Prepared by:
James C. Barker, Professor and Extension Specialist
Biological and
Agricultural Engineering
North Carolina State University, Raleigh, NC
Publication Number: EBAE 131-88
Last Electronic Revision: March 1996 (JWM)
Objectives
The manure management system should receive proper consideration in the planning stages from production and environmental perspectives for :
When planning new facilities or significant expansion of older ones, avoid selecting sites near residential developments, commercial enterprises, recreational areas, or other prime areas for non-agricultural uses. A site may seem ideal with respect to transportation, feed supply, accessibility or land ownership, but may be inappropriate because of existing or proposed development. When possible, locate production facilities near the center of a tract of land large enough to allow manure to be applied at agronomic rates (Table 2). Pollution control and waste storage or treatment areas should be located as remotely as possible from areas of high environmental sensitivity such as drainage ditches, streams or estuaries.
Wind Direction and Air Drainage
Refer to wind direction probability diagrams available from most technical agencies to locate facilities downwind of the warm season prevailing winds. The strategic planting of rows of trees or hedges serves both to shield the production and waste management areas from direct sight and to reduce the wind speed across these facilities allowing odorous gases more opportunity to rise vertically and dissipate into the atmosphere.
Drainage
The high rise house should be built above ground on a pad of gravel or other porous material or permeable, well-drained soil to prevent surface or groundwater intrusion into the manure collection area. The area surrounding the house should be graded to drain roof and surface water away to diversion terraces.
Moisture Control
Rows of cages mounted about 8 feet above ground cause droppings to be deposited uniformly in ridges or cones on an earth floor. Regular inspection and maintenance of bird watering systems should be performed to prevent leakage. Intermittent watering controlled by a time clock often reduces the chance of spillage. Excess water requires more evaporation and may overload the capability of drying systems. Pit manure which has become liquid generates excessive gases within the building and odors in the surrounding vicinity. It also becomes hard to contain, can cause severe stress on the building side walls, and handling during removal is difficult.
Ventilation of the high rise house is important for manure management. One method involves total enclosure of the house with thermostatically controlled exhaust fans located in the side wall of the manure storage area. Fresh air enters the building through slot inlets located at the roof line above the birds, passes down through the cages picking up body heat, and then circulates over the manure before being exhausted to the outside. The advantage of this method from a manure management standpoint is that it allows a high degree of control of air flow over the manure accumulation. The tradeoff is higher energy costs for fan operation.
Curtain Side-Walls
A second method of ventilating a high-rise house consists of providing curtain side walls adjacent to the cages and the manure storage area. Air moves across the manure mass by natural cross ventilation when the curtains are raised and upward around the birds by convection. Building side wall screens should periodically be cleaned of debris such as dust, spider webs and vines to allow maximum warm season cross ventilation. The advantage of this system is lower operating costs. Disadvantages include updraft movement of gases and odors to the vicinity of the birds and less moisture removal from the manure during still, humid conditions.
Air Circulation over Manure Mass
Drying should be enhanced by forced air circulation underneath the cages using hanging 36-inch, 0.5-hp panel fans over the manure cones. These fans should face one direction on one side of the house and the opposite direction on the other side, causing air to flow in a circular pattern. Air circulation not only reduces moisture content and offensive odors, but also helps to maintain a uniform temperature throughout the cage area.
Bird Density
Another factor affecting the manure moisture content in a high rise house is the bird density or number of birds per unit area of manure storage. Lower bird densities increase the coning effect of the manure thereby exposing more surface area to air flow and increasing drying. As bird densities increase, manure cones become less pronounced and are exposed to drying conditions for a lesser period of time before being covered by fresh manure. Based on an extensive three-year study, Cornell University suggests the following initial design parameters for the high rise system:
Doors at one end of the manure storage area should permit access by a tractor front end loader, a short-coupled four wheel drive vehicle, or a skid steer loader for cleaning. The material can be handled and spread with conventional solid or semi-solid manure handling equipment. If over-the-road hauling is necessary, care should be taken to avoid spillage and wind-blown debris. Spreading is usually done in the spring or fall when land is most accessible. Plowing or soil incorporation soon after spreading is advised to conserve nutrients, to prevent field odors, flies or pest problems, and to prevent pollution from rainfall runoff. Manure should be applied at rates within the fertilizer requirement of the crop. Sampling and analysis of the manure is suggested to determine its nutrient content. Table 1 provides information on average manure production rates and estimated available nutrient contents. Table 2 estimates application rates and minimum land areas needed for manure application for various crop ping schemes.
Table 1. LAYER UNPAVED DEEP PIT STORED MANURE FERTILIZER NUTRIENTS *
============================== ============================== =======
Type of Bird Bird Live Weight In-House Recommended
Production Age --------------------- Cage Manure
Unit initial final average Space Storage
Capacity,a
ft3/
ft2/ 1000-bd
weeks --------lbs-------- bird capacity
---------------------------------------------------------------------
Pullets
Nonlaying 0 - 20 3.0 1.5 0.33 255
Laying 20 - 52 3.0 4.0 3.5 0.50 631
Layers 52 - 4.0 4.0 4.0 0.50 721
============================== ============================== =======
Table 1. (continues..)
================================ ============================== =====
Type of Total Plant Total Plant Available Nutrientsb
Production Manurea Nutrient Nutrients ----------------------------
Unit Broadcast Soil Incorp.
tons/ ------------ ------------
1000-bd lbs/ lbs/
capacity/ lbs/ lbs/ 1000-bd lbs/ 1000-bd
year ton ton cap/yr ton cap/yr
---------------------------------------------------------------------
Pullets
Nonlaying 6.5 N 38 14 93 24 152
P2O5 56 39 253 42 271
K2O 30 21 134 22 144
Laying 16 N 38 14 233 24 380
P2O5 56 39 633 42 678
K2O 30 21 336 22 360
Layers 18 N 38 14 267 24 435
P2O5 56 39 723 42 775
K2O 30 21 384 22 412
================================ ============================== =====
* References: Depts of Biological & Agricultural Engineering, Poultry
Science; North Carolina State University; Jan 1990 Agronomic Division,
North Carolina Department of Agriculture
a Annual manure accumulation.
b Broadcast: surface spread manure uncovered for 1 month or longer.
Soil incorporated: surface spread manure plowed or disked into soil
within 2 days.
Table 2. LAND APPLICATION OF LAYER UNPAVED DEEP PIT STORED MANURE *
============================== ============================== =============
Type of Rate- Manure Application Ratea
Production Limiting -------------------------------------------
Unit Nutrient ---Grain--- --Grazed Pasture--- Hayland
Cereal Corn Fescue --Tifton44 Bermuda-
---range--- control
-soil inc @ --------broadcast @--------
# N/ac/yr = 100 150 200 275 325 400
# P2O5/ac/yr = 50 60 75 75 85 100
# K2O/ac/yr = 80 100 100 225 260 300
---------------------------------------------------------------------------
---------------tons/acre/year--------------
Pullets
Nonlaying N 4.2 6.4 14 19 23 28
P2O5 1.2 1.4 1.9 1.9 2.2 2.6
K2O 3.6 4.5 4.8 11 12 14
Laying N 4.2 6.4 14 19 23 28
P2O5 1.2 1.4 1.9 1.9 2.2 2.6
K2O 3.6 4.5 4.8 11 12 14
Layers N 4.2 6.4 14 19 23 28
P2O5 1.2 1.4 1.9 1.9 2.2 2.6
K2O 3.6 4.5 4.8 11 12 14
============================== ============================== =============
Table 2. (continues..)
======================== ============================== =====
Type of Minimum Land Area for Manure Applicationa
Production -------------------------------------------
Unit ---Grain--- ---Grazed Pasture-- Hayland
Cereal Corn Fescue --Tifton44 Bermuda-
---range--- control
-soil inc @ --------broadcast @--------
100 150 200 275 325 400
50 60 75 75 85 100
80 100 100 225 260 300
-------------------------------------------------------------
----------acres/1000-bird capacity---------
Pullets
Nonlaying 1.5 1.0 .47 .34 .29 .23
5.4 4.5 3.4 3.4 3.0 2.5
1.8 1.4 1.3 .60 .52 .45
Laying 3.8 2.5 1.2 .85 .72 .58
14 11 8.4 8.4 7.4 6.3
4.5 3.6 3.4 1.5 1.3 1.1
Layers 4.3 2.9 1.3 .97 .82 .67
15 13 9.6 9.6 8.5 7.2
5.1 4.1 3.8 1.7 1.5 1.3
======================== ============================== =====
* References: Depts of Biological & Agricultural Engineering, Soil
Science, Crop Sci.; North Carolina St Univ; Jan 1990 North Carolina
Agricultural Chemicals Manual Potash Institute of North America
a N leaching and denitrification and P2O5 soil immobilization
unaccounted for.
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