ENVS 286S: Research Proposal on Cover Crops and Soil Quality

This research proposal, developed for ENVS 286S, investigates the impact of barley, vetch, and fallow cover crops on soil quality. The methodology involves collecting soil samples from farms, measuring soil pH, organic carbon, cation exchange capacity (CEC), and soil infiltration. Data will be analyzed using regression analysis to determine the correlation between cover crop type and soil properties. The study aims to provide insights into which cover crops are most effective in enhancing soil health, with the expectation that different cover crops will yield varying results. The proposal details the experimental design, data collection methods, and statistical analysis to ensure the validity and reliability of the findings, including mock graphs illustrating expected outcomes.

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Kayla Lowisz
ENVS 286S 001
22 October 2018
Research Proposal 2nd Draft
Research Question: What cover crops work best in enhancing soil quality?
Methodology
Cover crops are grown to provide ground cover. In addition, they usually offer green
manure between crops and can also be sold for cash (Snapp 322-332). This study will focus on
barley, vetch and fallow cover crops. In this study, I will use various data collection methods
such as primary and secondary sources. The data to be collected will be from barley, vetch and
fallow planted in different areas of the farm. The cover crops will be planted in different parts of
the farm and soil from that particular region will be collected for analysis. The study will involve
the use of information from various recorded sources and obtaining data from 3 selected farms
which grow cover crops. Samples of the soil to be tested will be obtained through the random
sampling procedure, meaning other measures will not be considered when choosing what soil I
conduct my experiment on. I will simply pick the area at random. A primary data collection to
assess soil quality will be done by measuring soil pH, organic carbon, cation exchange capacity
(CEC), and soil infiltration.
The independent variable for this research will be the different types of cover crops
which will be planted while the dependent variable will be the soil. I will work with the
proposition that different cover crops have different abilities to enhance soil quality. As such, it

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is expected that the results obtained on soil quality will be different for different cover crops. To
ensure that the data obtained is free from bias, all the soil samples will be collected at the same
time and the cover crops planted will be allowed to grow to the same age.
Soil pH controls bioavailability of nutrients and pollutants. Plants cannot grow in very
acidic soils (pH below 5). Carbon and oxygen absorbed from the air and nitrogen compounds are
the source of plant nutrients. Organic carbon provides food for soil microbes, stabilizes soil
structure, increases water holding capacity, reduces run-off and erosion, and absorbs
contaminants (Dabney, Delgado & Reeves 1221-1250). Cation exchange capacity (CEC) is a
measure of the soil’s ability to hold positively charged ions. This property is extremely important
in influencing soil structure stability, nutrient availability, soil pH, and the soil’s reactions to
fertilizers. Infiltration is the process of water soaking into the soil. Water infiltration is the rate or
amount of water that enters the soil. Infiltration works as a reservoir that stores water for plant
growth. It carries nutrients and organic matter. Any water that does not infiltrate into the soil is
lost from a field as runoff or evaporation. Managing both water infiltration and plant available
water will be key to keeping fields productive, mitigating drought and floods, and reducing soil
loss due to water erosion.
Soil pH will be determined by measuring the concentration of hydrogen ions in soil when
in contact with water. I will mix soil and water in a 1:1 ratio. Dissolving minerals in the soil will
cause chemical reactions and proton exchanges. I will then use a pH probe and pH test kits/strips
to determine the actual pH of the soil. The soil organic carbon will be determined by using the
oxidation method with potassium chromate. This will help me to decide which cover crop
enhances the highest level of oxidation in the soil. CEC will be determined by measuring the
amount of cations that can be absorbed or exchangeable on the negative charge sites of the soil. I

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will first need to prepare a reagent and standard solutions. The solutions prepared for this part are
solutions using barium, lanthanum, cesium and standard solutions. The solutions must then be
extracted. They will receive a centrifugal procedure to increase application of dynamic forces
over the different elements of the solution. The cation concentrations will then be analyzed using
an AAS or ICM-MS.
Soil infiltration will be measured directly in the field by making a small ring of about
0.15 m in diameter. The standing vegetation will be cut off at the ground level. The litter will
then be removed from the surface before the rings are placed and measurements taken. This
process will be done for all the cover crops.
Details of Samples
This project focusses on experimenting three cover crops comprising Barley, Vetch and
Fallow. I will obtain the three samples from the farm selected by random sampling. The farm
from which the samples will be selected must meet the following conditions:
 Must be growing cover crops.
 The crops must have been grown on a period of 40 to 60 days to ensure maturity thus the
accuracy of the results.
I have chosen to collect samples in the period of spring since it’s the time when many farms
grow cover crops and the crops thrive the most. I will collect one soil sample from each cover
crop type on the farm (Wilson & Okigbo 233-250).
Search and Selection Procedure

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The research will be conducted by use of both online and search collection approach. The
search procedure will be based on the main topic and keywords of the study aim. It will also
involve the identification of the relevance of the paper to the study. The internet will be used as a
source of information although most of the work will be done on the field. I will record what is
obtained from the field and the internet will be only used for the explanation of technical terms.
To ensure that relevant and credible information is obtained, I will depend on peer-reviewed
sources and trusted websites.
Analysis
Data analysis is the systematic examination of data for the purpose of exploring theories,
solving operational problems and supporting decisions. The data collected during the research
will be classified in terms of the texture or water holding capacity (infiltration), cation exchange
capacity (CEC) as a measure of soil fertility and surface percentage of organic carbon. The data
will be analyzed using regression where the independent variables will be the different types of
cover crops and the dependent variables the measured soil properties. Graphs will be drawn to
show which cover crop gives the best soil quality. The table in which data will be filled will look
like this:
Soil PH Organic Carbon CEC Infiltration
Barley
Vetch
Fallow

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Mock Graphs
Measurement of Soil Carbon (Graph 1)
http://mycradock.co.za/04/sustainability-in-pasture-based-dairy-farming/
Graph 1 shows the statistically significant relationship between nitrogen and soil quality. The
points closest to the line indicate a strong correlation, whereas, points further away from the line
indicate weak correlation. I will develop similar graphs for the other measurements used in this
study.
Measurement of Soil Infiltration (Figure 1)

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http://www.fao.org/docrep/T0231E/t0231e05.htm
Infiltration rate is the rate at which water enters the soil at the surface. This is calculated with the
formula: F(t)= dF (t)
dt . Cumulative infiltration is the accumulated depth of water in filtering
during a given time period. I will calculate this with the formula: F ( t ) = ∫ f0
t
( τ ) dτ . “Typical
curves of infiltration rate, I, and cumulative infiltration, Z, are shown in Figure 1. Irrigation of
initially dry soil exhibits an infiltration rate with a high initial value which decreases with time
until it becomes fairly steady, which is termed the 'basic infiltration rate'.”
Regression on Project Variables
Consistent mock regression
The graph shows the results of regressions with the soil quality properties as the dependent
variable and the crop type as the independent variable. The graph is consistent with the expected
results after project completion.

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Inconsistent mock regression
The graph shows the results of regressions with the soil quality properties as the dependent variable and
the crop type as the independent variable. The graph is inconsistent with the expected results after
project completion.

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References
Snapp, S. S., et al. "Evaluating cover crops for benefits, costs and performance within cropping
system niches." Agronomy journal 97.1 (2008): 322-332.
Dabney, S. M., J. A. Delgado, and D. W. Reeves. "Using winter cover crops to improve soil and
water quality." Communications in Soil Science and Plant Analysis 32.7-8 (2009): 1221-1250.
Wilson, G. F., R. Lal, and B. N. Okigbo. "Effects of cover crops on soil structure and on yield of
subsequent arable crops grown under strip tillage on an eroded Alfisol." Soil and Tillage
Research 2.3 (2012): 233-250.

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Professors Feedback:
Please copy my comments (see below, either at the bottom or in the rubric) to the 2nd draft along with a short note
about how you addressed them (or why it didn’t make sense to address them). Note that these points total to 8, so I
divide your total points by 2 because this assignment is worth 4 points.
Small note: pH BELOW 7 is acidic, so very acidic soil would have pH below 5 (made changes on the PH statement
on methods). And organic material is a source of nutrients for plants (saying "carbon" sounds wrong since plants get
their carbon from the atmosphere) (changed to “Carbon and oxygen absorbed from the air and nitrogen
compounds are the source of plant nutrients.”).
Title 0 – missing or far off
the mark
0.1 - describes
research only vaguely
or is needlessly long
0.25 - succinctly
describes research
Methods: how and what
data will be collected
0 – missing or
obviously deficient
discussion of what
data will be collected
or how it will be
collected
0.75 – not all data are
clearly described
and/or methods of data
collection risk bias
1.5 – clearly describes
the data that will be
collected, how it will be
collected (in detail), and
how that collection will
be free from bias
COMMENT: you have
gone into nice detail
about your
measurements
Methods: valid
experimental design (note,
it is hard to see how you
could get full credit on this
section without a crystal
clear description of the data
to be collected in the section
above)
0 – missing or
seriously deficient
description of
experimental design
COMMENT: this is
much better than the
first draft, but I still
don't have a clear idea
of what you would
actually do. Please go
into detail on some of
the things you write
about in the first
paragraph... just to get
you started, here are
some of my questions:
Will you plant the
cover crops or will
you observe
established cover
crops? If the latter,
how long will a plot
have to be planted to
cover crops for
consideration? How
many samples per
cover crop per farm?
What kinds of farms?
What time of year will
you sample? ...and so
on. Actually envision
1.0 – poor description
of valid experimental
design or flawed
experimental design
2.0 – clear and complete
description of valid
experimental design
with consideration of
sampling units,
replicates, independent
and dependent
variables, etc.

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doing the experiment
and write down all of
the things you would
need to think about.
(Added all details
under the title details
of samples)
Analysis: statistics 0 – missing, seriously
deficient, or
inappropriate
description of statistics
to be used
COMMENT: you
write "regression" but
I thought the
treatments were
different cover crop
types? The items you
mention in the analysis
section are different
from the ones you
mention at the end of
the first
paragraph. (Made the
information on
measurements uniform
from the methods to
the analysis.
Elaborated more on
how regression will be
performed)
0.75 – statistics are
poorly described
and/or at least partially
inappropriate and/or
insufficient to address
the question/
hypothesis
1.5 – all statistics
clearly described,
appropriate, and
sufficient to address the
question/ hypothesis
Analysis: mock graphs 0 – missing or
seriously deficient
mock graphs
1.0 – at least some
mock graphs do not
contain both versions
(support/ no support),
at least some mock
graphs are inconsistent
with proposed
statistics, and/or mock
graphs are insufficient
to address question/
hypothesis
COMMENT: You can
make up your own
graphs, no need to
grab them from the
literature. The graphs
you chose involve
variables you are not
going to measure
(NUE, intake
opportunity time).
Instead, make up
graphs that involve
your independent
2.0 – two versions of
each mock graph (one
that would support
question/ hypothesis
and one that wouldn’t),
mock graphs
complement proposed
statistics, all mock
graphs included to
sufficiently address
question/ hypothesis

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variable (cover crop
type???) and your
dependent variables.
To do support/no
support for your
research question,
"support" might show
that some cover crops
are better than others,
whereas "no support"
might show them all
performing the same.
(graphs drawn)
Writing 0 – confusing
organization, multiple
spelling errors, and/or
multiple grammatical
errors
0.25 – slightly
confusing
organization, handful
of spelling errors,
and/or handful of
grammatical errors
COMMENT: Vastly
improved but still
needs work. Please
take a look at my
writing tips sheet (in
Resources section of
Sakai) and,
importantly, read the
next draft OUT LOUD
to yourself. Reading
out loud is an easy
strategy to greatly
improve writing! (I
have enacted the
required changes on
spellings and sentence
construction based on
the tips sheet provided.
I read the draft out
loud to ensure I was
constructing sentences
appropriately)
0.75 – transparent
organization, perfect
spelling, perfect
grammar