CENTRAL PLATTE NRD
NITROGEN MANAGEMENT CERTIFICATION TEST
NAME:
_____________________________________________________________
ADDRESS ______________________________________________________________
______________________________________________________________
SECTION A ---- The nitrate contamination concern
1
The U.S. Environmental Protection Agency's maximum contaminant level for nitratenitrogen in public water supplies is __________.
a) 5 ppm
b) 10 ppm
c) 15 ppm
d) 20 ppm
2
The only illness clearly caused by drinking water with elevated nitrate levels is
__________.
a) hypertension in adults
b) birth defects of the central nervous system
c) methemoglobinemia (blue baby syndrome) in infants under six
months of age
d) none of the above
3
The only people who need to be concerned with high nitrate drinking water are
__________.
a) pregnant women
b) those with young children
c) livestock producers
d) crop producers
e) all of the above
4
Microorganisms in the soil will convert what source of nitrogen into leachable
nitrate-nitrogen?
a) anhydrous ammonia
b) urea
c) manure
d) liquid formulations
e) all of the above
5
To increase nitrogen efficiency a producer can __________.
a) use nitrification inhibitors
b) use fertigation applications
c) use sidedress fertilizer applications
d) all of the above
1
6
Carefully managed sprinkler irrigated continuous corn on a deep silt loam soil can
have an annual nitrate-nitrogen leaching loss of __________.
a) 0 pounds per acre
b) 5 to 10 pounds per acre
c) 40 to 80 pounds per acre
d) 100 to 120 pounds per acre
7
In river valleys with sandy soils and shallow water tables, nitrate leaving the crop
root zone will reach the water table in __________.
a) a few weeks or months
b) one to two years
c) ten to twenty years
d) over one hundred years
SECTION B ---- Soil characteristics that influence nitrogen and water
management
8
Available water is the amount of water held by the soil between which two limits?
a) field capacity and field saturation
b) field capacity and permanent wilting point
c) field capacity and zero water content
d) saturation and permanent wilting point
9
In addition to water-holding capacity, the total amount of water available to the plant
also depends on __________.
a) the depth of the root zone
b) the soil parent material
c) the saturation point of the soil
d) the field slope
10
The initial infiltration rate of water on a dry soil is typically ______________.
a) nearly the same as for a wet soil
b) very rapid
c) dependent on soil texture
d) both b and c
11
The water infiltration rate of a soil can be affected by _____________.
a)
b)
c)
d)
e)
soil compaction
soil surface conditions
surface residue
number of irrigations
all of the above
2
12
Nitrate-nitrogen is _________________.
a) held by clay and organic material and is immobile
b) very mobile and will move with water
c) unavailable to plants until it is broken down by bacteria
d) is immobile at soil temperatures below 65 Fahrenheit
13
Losses of nitrogen through leaching can be minimized by __________.
a) well-timed nitrogen applications
b) well-managed irrigation applications
c) avoiding over-application of nitrogen fertilizer
d) all of the above
14
At the end of the growing season, there is _______ residual nitrate-nitrogen in the
soil.
a) seldom
b) never
c) always
d) occasionally
15
Nitrate leaching losses are a concern on ____________.
a) gravity irrigated fields
b) sprinkler irrigated fields
c) properly fertilized fields
d) all of the above
16
Under furrow irrigation, excess irrigation amounts impact nitrate leaching during
____________.
a) the first irrigation application
b) the last irrigation application
c) in-season applications
d) all of the above
SECTION D ---- How to determine the optimum rate of nitrogen fertilizer
17
The best way to determine where and how much residual nitrate-nitrogen is present
in the soil is to ____________.
a) properly collect samples for soil testing
b) collect a surface sample and assume deeper nitrate-nitrogen will be
unavailable
c) at present there is no acceptable, accurate way to make a determination
d) calculate based on last year's yield
18
Greater accuracy in estimating available soil residual nitrate-nitrogen is possible by
__________.
a) sampling to the depth of the effective root zone for the crop
b) collecting sample cores in depth increments
c) increasing the number of samples taken on a field
d) all of the above
3
19
Calculate the nitrogen fertilizer needed (lb/acre) for corn for the following:
Expected yield . . . . . . 180 bu/acre
Soil organic matter. . . 1.0 percent
Soil nitrate. . . . . . . . . .12.0 ppm
a)
b)
c)
d)
20
115 lb/acre
120 lb/acre
130 lb/acre
145 lb/acre
SECTION E ----- Giving credit for non-fertilizer nitrogen sources
The minimum estimated nitrogen contributed to the crop from mineralization for a
soil containing 2% organic matter is __________.
a) 14 lb/acre/yr
b) 28 lb/acre/yr
c) 42 lb/acre/yr
d) 56 lb/acre/yr
21
The estimated nitrogen credit for a crop following an 80% stand of alfalfa on a
medium-textured soil is _____.
a) 90 lb/acre
b) 120 lb/acre
c) 150 lb/acre
d) 200 lb/acre
22
If irrigation water contains 17 ppm nitrate-nitrogen and 12 inches are applied, how
much crop available nitrogen is in the water?
a) 23 lb of nitrogen/acre
b) 37 lb of nitrogen/acre
c) 47 lb of nitrogen/acre
d) 61 lb of nitrogen/acre
23
Nitrogen contained in irrigation water applied during the rapid nitrogen uptake
period of a plant is _______.
a) half as effective as the same amount of nitrogen fertilizer
b) just as effective as the same amount of nitrogen fertilizer
c) too variable to be a reliable nitrogen source
d) effective only in years with below normal temperatures
24
When calculating a water nitrogen credit for central Nebraska, a practical upper limit
on inches of water applied is __________.
a) 6 inches
b) 9 inches
c) 15 inches
d) 18 inches
SECTION F ----- How to properly apply nitrogen fertilizer
4
25
The potential for leaching of nitrate by rainfall is highest in the _________.
a) spring
b) summer
c) fall
d) mid-summer during rapid nitrate uptake
26
The percent of applied nitrogen fertilizer that is recovered in the harvested portion of
the crop is called the _______.
a) nitrogen use efficiency
b) nitrogen use ratio
c) nitrogen factor
d) fertilizer demand
27
Under excellent management, nitrogen use efficiencies can be as high as _______.
a) 100 %
b) 90%
c) 60 %
d) 30 %
28
High nitrogen use efficiencies can be attained only when __________.
a) nitrogen applications are near the minimum needed for optimum yields
b) applications are made near or during the rapid uptake period
c) applications are made with highly soluble nitrogen sources
d) a and b
e) a and c
29
The nitrogen use efficiency for fall-applied nitrogen is _______ compared to sidedress applied nitrogen.
a) lower
b) the same as
c) higher
d) none of the above
30
For sandy soils, the best choice for nitrogen fertilizer timing is _____________.
a) to use a small amount of nitrogen as a starter, with the remainder
sidedressed or applied with a sprinkler irrigation system
b) to apply most nitrogen prior to planting, with a small amount sidedressed
c) apply all the nitrogen before planting
d) none of the above
31
Nitrogen use efficiency can be increased by __________.
a) banding surface applied nitrogen
b) small consecutive applications through a sprinkler system
c) not exceeding the total nitrogen requirement for the crop
d) all of the above
5
32
When used with nitrogen fertilizer, nitrification inhibitors ________________.
a) slow the conversion from non-mobile ammonium to the mobile nitrate form
b) help prevent significant leaching from a heavy rainfall event within four
weeks of application
c) prevent the leaching of residual nitrate that is already in the soil at
application
d) a and b
e) b and c
33
The only form of nitrogen that is totally non-leachable immediately after application
is _______.
a) urea
b) anhydrous ammonia
c) ammonium nitrate
d) urea-ammonium nitrate solution
SECTION H -- Irrigation management for profitable crop production and water
quality protection
34
A typical application efficiency factor for conventional gated pipe irrigation systems
is _________.
a) 0.50
b) 0.60
c) 0.70
d) 0.80
35
A typical application efficiency factor for a center pivot or linear move irrigation
system is _______.
a) 0.75 - 0.80
b) 0.80 - 0.85
c) 0.85 - 0.90
d) 0.90 - 0.95
36
The average depth (inches per acre) of irrigation water applied can be determined if
you know _______.
a) the pumping rate and area irrigated
b) the volume of water pumped and area irrigated
c) the total time of irrigation and area irrigated
d) gpm and acre-inches per hour
37
The volume of irrigation water pumped is determined by multiplying
________________.
a) flow rate and irrigation time
b) irrigation time and area irrigated
c) flow rate and area irrigated
d) flow rate and the net application factor
6
38
1 cfs or 1 acre-inch/hr is equal to ______.
a) 375 gpm
b) 450 gpm
c) 540 gpm
d) 620 gpm
39
1 acre-inch is equal to _________.
a) 43,560 gallons
b) 34,687 gallons
c) 27,154 gallons
d) 328,851 gallons
40
Use the following flow rate and time to estimate the acre-inches of irrigation water
applied.
Pumping rate of 750 gpm
a)
b)
c)
d)
41
Pumping time of 8 hours
8.2 acre-inches
10.2 acre-inches
13.3 acre-inches
14.5 acre-inches
Determine the gross irrigation depth for one revolution from the following center
pivot irrigation information.
A center pivot irrigates 132 acres with a well that pumps 750 gpm.
A revolution is made in 72 hours.
a)
b)
c)
d)
1.0 inches
0.9 inches
0.8 inches
0.7 inches
42
The amount of water applied should not exceed ___________.
a) the capacity of the irrigation system
b) the amount of water storage space available in the active root zone
c) field capacity
d) one week of estimated crop ET
43
If an irrigation system has a system efficiency of 75% and a net irrigation of 2.4
inches is needed, what would the gross irrigation amount be?
a) 2.3 inches
b) 2.7 inches
c) 3.2 inches
d) 3.6 inches
7
44
For the last irrigation, the available soil water should be depleted to a level of
___________.
a) 30 %
b) 40 %
c) 50 %
d) 60 %
45
At full dent a corn plant will need approximately _______ inches of water to reach
maturity.
a) 7.5
b) 5.0
c) 2.5
d) 1.5
SECTION I ---- Understanding furrow irrigation management
46
Leaky gates and gaskets on gated pipe systems can result in ___________.
a) smaller set sizes
b) excess leaching
c) extra pumping costs
d) both b and c
e) all of the above
SECTION J ---- Irrigation water management for sprinkler irrigation
47
Under very dry, windy conditions, the water saved by positioning sprinkler nozzles
within the canopy is _____________.
a) around 20 percent
b) about 10 percent
c) under 5 percent
d) between 10 and 15 percent
CENTRAL PLATTE NRD RULES & REGULATIONS
48
A soils analysis must be submitted in Central Platte NRD’s Phase II/III Quality
Management Area: ___________
a) For each field or 80 acre tract growing corn, sorghum or potatoes
b) composite sample must consist of a mixture from no less than one three-foot
probe every five acres.
c) Only shallow samples are required.
d) a and b
e) a and c
8
49
Commercial Nitrogen fertilizer can be applied to corn or sorghum in a Phase III area of
Central Platte NRD’s Quality Management Area __________
a.) All applied as pre-plant/ pre-emergent if the total application for the year
is less than 80 pounds.
b.) All applied as pre-plant/pre-emergent if the total application for the year is
more than 80 pounds if an approved inhibitor is used.
c.) Split applied without an inhibitor if the majority of the fertilizer is applied as
sidedress/ post-emergent.
d.) All of the above.
50
How early can commercial nitrogen fertilizer be applied in Central Platte NRD’s Phase
II/III Quality Management Area? __________
a.) After November 1st
b.) When ground temperature is below 50 degrees
c.) March 1st
d.) Anytime after harvest
9