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POTATO
SWEET
Sweet
Potato
Production
B est
M anagement
P ractices
(BMPs)
endorsed by
SWEET POTATO BMPS 2000 1
WHY BMPS ARE
TABLE OF IMPORTANT TO LOUISIANA
CONTENTS
In Louisiana we are blessed with beautiful and
Introduction ...................... 3 abundant waters to enjoy fishing, hunting, boating or just
relaxing on the shore of a lake, river or bayou. Most of
Soil and Water the water in Louisiana’s rivers and lakes comes from
Management ...................... 4 rainfall runoff. As this runoff travels across the soil
surface, it carries with it soil particles, organic matter and
Pesticide Management and nutrients, such as nitrogen and phosphorus. Agricultural
Pesticides ......................... 12 activities contribute to the amount of these materials
entering streams, lakes, estuaries and groundwater. In
Nutrient Management .. 17
addition to assuring an abundant, affordable food supply,
General Farm BMPs ...... 23 Louisiana farmers must strive to protect the environment.
Research Overview ....... 25 Research and educational programs on environ-
mental issues related to the use and management of natu-
ral resources have always been an important part of the
LSU AgCenter’s mission. Working with representatives
from the agricultural commodity groups, the Natural
Resources Conservation Service (NRCS), the Louisiana
Department of Environmental Quality (LDEQ), the Louisi-
ana Farm Bureau Federation (LFBF) and the Louisiana
Department of Agriculture and Forestry (LDAF), the LSU
AgCenter has taken the lead in assembling a group of Best
Management Practices (BMPs) for each agricultural com-
modity in Louisiana.
BMPs are practices used by agricultural produc-
ers to control the generation and delivery of pollutants
from agricultural activities to water resources of the state
and thereby reduce the amount of agricultural pollutants
entering surface and ground waters. Each BMP is a culmi-
nation of years of research and demonstrations conducted
by agricultural scientists and soil engineers. BMPs and
accompanying standards and specifications are published
by the NRCS in its Field Office Technical Guide.
2 SWEET POTATO BMPS 2000
INTRODUCTION
Sweet
Sweet potatoes are an The runoff from sweet References are made to
important commodity in Louisi- potato fields can have a potential specific Natural Resources
ana. The total acreage planted in impact on the surface water Conservation Service (NRCS)
1999 was approximately 24,925 quality throughout the regions production codes in this publica-
acres. Most are grown in 11 where sweet potatoes are grown. tion. These production codes are
parishes: West Carroll, The quality of water in the explained in the text. More
Morehouse, Franklin, Avoyelles, streams, rivers, bayous, lakes and detailed information about these
St. Landry, Evangeline, Acadia, coastal areas of Louisiana is practices can be found in the
St. Martin, Rapides, Grant and extremely important to all resi- NRCS Field Office Technical
Richland. The gross farm value dents. Guide (FOTG). The FOTG can
Potato
of Louisiana-grown sweet pota- The intent of Best Manage- be found in all Soil and Water
toes in 1999 was about $72 ment Practices (BMPs) is to Conservation District Offices, all
million. Value added of fresh provide the growers of sweet NRCS field offices and on the
market potatoes is determined by potatoes some guidelines on NRCS web page. Additionally,
the increase in value of the what practices they can imple- under voluntary participation by
harvested potatoes that are ment to reduce the impact these the producer, technical assistance
washed, graded, packed and agricultural practices may have to develop and implement a
shipped. The estimated value on the environment. If properly farm-specific conservation plan
added for the 1999 crop was $53 implemented, with appropriate is available through the Conser-
million, for a total economic incentives where needed, the vation Districts, NRCS field
value to the state of more than practices described in this publi- offices and the LSU AgCenter
$125 million. Sweet potatoes are cation will help to improve water parish offices.
the single most important veg- quality without placing unrea-
BMPs
etable crop in Louisiana in terms sonable burdens on the agricul-
of acreage planted and economic tural industry of Louisiana.
value.
SWEET POTATO BMPS 2000 3
SOIL AND WATER MANAGEMENT
SOIL AND WATER MANAGEMENT
Irrigation Management
(NRCS Code 449)
Furrow Irrigation Systems Furrow Irrigation
Crop residue cover and tillage practices
play important roles in the way crops use
water and also affect the ability of irrigation
systems to replace that water. Tillage prac-
tices (NRCS Code 329) and crop residue
management (NRCS Code 344) play impor-
tant roles in the way irrigation systems
perform and are managed. Tillage practices
affect the way that water moves into and off
of the soil (infiltration and runoff).
Many factors affect the Tillage practices affect Center Pivot
performance of furrow irrigation furrow irrigation systems by
systems. Physical conditions, altering the infiltration character- Irrigation Systems
such as soil texture, soil struc- istics of the soil and by altering (NRCS Code 442)
ture, field slope, field length, crop residue in the furrow. Both
furrow shape and the amount of factors affect the ability of the Crop residues serve a
crop residue cover, all have some furrow to convey water down the largely positive role in center
impact on the performance of the field. As tillage practices become pivot irrigation management.
irrigation system. The way the less intensive, infiltration rates Selecting a tillage system that is
system is managed, including the often increase. best suited for a particular field
furrow flow rate, length of situation can be a very important
The need to match manage- decision. Disregard for the
application time and irrigation ment factors with the physical
frequency, also affects system importance of this decision could
conditions present at the time of directly affect the effectiveness
performance. Irrigation system irrigation is critical. In some
performance is often measured in of the water application system,
cases, a change in tillage practice as well as other crop production
terms of the percentage of the may cause changes in infiltration
water applied that remains in the practices.
rates that are too severe to over-
active root zone after the irriga- come with management factors In general, concerns associ-
tion (application efficiency). alone. In some cases physical ated with tillage practices selec-
Thus, deep percolation (water changes to the system may be tion and center pivot operation
passing through the root zone) necessary. The field slope or are related to the potential for
and runoff (tailwater)(NRCS length of run may need to be runoff and erosion. The potential
Code 447) should be held to a changed or furrow packing may for runoff exists whenever the
minimum while supplying be used to help overcome prob- water application rate of the
adequate water to the crop along lems associated with extreme irrigation system exceeds the
the length of the furrow. increases in infiltration character- infiltration rate of the soil.
istics.
4 SWEET POTATO BMPS 2000
SOIL AND WATER MANAGEMENT
(NRCS) or Soil and Water
The potential for runoff exists
whenever the water application rate
Conservation District for compli-
of the irrigation system exceeds the ance with conservation plans in
infiltration rate of the soil.
making these decisions.
Crop residues also act like
small dams for temporary soil
surface storage of excess water.
Water applied in excess of the
soil infiltration rate will be
blocked from running off the
field long enough for infiltration
to occur. This results in more
uniform water application. In the
process, soils that would have
been transported with the runoff
water remain near their point of
origin.
Center Pivot Irrigation Another option is to alter
the operating characteristics of
To lower pumping costs, tillage or water application, can the irrigation system. For ex-
some row crop farmers fit their reduce infiltration. For example, ample, by selecting a sprinkler
machines with low to medium as the size and number of water package based on soil type and
pressure sprinkler packages. On droplets increase, fine soil par- field topography, you can match
occasion, sprinkler packages may ticles are consolidated on the more closely the water applica-
be improperly matched with the surface to form a thin crust. As tion rate of the center pivot with
soil infiltration rate. Irrigation the soil crust develops, the water the soil infiltration rate. By
system management and tillage infiltration rate tends to decrease. considering the interaction
practices may be used to control Soil surface crusts can result in between the sprinkler package
runoff if changes in the irrigation infiltration rate reductions of up and soil, selection of an unsuit-
system itself are desirable. to 75 percent. One way to com- able sprinkler package can be
bat the negative effect of water avoided.
One option is to reduce the
droplets is to be sure crop resi-
application depth per irrigation.
dues are distributed evenly over
In doing so, the operator reduces
the soil surface. Crop residues
the potential for runoff but
spread in this manner protect the
increases the opportunity for soil
soil by absorbing energy carried
evaporation over the course of
by falling water droplets. This
the growing season. Although
limits soil crust development,
crop residues can help reduce the
resulting in a more consistent
magnitude of soil evaporation
infiltration rate throughout the
losses, repeated wetting of the
growing season.
soil surface will limit the water
savings attributed to crop resi- Tillage practices that result
dues. in minimal soil disturbance
Sweet potato residues, which
should be used when topography
Runoff also may be gener- are produced in less quantity,
is rolling. On highly erodible are considerably more fragile
ated if the soil infiltration rate is
land, it is important to check than small grain or corn
reduced over a period of time. A residues.
with your local Natural Re-
number of factors, such as soil
sources Conservation Service
texture and structure, surface
SWEET POTATO BMPS 2000 5
SOIL AND WATER MANAGEMENT
The combination of improved water application uniformity “Irrigation return flow” is
resulting from more consistent infiltration rates, less runoff and that portion of water which
reduced soil evaporation losses make crop residues a major factor in returns to its source after being
the water conservation effort. Residue management (NRCS Code used to irrigate crops. With
344) also can be a crucial component to minimizing the effect of increasing environmental con-
irrigation on surface water quality. cern, the term “irrigation return
flow” has been extended to
IRRIGATION PRACTICES THAT CAN REDUCE include irrigation water that
makes its way to any body of
OR PREVENT EROSION INCLUDE: water after its use on a crop.
Manage crop residues to reduce surface water contamination Tailwater from furrow
(NRCS Code 344). irrigation and runoff caused by
Living vegetation and crop residues left on excessive irrigation or poor
the soil surface are important in: system design can make its way
intercepting rainfall and reducing the into drainage ditches which
impact of raindrops on the soil surface eventually lead to bayous, rivers
and lakes. Water from irrigated
reducing erosion and sedimentation by
decreasing runoff velocity
land that is artificially drained
must go somewhere, often into
increasing structural stability of soil aggregates the same water body it was taken
increasing biological activity in the soil from.
screening out soil particles from runoff water Irrigation return flow is
becoming an important issue
Conservation Cropping Sequence - (NRCS Code 328) because of its potential to be a
Systems in which crops are alternated. nonpoint source of pollution.
May reduce weed pressure in sweet potatoes. This is not the only reason sweet
May reduce some disease problems. potato producers should use
Where erosion is a problem, high residue crops included in the return flow management prac-
rotation reduce soil loss. tices, however. Excessive runoff
is a symptom of poor irrigation
system design or poor manage-
Cover and green manure crops - (NRCS ment of irrigation water. It is also
Code 340) Such crops are usually planted water that is wasted. Wasting
when the primary commodity crop is not water not only has immediate
growing. financial ramifications, but it also
Protect soils from erosion and reduce
threatens the long-term availabil-
sedimentation.
ity of water for irrigation. Sound
Filter runoff waters to reduce pesticide and nutrient losses. management practices can reduce
irrigation return flow while
Precision level the land to optimize
ensuring the most efficient use of
furrow slopes to reduce soil erosion
our water resources.
(NRCS Code 462)
The major concern is the
direct runoff that may occur from
irrigated land. Many of the
TREATMENT OF IRRIGATION fertilizer nutrients and chemicals
used in agriculture are easily
RETURN FLOW adsorbed onto soil particles.
Install vegetative buffering (filter) strips When runoff occurs, soil par-
(NRCS Code 393) ticles containing these adsorbed
6 SWEET POTATO BMPS 2000
SOIL AND WATER MANAGEMENT
materials are picked up and transported out of the field. Eroded
sediments constitute the major potential for pollution from surface
return flows. In addition, soluble chemicals are dissolved by runoff
and carried with the water as it flows over the soil.
There are three basic approaches to reducing
pollutants in surface return flows (NRCS Code 570):
eliminating or reducing surface runoff
eliminating or reducing soil loss Residue
reducing pollutants from irrigation return flow
Management
The first two approaches are achieved by properly designing, (NRCS Code 344)
operating and managing irrigation systems. Following the directions Living vegetation and crop
on the pesticide label will usually solve any problems associated with residues left on the soil surface
applying agricultural chemicals. are important in:
The third approach involves using grass buffer strips (NRCS intercepting rainfall and
Code 386), artificial wetlands (NRCS Code 645), settling basins and reducing the impact of raindrops
ponds (NRCS Code 350) and similar structures to reduce pollutant- on the soil surface
bearing sediments. Treating return flow is more costly and trouble-
some than preventing it. reducing erosion and
sedimentation by decreasing
runoff velocity
increasing structural
stability of soil aggregates
increasing biological
activity in the soil
screening out soil par-
ticles from runoff water.
Buffer strips Wetlands
Crop residues protect the
soil surface from the impact of
raindrops and act like a dam to
Proper irrigation water management (NRCS Code 449) means slow water movement. Rainfall
timing and regulating water applications in a way that will satisfy the stays in the crop field, allowing
needs of a crop and efficiently distribute the water without applying the soil to absorb it. The decom-
excessive amounts of water or causing erosion, runoff or percolation position of these residues also
losses. Good irrigation water management can reduce moisture increases the soil organic matter.
extremes. The sweet potato producer should have a good understand- Soils with high organic matter
ing of the factors influencing proper irrigation scheduling and water content are less likely to erode
management. The timing of than soils with low organic
irrigation and the total amount matter content.
applied per irrigation should be
based on both the crop’s water
use and the moisture content of
the soil, as well as on expected
rainfall.
SWEET POTATO BMPS 2000 7
SOIL AND WATER MANAGEMENT
The table below shows the effects of residue cover on surface Field Borders
runoff and soil loss. An increase in residue cover significantly de-
creases runoff and sediment from a field. Typically, 30 percent (NRCS Code 386)
residue cover reduces soil erosion rates by 50 percent to 60 percent and Filter Strips
compared to conventional tillage practices.
(NRCS Code 393)
Sediment directly damages In addition, sediment is often
water quality and reduces the rich in organic matter. Field borders and filter
usefulness of streams and lakes Nutrients such as nitrogen and strips are strips of grasses or
in many ways. These may phosphorus and certain other close-growing vegetation
include: pesticides may enter streams planted around fields and along
Impaired fish spawning areas with sediment. The drainageways, streams and other
Reduced light penetration for
detrimental effects of these bodies of water. They are de-
aquatic life
substances accompanying the signed to reduce sediment,
Increased water purification
sediment may include: organic material, nutrients and
costs Rapid algae growth chemicals carried in runoff.
Lower recreational value Oxygen depletion as organic In a properly designed filter
Clogged channels and matter and algae decompose strip, water flows evenly through
increased flooding Fish kills from oxygen the strip, slowing the runoff
Increased dredging to maintain depletion velocity and allowing some
navigation Toxic effects of pesticides on contaminants to settle from the
Reduced storage capacity for aquatic life water. In addition, where filter
reservoirs Unsafe drinking water strips are seeded, fertilizers and
because of nitrate or pesticide herbicides no longer need to be
content applied right next to susceptible
water sources. Filter strips also
Effects of surface residue cover on runoff and soil loss increase wildlife habitat.
Soil particles (sediment)
Residue Runoff Sediment in Soil settle from runoff water when
Cover Runoff Velocity Runoff Loss
flow is slowed by passing
% % of rain ft./minute % of runoff tons/acre
through a filter strip. The largest
0 45 26 3.7 12.4 particles (sand and silt) settle
41 40 14 1.1 3.2 within the shortest distance.
71 26 12 0.8 1.4 Finer particles (clay) are carried
93 0.5 7 0.6 0.3 the farthest before settling from
runoff water, and they may
remain suspended when runoff
velocity is high. Farming prac-
tices upslope from filter strips
affect the ability of strips to filter
sediment. Fields with steep
slopes or little crop residue will
deliver more sediment to filter
strips than more gently sloping
fields and those with good
residue cover. Large amounts of
sediment entering the filter strip
may overload the filtering capac-
Field border
ity of the vegetation, and some
may pass on through.
8 SWEET POTATO BMPS 2000
SOIL AND WATER MANAGEMENT
Filter strip effectiveness depends on five factors: 3. Infiltration rate of the soil
1. The amount of sediment reaching the filter strip. This is Soils with higher infiltration
influenced by: rates will absorb water and the
type and frequency of tillage in cropland above the filter strip. accompanying dissolved nutri-
The more aggressive and frequent tillage is above filter strips, the ents and pesticides faster than
more likely soil will erode. soils with low infiltration rates.
soil organic matter content. Parish soil survey reports include
a table listing the infiltration rate
time between tillage and a rain. The sooner it rains after a
group for the soils identified in
tillage operation, the more likely soil will erode.
each parish.
rain intensity and duration. The longer it rains and thus the
more sediment is deposited, the less effective filter strips become as
they fill with soil. 4. Uniformity of water flow
slope and the length of run above the filter strip. Water flows through the filter strip
faster down steeper slopes. Filter strips below steep slopes need to be Shallow depressions or rills
wider in relation to the cropland drained above to slow water and need to be graded to allow uni-
sediment movement adequately. form flow of water into the filter
strip along its length. Water
In general, a wider, uniformly shaped strip is more effective at concentrated in low points or rills
stopping or slowing pollutants than a narrow strip. As a field’s slope will flow at high volume, so little
and/or watershed size increases, wider strips are required for effec- filtering will take place.
tive filtering. The following table gives the suggested filter strip
width based on slope. For a more accurate determination of the size
filter strip you will need for your individual fields, consult your local 5. Maintenance of the filter
NRCS or Soil and Water Conservation District office. strip
When heavy sediment loads
Suggested Vegetated Filter Strip Widths on Percent Slope are deposited, soil tends to build
up across the strip, forming a
Land Slope, % Strip Width, Feet miniature terrace. If this becomes
0-5 20 large enough to impound water,
5-6 30 flow will eventually break over
6-9 40 the top and become concentrated
9 - 13 50 in that area. Strips should be
13 - 18 60 inspected regularly for damage.
*Widths are for grass and legume species only and are not Maintenance may include minor
intended for shrub and tree species. Adapted from the grading or re-seeding to keep
NRCS Field Office Technical Guide, 1990 filter strips effective.
In summary:
2. The amount of time that water is retained in the filter
Vegetative filter strips can
strip. This is influenced by:
reduce sediment effectively if
width of the filter area. Filter strips should vary in width, water flow is even and shallow.
depending on the percent slope, length of slope and total drainage
area above the strip. Filter strips must be
properly designed and con-
type of vegetation and quality of stand. Tall, erect grass can
structed to be effective.
trap more sediment than can short, flexible grass. The best species
for filter strips are tall perennial grasses. Filter strips may include Filter strips become less
more than one type of plant and may include parallel strips of trees effective as sediment accumu-
and shrubs, as well as perennial grasses. In addition to potential for lates. With slow accumulation,
improving water quality, these strips increase diversity of wildlife and/or dissolved pesticides into
habitat. surface waters.
SWEET POTATO BMPS 2000 9
SOIL AND WATER MANAGEMENT
RELATED CONSERVATION PRACTICES:
Land Smoothing
(NRCS Code 466):
The removing of irregularities on the land surface by use of
special equipment. This improves surface drainage, provides for
more effective use of precipitation, obtains more uniform plant-
ing depths, provides for more uniform cultivation, improves
equipment operation and efficiency, improves terrace alignment
and facilitates contour cultivation.
Chiseling and Subsoiling (NRCS Code
324):
Loosening the soil, without inverting (plowing) and with a
minimum of mixing of the surface soil, to shatter restrictive
layers below normal plow depth that inhibit water movement or
root development.
Surface Drainage - Field Ditch
(NRCS Code 607):
A graded ditch for collecting excess water in a field or for
irrigation water drainage. This practice intercepts or collects
surface water and carries it to an outlet.
Grassed Waterways (NRCS Code 412):
Natural or constructed channels that are shaped or graded
to required dimensions and established in suitable vegetation for
the stable conveyance of runoff. They are designed to convey
runoff without causing erosion or flooding and to improve water
quality.
Buffer Zones
(NRCS Code 342)
Similar to vegetated filter strips, buffer zones provide a
physical separation between adjacent areas, such as between a
crop field and a body of water. Unlike filter strips, buffer zones
may not necessarily be designed to filter water that flows
through them.
10 SWEET POTATO BMPS 2000
WEET OTATO S
SOIL AND WATER MANAGEMENT
Riparian Zones (NRCS Code 644)
A riparian zone consists of the land adjacent to and includ-
ing a stream, river or other area that is at least periodically influ-
enced by flooding in a natural state. Similar to vegetated filter
strips, plants in riparian areas effectively prevent sediment,
chemicals and organic matter from entering bodies of water.
Unlike filter strips, riparian zones use plants that are of a higher
order, such as trees or shrubs, as well as grasses or legumes.
Vegetated filter strips are often used in riparian areas as initial
filtering components next to crop field borders.
For more information on these practices and how to
implement them, contact your local NRCS or Soil and
Water Conservation District Office or call your county
agent.
SWEET POTATO BMPS 2000
WEET OTATO S 11
PESTICIDE MANAGEMENT
AND PESTICIDES
Introduction Rain or irrigation
starts pesticides
moving into and
Soil-incorporated
systemic pesticide
through soil.
To preserve the availability of Pesticide is taken up
by plants, broken
clean and environmentally safe down by organisms,
water in Louisiana, contamination of sunlight or chemical
reactions. Pesticide is carried
surface and groundwater by all into and through
agricultural and industrial chemicals Rainfall runoff soil. Movement
through soil is
will also move
must be prevented. Some sources of pesticides across affected by soil and
contamination are easily recogniz- the soil surface. pesticide
properties and
able from a single, specific location. amount and
Other sources are more difficult to timing of water.
Pesticide residue
pinpoint. Nonpoint-source pollution Pesticides can directly enter and by-products
of water with pesticides is caused by groundwater by spills around poorly
not absorbed are
broken down into
rainfall runoff, particle drift or constructed or sealed wells, or wells the groundwater.
with improper casting, or by back-
percolation of water through the siphoning during spray tank filling.
soil. Pest management practices will Movement with
groundwater –
be based on current research and WATER TABLE additional
extension recommendations. By breakdown
generally slowed,
using these recommendations, but depends on
pesticide usage will follow environ- Groundwater flow chemical nature
and groundwater.
mentally sound guidelines.
Pest Management Procedures
Pesticides will be applied only when they are necessary for the protection
PESTICIDE MANAGEMENT AND PESTICIDES
of the crop. The pesticide will be chosen following guidelines to assure that the
one chosen will give the most effective pest control with the least potential
adverse effects on the environment.
Water quality, both surface and ground, will be protected by following all
of the label recommendations and guidelines dealing with water
quality.
All label statements and use directions designed specifi-
cally to protect groundwater will be followed closely.
Specific Best Management Practices designed to protect
surface water will be followed closely.
Erosion control practices (such as pipe drops, etc.) will
be used to minimize runoff that could carry soil particles with
adsorbed pesticides and/or dissolved pesticides into surface
waters.
12 SWEET POTATO BMPS 2000
Pesticide These practices will be
followed:
Application Select the pesticide to give
the best results with the least
Management practices such potential environmental impact
as the pesticide selected, the outside the spray area.
application method, the pesticide Select with care and care-
rate used and the application fully maintain application equipment.
timing influence pesticide move- Carefully calibrate the
ment. Pesticides should be application equipment at the
applied only when needed to beginning of the spray season and
prevent economic loss of a crop. periodically thereafter. Spray
Using chemicals at rates according to recommendations.
above those specified by the Minimize spray drift by
label is ILLEGAL and an envi- following the label instructions and
ronmental hazard because more all rules and regulations developed
pesticide is exposed to erosion, to minimize spray drift (the physical movement of spray particles
runoff or leaching. In pesticide at the time of or shortly after application).
application, “the label is the
law.” Poor timing of a pesticide Before applying a pesticide, make an assessment of all of
application also can result in the environmental factors involved in all of the area surrounding
pesticide movement into water the application site.
sources, as well as give little Carefully maintain records of all pesti-
control of the targeted pest. cide applications, not just a record of Re-
Certain areas on your farm stricted Use Pesticides.
such as streams and rivers,
wellheads, and lakes or ponds
are sensitive to pesticides. You
should create buffer zones
around these areas where pesti-
cide use will be reduced or
eliminated. By buffering these Pesticide Selection
PESTICIDE MANAGEMENT AND PESTICIDES
areas, you may reduce water
When selecting pesticides, a farmer should consider
quality problems. Areas such as
chemical solubility, adsorption, volatility and degradation
roads, off-site dwellings and
characteristics. Chemicals that dissolve in water readily
areas of public gatherings should
can leach through soil to groundwater or be carried to
be identified. You may want to
surface waters in rainfall or irrigation runoff. Some chemi-
limit the use of pesticides near
cals hold tightly to, or are adsorbed on, soil particles, and
these types of areas, too.
do not leach as much. But even these chemicals can move
The water table separates
the unsaturated zone
with sediment when soil erodes during heavy rainfall.
from the saturated zone Runoff entering surface waters may ultimately recharge
(groundwater) groundwater reserves. Chemicals that are bound to soil
particles and organic matter are subject to the forces of
Rainfall runoff
leaching, erosion or runoff over a longer period, thus
Unsaturated zone increasing the potential for water pollution.
WATER TABLE
Groundwater
Saturated zone
SWEET POTATO BMPS 2000 13
These practices will be followed: Exceptions for
Selection will be based upon recommendations by qualified
consultants, crop advisors and upon the published recommendations
Farmers
of the LSU AgCenter, Cooperative Extension Service. Farmers disposing of used
The selection of the pesticide to be used will be based upon its pesticide containers for their own
registered uses and its ability to give the quality of pest control use are not required to comply
required. with the require-
ments of the
The selection will also be based upon its impact on hazardous waste
beneficials, other non-target organisms and on the general environ- regulations
ment. provided that
they triple rinse
Pesticide Storage and or pressure wash
each container
Safety
and dispose of the residues on
their own farms in a manner
consistent with the disposal
instructions on the pesticide
Pesticide
storage shed label. Note that disposal of
pesticide residues into water or
where they are
likely to reach
Farmers and commercial ronment. Pesticides should not surface or
pesticide applicators are subject be stored in an area susceptible groundwater
to penalties if they fail to store or to flooding or where the charac- may be consid-
dispose of pesticides and pesti- teristics of the soil at the site ered a source of
cide containers properly. Each would allow escaped chemicals pollution under
registered pesticide product, to percolate into groundwater. the Clean Water
whether general or restricted use, Storage facilities should be dry Act or the Safe
contains brief instructions about and well-ventilated and should Drinking Water Act and therefore
storage and disposal in its label- be provided with fire protection illegal.
ing. The Louisiana Pesticide Law equipment. All stored pesticides After the triple rinse proce-
addresses specific requirements should be labeled carefully and dure, the containers are then
PESTICIDE MANAGEMENT AND PESTICIDES
for storage and disposal. The segregated and stored off of the “empty” and the farmer can
applicator must follow these ground. Pesticides should not be discard them in a sanitary waste
requirements carefully and stored in the same area as animal site without further regard to the
ensure that employees follow feed. The facility should be kept hazardous waste regulations. The
them as well. locked when not in use. Further empty containers are still subject
The recommended proce- precautions include appropriate to any disposal instructions
dures do not apply to the disposal warning signs and regular in- contained within the labeling of
of single containers of pesticides spection of containers for corro- the product, however. Disposal in
registered for use in the home sion or leakage. Protective a manner “inconsistent with the
and garden, which may be dis- clothing should be stored close labeling instructions” is a viola-
posed of during municipal waste by but not in the same room as tion of EPA guidelines and could
collection if wrapped according the pesticides because they may lead to contamination of water,
to recommendations. become contaminated. Decon- soil or persons and legal liability.
tamination equipment should be
Storage sites should be present where highly toxic
carefully chosen to minimize the pesticides are stored.
chance of escape into the envi-
14 SWEET POTATO BMPS 2000
Agricultural Chemicals and Worker Safety
The EPA has general author- and exposure to pesticides. The
ity to regulate pesticide use in rule sets forth minimum stan- The Occupational
order to minimize risks to human dards for the protection of farm Safety and Health
health and the environment. This workers and pesticide handlers Act (OSHA)
authority extends to the protec- that must be followed. The The federal govern-
tion of farm regulations include standards ment also regulates farm
workers requiring oral warnings and employee safety under the
exposed to posting of areas where pesticides Occupational Safety and
pesticides. All have been used, training for all Health Act (OSHA).
employers handlers and early re-entry OSHA applies to all
must comply workers, personal protective persons (employers)
with ALL equipment, emergency transpor- engaged in business affect-
instructions of the Worker Pro- tation and decontamination ing interstate commerce.
tection Standard concerning equipment. The federal courts have
worker safety or be subject to The EPA decided that all farming
penalties. Labels may include, regulations and ranching operations,
for example, instructions requir- hold the regardless of where goods
ing the wearing of protective producer of produced are actually sold
clothing, handling instructions the agricul- or consumed, affect inter-
and instruc- tural plant on a farm, forest, state commerce in some
tions setting a nursery or greenhouse ultimately respect, and thus are
period of time responsible for compliance with subject to OSHA’s require-
before work- the worker safety standards. This ments. In general, every
ers are al- means the landowner must employer has a duty to
lowed to re- ensure compliance by all em- provide employees with an
enter fields after the application ployees and by all independent environment free from
of pesticides (Restricted Entry contractors working on the hazards that are causing or
Interval). property. Contractors and em- are likely to cause death or
Employers should also read ployees also may be held respon- serious injury.
the Worker Protection Standard sible for failure to follow the
regulations governing the use of regulations.
PESTICIDE MANAGEMENT AND PESTICIDES
SWEET POTATO BMPS 2000 15
In summary: a container free of leaks, abiding bags to the fullest extent possible.
by any specific recommendations The sides of the container will cut
A. All label directions will be
on the label. The storage area must and opened fully, without folds or
read, understood and followed.
be maintained in good condition, crevices, on a flat surface; any
B. The Louisiana Department without unnecessary debris. This pesticides remaining in the opened
of Agriculture and Forestry enclosure will be at least 150 feet container will be transferred into
(LDAF) is responsible for the away and down slope from any the spray mix. After this procedure
certification of pesticide applica- water wells. the containers will be disposed of
tors. All applicators of restricted in a sanitary landfill.
E. All uncontained pesticide
use pesticides in Louisiana must
spills of more than one gallon H. Application equipment
successfully complete a certifica-
liquid or four pounds dry weight will be triple rinsed and the rinsate
tion test administered by the
will be reported to the director of applied to the original application
LDAF. The LSU AgCenter con-
Pesticide and Environmental site or stored for later use to dilute
ducts training sessions and pub-
Programs, Louisiana Department a spray solution
lishes study guides in various
of Agriculture and Forestry within
categories covered by the test.
24 hours by telephone (225-925-
Contact your county agent for
3763) and by written notice within
dates and times of these trainings.
three days. Spills on public road-
C. All requirements of the ways will be reported to the
Worker Protection Standard (WPS) Louisiana Department of Transpor- Wash pad with
will be followed, including, but not tation and Development. Spills into collection pond
limited, to: navigable waters will be reported
• Notifying workers of a to LDEQ, Coast Guard, USEPA. I. Mix/load or wash pads
pesticide application (either oral F. Empty metal, glass or (NRCS production code Interim)
or posting of the field), abiding by plastic pesticide containers will be will be located at least 150 feet
the restricted entry interval (REI). either triple rinsed or pressure away and down slope from any
• Maintaining a central washed, and the rinsate will be water wells and away from surface
notification area containing the added to the spray solution to water sources such as ponds,
safety poster; the name, address dilute the solution at the time or streams, etc. The pads will be
and telephone number of the stored according to the LDAF rules constructed of an impervious
nearest emergency medical facility; to be used later. Rinsed pesticide material, and there will be a system
and a list of the pesticide applica- containers will be punctured, for collecting and/or storing the
tions made within the last 30 days crushed or otherwise rendered runoff.
that have an REI. unusable and disposed of in a J. Empty containers will not
sanitary landfill. (Plastic containers
PESTICIDE MANAGEMENT AND PESTICIDES
• Maintaining a decontami- be kept for more than 90 days after
may be taken to specific pesticide the end of the spray season.
nation site for workers and han- container recycling events. Contact
dlers. your county agent for dates and K. Air gaps will be main-
• Furnishing the appropriate locations in your area.) tained while filling the spray
personal protective equipment tank to prevent back-siphoning.
G. All pesticides will be
(PPE) to all handlers and early removed from paper and plastic
entry workers, and ensuring that
they understand how and why they Air gap
should use it.
This...
• Assuring that all employees backflow ...Not This
required to be trained under the protection chemicals
Worker Protection Standard have siphoned back
into water supply
undergone the required training.
D. Pesticides will be stored
in a secure, locked enclosure and in
16 SWEET POTATO BMPS 2000
NUTRIENT MANAGEMENT
NUTRIENT MANAGEMENT
UTRIENT
Similarly, practices that limit the provide optimum economic
buildup of nutrients in the soil, yields.
which can leach to groundwater Decomposition of organic
or be picked up in runoff, and matter results in simpler inor-
practices that ensure the safe use ganic N forms such as ammo-
of agricultural chemicals also are nium (NH4+) and nitrate (NO3-).
considered BMPs. In general, These are soluble in soil water
soil conservation and water and readily available for plant
quality protection are mutually uptake. The ammonium form is
beneficial; therefore the BMPs attracted to and held by soil
described here are the best means particles, so it does not readily
of reducing agricultural leach through the soil with
nonpoint-source pollution result- rainfall or irrigation water.
ing from fertilizer nutrients. Nitrates, on the other hand, are
not attached to soil particles and
Nitrogen
Introduction Nitrogen (N) is a part of all
do move downward with soil
water and can be leached into
A sound soil fertility pro- plant and animal proteins. There- groundwater or run off into
gram is the foundation upon fore, human survival depends on surface waters.
N
which a profitable farming an abundant supply of N in
Excessive nitrate concentra-
business must be built. Agricul- nature. Approximately 80 percent
tions in water can accelerate
tural fertilizers are a necessity of the atmosphere is nitrogen
algae and plant growth in streams
for producing abundant, high gas, but most plants cannot use
and lakes, resulting in oxygen
quality food, feed and fiber this form of nitrogen. Supple-
depletion. Nitrate concentrations
crops. Using fertilizer nutrients mental nitrogen must be supplied
above a certain level in drinking
in the proper amounts and through the soil. A crop well
water may injure some animals
applying them correctly are both supplied with N can produce
or human infants.
economically and environmen- substantially higher yields, on
tally important to the long-term the same amount of water, than Phosphorus
profitability and sustainability of one deficient for N. Properly
Phosphorus (P), like nitro-
crop production. The fertilizer fertilized crops use both N and
gen, is essential for plant growth.
nutrients that have potential to water more efficiently, thus
Naturally occurring P exists in a
become groundwater or surface improving environmental quality
phosphate form either as soluble
water pollutants are nitrogen and and profitability.
P
inorganic phosphate, soluble
phosphorus. In general, other Supplemental N will be phosphate, particulate phosphate
commonly used fertilizer nutri- necessary on almost all non- or mineral phosphate. The min-
ents do not cause concern as legume crops in Louisiana for eral forms of phosphorus (cal-
pollutants. maximum profits. Rely on N cium, iron and aluminum phos-
Because erosion and runoff recommendations based on phates) are low in solubility. The
are the two major ways Louisiana research. These recom- amount of these elements (cal-
nonpoint-source pollutants move mendations take into account cium, iron and aluminum)
into surface water resources, maximum economic yield poten- present in reactive forms varies
practices that reduce erosion or tials and soil texture. Nitrogen with different soils and soil
runoff are considered Best recommendations from the LSU conditions. They determine the
Management Practices (BMPs). AgCenter are usually ample to
SWEET POTATO BMPS 2000 17
NUTRIENT MANAGEMENT
amount of phosphorus that can to living organisms, but
be fixed in the soil. becomes available as it
The immediate source of detaches from sedi-
phosphorus for plants is that ment. Only a small part
which is dissolved in the soil of the phosphate
solution. A soil solution contain- moved with sediment
ing only a few parts per million into surface water is
of phosphate is usually consid- immediately available
ered adequate for plant growth. to aquatic organisms.
Phosphate is absorbed from the Additional phosphate
soil solution and used by plants. can slowly become
It is replaced in the soil solution available through bio- Algae bloom
from soil minerals, soil organic chemical reactions, however. The groundwater (NRCS Production
matter decomposition or applied slow release of large amounts of Code 590). A nutrient manage-
fertilizers. phosphate from sediment layers ment plan should be developed
in lakes and streams could cause for the proposed crop by using
Phosphate is not readily
excessive algae blooms and soil analyses from approved
soluble. Most of the ions are
excessive growth of plants, laboratories.
either used by living plants or
thereby affecting water quality.
adsorbed to sediment, so the
potential of their leaching to Nutrients will be used to
groundwater is low. That portion obtain optimum crop yields
of phosphate bound to sediment while minimizing the movement
particles is virtually unavailable of nutrients to surface and
Nutrient Application Rates
Nutrient application rates Soil testing is the founda-
will be based on the results of a tion of a sound nutrient man-
soil analysis. Select only those agement program.
materials recommended for use A soil test is a series of
by qualified individuals from the chemical analyses on soil that
Louisiana Cooperative Extension estimates whether levels of
Service, Louisiana Agricultural essential plant nutrients are
Experiment Station, certified sufficient to produce a desired predict which nutrient(s) and
crop advisors and certified crop and yield. When not taken how much of that nutrient(s)
agricultural consultants and/or up by a crop, some nutrients, should be added to produce a
published LSU AgCenter data. particularly nitrogen, can be lost particular crop and yield. Take
from the soil by leaching, runoff soil tests at least every three
or mineralization. Others, like years or at the beginning of a
phosphorus, react with soil different cropping rotation.
minerals over time to form
compounds that are not available
for uptake by plants. Soil testing
can be used to estimate how
much loss has occurred and
18 SWEET POTATO BMPS 2000
WEET OTATO S
NUTRIENT MANAGEMENT
Recommended Practices
1. Soil test for nutrient status and pH to: 5. Inject fertilizers or incorporate surface
• determine the amounts of additional applications when possible to:
nutrients needed to reach designated yield goals • increase accessibility of fertilizer nutri-
and the amount of lime needed to correct soil ents to plant roots
acidity problems • reduce volatilization losses of ammonia
• learn the Cation Exchange Capacity N sources
(CEC) and the organic matter concentration so • reduce nutrient losses from erosion and
as to determine how much of these nutrients the runoff
particular soil is capable of holding
6. Rotate crops when feasible to:
• optimize farm income by avoiding exces-
• improve total nutrient recovery with
sive fertilization and reducing nutrient losses by
different crop rooting patterns
leaching and runoff
• reduce erosion and runoff
• identify other yield-limiting factors such
as high levels of salts or sodium that may affect • reduce diseases, insects and weeds
soil structure, infiltration rates, surface runoff 7. Control nutrient losses in erosion and
and, ultimately, groundwater quality runoff by:
2. Base fertilizer applications on: • using appropriate structural controls
• soil test results • adopting conservation tillage practices
• realistic yield goals and moisture pros- where appropriate
pects • properly managing crop residues
• crop nutrient requirements • land leveling
• past fertilization practices • implementing other soil and water con-
• previous cropping history servation practices where possible
3. Manage low soil pH by liming according • using filter strips
to the soil test to: 8. Skillfully handle and apply fertilizer by:
• reduce soil acidity • properly calibrating and maintaining
• improve fertilizer use efficiency application equipment
• improve decomposition of crop residues • properly cleaning equipment and dispos-
ing of excess fertilizers, containers and wash
• enhance the effectiveness of certain soil
water
applied herbicides
• storing fertilizers in a safe place
4. Time nitrogen applications to:
• correspond closely with crop uptake
patterns
• increase nutrient use efficiency
• minimize leaching and runoff losses
SWEET POTATO BMPS 2000
WEET OTATO S 19
NUTRIENT MANAGEMENT
Nutrient Management
Plans (NMPs)
Both the U.S. Environmental Protection Agency (EPA) and the
U.S. Department of Agriculture (USDA) are encouraging a volun-
tary approach to handling nonpoint-source issues related to agricul-
ture. Another important part of a
The implementation of Nutrient Management Plans (NMP) by successful NMP are BMPs.
all agricultural producers will ensure that fertilizers are managed in BMPs, such as soil testing, help
an environmentally friendly fashion. you select the right nutrient rate
and application strategy so that
crops use nutrients efficiently.
This not only reduces nutrient
losses and protects the environ-
Developing a Nutrient Management Plan ment but also increases farm
An NMP is a strategy for making wise use of plant nutrients to profitability. BMPs may include
enhance farm profits while protecting water resources. It looks at managing the farm to reduce soil
every part of your farming operation and helps you make the best erosion and improve soil tilth
use of manures, fertilizers and other nutrient sources. Successful through conservation tillage,
nutrient management requires thorough planning and recognizes planting cover crops to use
that every farm is different. The type of farming you do and the excess nutrients or using filter
specifics of your operation will affect your NMP. The best plan is strips and buffers to protect water
one that is matched to the farming operation and the needs of the quality.
person implementing the plan.
The Parts of an NMP
An NMP looks at how nutrients are used and managed through-
out the farm. It is more than a nutrient management plan that looks
only at nutrient supply and needs for a particular
field. Nutrients are brought to the farm through
feeds, fertilizers, animal manures and other off-farm
inputs. These inputs are used, and some are recycled
by plants and animals on the farm. Nutrients leave
the farm in harvested crops and animal products.
These are nutrient removals. Ideally, nutrient inputs
and removals should be roughly the same. When
nutrient inputs to the farm greatly exceed nutrient
removals from the farm, the risk of nutrient losses to
groundwater and surface water is greater. When you
check nutrient inputs against nutrient removals, you
are creating a mass balance. This nutrient mass
balance is an important part of an NMP and impor-
tant to understand for your farming operation.
20 SWEET POTATO BMPS 2000
WEET OTATO S
NUTRIENT MANAGEMENT
The Basic Steps
NMPs consist of four major
parts: evaluation of nutrient where nutrient use will be
needs, inventory of nutrient reduced or eliminated. By
supply, determination of nutrient buffering these areas, water
balance, and preventive mainte- quality problems may be de-
nance and inspection. creased.
nitrogen, phosphorus
and potassium should be
Soil Testing listed in the plan for each field.
Complete and accurate soil
Evaluation of tests are important for a success-
Most soil and plant analysis labs
will give you recommended
Nutrient Needs ful nutrient management plan. application rates based on the
You will need soil tests every soil test results. Your county
Maps and Field Information
three years to determine how agent can help you with this.
You will need a detailed much nutrient addition is
map of your farm. The map needed. The needed nutrients
should include: can be supplied from commer- Inventory of
• farm property lines cial fertilizer and/or organic
• your fields with the field sources. Be sure to take repre- Nutrient Supply
identification sentative soil samples and have Many of the nutrients
them tested by a reputable needed to grow your crops are
• the location of all surface laboratory familiar with Louisi-
waters such as streams, rivers, already present on your farm in
ana soils and crop production. the soil, in animal manures or in
ponds or lakes Your county agent can help you crop residues. Knowing the
• direction of surface flows submit samples to the LSU Soil amounts of nutrients already
• arrows showing the direc- Testing Laboratory. present in these sources is impor-
tion that streams or rivers flow tant so that you do not buy or
• a soils map, if available apply more nutrients than
needed.
This map will serve as the
basis for the entire plan, so each
field should have a unique Determine the Quantity of
identification. In addition to the Nutrients Available on Your
map, prepare a list of the crops to Farm
be grown in each field with a Supply planning starts with
realistic yield goal for each crop. an inventory of the nutrients
Most of this information is produced on the farm. This
available at your local USDA information will allow you to
Farm Service Center. Determine Nutrients balance your nutrient purchases
Needed for Each Field with what is available on your
Once you have set realistic farm for the realistic production
Locate Critical Areas yield goals and you have your potential of the crops grown.
Certain areas on your farm soil test results, you can deter-
such as streams and rivers, mine the nutrients your crops
wellheads and lakes or ponds are will need. The amount of nutri-
sensitive to nutrient overload. ents needed should be based on
You should create buffer zones your local growing conditions. At
around these areas on your map a minimum, the amounts of lime,
SWEET POTATO BMPS 2000
WEET OTATO S 21
NUTRIENT MANAGEMENT
Determining
Nutrient Balance
Balance Between Supply and
Need
Once you have determined
both the supply and need of Where Can You Obtain
nutrients for each of your fields,
a critical aspect of NMPs is Information Needed for Your
balancing the two. This can be NMP?
done in several ways. Most
NMPs are developed based on The LSU AgCenter, the USDA Natural
nitrogen, but other factors such Resources Conservation Service, the Louisi-
as phosphorus or metals could ana Department of Agriculture and Forestry,
control how much you can put certified crop advisors or other private con-
out under certain conditions. A sultants will be able to assist you in develop-
phosphorus index is being ing parts of a comprehensive nutrient manage-
developed to help producers ment plan.
determine when nutrient man- An NMP is a good tool to help you use
agement based on phosphorus your on- and off-farm resources more effi-
would be advisable. ciently and prevent future problems. A suc-
cessful NMP will help you obtain the maxi-
mum profit while protecting the environment.
Preventive
Maintenance and
Inspections
Keeping good, detailed
records that help you monitor
your progress is essential to
know if your NMP is to accom-
plish the goals you have set. You
should keep all results from soil
and plant and examine how they
change with time with your
management practices. Records
should be kept on crop yields,
nutrient application rates, timing
and application methods. Keep
detailed schedules and records
on calibration of spraying and
spreading equipment. When you
have a major change in produc-
tion, update your plan to reflect
these changes.
22 SWEET POTATO BMPS 2000
GENERAL FARM BMPS
Water well Used engine oil, Irrigation water
protection - grease, batteries, quality
Farm*A*Syst/ tires, etc. Irrigation water (surface
Home*A*Syst and/or well) should be tested in
• Used engine oil should be
should be used the spring to determine the
stored in a waste oil container
every three salinity (salt) level before irrigat-
(tank or drum) until recycled.
years to deter- ing fields. Take samples to an
mine potential • Empty paint cans, anti- approved laboratory for analysis.
threats to water freeze containers, used tires, old
wells. Threats batteries, etc., will be stored in a
identified will secure area until they can be
be ranked and disposed of properly.
measured to
correct the
most serious.
Fuel storage tanks
Above-ground fuel storage tanks in Louisiana are regulated
by the State Fire Marshal and by the EPA if surface water is at risk.
Above-ground tanks containing 660 gallons or more require
secondary containment. The State Fire Marshal recommends that
some sort of secondary containment be used with all fuel storage
tanks. This could include the use of double-walled tanks, diking
around the tank for impoundment or remote impoundment facili-
ties.
These practices are to be followed:
GENERAL FARM BMPS
Any existing above-ground fuel storage tank of 660 gallons or It is recommended that the
more (1320 gallons if more than one) must have a containment wall storage tank be on a concrete
surrounding the tank capable of holding 100 percent of the tank’s slab to prevent any spillage from
capacity (or the largest tank’s capacity if more than one) in case of entering surface and groundwa-
spillage. ter.
The tank and storage area should be located at least 40 feet The storage area should
from any building. Fuel storage tanks should be placed 150 feet and be kept free of weeds and other
downslope from surface water and water wells. combustible materials.
SWEET POTATO BMPS 2000 23
The tank should be All tanks that catch on fire
conspicuously marked with the must be reported to the State Fire
name of the product that it Marshal within 72 hours of the
contains and “FLAMMABLE – fire.
KEEP FIRE AND FLAME Underground storage
AWAY.” tanks are defined as containing
The bottom of the tank more than 10 percent of their
should be supported by concrete total volume beneath the soil
blocks approximately 6 inches surface. Underground tanks
above the ground surface to represent more of a problem than
protect the bottom of the tank above-ground tanks because
from corrosion. leaks can often go for long
periods without being detected.
If a pumping device is
This poses a serious threat to
used, it should be tightly and
groundwater sources in the
permanently attached and meet
vicinity of the tank. If you have
NFPA approval. Gravity dis-
an underground fuel storage tank,
charge tanks are acceptable, but
you need to contact the State Fire
they must be equipped with a
Marshal’s Office for regulations
valve that will automatically
affecting these storage tanks.
close in the event of a fire.
Plans for the installation
of all storage tanks that will 10% of tank is below
contain more than 60 gallons of ground level
liquid must be submitted to the
State Fire Marshal for approval.
This tank would be classified as
an underground fuel tank.
GENERAL FARM BMPS
24 SWEET POTATO BMPS 2000
WEET OTATO S
RESEARCH OVERVIEW
AGRICULTURAL SCIENTISTS WORK TO
SUSTAIN THE ENVIRONMENT
William H. Brown
The word “environment” The stage was set for contem-
means different things to different porary LSU AgCenter environmental
people. To some it stirs visions of research programs when “Focus
clear, pristine streams and lakes; to 2000: Research for the 21st Cen-
others vistas of forests or prairies; to tury,” a strategic plan for the Louisi-
William H. Brown, Associate Director and
still others, clean, fresh mountain air. ana Agricultural Experiment Station Associate Vice Chancellor, LSU AgCenter
To agriculturalists, who produce (LAES), was adopted in 1990. One
food and fiber for the citizens of the thrust of this plan was to protect the for the LAES environmental re-
United States and a substantial part environment by “ developing search programs conducted since.
of the rest of the world, a quality production systems that protect the
environment means acres of produc- AgCenter environmental
soil and minimize the need for
tive soil, clean air and an adequate research programs can be grouped as
fertilizer, water, tillage, and other
supply of quality water for irriga- follows: conservation tillage,
inputs.” Adoption of Focus 2000 led
tion, livestock consumption and management of wastes and residues
to establishment of the Soil, Water
human use. All these visions are for beneficial uses, water quality,
and the Environment Research
both accurate and incomplete. To integrated pest management and
Advisory Committee (RAC), which
complete the picture, one must nutrient management.
provided researchers a forum for
appreciate the array of agricultural exchanging information on environ-
research conducted in Louisiana and mental programs and for forming CONSERVATION TILLAGE
at other agricultural experiment new collaborations with colleagues.
stations across the country. Many of AgCenter programs in conser-
these topics are not commonly vation tillage for cotton production
thought of as environmental, yet on Macon Ridge soils demonstrated
they have a major impact on the Agricultural not only that cotton could be suc-
quality of our air, soil and water cessfully produced with little or no
resources.
scientists were tillage, but, when combined with a
among the winter cover crop, soil erosion could
AIR, SOIL AND WATER be reduced by up to 85 percent, soil
original organic matter could be slowly but
Agricultural scientists were steadily rebuilt, and that nitrogen
among the original environmental- environmentalists. fertilizer requirements could be
ists. For most of this century, stabilized at about 70 pounds or less
agricultural researchers have recog- per acre, depending on the cover
nized the importance of sustaining One product of the Soil, Water crop grown. This pioneering re-
the natural resource base on which and Environment RAC was sponsor- search, along with advances in
agricultural production relies. For ship of an environmental conference herbicide technology, paved the way
example, the 1930s saw the initia- in 1995. This conference included for the adoption of practical conser-
tion of widespread programs at land- LAES research presentations on land vation tillage production systems
grant universities and at the federal use management, waste manage- (sometimes called “stale seedbed”
level to reduce soil erosion, to keep ment, forestry, pest management, systems) now widely used on
the soil covered with vegetation and water quality and conservation Louisiana cropland, resulting in
to improve drainage to enhance soil tillage and presentations from major soil erosion reductions.
productivity. Through the ensuing numerous state and federal agencies Another area in which
years, many research programs have including the Louisiana Department AgCenter scientists have pioneered
been conducted to provide informa- of Environmental Quality, the has been in the development of
tion for improving the environmental Barataria-Terrebonne National conservation tillage systems for rice
“friendliness” of food and fiber Estuary Program and the Natural in southwest Louisiana. Although
production and processing. Resources Conservation Service. still being developed and refined,
Conference participants set the stage conservation tillage promises to
SWEET POTATO BMPS 2000
WEET OTATO S 25
RESEARCH OVERVIEW
offer rice producers a practical way can be incorporated into the soil to
of growing rice while reducing the enhance soil structure and plant
sediment load of the water leaving growth. The LSU AgCenter’s
their fields. Callegari Organic Recycling Center
provides the facilities for both
research and training in the com-
WASTE MANAGEMENT posting process. The AgCenter has Water table management is a
conducted 12 one-week programs technology that uses underground
Waste management pro- tubes to drain excess water from
grams deal with the manures and which have trained more than 200
people from 29 states and five fields to prevent water logging
residues that result from animal damage to crops during wet weather
production and processing and the countries in the proper techniques of
composting organic residues. and also to irrigate from below the
development of methods to benefi- surface during drought. Cooperative
cially use the solid wastes that studies with USDA scientists focus
originate from both agricultural on how water table management can
WATER QUALITY
operations and urban activities. A enhance crop production (sugarcane
program is under way to determine Water quality research especially) while improving the
the extent to which dairy manures studies cut across many crops and quality of the water drained from the
and related fecal coliform indicator soil types. These studies provide field.
organisms move into water bodies basic information on how precipita-
when irrigated onto pastureland in tion moves off the land, through the
“no discharge” systems. Further soil and what it carries with it. This INTEGRATED PEST MANAGEMENT
knowledge about how to minimize information is fundamental to our
understanding of how water trans- Integrated pest management
the environmental impacts of
ports nutrients and chemicals (IPM) refers to the integrated use of
dairying is vital for Louisiana’s
through the soil and how rainfall or all appropriate methods to control
economically important dairy
irrigation water can be managed to agricultural pests such as weeds,
industry in the environmentally
improve both crop production and insects, diseases and nematodes.
sensitive Lake Pontchartrain drain-
the environment. IPM systems employ judicious use
age basin.
of pesticides along with cultural
AgCenter soil scientists and practices, genetic resistance and
agricultural engineers have teamed other available means to reduce
with USDA researchers to determine dependence on pesticides. Reduced
the complex mechanisms by which pesticide usage is based on careful
Another area of intense re- water moves through Louisiana’s scouting and precision application
search activity deals with establish- alluvial soils, how rapidly it moves methods. Although most pesticides
ing benchmarks for poultry litter and the extent to which it transports used today are much less toxic to
disposal in north Louisiana. Poultry certain nutrients and pesticides. non-target organisms and used in
litter, a byproduct of broiler produc- Other studies have shown that much smaller quantities (ounces
tion, is a valuable source of nutrients subsurface drainage can reduce soil rather than pounds per acre), the end
for pasture and forest lands, but erosion and improve water dis- result of IPM is that relatively fewer
excessive application can overload charges into drainage systems. pesticides are introduced into the
the soil’s ability to assimilate Studies of corn production over five environment. Some crops are now
phosphorus. And, if allowed to move years showed that subsurface resistant to selected herbicides or to
into water bodies, phosphorus could drainage reduced soil loss by 30 certain insect pests because of recent
cause eutrophication problems. percent, nitrogen loss by 20 percent advances in plant genetic engineer-
Several studies are under way that and phosphorus loss by 36 percent. ing. The fruits of several decades of
will define safe application levels, A similar nine-year study with intensive molecular biology research
the fertility value and alternative soybeans showed 48 percent less have provided LAES entomologists
beneficial uses for poultry litter. soil loss, 39 percent less nitrogen and weed scientists with additional
loss, 35 percent less phosphorus loss tools to develop practical production
Many agricultural and urban
and 36 percent less potassium loss. systems that use these special plants
residues can be treated by com-
posting to reduce volume, eliminate to combat competing or damaging
odors and neutralize undesirable pests while minimizing pesticide
components. The resulting compost use.
26 SWEET POTATO BMPS 2000
RESEARCH OVERVIEW
NUTRIENT MANAGEMENT extension specialists, in cooperation the production of food and fiber for
with farmers representing the a growing world population will
Nutrient management,
Louisiana Farm Bureau Federation, have environmental consequences.
actually one of the oldest of the
and representatives of state and Agriculture and cities must co-exist,
agricultural sciences, determines the
federal agencies such as the Natural however, if society, as we know it, is
need for supplementing the soil’s
Resources Conservation Service to continue and to prosper. Some
natural fertility with the appropriate
(NRCS), Louisiana Department of forecasts suggest that the world’s
types and amounts of nutrients to
Agriculture and Forestry (LDAF), food demand will triple over the next
achieve the genetic potential of
Louisiana Department of Environ- 40 years. To meet that demand, we
today’s improved seeds. It is impor-
mental Quality (LDEQ), Department must continue to invest in science
tant, both environmentally and
of Natural Resources (DNR), and technology so that we can learn
economically, that nutrients not be
Agricultural Research Service how to use reasonable and effective
applied to producers’ fields in
(ARS) and others launched an effort measures to blend sustainable
excessive amounts.
to integrate the best information economic growth with acceptable
Nutrient management available into a series of “best environmental impacts.
research starts with LAES agrono- management practices” or BMPs.
mists who determine the nutrient The BMPs cover all of the major
needs for the many crops produced plants and animals produced in
on the diverse soil types of Louisi- Louisiana.
ana. Soil scientists determine
nutrient interactions and availability Two research stations,
in the various soil types and textures. Southeast and Iberia, have operated Compiled by:
The Soil Testing Laboratory pro- sites for the National Atmospheric
Fred Sanders, Ph.D., and
vides individual field analyses that Deposition Program (NADP) since
the early 1980s. This program,
Mike Cannon, Ph.D.
determine the nutrients that need to
be added and their amounts for supported in part by state agricul-
tural experiment stations nationwide, Other AgCenter contributors
specific crops and locations. This
has provided measurements of were:
information is provided to extension
agents so they can make specific precipitation acidity and atmo- Eddie Funderburg, Ph.D.
fertility recommendations to farm- spheric nutrient deposition at more Mary Grodner, Ph.D.
ers. Finally, new technologies are than 200 sites for 20 years. The Dearl Sanders, Ph.D.
now being investigated, usually NADP is now developing a national Bill Branch
called “precision farming systems,” mercury deposition network, and the
that will allow variable, on-the-go AgCenter will provide two monitor- Sweet Potato BMP review
precision nutrient applications ing sites, the Hammond and the
committee:
within fields based on intensive soil Sweet Potato research stations, that
testing, crop production history and will be operated by the Louisiana
DEQ. The AgCenter also operates a Jack Bagent, Ph.D.
other pertinent factors.
network of meteorological recording Bill Hadden
Taken together, today’s sites at the research stations called Chris Clark, Ph.D.
producers are armed with an array of the Louisiana Agriclimatic Informa- Michael Jordan, NRCS
science-based data, sophisticated tion System (LAIS). The LAIS Sam Rogers, ARS
testing services and the latest provides research scientists with an Gary Goay, LDEQ
technology to enable them to apply extensive database of the state’s Ed Britton, DNR
only the required nutrients in only recent meteorology in support of
the needed amounts at only the Lamar Bush, Grower
their research programs. Irv Daniel, Grower
proper locations for optimum crop
performance. Mark Fields, Grower
FUTURE FOOD DEMANDS Larry Fontenot, Grower
Ray Poret, Grower
OTHER The earth’s environment has
ACTIVITIES Jerry Self, Grower
never been static. It has been subject
Integrating the best science Jim Sowell, Grower
to both dramatic upheavals and slow,
with economic constraints and evolutionary changes. Our crowded Mitch Stelly, Grower
environmental concerns is challeng- cities and sprawling suburbs have Ken Thornhill, Grower
ing. In 1993, AgCenter scientists and environmental impacts. Likewise,
SWEET POTATO BMPS 2000 27
T he complex nature of nonpoint pollution means programs designed to
reduce its impact on the environment will not be easy to establish or
maintain. Controlling these contaminants will require solutions as diverse
as the pollutants themselves. Through a multi-agency effort, led by the
LSU AgCenter, these BMP manuals are targeted at reducing the impact
of agricultural production on Louisiana’s environment. Agricultural
producers in Louisiana, through voluntary implementation of these
BMPs, are taking the lead in efforts to protect the waters of Louisiana.
The quality of Louisiana’s environment depends on each of us.
Visit our website:
www.lsuagcenter.com
Produced by LSU AgCenter Communications
Louisiana State University Agricultural Center, William B. Richardson, Chancellor
Louisiana Agricultural Experiment Station, R. Larry Rogers, Vice Chancellor and Director
Louisiana Cooperative Extension Service, Jack L. Bagent, Vice Chancellor and Director
Pub. 2832 (1M) 12/00
Issued in furtherance of Cooperative Extension work, Acts of Congress of May 8 and June 30, 1914, in cooperation with the
United States Department of Agriculture. The Louisiana Cooperative Extension Service provides equal opportunities in
programs and employment.
Originally developed through a cooperative agreement with the Louisiana Department of Environmental Quality,
Contract 522100.
28 SWEET POTATO BMPS 2000
