provide nutrient-rich manure for gardening. However, there are also challenges to keeping poultry in a suburban-urban setting.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 24.70 mb
Pages: 7
9/16/2021 (new)
Authors: Steve Higgins
A typical small ruminant operation needs to graze, feed and water animals daily. In addition, other activities such as milking, winter feeding, kidding or lambing, managing sick stock and handling for herd health need to be accomplished routinely or seasonally. An excellent way to promote efficiency is to create a centralized area or hub for all livestock related activities.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.75 mb
Pages: 6
6/9/2021 (new)
Authors: Gabriel Abdulai, Joshua Jackson, Karla Ladino
Unmanned aircraft systems (UAS), commonly known as drones, play an increasingly important role in production agriculture. UAS are already widely used in agriculture for monitoring livestock, inspecting fence lines, and evaluating crops and pastures (e.g., yield, quality, nutrients, water stress, pest pressure, disease impact). The cost of using a UAS will depend on a variety of factors, including platform-based capabilities, maintenance, and insurance. As with any investment, the economic benefit derived from using a UAS should be determined prior to purchase.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.40 mb
Pages: 9
2/16/2021 (new)
Authors: Joshua Jackson
The escape of livestock is a serious concern for producers. Escaped animals can potentially damage property and/or injure people, especially when they are loose in undesired areas. Fence line inspection and the monitoring of gates, wires, and latches is a time-consuming task that must be regularly conducted to mitigate the risk of escape. The use of drones to evaluate fence lines is one of the newer methods being evaluated for farmers. With their onboard camera, rapid flight speed, and ability to fly over obstacles, drones have potential to expedite fence line inspection.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.50 mb
Pages: 7
1/8/2021 (new)
Authors: Steve Higgins
A raised bed is an excellent addition to many backyard gardens. A modification of this design may be of interest to gardeners. A raised wicking bed is a self-contained method for growing vegetables, fruits, herbs, and flowers. The bed provides a built-in water reservoir that allows plants to water themselves. The design is ideal for individuals who are new to gardening, but experienced gardeners will find it helpful as well. The greatest benefit of this system is that it provides control of the water supply to the plants within the defined area.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 4.40 mb
Pages: 6
10/28/2020 (new)
Authors: Steve Higgins
A wicking container is a self-contained method for growing vegetables, fruits, herbs, and flowers. This container provides a built-in water reservoir that allows a plant to self-irrigate. The design is ideal for individuals who are new to gardening or have limited space, but is also used by seasoned gardeners. The greatest benefit of the system is that it provides the plant with control of its water supply, which helps free up more of the gardener's time.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.80 mb
Pages: 5
10/23/2020 (new)
Authors: Joshua Jackson
On cattle operations, the use of a scale system to weigh animals is vital to the proper administration of health products such as dewormers and antibiotics, and for making management decisions. A scale system mounted to a chute allows animals to be securely restrained for measuring weights accurately and minimally impacts cattle flow through the working facilities. Excitable animals can be properly restrained and, with their movement limited, cattle can be weighed accurately.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 6.83 mb
Pages: 9
8/28/2020 (new)
Authors: Steve Higgins
Water source layout is a critical infrastructure component for cattle and cattle producers. Strategic water resource layout is a part of a farmstead plan that does not always get adequate attention, despite its critical importance. Nonetheless, when farm infrastructure planning incorporates the latest practices, rules, and knowledge, the resulting design can satisfy generations of users.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.56 mb
Pages: 6
8/6/2020 (new)
Authors: Steve Higgins
A typical cow-calf grazing operation needs to feed and water cattle on a daily basis. Ideally, this is accomplished by rotating cattle from field to field and providing them with a convenient source of water to drink. Cattle operations can better manage cattle when facilities are designed to meet the needs of cattle and the producer. Land use-planning can increase production and reduce production costs.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 884 kb
Pages: 4
8/6/2020 (new)
Authors: Morgan Hayes, Steve Higgins
Beef cattle production is directly affected by soils, but active soil management is limited. Most producers' soil management decisions are limited to submitting a soil sample, getting the analysis back, and then applying the tons of fertilizer or lime recommended at the bottom of the sheet. Meanwhile, producers request assistance to reduce or eliminate mud, weeds, gully erosion, and compaction (if they have identified compacted ground). Occasionally, producers don't have enough forage or hay to get cattle through drought or winter because of low forage production. These issues may have little to do with soil fertility but instead be directly related to soil properties.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 143 kb
Pages: 2
7/15/2020 (new)
Authors: Morgan Hayes, Joshua Jackson
Hoop barns are a cost-effective alternative to pole barns. For example, a farmer might choose a hoop barn when deciding to expand hay sales, or for providing cover for costly equipment. Hoop barns have the additional benefit of being a construction project that can be done by the farmer (and a group of friends), which can provide an additional cost savings. This publication goes through the steps involved by following the construction of two hoop barns built by a local farmer. In this case, hoop barns were built to increase the farm's hay storage capacity.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 8.14 mb
Pages: 14
5/14/2020 (new)
Authors: Steve Higgins
The benefits of lanes can be applied to pasture-based Kentucky cattle operations of any size. Lanes can be used to move cattle from pasture to pasture, and to access structures or barns, handling facilities, load-out areas, and areas with shade.
Departments: Agricultural Economics, Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.89 mb
Pages: 2
5/14/2020 (new)
Authors: Morgan Hayes, Steve Higgins
Understanding soil mechanics and management in winter-feeding areas could improve beef cattle production, with less effort on the producer and cattle. This publication is intended to guide evaluating soil strength for winter-feeding areas, the pollution potential of winter-feeding areas, and to provide solutions for correcting structural deficiencies and reducing mud on both the ground and on the cattle.
Departments: Agricultural Economics, Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 93 kb
Pages: 2
3/30/2020 (new)
Authors: Morgan Hayes, Katie Jackson, Joe Taraba
Heat stress is prevalent in most livestock species, but especially in dairy animals where large quantities of energy are necessary to sustain milk production. Both dairy goats in lactation and meat goats, which are being fed for growth, are susceptible to heat stress. Knowing the physiological signs to observe (like panting or excessive drinking) can make heat stress more apparent.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 159 kb
Pages: 3
3/30/2020 (new)
Authors: Morgan Hayes, Katie Jackson, Joe Taraba
Farmers who raise goats for meat or milk need guidance in the interrelated tasks of choosing a barn design and managing temperatures for their herd. Barn orientation, ventilation design, and stocking density are all important considerations which impact goats socially and physiologically, potentially impacting production. While other species are relatively well studied in these areas, research on goats is somewhat limited. The goal of this publication is to provide recommendations drawn from research in goats and sufficiently similar species.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 175 kb
Pages: 5
3/9/2020 (new)
Authors: Joe Dvorak, Joshua Jackson, Cameron Minch, Tucker Sheffield
Unmanned aerial vehicles (UAVs) are quickly becoming more integrated into producers' on-farm operations. With the advent of this new technology, users must understand how to convert raw UAV data into an applicable medium. Often the goal of UAV flights is to create a map of the output from a certain type of sensor. Thompson et al. (2018) have defined a general mapping process independent of drone type, sensor type, and mapping software. However, general mapping is significantly different than trying to record a three-dimensional model of the plant canopy structure. This article expands upon the workflow and details the process for developing a canopy model of a crop.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.28 mb
Pages: 5
2/13/2020 (new)
Authors: Steve Higgins
Livestock housing, whether simple or sophisticated, must perform the required functions. It should meet the thermal and physical needs of the animal; it should provide a place to store and feed materials without damage or loss; it should increase the performance of cattle; and, it should allow the producer to conduct all chores associated with cattle production efficiently. A building can contribute to management efficiency and animal performance, which itself is defined by productivity, health and welfare. The building should create optimum environmental conditions for cattle by providing light, air flow, appropriate flooring, space, and ventilation.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 956 kb
Pages: 3
2/3/2020 (new)
Authors: Morgan Hayes, Joshua Jackson
Cattle-handling facilities should be designed to match the management goals of the operation. The safety of workers and cattle should be the highest priority when designing or reworking a handling facility. A well-designed facility will make working cattle faster, safer, less labor intensive, and less frustrating.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 126 kb
Pages: 4
11/21/2019 (new)
Authors: Steve Higgins
Barn floor design is critical to the physical and thermal comfort, health and safety of cattle. Generally speaking, barn flooring is the surface on which an animal stands, lies down, and excretes its urine and manure. Therefore, to meet animal needs, it must be durable, not slippery, and well drained, as well as comfortable, warm, and dry. In addition to providing animal comfort, the flooring should easily be cleaned. No single material, from concrete to soil, meets all of these specifications.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.55 mb
Pages: 3
11/11/2019 (new)
Authors: Steve Higgins
The creation of a creep pen or pasture area can be accomplished using various methods and materials. Using what is on hand and/or revitalizing an unused area of the farm that has infrastructure may reduce expenses. The cost of one fallen calf could pay for the implementation of the practice. This practice may benefit spring calves over fall calves, so that might be a consideration when choosing a time to plan construction of your creep area.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.25 mb
Pages: 3
11/11/2019 (new)
Authors: Steve Higgins
The loose housing system increases the productivity of the replacement herd and the stockman by providing the optimum environment for production and management. While there is work in creating the system upfront, the design will reduce effort later by creating greater efficiency, flow, and movement of materials.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.94 mb
Pages: 4
7/29/2019 (major revision)
Authors: Steve Higgins, Lee Moser
One of the most challenging and costly aspects of beef cattle production in Kentucky is winter-feeding. Many producers complain about the time required to feed stored forages, the mud, the drudgery that it creates for the operator, and the decline in production. The intense traffic associated with winter-feeding on unimproved surfaces causes mud, compaction, erosion, and loss of desirable vegetation, often resulting in annual pasture renovations to address areas impacted by winter-feeding practices. Fenceline feeding systems offer an alternative to traditional in-field bale feeding during the wet winter conditions that Kentucky often experiences. These structures can be utilized to reduce the impact of winter-feeding on pastures and improve the operational efficiency of a winter-feeding area.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.55 mb
Pages: 13
6/18/2019 (new)
Authors: Steve Higgins, Lee Moser
Planning and design are critical steps when modernizing a farm to meet the current and future operational needs. Farm renovations and redevelopment must always consider the cost/benefit of changes, while staying consistent with good agricultural practice guidelines that conserve labor and the resources of the farm. The process of developing a farm map will be used to guide producers on the concepts and considerations necessary to make decisions related to planning renovations and developing new infrastructure on the farm.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.32 mb
Pages: 4
6/17/2019 (new)
Authors: Joshua Jackson
Most producers would like information on cattle weight to improve management. The widespread use of cattle scales on most farms in Kentucky is limited by the cost of purchasing the equipment. Local cattlemen's associations or extension office's frequently have scale systems to rent or borrow. This has challenges due to scheduling conflicts, reliability, rental fees, or the scale may not align with the handling facility layouts. There are two options for producers to obtain cattle weights--in the alley or at the chute. An alley scale provides the ability to measure cattle weight independent of the head gate or cattle chute. This publication describes the measurement of cattle in the alley leading to a head gate or cattle chute.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.90 mb
Pages: 6
5/13/2019 (new)
Authors: Matthew Dixon, Morgan Hayes, Joshua Jackson
Wind is variable in time and space. This is especially true across the state of Kentucky, considering the geographical variety from the Eastern Kentucky mountains to the flatter grain production region in Western Kentucky. In particular, there is a region of potentially variable wind around Cincinnati, near the Ohio River. In trying to account for this variability, monthly wind maps across the state of Kentucky have been developed using the past 30 years of recorded wind data. These data can be used to assist in site evaluations for barns and planning farmstead layouts. Knowing wind speed and direction will help optimize the natural ventilation taking place within agricultural buildings.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.02 mb
Pages: 3
4/10/2019 (new)
Authors: Steve Higgins, Lee Moser
Research shows that cattle benefit from summer shade and winter shelter. Pastured cattle seek shelter around structures, under trees, and in forested streamside zones. These areas are often heavily trafficked and become muddy, compacted loafing areas. Mud creates further stress on cattle and compounds the problems of temperature stress and feed inefficiencies. One option that could be used to lure cattle from these areas and provide winter shelter and summer shade is a constructed windbreak fence on a mound.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.80 mb
Pages: 4
2/18/2019 (new)
Authors: Steve Higgins, Lee Moser
Farm gates are a necessity for controlling traffic and increasing security. There are many design considerations for optimizing a system of farm gates. Very few gates incorporate all the recommended design components that will be discussed in this publication. However, to move people, materials, equipment, and livestock through a gateway, the gateway should economize time, be navigable, and operate in an efficient manner. Time spent operating a poorly designed gateway is time wasted and a hindrance to production. This publication is a guide to aid producers in creating more functional designs for gateways.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.50 mb
Pages: 6
1/23/2019 (new)
Authors: Steve Higgins, Michele McHugh, Lee Moser
Opening farm gates for trucks, tractors, equipment, and livestock is unavoidable. However, opening a large gate, or a set of gates, for a person on foot is extremely inefficient, especially if the entrance does not put the producer where they need to be. An inconveniently located gate can lead to additional steps and unnecessary movements. Opening gates may require dealing with clasps, chains, or ropes just to get the gate unfastened. The gate may then have to be lifted or dragged open and closed. The bottom-line is that entering a poorly installed and unmaintained gateway can make the experience of opening and closing gates a time consuming nuisance.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 9.30 mb
Pages: 4
11/7/2017 (new)
Authors: Steve Higgins, Lee Moser
Abundant, clean drinking water is an essential nutrient for livestock. The obvious water source that is recommended by veterinarians is city water. However, city water has its drawbacks. City water distribution systems are often expensive to install and have a recurring usage charge. In some instances, city water is unavailable, may have inadequate pressure, or producers consider it too expensive to operate, forcing them to use streams and ponds to water livestock. Collecting rainwater from a catchment area, is a low cost, high quality alternative water source that can supplement traditional water distribution systems and improve the environmental quality of farming operations. Rainwater harvesting involves the collection of rainfall from rooftops or land based catchments systems for storage and distribution as needed. Capturing rainfall has the added benefit of improving water quality by reducing soil erosion and runoff. Strategically installed rainwater harvesting systems can be used to direct stormwater around sensitive areas of the farm where animal waste is present, thus reducing the potential for nutrient and pathogen delivery to nearby waterways. Rainwater harvesting and stormwater management techniques can also reduce the volume of water that must be managed in liquid manure management systems by diverting clean water away from manure pits and lagoons.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 807 kb
Pages: 5
10/16/2017 (minor revision)
Authors: Steve Higgins, Stephanie Mehlhope, Lee Moser, Sarah Wightman
Many livestock producers would say that mud is a natural part of livestock production. But the creation of mud costs producers money and makes them less competitive. Livestock that walk through mud require more feed for energy but actually eat less because walking in mud requires more effort to get to feed and water. Therefore, mud decreases average daily gains. Mud accumulation on the coat increases the amount of energy needed to generate heat in the winter or to keep cool in the summer. Also, it can lower sale prices due to hanging tags. The creation of mud also increases animal stress and leads to a variety of health problems, including protozoan and bacterial infections. It is essential that livestock producers understand that mud hinders cost-efficient livestock production and efforts should be made to limit the creation of mud. This publication explains how mud is created and describes different types of hardened surfaces and pads that agricultural producers should use to reduce mud creation and ultimately increase production efficiency and protect natural resources.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.73 mb
Pages: 8
8/8/2017 (new)
Authors: Carmen Agouridis, Steve Higgins, Joshua Jackson, Lee Moser
Kentucky's abundant forage and extensive stream system have helped the Commonwealth become the largest beef producing state east of the Mississippi River. While streams and ponds serve as a water source for many operations, livestock can quickly degrade soil and water quality by trampling streambanks and defecating and urinating in and around waterbodies. These actions increase sediment, pathogen, and nutrient loads to streams, rivers, and lakes which in turn can causes eutrophication. To help protect the health of Kentucky's soil and water, producers can implement best management practices (BMPs). These practices help reduce the sources of pollutants and/or the transport of pollutants to waterways. One such practice or BMP is limiting cattle access to streams and ponds. When producers exclude livestock access to stream and ponds and their associated riparian buffers, an alternative source of water is required. Automatic water fountains are one commonly used means of providing cattle with water from an alternate source. A water tank constructed using a heavy equipment tire may serve as a viable option for supplying livestock with an alternate source of water.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 4.65 mb
Pages: 8
10/20/2016 (new)
Authors: Carmen Agouridis, Somsubhra Chattopadhyay, Richard Warner
Understanding the effectiveness of BMPs based on their location in the watershed and in relation to different types of pollutants is an important part of protecting waterbodies. One way to do this is with the use of models.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 652 kb
Pages: 3
6/6/2016 (new)
Authors: Steve Higgins, Lee Moser
The traditional farmstead planning process might have been ideal for farming operations set up on blank slate farms that were surveyed based on 640-acre sections. However, these concepts are more challenging for irregular shaped farms in Kentucky with existing structures built more than a half century ago. Older farm buildings may be underutilized because they were constructed using what would be considered obsolete technologies today. It is essential that producers take the time and obtain the necessary help to develop their farming operation plan in order to realize their potential and achieve their goals.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 516 kb
Pages: 3
2/25/2016 (new)
Authors: Steve Higgins, Lee Moser, Kylie Schmidt
Once a drought occurs, it can be difficult to effectively manage your resources and overcome the conditions that drought creates. At the heart of effective drought management is preparedness. A systems-management approach is an ideal tool for drought preparedness, as its goal is to improve each component of the farming operation (soils, forages, facilities, stock, etc.) and improve the connections between the components (i.e. the system). The goal of this publication is to aid beef producers in implementing best management practices (BMPs) that take a systems approach to maximizing farm water use efficiency, while operating under the assumption that water is becoming an increasingly uncertain resource that is vital to the future of the farm.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.40 mb
Pages: 7
2/9/2016 (new)
Authors: Carmen Agouridis, Whitney Blackburn-Lynch, Tyler Sanderson
Knowing the amount of water flowing in a stream can improve management practices such as those related to streambank erosion, pollutant loading and transport, and flood control. Streamflow or discharge is defined as the volume of water moving past a specific point in a stream for a fixed period of time.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.29 mb
Pages: 4
2/9/2016 (new)
Authors: Carmen Agouridis, Somsubhra Chattopadhyay
Sediments in waterbodies cause a number of problems such as harming aquatic habitats, filling reservoirs, and worsening flooding. High amounts of sediment in the water inhibit the ability of fish and aquatic macroinvertebrates to move, breathe, hunt and reproduce. Accumulated sediments in reservoirs reduces their useful life and increases costs associated with maintenance. Streams experiencing such sediment buildup carry less water during storm events.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.51 mb
Pages: 4
2/9/2016 (new)
Authors: Carmen Agouridis, Richard Warner
Increased levels of urbanization result in reductions in the amount of rainfall that infiltrates and evapotranspires and increases the amount of rainfall that becomes runoff. These changes can result in flooding, streambank erosion, and water quality degradation. Hydrologic models are useful in understanding watersheds and how changes in a watershed can affect hydrology. Hydrologic models can predict the amount of rainfall that becomes runoff under different scenarios.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 844 kb
Pages: 5
11/11/2014 (new)
Authors: Carmen Agouridis
Karst refers to terrain largely drained by subsurface conduits and caves. Karst landscapes are characterized by surface features such as springs, sinkholes, shallow depressions, and rolling hills. Karst regions are also known for their subsurface or below-ground features such as conduits and caves. What makes a karst region unique is the way runoff drains from the land. In karst regions, some of the runoff flows into surface features such as sinkholes where it then travels underground. Some of this infiltrated water re-emerges at springs, and some continues moving underground.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.70 mb
Pages: 4
8/11/2014 (new)
Authors: Steve Higgins, Kylie Schmidt
Liquid manure storage structures, such as a lagoon, holding pond, or pit, serve an essential purpose on an active livestock operation. However, when this structure is no longer actively managed it can become a major liability to the producer because of its potential to have a discharge. The discharge from a liquid manure storage structure can contain pollutants such as nutrients, heavy metals, hormones, pathogens, and agriculture chemicals, all of which can pose serious threats to human health and aquatic ecosystems. Because of the pollution potential, livestock producers ceasing their operation are required to close their liquid manure storage structure(s) as part of their Kentucky No Discharge Operational Permit. To help offset the costs of closing the structure, producers may want to apply for cost share funds through the Division of Conservation. Before beginning to close a liquid manure structure, the Kentucky Division of Water (KDOW) must be provided with a closure plan. This publication outlines the preferred practices and steps for closing a liquid manure structure to meet the guidelines of the KDOW.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 106 kb
Pages: 2
7/23/2014 (new)
Authors: Carmen Agouridis, Matthew Burnette
Streambank erosion refers to the removal of soil and other material, such as rock and vegetation, from the streambank. Streambank erosion is a naturally occurring process, but the rate at which it occurs is often increased by anthropogenic or human activities such as urbanization and agriculture. Changes in land use can cause streambanks to erode at rates much faster than those seen in natural, undisturbed systems.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.11 mb
Pages: 8
5/14/2014 (new)
Authors: Steve Higgins, Kylie Schmidt, Sarah Wightman
As health and food safety concerns grow, dairy producers are facing more stringent regulations. In 2010, the European Union (EU) set the somatic cell count (SCC) upper limit, an indicator of milk quality, for exported milk at 400,000 cells per milliliter. However, the current U.S. SCC limit is 750,000 cells per milliliter. As of January 2012, any U.S. milk used in export markets must meet the EU standards. It is projected that US milk processors will gradually adopt the EU upper limit, making it difficult for dairy producers to sell milk containing more than 400,000 somatic cells per milliliter. Dairy producers will have to find innovative and cost-effective ways to reduce the somatic cell count of their milk. This publication will discuss how agriculture best management practices can be used to lower SCC.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 350 kb
Pages: 4
4/23/2014 (new)
Authors: Steve Higgins, Kylie Schmidt
Producers must understand that dry cows and bred heifers are the next milking herd, so focusing on their management can maintain or actually increase future profitability. This publication focuses on environmental management strategies that improve dry cow and bred heifer performance.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 454 kb
Pages: 3
3/4/2014 (new)
Authors: Carmen Agouridis, Evan Wesley
Stream restoration is the re-establishment of the structure (dimension, pattern, and profile) and function (transport of water, sediment, and nutrients; habitat provision) of a degraded stream as closely as possible to pre-disturbance conditions.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.63 mb
Pages: 5
1/6/2014 (new)
Authors: Carmen Agouridis
Groundwater is an important water source for activities such as drinking, bathing, cooking, and crop irrigation. Keeping our groundwater sources clean is becoming more challenging with an ever growing population. In watersheds underlain with karst, such as many of those in Kentucky, the groundwater is more susceptible to contamination. This is because surface waters, such as runoff and in some cases streamflow, travel into the subsurface of karst by way of fractures, sinkholes, swallow holes, conduits and caves Such direct paths into the groundwater mean that pollutants reach the aquifer much more quickly with little to no filtration. Thus, while waters from springs and wells may look clean, they may actually contain unsafe levels of pollutants such as bacteria and nitrogen.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 2.00 mb
Pages: 3
11/14/2013 (new)
Authors: Carmen Agouridis, Rachel Williams
Fresh water is an essential natural resource that is used every day for drinking, bathing, cooking, cleaning, and recreation. In Kentucky, the water used for these tasks mainly comes from streams and rivers, but it can also come from groundwater. Because our streams, rivers, and aquifers are so vital to our daily lives, it is important that we protect them from trash, debris, and other pollutants found in stormwater. What happens to the land around these water sources affects their condition and health.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.20 mb
Pages: 2
8/21/2013 (new)
Authors: Carmen Agouridis, John McMaine
As more land is covered by impervious surfaces, less rainfall infiltrates into the ground and instead becomes runoff. Too much runoff is problematic. Flooding increases, streambanks erode, and water quality is reduced. An increase of impervious area of as little 10 percent has been shown to negatively impact streams. The purpose of this publication is to explain low impact development strategies and how they can be used to improve stormwater management by reducing impacts on streams.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 5.30 mb
Pages: 8
4/25/2013 (new)
Authors: John Wilhoit
Round bales of hay or straw can be used to mulch between rows of plastic film mulch used in vegetable production. This practice may be particularly useful for organic production where herbicide use is prohibited. To make the job of unrolling round bales between rows of plastic easier, a commercially available three-point hitch mounted bale unroller was modified by extending the toolbar and adding a second mast so that the bale is offset, allowing the tractor to straddle a row of plastic while unrolling the bale between the rows.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 3.40 mb
Pages: 3
1/22/2013 (new)
Authors: Czarena Crofcheck, Tabitha Graham, Michael Montross
As the world's population swells and the needs of developing countries increase, the world's overall energy usage also continues to rise. Recent international legislation emphasizes the effects of climate change and the crucial need to find a way to decrease the greenhouse gas (GHG) emissions being released into the environment. Consequently, power plants have an increased urgency to find a viable way to decrease their GHG emissions. This issue has prominent implications for Kentucky due to our economy's dependence upon coal production.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.94 mb
Pages: 3
11/9/2012 (new)
Authors: Carmen Agouridis, Ross Guffey, Richard Warner
Non-point source pollution (NPS) occurs when rainfall and snowmelt flows over the ground, picking up pollutants such as pathogens, sediments, and nutrients on its way to streams, rivers, lakes, and other bodies of water. More than 50 percent of the nation's rivers and streams and nearly 70 percent of the nation's lakes are impacted by NPS. Pathogens, sediments, and nutrients are the biggest contributors to impairment of rivers and streams while mercury, nutrients, and PCBs (polychlorinated biphenyls) are the biggest contributors to the impairment of lakes. One method of managing NPS pollution is through the use of structural best management practices (BMPs). Structural BMPs are designed to decrease the volume of runoff that enters water bodies by increasing infiltration rates. Examples of structural BMPs include rain gardens, stormwater wetlands, and riparian buffers. A newer structural BMP is a weep berm.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 4.40 mb
Pages: 8
3/27/2012 (new)
Authors: Steve Higgins, Sarah Wightman
Nutrients are constantly cycling through farms. Nutrients come onto a farm in the form of feed, commercial fertilizers, manure, or compost, and they leave the farm with harvested crops, sold livestock, and off-site disposal of manure and other waste. Sometimes nutrients are even lost to the air, soil, or water. Nutrient management allows farmers to use nutrients (specifically nitrogen, phosphorus, and potassium) wisely for optimal economic benefit with minimal impact on the environment.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 345 kb
Pages: 5
3/19/2012 (new)
Authors: Will Adams, Michael Montross, Sue Nokes, Tim Stombaugh
For many social, political, and economic reasons, biofuels are moving quickly from the fuel of tomorrow to the fuel of today. Researchers at the University of Kentucky are working on a new system of biofuel production that involves on-farm processing of biomass. This factsheet provides a general overview of this new concept that could have a great impact on agriculture and the fuel-production industry.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 235 kb
Pages: 2
3/8/2012 (new)
Authors: Kathryn Gray, Michael Montross, Sue Nokes, Tim Stombaugh
Butanol is a type of alcohol that has received renewed interest recently as a potential green alternative to petroleum fuels. This factsheet gives a basic history and description of butanol and its potential use as a biofuel in gasoline and diesel engines.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 220 kb
Pages: 2
10/18/2011 (new)
Authors: Steve Higgins, Sarah Wightman
A karst landscape develops when the limestone or dolostone bedrock underneath the soil dissolves and/or collapses due to weathering. A karst system can be recognized by surface features such as depressions, sinkholes, sinking streams, and caves. In karst systems, surface water and groundwater are interconnected: surface water runoff flows into sinkholes and sinking streams and recharges the groundwater; likewise, springs maintain stream flow in the dry season. Kentuckians living in karst areas need to be acutely aware that any pollutants that reach either surface water or any karst feature can pollute the entire groundwater system (also called an aquifer). In addition, the cave system that accompanies a karst aquifer can allow pollutants to contaminate miles of water resources in just a few hours.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 487 kb
Pages: 4
7/28/2011 (new)
Authors: Steve Higgins, Sarah Wightman
Kentucky's abundant forage makes it well suited for grazing livestock. Livestock producers can make additional profits by adding a few pounds before marketing calves; however, adding those pounds requires keeping calves during the winter months, when pasture forages are dormant and supplemental feed is required. The areas used to winter calves need to be conducive to feeding and need to avoid negatively impacting the environment, especially water quality.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 260 kb
Pages: 5
7/28/2011 (new)
Authors: Steve Higgins, Sarah Wightman
The U.S. Environmental Protection Agency states that agricultural sediment, pathogens, and nutrients account for more than 50 percent of water pollution in the United States. Animal confinement facilities, widely used for holding, feeding, and handling animals, are potential sources of that pollution. The pollution load of these facilities can be reduced by installing and maintaining best management practices. The BMPs may be implemented as part of permit compliance or may be used to ensure that a permit is not needed.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 300 kb
Pages: 5
7/26/2011 (new)
Authors: Carmen Agouridis, Joe Luck, Jonathan Villines
Managing runoff in urban areas offers many challenges for engineers, landscape architects, and planners. As cities grow, the amount of impermeable surfaces--those that do not allow water to infiltrate into the ground--increases. Examples of impervious surfaces are asphalt roads, concrete sidewalks, parking lots, building roofs, and areas of highly compacted soils such as in subdivisions. If not properly managed, the stormwater runoff produced by these impermeable surfaces can have negative effects on nearby surface waters.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 720 kb
Pages: 7
7/15/2011 (new)
Authors: Carmen Agouridis, Joe Luck, Jonathan Villines, Sarah Wightman
Stormwater is excess water from rainfall and snowmelts that flows over the ground and does not infiltrate the soil. It is a concern not just in urban areas but in suburban and agricultural locations as well. As stormwater runoff flows over the land or impervious surfaces, it picks up and transports trash and debris as well as pollutants such as pathogens, nutrients, sediments, heavy metals, and chemicals. This publication reviews some of these techniques and provides a list of recommended resources for additional information.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 330 kb
Pages: 8
7/13/2011 (new)
Authors: Carmen Agouridis, Steve Higgins, Sarah Wightman
Kentucky's abundant forage makes it well suited for grazing livestock, but the pasturing and pasture feeding of livestock need to be managed. Allowing cattle to behave as they would naturally can lead to overgrazing, congregation in sensitive areas, buildup of mud, loss of vegetation, compaction of soils, and erosion.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 284 kb
Pages: 5
7/13/2011 (new)
Authors: Carmen Agouridis, Steve Higgins, Sarah Wightman
This publication provides livestock producers with instructions on how to install a stream crossing that provides animal and vehicular access across streams. This best management practice (BMP) is intended for use with exclusion fencing that restricts cattle access to the stream. Implementation of a stream crossing with exclusion fencing will improve water quality, reducing nutrient, sediment, pathogen, and organic matter loads to streams.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.10 mb
Pages: 7
7/7/2011 (new)
Authors: Steve Higgins, Sarah Wightman
Abandoned wells are often the only structures remaining after an old house or barn has been removed. If left unmanaged in agricultural areas, these abandoned wells can pose a serious threat to livestock and human safety because of the large surface openings they often have.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 400 kb
Pages: 3
6/15/2011 (new)
Authors: Steve Higgins, Donald Stamper, Sarah Wightman
Gully erosion creates large eroded channels that become problematic for many farms. Gullies form in natural drainage swales when vegetation in the swale is lost through overgrazing or tillage practices. They cause valuable soil to erode, and they form large channels that drain runoff into streams. This runoff can carry sediment, nutrients, and pathogens that can degrade the water quality.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 900 kb
Pages: 4
6/2/2011 (new)
Authors: Joe Luck, Scott Shearer, Tim Stombaugh
The potential economic and environmental benefits of these systems are gaining the attention of producers and custom applicators looking to reduce their overall chemical costs. The purpose of this publication is to describe the basic operation and benefits of automatic section control systems.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 1.05 mb
Pages: 4
5/5/2011 (new)
Authors: Steve Higgins, Donald Stamper, Sarah Wightman
Water supply is a key component in livestock production. One option producers have when providing water is to develop an existing spring, which occurs when groundwater running along an impervious rock layer hits a fracture and discharges on the surface.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 814 kb
Pages: 4
3/29/2011 (new)
Authors: Carmen Agouridis, Steve Higgins, Sarah Wightman
Shade is a must for pasture-based grazing systems. It curtails heat stress, which is detrimental to cattle and causes a decrease in milk production, feed intake, weight gains, and fertility.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 866 kb
Pages: 8
8/23/2010 (reprinted)
Authors: John Wilhoit
Lower-cost cold storage options can benefit market growers by helping preserve produce freshness and quality for a few additional days. Produce losses can be significantly reduced, especially for growers transitioning to a higher level of production who have excess produce to carry over from one day's market to the next.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 265 kb
Pages: 4
7/29/2010 (new)
Authors: Dave Ash, George Duncan, John Wilhoit
Curing facilities for housing tobacco can be expensive. However, using pallet racks for suspending stick tobacco, a recently developed technique for curing burley tobacco, can offer tobacco growers an alternative that substantially reduces long-term investment.
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 513 kb
Pages: 6
11/14/2008 (new)
Authors: Tim Stombaugh
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 179 kb
Pages: 2
10/23/2008 (new)
Authors: Sam McNeill, Scott Shearer, Tim Stombaugh, John Wilhoit
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 110 kb
Pages: 2
10/23/2008 (new)
Authors: Sam McNeill, Greg Schwab, Scott Shearer, Tim Stombaugh, John Wilhoit
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 201 kb
Pages: 2
3/30/2007 (new)
Authors: Jose Bicudo, Anshu Singh
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 245 kb
Pages: 8
9/30/2006 (new)
Authors: Jose Bicudo
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 216 kb
Pages: 4
4/30/2006 (new)
Authors: Czarena Crofcheck, Michael Montross, Tim Stombaugh
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 220 kb
Pages: 2
4/30/2006 (new)
Authors: Czarena Crofcheck, Michael Montross, Tim Stombaugh
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 263 kb
Pages: 4
9/1/2005 (new)
Authors: Ben Koostra, Doug McLaren, Tim Stombaugh
Departments: Biosystems and Agricultural Engineering, Forestry and Natural Resources
Series: Agricultural Engineering (AEN series)
Size: 305 kb
Pages: 6
4/1/2005 (new)
Authors: George Duncan, Larry Swetnam, Linus Walton
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 631 kb
Pages: 8
2/1/2005 (new)
Authors: George Duncan, Richard Gates
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 630 kb
Pages: 4
7/1/2004 (new)
Authors: George Duncan
Departments: Biosystems and Agricultural Engineering
Series: Agricultural Engineering (AEN series)
Size: 552 kb
Pages: 12
