Section 3 - Soil Nutrient Management Flashcards
1
Q
To identify the most efficient nutrient application rate from soil test results, soil tests must be calibrated against crop responses to applied nutrients in field experiments conducted over a wide range of soils and climate conditions. Yield responses from various rates of applied nutrients can then be related to the number of available nutrients indicated by the soil test. An accurately calibrated soil test.
(1) correctly identifies the degree of nutrient deficiency or sufficiency and
(2) supports the estimated nutrient rate required to optimize crop productivity.
A
True
2
Q
Chelate‐micronutrient relationships and stability in soils are utilized in soil testing for micronutrients. Knowledge of chelate availability in soil provides the basis for developing the DTPA soil test for Fe, Zn, Cu, and Mn, which is used in most soil‐testing laboratories.
A
True
3
Q
Meeting food security needs for a growing population (estimated to be 9.5 billion in 40 years) will require approximately 50–70% increase in food production on approximately the same or less agricultural land area used today.
A
True
4
Q
High crop yields are impossible with low levels of fertility. Soil nutrient supply can be controlled; however, the initial cost of building soil fertility from low to high levels may discourage growers if viewed as an annual investment. Residual nutrient availability from past applications should be included in analyses of nutrient economics.
A
True
5
Q
Each nutrient has a specific nutrient absorption rate in a plant leaf which has a specific solution concentration.
A
True
6
Q
What are the three soil qualifications that determine their permanence and sensitivity to management?
A
1) Ephemeral
2) Intermediate
3) Permanent
7
Q
Soil test calibration studies also provide data to establish fertilizer recommendations. For example, at each field location, P rate required for optimum yield can be determined and displayed.
A
True
8
Q
Soil enriching benefits from manure, in addition to those from nutrients, are related to the OM that improves soil structure and moisture relations, increase the mobility of P, K, and micronutrients, and stimulates microbial activity. There is considerable variability in manure, depending on methods of storing and handling; however, with current fertilizer, labor, and equipment costs, it is usually profitable for the grower to use livestock manure.
A
True
9
Q
Land managers must adopt economically viable technologies that maintain, enhance, or protect the productive capacity of our soil resources to ensure future food and fiber supplies. While organic nutrient sources are important to meeting the nutritional needs of higher-yielding cropping systems, inorganic fertilizer nutrients will remain the predominant nutrient source.
A
True
10
Q
The best extractant should mimic what the roots see in the rhizosphere.
A
True
11
Q
Foliar applications do not replace soil applications of macronutrients but work fine for ___.
A
micronutrients
12
Q
Late foliar applications can increase nutrient concentrations in the final product (grain, fruit).
A
True
13
Q
___: application of nutrients, primarily N, P, K, and S, through an irrigation system. Can be performed in the furrow, center pivot (overhead sprinklers), and micro-irrigation (drip) systems.
A
Fertigation
14
Q
The growth stage is important in plant analysis because nutrient status and demand vary during the season. Nutrient concentration in vegetative parts usually decreases with maturity. Misinterpretation of plant analysis results is common if sampling time is not identified correctly.
A
True
15
Q
Nutrient analysis on ___ ___ is important in diagnosing the nutrient needs of growing plants.
A
fresh tissue
16
Q
Exchangeable plus solution K+ is usually extracted with 1 M NH4OAc. The NH4OAc soil test extracts + in concentrations related to K availability to plants; however, as with P, crops vary in their responsiveness to K.
A
True
17
Q
In addition to leaf symptoms, nutrient deficiencies have a marked effect on ___ ___.
A
root growth
18
Q
Identify 3 factors why with cooler temperatures nutrient uptake is reduced.
A
- mass flow of nutrients is reduced by decreased growth rate and transpiration
- diffusion rate decreases with declining temperature and a lower concentration gradient
- Mineralization of organically bound nutrients is reduced.
19
Q
Crop residue management (tillage) systems have been developed to leave more crop residue on the surface to reduce soil and/or water loss compared with conventional or full tillage systems wherein all residues are incorporated into the soil after harvest and/or before planting.
A
True
20
Q
Why is higher soil test P required for a given runoff P concentration in clay soils compared to stand soils?
P is adsorbed more strongly in sandy soils.
P is adsorbed less tightly in sandy soils.
P is held less tightly in the clay compared to the sandy soils.
P leaching occurs more in clay soils through macropore flow.
A
P is adsorbed less tightly in sandy soils.
21
Q
Measuring which of the following soil properties would provide a good indication of root penetration, air-filled pore space, and microbial activity in the soil?
Soil OM
sodicity
bulk density
microbial biomass
A
bulk density
22
Q
What are the four R’’s
A
- Rate
- Time
- Source
- Place
23
Q
Two growers have the same low P soil and plant sorghum. Farmer A broadcasts 45 lb P2O5/a and, Farmer B bands the same rate below the seed at planting. 100 lb N/a were applied to each field. The following results were obtained.
Farmer A Farmer B
Unfertilized grain yield (lb/a) 2400 2400
Unfertilized grain N content (%) 1.2 1.2
Unfertilized grain P content (%) 0.2 0.2
Fertilized yield (lb/a) 3600 4200
Fertilized grain N (%) 1.8 2.4
Fertilized grain P (%) 0.24 0.3
(Hint: nutrient (%) use efficiency=(nutrient uptake–nutrient in unfertilized)*100)/nutrient applied)
a. Calculate the fertilizer P use efficiency (%) for the two growers.
b. Calculate the fertilizer N use efficiency (%) for the two growers.
c. How much fertilizer N remains in the soil profile after harvest for the two growers? .
A
24
Q
When solution P decreases with plant uptake, P minerals dissolve or adsorbed P desorbs to resupply soil solution P. Chemical extractants used for P soil tests simulate this process, as they reduce solution Al or Ca. As solution Al or Ca decreases during extraction, native Al‐P or Ca‐P minerals dissolve to resupply solution Al or Ca. Solution P then increases, which provides a measure of the soil’s ability to supply or buffer plant-available P.
A
True
25
List 6 reasons why soil testing is important for agricultural development?
1. Increasing yield
2. Farm profitability
3. Crop resilience
4. Efficient resource use
5. Food & income security
6. Environmental quality
26
The maximum economic yield represents the yield level where the last unit of input pays for itself and is less than the maximum yield.
True
27
Pre-season approach: (Site-Specific Nutrient management)
- Previous crop yield data obtained from a yield monitor combine
- Soil test data obtained from the grid, cell, or zone sampling
- Digital orthophoto quarter quads (DOQQQ) – aerial photographs
- Aerial or satellite provided NDVI
- Digital elevation
- Soil electricity conductivity (EC) – correlation with soil texture, depth, salinity, etc.
True
28
Broadcast applied N usually is less efficient than subsurface applied N in high surface residue cropping systems. Use the following data to calculate the % fertilizer N recovery for each system. What caused the difference?
(Hint: N(%) recovery = (method of application N uptake – (N in unfertilized)\*100)/N applied)
Broadcast N Subsurface N Unfertilized
N rate 100 lb N/a 100 lb N/a 0 lb N/a
Grain yield 98 bu/a 110 bu/a 75 bu/a
Test Weight 56 lb/bu 56 lb/bu 56 lb/bu
% Grain N 2.1% 2.4% 1.8%
Unfertilized N uptake: (75 bu/a) (56 lb/bu) (1.8% N) = 75.6 lb N uptake
Broadcast N uptake: (98 bu/a) (56 lb/bu) (2.1% N) = 115.3 lb N
% N recovery = [(115.3 lb N - 75.6 lb N) / 100 lb N] x 100 = 39.7%
Subsurface N uptake = (110 bu/a) (56 lb/bu) (2.4% N) = 147.8 lb
% N recovery = [(147.8 lb N - 75.6 lb N) / 100 lb N] x 100 = 72.2%
Immobilization of broadcast fertilizer N by surface residue, volatilization, etc., reduced N availability to crops and reduced fertilizer N recovery.
29
Water use efficiency (WUE) is the yield of the crop in bushels, pounds, or tons per acre-inch of water from the soil, rainfall, and irrigation. Any practice that promotes plant growth and the more efficient use of sunlight in photosynthesis to increase crop yields will increase WUE.
True
30
Each visual symptom is related to a nutrient function in the plant. Most nutrients have several functions, making it difficult to identify the reason for a particular deficiency symptom.
True
31
What are three factors that indicate physical soil loss by water and wind reduces soil productivity?
1) decreasing topsoil thickness and rooting depth
2) decreasing OM and microbial activity, which decreases nutrient supply
3) decreasing depth to higher subsoil clay content, which decreases infiltration and plant available H2O
32
A nutrient management plan includes:
- Field and soil map
- Soil testing and plant analysis
- Crop and crop rotation
- Yield expectation
- Nutrient sources
- Recommended rates
- Application timing
- Placement method
- Proximity to sensitive areas
True
33
It is important to recognize that nutrient movement to
surface- and ground-water occurs in natural ecosystems. Water quality standards for drinking water have been established for all elements that adversely affect health when present in high concentrations.
True
34
If you apply zinc to phosphorus-deficient soil, your yield will at least be better than what it was before you applied it since zinc and phosphorus do not have negative interactions.
True
False
False
35
Many factors can interfere with the foliar application, so:
- Foliar nutrients should be applied before plant demand is high
- Plants with severe nutrient deficiency respond quickly to foliar application
- Plants with hidden hunger may show yield response
- Excessive foliar nutrient application can cause leaf burning
- Application when leaves are wet increases absorption and response
- Heat or moisture stress reduces the nutrient absorption rate
- Leaf cuticle thickness with plant age: applications are more effective early in the season
- Nutrient application can be reduced by physical droplet runoff: use surfactant
True
36
What does MAR stand for?
Maximum accumulation rate
37
Soybean:
- Uptake Order: N\>K\>Ca\>P\>Mg\>S
- N and P redistribution from leaves into grains, while K redistribution from the stem into grains
- K maximum accumulation rate takes place earlier (R2-R3
True
38
Earlier planting dates extend the growing season for spring-planted crops, which generally increase yield potential. For example, soybean yield response to increasing soil test K level was greater with earlier planting.
True
39
\_\_\_ ___ \_\_\_: With mobile nutrients, soil test buildup and/or maintenance programs are not viable, because these nutrients are readily mobile in the root zone in many soils.
Mobile Nutrient Recommendations
40
Greenhouse Strip Tests Simple greenhouse tests involve growing plants in small amounts of soil collected from a field suspected of being nutrient deficient to assess nutrient availability.
True
41
\_\_\_ ___ \_\_\_ can be related to factors other than nutrient stress.
Visual deficiency symptoms
42
\_\_\_ \_\_\_: nutrients applied directly to leaves to remedy obvious (visual) nutrient deficiencies or prevent hidden hunger (not visual) that impacts crop yield or quality
Foliar application
43
When buying land, the producer may choose high- or low-priced property. The higher-priced land is generally more productive, is fertile, and has better improvements. The lower-priced land may be a good buy, provided the land is not severely eroded or has no other physical limitations to productivity. Low-priced land is usually infertile and may need considerable lime and/or nutrients. Adequate liming and fertilization, as indicated by soil tests and combined with other good practices, can rapidly increase productivity.
True
44
At optimum N rates, about 10–20% may be residual for next year's crop if it is not leached below the root zone. The residual value of P and K can vary from 25 to 60%, depending on the rate applied, crop removal, and soil properties influencing P and K availability.
True
45
What does NSI stand for?
Nitrogen Sufficiency Index
46
Under normal conditions, if a plant nutrient is mobile in the plant, its deficiency symptom will first show up in older leaves.
True
False
True
47
The Late 1940s, soil testing became an important practice for determining the need for lime and fertilizer in the United States
True
48
What can I do to improve soil quality on my farm or garden?
1. Plant cover crops!!!!!!!!
2. Keep something growing year-round! Never expose the soil to raindrops!
3. Leave lots of plant residue on the soil surface. Mulch garden!
4. Avoid tillage if at all possible!
5. Soil test and follow the recommendations.
6. Plant crops adapted to your area and time of planting.
49
The plant sap test is used for:
semi-quantitively determine the concentration of
essential nutrient in plant tissue
determine soil nutrient concentration
accessing soil air quality
determine plant growth
semi-quantitively determine the concentration of
an essential nutrient in plant tissue
50
As plant nutrients cycle through the soil-plant-atmosphere continuum, some will be recovered through plant uptake, incorporated into OM, adsorbed to mineral and OM surfaces, and precipitated as solid minerals. The remaining nutrients can be transported from the field through runoff and subsurface lateral flow toward streams and rivers, and by leaching to groundwater.
True
51
Most of the errors that take place in the soil testing processes are caused by not taking the correct soil sample.
True
False
True
52
What does CNR stand for?
Critical Nutrient Range
53
What are the three objectives of soil testing?
1. provide an index of nutrient availability in soil.
2. predict the probability of obtaining a profitable response to fertilizer or lime.
3. provide a basis for the development of fertilizer and lime recommendations.
54
What is Chlorosis?
Uniform or interveinal yellowing or light green coloring of leaves
55
The amount of nutrients required depends on the plant (crop, yield level, variety/hybrid, planting rate), environmental conditions (moisture and temp), soil (properties, fertility, landscape), and soil/crop management
True
56
Plant response to fertilization can be greatly increased if nutrients are applied properly. Under reduced and no-tillage systems, surface accumulation of residue and nutrients combined with cooler temperatures and higher moisture in the spring can influence nutrient use. In many cropping systems, especially with low soil test P and/or K, nutrients applied below the soil surface often enhance plant growth and yield.
True
57
Simple greenhouse tests involve growing plants in small amounts of soil collected from a field suspected of being nutrient deficient to assess nutrient availability.
True
58
What is stunting?
Reduced plant height, shortened internodes, and leaves may remain dark green or exhibit light green or chlorotic symptoms
59
Since organic S represents ≈ 90% of total S in most soils, S soil tests that estimate mineralizable S might be more accurate in identifying S deficient soils. Ca(H2PO4)2 or KH2PO4 extractable S represents some mineralizable organic S and should be a better indicator of S availability.
True
60
A farmer uses conventional tillage on a 2.5% OM soil (0-6 in. sample depth). Soil loss by erosion on this soil is 20 tons/ac/yr. How much total soil N does he lose each year? (Assume OM N=5%)
N lost = (20 tons/ac/year) x (2.5% OM) x (5% N SOM) x 2000 lb/ton = 50 lbs/ac/year
61
What is the equation for NUE?
Nitrogen Use Efficiency (NUE) = (Yield with N – Yield no N)/(N Fertilizer)
62
N2O is released naturally from soils through nitrification and denitrification reactions. Increasing mineral N in soils increases the amount of N available for nitrification and denitrification, and ultimately N2O emission. Mineral N is increased either directly or indirectly.
True
63
What are some examples of Permanent soil qualifications?
1) Soil depth
2) Slope
3) Climate
4) Restrictive Layers
5) Texture
6) Stoniness
7) Mineralogy
64
Name 3 items that the 4Rs influence many performance indicators.
1. Social, economic, and environmental performance
2. Influenced by crop and soil management as well
3. Whole system outcomes
65
Lime applications guided by soil testing and plant requirement are essential for maximum returns from fertilizer. Net returns from liming are high when applied where needed, where returns vary with lime rate, lime cost, yield response to liming, and crop price. In spite of a high return, lime is often neglected in the fertility program because (1) responses to lime are often not as visual as those obtained with N, P, or K unless the soil is particularly acidic and (2) liming effects last for 5–7 years and returns are not all realized the first year.
True
66
Name 5 reasons why plant analyses are performed.
1. verify the accuracy of an assessment of visual deficiency symptoms
2. identify plant nutrient shortages before they appear as symptoms
3. help in determining the relative nutrient‐supplying capacity of the soil
4. quantify the effect of nutrient addition on nutrient concentration in the plant
5. study the relationship between plant nutrient status and crop performance (i.e., yield)
67
Beneficial effects of manure use:
- Source of plant-available nutrients
- Increased soil OM, CEC, and buffer capacity
- Increased mobility and availability of P and micros due to OM complexation
- Increased soil H2O and nutrient holding capacity
- Improved soil structure, decreased bulk density, and increased infiltration
- Increased soil pH and reduce Al3+ toxicity in acid soils
True
68
Soil quality, also referred to as soil health, is defined as how well soil does what we want it to do. Healthy soil gives us clean air and water, bountiful crops and forests, productive grazing lands, diverse wildlife, and beautiful landscapes.
True
69
4R Nutrient Stewardship utilizes fertilizer best management practices (BMP) addressing the right fertilizer source, at the right rate, at the right time, and in the right place.
True
False
True
70
What are six benefits from crop rotations when primarily used to soil increase crop productivity and
enhance soil health?
1) reducing wind and water erosion of topsoil
2) maintaining or increasing OM
3) increasing soil N supply with legumes in the rotation
4) utilizing residual nutrients applied in previous crop
5) improving soil structure, water infiltration, and nutrient redistribution
6) reducing weed, insect, and disease pest pressure
71
While agriculture is not a major contributor to CO2 emission, it is not predominately involved in CO2 sequestration. Agricultural soil and crop management contribute to greenhouse gas emissions through numerous processes, where CH4 and N2O are the major sources. CH4 and N2O emissions have increased only slightly over the last two decades.
True
72
What are some examples of Intermediate soil qualifications?
1) Aggregation
2) Microbial biomass
3) Respiration-24-hr burst
4) Microbial diversity index
5) Faunal diversity index
6) Active C
7) Organic matter content
73
Name 4 advantages of fertigation.
1. Uniform nutrient/H2O distribution in the root zone
2. Optimizes nutrient application timing with respect to crop demand
3. Reduces nutrient application costs
4. Reduces nutrient application rates
74
Soil quality is an elusive concept and it can not be measured using field and lab parameters.
True
False
False
75
Cell Sap Tests - Semiquantitative estimates of plant N, P, and K can be rapidly obtained with simple plant tissue tests conducted in the field. Plant leaves or stems are chopped up and extracted with reagents specific to each nutrient. Plant tissue can also be squeezed with a garlic press to transfer plant sap to filter paper and color‐developing reagents are then added. The color intensity of the cell sap/reagent mix is compared with a standard chart that indicates very low, low, medium, or high nutrient content.
True
76
10 g of NH4NO3 (34% N) is added to 3000 g of greenhouse soil with no N. Calculate the following
per 3000 g of soil AND lb per acre (assume 1acre = 2 million lb).
a. mg NH4NO3 added
b. mg N added
c. ppm N added
d. ppm NO3 added
e. ppm NH4 added
f. % N in soil after adding N
g. lb N/ afs added
a. mg NH4NO3/3000 g soil = 10 g NH4NO3/3000 g soil x (1000mg/1g) = 10000 mg NH4NO3/3000 g soil
mg NH4NO3/lb per acre = 10 g NH4NO3/3000 g soil = 10 lb NH4NO3/3000 lb soil x (100/3000)/(100/3000) = (1000/3000) lb NH4NO3/100 lb soil = (1000/3000) lb NH4NO3 x 20000 = 6666 lb NH4NO3/acre
b. mg N/3000 g soil = 10000 mg NH4NO3/3000 g soil x 0.34 = 3400 mg N/3000 g soil
mg N/lb per acre = 6666 lb NH4NO3/acre x 0.35 = 2266 lb N/acre
c. ppm N = 2266 lb N/acre / 2 = 1133 ppm N
d. ppm NO3 = 1133 ppm N x (62/28) = 2508 ppm NO3
e. ppm NH4 = 1133 ppm N x (18/28) = 750 ppm NH4
f. %N = 1133 ppm N/10,000 = 0.1133%
g. lb N/acre = 6666 lb NH4NO3 / acre x 0.34 = 2266 lb N/acre
77
Good soil fertility, nutrient availability, efficient plant use:
- Optimal soil pH
- Sufficient soil OM
- Porous soil structure
- Removal/neutralization of toxic elements
True
78
What does CNC stand for?
Critical Nutrient Concentration
79
Plants that are ___ nutrient deficient exhibit a visual deficiency symptom. Plants that are ___ deficient usually exhibit no visual symptoms although yield potential can be substantially reduced.
severely
moderately
80
What are 5 disadvantages of foliar applications?
1. Absorption time can be short (depending on nutrient & environmental conditions)
2. The quantity of macronutrients absorbed is relatively small
3. Compatibility with pesticides is variable
4. Solution concentration is generally small (several applications)
5. Time of day, weather conditions, and plant growth stage influences nutrient absorption
81
A homeowner applies ten-40 lb bags of N fertilizer (10-0-0) to a 2000 ft2 fescue lawn.
(a) Calculate the rate of N applied per acre.
(b) In your opinion, indicate whether this is a normal, high, or low N rate. (Hint = area of acre = 43,560 ft2; 1 gal UAN = 10.6 lb).
A)
Total weight = 10x40lbx0.10N = (40lbN/2000ft2) x (43,560 ft2/acre) = 871 lb N/Acre
B)
N application rate is high
82
What are 4 advantages of foliar applications?
1. High nutrient response if the plant is deficient
2. Micronutrients can meet much of the plant’s need
3. Can be combined with foliar applications
4. With the tree, crops are the most efficient means of correcting a deficiency
83
\_\_\_ ___ \_\_\_ \_\_\_:distributing nutrients based on spatial variation in yield potential, soil test levels, and other spatially variable factors that influence soil nutrient availability and crop nutrient demand
Site-Specific Nutrient management
84
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ represents the yield level where the last unit of input pays for itself and is less than maximum yield.
potential maximum yield
Potential maximum economic yield
Economic optimum N rate yield
Maximum water use efficiency yield
Potential maximum economic yield
85
What are the 4 items that the 4R's must consider?
1. $
2. Environmental Impact
3. Social Impact
4. Fertilizer Supply
86
The optimum plant health and productivity of a cropping system depends on an adequate supply of plant nutrients. What are the five items that plants rely on for the quantity of nutrients required?
1. Plant species and variety
2. Yield potential
3. Soil properties
4. Environment
5. Management
87
What is the equation for NDVI
NDVI = (NIR-PAR)/(NIR+PAR)
88
Which of the following soil nutrients is most immobile in soil and is most advantageous when placed near the roots?
N
P
K
B
P
89
Time of day will factor into the concentration of application
True
90
A golf green manager applied N to each green at 75 lb N/a. Each green is 600 ft2. Calculate the following:
a. lb N / green
b. lb UAN / green (use 28% N for UAN)
c. gal UAN / green
a. lb N / green
= (75 lb N/a) x (600 ft2/green) x (1 acre/43560 ft2) = 1.03 lb N/green
b. lb UAN / green (use 28% N for UAN)
= 1.03 lb N/green x (1/0.28) = 3.68 lb UAN / green
c. gal UAN / green
= 3.68 lb UAN / green x (1gal/10.6lb) = 0.34 gal/green
91
Total analysis is performed on specific plant parts (e.g., petioles, stems, leaves) in a laboratory. After sampling, plant material is dried, ground, and nutrient content determined following wet digestion with concentrated acid or dry ashing in a high‐temperature oven. As in tissue tests, the plant part selected is important, with the most recently matured leaf preferred. Samples should be kept dry or refrigerated and protected from contamination.
True
92
What is the equation for NSI?
NSI = Average reading from unknown samples/average meter reading reference
93
Soil erosion represents the greatest threat to sustained soil productivity.
True
94
Knowing the relationship between ___ \_\_\_ and ___ \_\_\_ ___ is essential for providing an accurate nutrient recommendation.
test results
crop nutrient response
95
Understanding ___ \_\_\_ in the plant is important to accurately identify a specific nutrient‐deficiency symptom.
nutrient mobility
96
Increasing Ca supply affects the absorption of Mn, Fe, and Zn. Why?
It enhances the oxidizing ability of roots, decreasing Mn, Fe, and Zn solubility.
It enhances the reducing ability of roots, increasing Mn, Fe, and Zn solubility.
It enhances the oxidizing ability of roots, increasing Mn, Fe, and Zn solubility.
It enhances the reducing ability of roots, decreasing Mn, Fe, and Zn solubility.
It enhances the oxidizing ability of roots, decreasing Mn, Fe, and Zn solubility.
97
What are three recommendations for grid sampling?
1. A grid is superimposed on the field. The common grid size is 2 acres or approximately 300 feet aside.
2. At each intersection of grid lines, 5 to 10 soil cores are taken within a 10-foot circle
3. Cores are composited to make up the sample for that point.
98
Cover crops are planted after crop harvest to protect the surface soil from erosion during the non-crop periods. These crops may be a nonlegume, a legume, or a mixture of the two. If the cover crop is incorporated
into the soil with tillage prior to planting the primary crop in the rotation, it becomes a green manure crop.
Green Manure Crops
99
Adoption of the best management practices (BMPs) should increase yield/quality, increase profitability, maintain or improve soil fertility, and avoid damage to the environment.
True
100
According to, "Basis for Soil Test in Alabama" in Table 3, there are ________________ levels for P and K ratings, respectively.
3 and 3
3 and 2
1 and 3
2 and 3
2 and 3
101
Surface- and Groundwater Quality
Nutrients and sediments from agriculture commonly impair inland surface waters. Organic compounds, metals, and nitrates are the primary contaminants of groundwater. The nutrients of primary environmental concern in agriculture are N and P.
True
102
In turfgrass production, the application of which of the following elements improves winter hardness in northern climates and is also beneficial in southern climates.
K
S
N
P
K
103
Many interrelated physical, biological, and chemical properties determine the health of soil. Most of these properties are relatively easy to measure and should be periodically assessed to guide soil and crop management decisions that can sustain crop productivity
True
104
Tap root systems have ___ volume, density and length.
less
105
You want to apply a 3% FeSO4 solution (weight basis) to peach trees. Calculate the amount of FeSO4 needed to make 1000 gallons of the solution (water = 62.4 lb/gal).
1000 gal\* (62.4 lb/gal) \*(3%) = 1872 lb FeSO4
106
When soil test interpretations differ among regions and crops, the P concentration extracted also varies between tests.
True
107
Fibrous root systems have ___ volume, density and length.
more
108
\_\_\_ ___ broadly refers to tillage system that leave 30% of the soil surface covered with residue after planting.
Conservation tillage
109
Nutrient‐deficiency symptoms appearing during ___ \_\_\_ may disappear as the growing season progresses, or there may be no measurable yield benefit.
early growth
110
What are some examples of Ephemeral soil qualifications?
1) Water content
2) Field Soil respiration
3) pH
4) Mineral N
5) Available K
6) Available P
7) Bulk Density
111
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ represents crop yield per unit of water used from soil, precipitation, and irrigation
PUE
KUE
WUE
NUE
WUE
112
Narrow field strip tests where selected nutrient treatments have been applied can help verify the accuracy of nutrient recommendations. The test results must be interpreted with caution if they are un-replicated. Replication of strip tests on several farms is also helpful
True
113
Which of the following is the cheapest buy per ton of fertilizer material?
0-12-0 at $300.00
0-47-0 at $675.00
0-30-0 at $650.00
13-0-44 at $550.00
0-47-0 at $675.00
0-12-0 @ $300
2000 x 0.12 = $240 lb therefore $300/240lb = $1.25$/lb
0-47-00 @ $675
2000 x 0.47 = $940 lb therefore $675/940lb = 0.72c/lb
0-30-0 @ $650
2000 x 0.30 = $600 lb therefore $650/600 = $1.08/lb
114
Telemetry of data farm machinery to cloud-based systems integrated with machine learning algorithms using open-source software. An example of Ag is the growth of QGIS, R and Phyton.
True
115
\_\_\_ ___ \_\_\_: With immobile nutrients, crop yield potential is limited by the number of nutrients available at the soil‐root interface. Generally, solution concentrations of immobile nutrients are low, and replenishment occurs through exchange, mineralization, and mineral solubility reactions.
Immobile Nutrient Recommendations
116
What is necrosis?
Death of leaf tips, margins, or interveinal regions of leaves
117
Name six benefits of conservation tillage practices.
1) Prevent erosion
2) Increase soil organic matter
3) Reduce or eliminate traffic pans
4) Improve water infiltration and soil moisture-holding capacity
5) Increase yields
6) IMPROVE SOIL QUALITY!!
118
Profile NO3-N is determined prior to planting. The laboratory reported the following data. How many lb N/ac-4 ft are present in the profile? If the sample were combined into one 4 ft sample calculate the ppm N. (Hint use an average weight of 2 million lbs for 6” and 4 million for 1 ft depths.)
Soil Depth ppm NO3-N
0–6 inches 3.5
6–12 inches 4.0
1–2 feet 3.0
2–3 feet 1.5
3–4 feet 1.0
Soil Depth ppm NO3-N lb N/ac-4ft
0–6 inches 3.5 7
6–12 inches 4.0 8
1–2 feet 3.0 12
2–3 feet 1.5 6
3–4 feet 1.0 4
ppm N = (3.5\*0.5)/4 + (4\*0.5)/4 + (3\*1)/4 + (1.5\*1)/4 + (1\*1)/4 = 2.31 ppm
119
Mechanization led to increased farm size and the large‐scale use of synthetic N fertilizers increased crop yields. What are three factors that contributed?
1. Nutrient removal increased with higher yields
2. Soil reserves of plant nutrients, particularly P and K, began to be depleted
3. Resulting in nutrient deficiencies and lower yields
120
Name three factors that help with improving soil
health can have a large influence on profitability.
1) increasing plant vigor and yield
2) reducing risk of yield loss stress (e.g., drought, pests pressure)
3) reducing input costs (e.g., less tillage, fertilizer, and pesticides use)
121
Application of nutrients to correct nutrient stress identified with a tissue test may not be feasible. List the 4 reasons why?
1. the deficiency may have already caused yield loss
2. the crop may not respond to the applied nutrient at the specific growth stage tested
3. the crop may be too large to apply nutrients
4. climatic conditions may be unfavorable for fertilization
122
Soil H2O supply influences nutrient availability and use, while nutrient supply can influence H2O use.
True
123
Which of the following is a disadvantage of conservation tillage system?
decrease soil temperature in spring
increased acreage of sloping land
decreased potential for rodents, insects, and diseases
decreased management ability to handle the system
decrease soil temperature in spring
124
Name 4 techniques are commonly employed to assess the
nutrient status of a soil.
1. nutrient‐deficiency symptoms of plants
2. tissue analysis of plants growing on the soil
3. remote sensing
4. soil analysis
125
What 6 variables are typically reported on a soil test?
pH, P, K, Ca, Mg (lbs/A)
126
Corn:
- Update Order: N\>K\>Ca\>P\>Mg\>S
- N and P redistribution from leaves into grains, while K redistribution from the stem into grains
- Ac Rt: accumulation rate at V10-V14 and % of accumulation by R1
- Don’t delay Nitrogen because it’s needed for plant growth and development, best time is an apply starter and up to V6
True
127
Name three unique conservation tillage methods that
require specialized equipment
1) no-tillage—all crop residue left on soil surface
2) strip-tillage—a narrow strip tilled before or at planting
3) ridge-tillage—a single-pass tillage planting operation
128
The following fertilizers are available to a fertilizer dealer. 18-46-0; 46-0-0; 0-0-60; 10-34-0; 28-0-0. Determine how much of the appropriate fertilizer materials and water are required for 1000 gallons of 5-5-5 liquid fertilizer. (Assume 10 lb/gal density for all liquid fertilizers; solubility of KCl in water is 3 lbs KCl/gallon). (Hint: 1000 gallons fertilizer (10 lb/gal) = 10,000 lb fertilizer.)
Step 1)
Use 10-34-0
P2O5(lb) = 10,000 \* 0.05 = 500 lbs/0.34 = 1470 lb / 10 lb/gal = 147 gal of 10-34-0
Nitrogen Content = 147-gal x 10 lb/gal x 0.1 = 147 lb (This will be credited in the nitrogen fertilizer below)
Step 2)
Use 28-0-0
N(lb) = 10,000 \* 0.05 = 500 lbs – 147 lb N = 353 lb N/0.28 = 1261 lb /10lb/gal = 126.1 gal of 28-0-0
Step 3)
Use 0-0-60
K2O(lb) = 10,000 \* 0.05 = 500 lbs / 0.60 = 833 lb / 3lb/gal = 278 gal of 0-0-60
Total = 147+126.1+278 = 551.1 gal of fertilizer which means that 448.9-gal of H2O is needed for a total of 1000 gallons.
129
The function Y = 90 + 0.6X - 0.0025X2 describes the crop response to fertilizer N.
a. Calculate the N rate for maximum yield. (dY/dX) = 0.6 – (2\*0.0025X)
b. Calculate the N rate for maximum profit ($2.50/bu; $0.24/lb N). (Use dY/dX =$0.24/lb N/$2.5/bu)
c. Grain price drops 20% and fertilizer cost increases 20%. Calculate N rate for maximum profit. (Use dY/dX =$0.288/lb N/$2.0/bu)
a. Calculate the N rate for maximum yield. (dY/dX) = 0.6 – (2\*0.0025X)
dY/dX = 0.6 – 0.005X
0 = 0.6 – 0.005X
X = 120 lb N (Fertilizer N when Maximum Yield Occurs)
Therefore
Y = 90 + 0.6(120) – 0.0025(120)2 = $126/bu Maximum Yield
b. Calculate the N rate for maximum profit ($2.50/bu; $0.24/lb N). (Use dY/dX =$0.24//lb N/$2.5/bu)
```
(0.24/2.5) = 0.6 – 0.005X
X = 100 lb N
```
c. Grain price drops 20% and fertilizer cost increases 20%. Calculate N rate for maximum profit.
(Use dY/dX =$0.288//lb N/$2.0/bu)
```
(0.288/2.0) = 0.6 – 0.005X
X = 91.2 lb N
```
130
SERA-6 (https://aesl.ces.uga.edu/sera6/ (Links to an external site.)), Southern Extension and Research Activities Information Exchange Group 6 publishes P critical concentration values (see also Soil Test Methods for Southeastern US, Table 1). Since AL, GA, and SC use Mehlich 1 extractant, they all have the same ratings for P.
True
False
False
131
What is new growth cessation?
Death of new shoots, terminal/axillary buds, or flowers; new leaves die back or exhibit resetting
132
A nutrient management plan is being developed for an agricultural field. In order to attain increased plant productivity (yield and quality) and profitability, which of the following should not be implemented?
applying mobile nutrients just after the maximum uptake or growth period.
Recognizing specific plants with high requirements for certain nutrients.
Estimating nutrient needs through realistic yield expectations.
Reviewing plant analysis information for areas with nutrient levels below or above their range
applying mobile nutrients just after the maximum uptake or growth period.
133
\_\_\_ \_\_\_: Soil test interpretation for purposes of making nutrient recommendations is influenced by the mobility of the nutrient.
Nutrient Mobility
134
Which of the following is an effect of increased soil tillage on plants?
Increased soil tillage reduces seed germination.
Increased soil tillage reduces seed placement into moist soil.
Increased soil tillage increases compaction.
Increased soil tillage can enhance root growth.
Increased soil tillage increases compaction.
135
Nutrient‐deficiency symptoms appear when the nutrient supply is so ___ that the plant cannot function properly.
low
136
Name the 5 nutrient‐deficiency symptoms that plants are characterized by.
1. Chlorosis
2. Nerosis
3. Reddening
4. Stunting
5. New growth cessation
137
What is reddening?
Accumulation of anthocyanins causes red or purple color on leaf margins, interveinal regions, or whole leaves
138
Which of the following is NOT true of the effects of soil OM on plants and soil?
increase in soil CEC
increase in soil compaction
increase in soil aggregation
modification of pesticide activity
increase in soil compaction
139
Plant analysis methods include tests on fresh tissue in the field and analyses performed in a laboratory.
True
140
Extraction with hot water is the most common soil test for B. Critical levels for most crops are \< 0.5 ppm B. When hot water‐extractable B is \> 4–5 ppm, B toxicity can occur. Like NO3‐, Cl‐ is soluble, so extraction with water is used. Soil samples should be taken to at least a 2 ft depth. The critical water-extractable Cl‐ level is 7–8 ppm for most crops. No reliable Mo soil test has been developed, although both water and NH4‐ oxalate extracts have been used. Fortunately, Mo deficiency is uncommon in the United States.
True
