MODEL ROOF PROGRAM BIOCHAR RESEARCH Effect of Lignocellulosic Biochars on Plant Water Use Efficiency of Four Pitch Pine Scrub Oak taxa in Pot Trials in Waltham MA Jeff Licht, UMass Boston-Waltham, School of the Environment Chris Burns, UMass Amherst, Department of Resource Economics
Research Questions We Asked Previously 1. Does biochar-treated calcine clay respire C more slowly than an untreated version? (yes) 2. Does biochar treatment affect survival rates of pitch pine scrub oak taxa? (yes, in three out of four cases we examined) The focus of the current study is to characterize the effect of biochar on a key aspect of plant/water relations, namely water use efficiency (WUE) and atempt to partition soil and leaf contributions to WUE We identified several hypotheses related to this question
Hypotheses 1. 2. 3. 4. Hθ1: there is no significant difference between the δ13cleaf signatures of PPSO taxa grown in calcined clay, calcined clay with biochar, or indigenous soil Hθ2: there is no significant difference between the δ13csoil signatures of calcined clay, calcined clay with biochar or indigenous soil Hθ3: there is no significant difference in instantaneous leaf water use efficiency (WUE) as determined by (LiCor II PPS) µmol CO2/mol H2O of PPSO taxa grown in calcined clay, calcined clay with biochar or indigenous soil Hθ4: there is no significant difference in intrinsic leaf water use efficiency (WUE) as measured by the δ13cleaf signatures of PPSO taxa grown in calcined clay, calcined clay with biochar or indigenous soil
The Study
Study Method We conducted a pot study using six iterations of taxa planted in one of three media in Waltham MA coupled with the same taxa growing in indigenous soil in a pitch pine scrub oak community in Plymouth MA. There were a total of 24 pot subjects for each specie plus iterations of the same species in the wild
Study Taxa Baptisia tinctoria Lupinus perennis Vaccinium angustifolium Quercus ilicifolia These species are rapidly disappearing from their habitats in MA and are already extirpated or endangered in ME, NH and VT. One of our side interests was the possibility of using biochar to promote re-establishment of species subject to the effects of summer drought.
Study Biochars Red oak The Beacon NWLB L-M
Study Media Calcined clay/char* Calcined clay PPSO indigenous soil Calcined clay/biochar = 10% concentration of either red oak or L-M*
Steps for testing hypotheses about WUEleaf 1. post-photosynthate (instantaneous) WUE data 2. stable isotope δ13c (intrinsic) WUE data 3. compare the two WUE data 4. compare WUE data with soil δ13c data WUE data is harvested either as instantaneous occuring at the time measurements are taken or Intrinsic which represent long term C sequestration
WUEleaf instantaneous
WUELEAF (mol CO2/mol H20) 2010 WUEleaf performed by portable photosynthesis has been defined (e.g., Farquhar 1981) as photosynthesis/transpiration or A/E. In 2010, Bergweiler and Licht conducted CIRAS-2 portable photosynthesis analysis including one PPSO specie grown in a calcined clay-recycled leaf medium. Readings were taken during presenesence (late August) similar to LicCor measurements in 2012 in Waltham and Plymouth.
STEP ONE WUELEAF (mol CO2/mol H20) 2012 Instantaneous We looked at WUE through the lens of biochar. To the lef are examples of PPSO Pn and Tr graphs. These represent photosynthesis of plants in three experimental soils and indigenous soil. These are converted through an A/E formula (photosynthesis/transpiration) to determine WUEleaf. This is an instantaneous measurement method.
All Plant Leaves WUELEAF (mol CO2/mol H20) 2012 Mean WUE Calcine Baptisia tinctoria Calcine Quercus illicifolia Calcine Lupinus perennis Calcine Vaccinium angustifolium 3.141 1.917 4.217 1.552 Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oakvaccinium angustifolium 1.105 1.835 3.990 1.590 Licht-McLaughlin Baptisia tinctoria Licht-McLaughlin Quercus illicifolia Licht-McLaughlin Lupinus perennis Licht-McLaughlin Vaccinium angustifolium 1.347 2.448 2.101 0.990 PPSO Baptisia tinctoria PPSO Quercus illicifolia PPSO Lupinus perennis PPSO Vaccinium angustifolium 9/20/2012 9/20/2012 9/20/2012 9/20/2012 1.378 1.711 1.527 0.842 Sample ID Data gathered in Waltham and Plymouth MA on four occasions in August and September 2012. The results were mixed: Unsurprisingly, sandier Plymouth soil is subject to lower water holding capacity which translated into lower WUE
WUEleaf intrinsic
All Plant Leaves WUELEAF (δ13c) 2012 Intrinsic This method requires harvesting leaf samples in the field, grinding in a mill, weighing 2 mg samples and packing in tin capsules. These were inserted into a continuous flow isotope ratio mass spectrometer and combusted using an elemental analyzer at the EAF Laboratory at UMB. δ13c/ δ12c (carbon) signatures are compared with a -8 o/oo VDPB standard of atmospheric C to measure abundance or depletion of C relative to VDPB. Note: harvesting occurred at the same time as the IRGA measurements
STEP TWO The results obtained from these tests were as follows: Sample ID Calcined clay All species Red Oak Biochar (10%)/Calcined clay (90%) all species Licht-McLaughlin (10%)/Calcined clay (90%) all species PPSO all species δ13c 10/5/2012 10/5/2012 10/5/2012 10/5/2012-29.18-26.63-28.87-27.70 In graph one above, red oak char/calcined clay was found to affect physiological response with regards to less C depletion for all species. In Graph 2 we find δ13c data are interpreted as intrinsic WUEleaf (e.g., Farquhar et al, 1979; Ehleringer et al, 2000; McCarthy et al, 2012). least depletion to VDBD (-8o/oo) δ13c Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oak Vaccinium angustifolium 10/5/2012 10/5/2012 10/5/2012 10/5/2012-26.55-26.41-25.92-26.30
Let s compare results to this point: Mean WUE Sample ID Calcine Baptisia tinctoria Calcine Quercus illicifolia Calcine Lupinus perennis Calcine Vaccinium angustifolium 3.141 1.917 4.217 1.552 Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oakvaccinium angustifolium Licht-McLaughlin Baptisia tinctoria Licht-McLaughlin Quercus illicifolia Licht-McLaughlin Lupinus perennis Licht-McLaughlin Vaccinium angust. PPSO Baptisia tinctoria PPSO Quercus illicifolia PPSO Lupinus perennis PPSO Vaccinium angustifolium Sample ID INSTANTANEOUS Mean WUE Calcine Baptisia tinctoria Calcine Quercus illicifolia Calcine Lupinus perennis Calcine Vaccinium angustifolium -29.09-28.84-28.94-29.29 1.105 1.835 3.990 1.590 Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oakvaccinium angustifolium -26.55-26.41-25.92-26.30 1.347 2.448 2.101 0.990 Licht-McLaughlin Baptisia tinctoria Licht-McLaughlin Quercus illicifolia Licht-McLaughlin Lupinus perennis Licht-McLaughlin Vaccinium angust. -27.27-28.98-28.94-30.29 9/20/2012 9/20/2012 9/20/2012 9/20/2012 1.378 1.711 1.527 0.842 PPSO Baptisia tinctoria PPSO Quercus illicifolia PPSO Lupinus perennis PPSO Vaccinium angustifolium -28.63-28.20-26.18-27.09 INTRINSIC
STEP THREE Waltham and Plymouth PPSO soil δ13c 2012 Sample ID Calcined clay (no treatment) Red oak biochar/calcined clay Licht-McLaughlin/calcined clay PPSO (no treatment) δ13c -19.18-24.85-28.23-28.82 We also performed a stable isotope analysis of soil C status as a function of soil δ13c signatures. Previously (in 2011) we found -18.3 δ13c for expanded shale, a close cousin of the calcined clay (-19.18). Subsequent re-testing of red oak and Licht-McLaughlin δ13c signatures In 2013 yielded similar values to the original data.
STEP FOUR The results of a 3-way comparison of two WUE and soil was interesting in several ways. On the next screen we find a short summary. Sample ID INSTANTANEOUS Calcine Baptisia tinctoria Calcine Lupinus perennis Red oak Vaccinium angustifolium Licht-McLaughlin Quercus illicifolia Mean WUE Sample ID 3.141 4.217 1.590 2.448 Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oakvaccinium angustifolium Sample ID SOIL MEDIA Calcined clay (no treatment) Red oak biochar/calcined clay Licht-McLaughlin/calcined clay PPSO (no treatment) INTRINSIC δ13c -19.18-24.85-28.23-28.82 Mean WUE -26.55-26.41-25.92-26.30
SUMMARY OF COMPARISONS 1. biochar effects were not shown to persist throughout WUE comparisons 2. long term (intrinsic) WUE red oak biochar gains were seen across the taxa spectrum 3. pure engineered clay showed much less depletion than the two chars yet when engineered clay was diluted with a 10% char concentration two species Vaccinium and Quercus had a higher instantaneous WUE than the same species grown in the engineered clay. This is particularly interesting because both woody species display greater water holding capacity (root, leaf and stem biomass); we did not expect to see any significant differences between treatments (char versus clay versus indigenous). These differences were significant at P-value=<.01. 4.
Sample ID INSTANTANEOUS Calcine Baptisia tinctoria Calcine Lupinus perennis Red oak Vaccinium angustifolium Licht-McLaughlin Quercus illicifolia Mean WUE Sample ID 3.141 4.217 1.590 2.448 Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oakvaccinium angustifolium Sample ID SOIL MEDIA Calcined clay (no treatment) Red oak biochar/calcined clay Licht-McLaughlin/calcined clay PPSO (no treatment) 1. INTRINSIC δ13c -19.18-24.85-28.23-28.82 Mean WUE -26.55-26.41-25.92-26.30 biochar effects were not shown to persist throughout WUE comparisons as evidenced by the instantaneous WUE data above lef
Sample ID INSTANTANEOUS Calcine Baptisia tinctoria Calcine Lupinus perennis Red oak Vaccinium angustifolium Licht-McLaughlin Quercus illicifolia Mean WUE Sample ID 3.141 4.217 1.590 2.448 Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oakvaccinium angustifolium Sample ID SOIL MEDIA Calcined clay (no treatment) Red oak biochar/calcined clay Licht-McLaughlin/calcined clay PPSO (no treatment) INTRINSIC δ13c -19.18-24.85-28.23-28.82 Mean WUE -26.55-26.41-25.92-26.30 2. long term (intrinsic) WUE red oak biochar gains were seen across the taxa spectrum
Sample ID INSTANTANEOUS Calcine Baptisia tinctoria Calcine Lupinus perennis Red oak Vaccinium angustifolium Licht-McLaughlin Quercus illicifolia Mean WUE Sample ID 3.141 4.217 1.590 2.448 Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oakvaccinium angustifolium Sample ID SOIL MEDIA Calcined clay (no treatment) Red oak biochar/calcined clay Licht-McLaughlin/calcined clay PPSO (no treatment) INTRINSIC δ13c -19.18-24.85-28.23-28.82 Mean WUE -26.55-26.41-25.92-26.30 3. pure engineered clay showed much less depletion than the two chars
Mean WUE Calcine Baptisia tinctoria Calcine Quercus illicifolia Calcine Lupinus perennis Calcine Vaccinium angustifolium 3.141 1.917 4.217 1.552 Red oak Baptisia tinctoria Red oak Quercus illicifolia Red oak Lupinus perennis Red oakvaccinium angustifolium 1.105 1.835 3.990 1.590 Licht-McLaughlin Baptisia tinctoria Licht-McLaughlin Quercus illicifolia Licht-McLaughlin Lupinus perennis Licht-McLaughlin Vaccinium angust. 1.347 2.448 2.101 0.990 PPSO Baptisia tinctoria PPSO Quercus illicifolia PPSO Lupinus perennis PPSO Vaccinium angustifolium 9/20/2012 9/20/2012 9/20/2012 9/20/2012 1.378 1.711 1.527 0.842 Sample ID INSTANTANEOUS 4. yet when engineered clay was diluted with a 10% char concentration two species Vaccinium and Quercus had a higher instantaneous WUE than the same species grown in the engineered clay. This is particularly interesting because both woody species display greater water holding capacity (root, leaf and stem biomass); we did not expect to see any significant differences between treatments (char versus clay versus indigenous). These differences were significant at P-value=<.01.
SUMMARY (continued) 5. The most significant and difficult aspect of partitioning signatures is the setled science of soil δ13c as an artifact of plant δ13c. Twenty years of reports underscore the primacy of plants, specific leaves on the plant, along with precipitation, soil depth, soil nutrient and stomatal conductance to determine soil C abundance/depletion. Particularly in the case of PPSO, that group would have more abundant δ13c than nonstressed plants, according to accepted theory, growing in either the same or other media (given the same soil depth and precipitation levels). In other words their abundance reflects their phytohistoric adaptation to stress. Thus our results are problematic. We found PPSO WUEleaf --both mol CO2/mol H20 ( =1.3645) and δ13c ( =-28.82) had lower WUEleaf (IRGA) and were less abundant in situ (δ13c) than values for similarly sized taxa in controlled (Waltham soil) conditions. The differences were significant (P-value=<.01). We have not worked out an explanation for these findings but we offer some thoughts regarding effect of biochar on WUE which we believe has occurred.
POSSIBLE EXPLANATIONS FOR APPEARANCE OF CHANGE IN PLANT CHEMISTRY AND PHYSIOLOGY DUE TO BIOCHAR INPUTs Our first premise is: carbon isotope paterns in our plant leaves improved nutrition/water relations brought about by adding biochar. We have not performed the chemistry required to make that a firm statement but evidence of water relation changes exists. Second, although there may be no direct input of biochar-derived carbon to leaves, biochar may be affecting carbon isotopes in photosynthate by improving nutrient status which would result in faster photosynthesis and thus improving water availability. Further experiments with these and other, similar plant communities (e.g., headland species) may provide more decisive evidence that, perhaps, biochar may be partitioned, not as a change from soil to plant, but as an artifact of leaf-level post-photosynthate.
Findings 1. 2. 3. 4. The null hypothesis was rejected at 5% level of significance. δ13cleaf signatures of PPSO taxa grown in red oak biochar showed significant level of depletion compared with nonbiochar grown PPSO taxa, P-value=<.001 The null hypothesis was rejected at 5% level of significance. δ13csoil signatures of biochar amended media showed significant level of depletion compared with calcined clay and indigenous soils, P-value=<.001 The null hypothesis was confirmed. WUEINS expressed as a function of A/E (µmol CO2/mol H2O) was only significantly higher for two of four PPSO exposed to both biochars The null hypothesis was rejected at 5% level of significance. Intrinsic leaf water use efficiency (WUE) of PPSO taxa grown in red oak biochar was significantly higher than non-biochar grown PPSO taxa, P-value=<.001
Research reported here was funded by a private industry grant and generous technical support from Deans at the School of the Environment at the University of MA Boston and School of Agriculture at the University of MA Amherst. The Beacon TLUD fabricated by Hugh McLaughlin PhD is now permanently in residence in Waltham. Licht-McLaughlin lignocellulosic biochar has been identified here only as a non-wood based biochar in keeping with the author s wishes to provide a non-enabling disclosure of this technology.
QUESTIONS?
Air Temperature, VpD, PAR and VSM measurements 2012-2013 IRGA IRGA IRGA Following McCarthy et al (2012), we utilized atmospheric and soil measurements derived from portable photosynthesis (LiCor) and direct VSM in lieu of field lysimetry to further confirm WUE impressions. Data (VpD, PAR and Temperature) were similar at both Waltham and Plymouth sites. Precipitation rates between sites were also similar (+/- 2 C.).