lettuce response to biochar and fertilizer...biochar. • observe the differences in soil properties...
TRANSCRIPT
Department of Chemical and Biological Engineering, Ames, IA BioMaP REU Program
July 2012
Jerson Valenzuela, Bernardo del Campo, Robert C. Brown
Acknowledgements: This material is based upon work supported by the National Science Foundation under Grant No. EEC 0851519.
Lettuce Response to Biochar and Fertilizer
Introduction Biochar is a co-product of thermochemical conversion of biomass.
Studies have demonstrated its ability to reduce greenhouse gas
emissions by sequestering carbon and improve soil characteristics
such as water retention, pH CEC, etc. A test was conducted to
observe the effects of 2 different biochar soil mixtures on plant
growth.
Results
Some problems were encountered when starting this experiment. Volume
from the premixed samples of soil (Control) were lost from water added to
collect leachate, so sand was added to even the volume out. To prevent this
from happening on the non-premixed samples, we placed paper towel
underneath so there would be no loss of sample. Also, the plants which
were growing from the samples with fertilizer, in both the premixed and
non-premixed samples, died. Germinated seeds were added to observe their
growth, but were excluded from the collected measurements.
Conclusion
• Adding biochar to soil changes the chemical and physical properties of
the soil.
• High amendment rates could dramatically impact the pH level of the
soil and the availability of nutrients, special attention should be paid to
processing conditions and types of biochar applied. Premixed biochar
and soil look necessary for stabilization of the soil and better growth.
• 50% of biochar for this type of soil seemed too much. It increased pH
levels higher than they were desired. Smaller additions and longer
mixing times are strongly recommended
Methodology
Treatments were split in:
Soil only and Red Oak and Corn Stover Biochar mix (50% by weight).
Half of the plots were prepared, one week before planting and the other half
were prepared on the day of planting.
Half of those plots were fertilized with 1g of fertilizer (15-15-15) [Photo 2.]
Each combination of Biochar x preparation and Fertilization rate were done
in triplicates (appropriately randomized)
Water was applied Monday and Friday with 20 mL of water.
Leachate was collected at the beginning and at the end and the pH was
measured.
Objectives
• Study the differences between
plant growth in premixed soils,
and non-premixed soils with
biochar.
• Observe the differences in soil
properties
Ph
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2:
Tak
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Ph
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Tak
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Sample pH BpH
Control (Soil) 7.80 7.50
Soil + R.O. B.C. 50% 9.05 7.85
Soil + C.S. B.C. 50% 8.29 7.65
Table 1 shows the pH balance
of the soils prior to use. Note
the high levels of pH in the two
samples mixed with biochar.
Treatment C (%) N (%) OM (%)
BCRF Soil 3.5 0.1 6.5
Soil + R.O. BC 12.9 0.2 23.2
Soil + C.S. BC 13.5 0.3 24.2
Treatment NO3-N P Mehlich 3 K Mehlich 3
BCRF Soil 19 32 193
Soil + R.O. BC 8 15 210
Soil + C.S. BC 1 110 2621
Treatment N (%) NO3-N NH4-N
BCRF Soil 0.1 19.0 9.0
Soil + R.O. BC 0.2 8.0 1.0
Soil + C.S. BC 0.3 1.0 BDL
Tab
le 4
Tab
le 2
Tab
le 3
Table 2 shows the percentage of
Carbon, Nitrogen, and Organic
Matter the samples hold. Note the
increased amount of Carbon and
Organic Matter.
Table 3 shows the percentage
of NPK nutrients without
fertilizer.
Table 4 shows the
percentage of Nitrogen
within the samples.
Chart 1 shows the
pH levels from the
leachate collected
from each sample.
Note that in the
premixed samples,
the leachate
collected contained
more soil than that
of the non-
premixed.
Chart 2 shows the average heights of both the premixed and non-
premixed samples without fertilizer. Referring to the previous tables
shown, high pH levels can be found in the soils with biochar. The
Control samples were the soil samples, and had a small pH level
[Table 1]. The nutrients shown [Table 2, Table 3, and Table 4] affect
plant growth.