Comparison of Incorporated and Non-Incorporated Cover Cropping with an Organic Sunflower Fuel Project

Our results from this project showed some significant differences between the two experimental (treatment) groups. First, the June 21st plant tissue analyses (see Table 1) indicates that nitrogen(N) is 0.5% higher,Iron (Fe) almost 100ppm higher, and Aluminum (Al) about 80ppm higher in the incorporated (I) than the non-incorporated (NI) treatments. Differences were consistent between all replications. When cover crop biomass is incorporated, the material is rapidly decomposed and nutrients contained in the biomass released. In contrast, the nutrients in the biomass left on the soil surface(mulched) will be released more slowly. This is the likely explanation of the higher concentration of N in the I treatment.

In 2010 the contrasts may have been greater because of the dry weather;the decomposition of surface mulch is even slower than in a normal year. From this point onward, the roles should be reversed;greater quantities of nutrients should be released in the mulched treatment because the I biomass has already decomposed. The difference is not in fertilizer value, but the dynamics of release:faster with incorporation, more gradual over the season when mulch is left. You would also expect to see less signs of heat stress with the NI cover cropping. The higher Iron and Aluminum contents of the plant samples may be due to soil contamination:in the I treatments, there is more soil splash onto the plants and this may explain the results in the June 21st samples. Moreover,Sufficiency Ranges from agronomic and plantation crop interpretative values (see Table 2) for sunflowers from 25 mature leaves from new Summer growth shows that both treatment groups in this study were well within the acceptable ranges.

Second, there were not any statistical differences between treatments at bloom taken from the July 20th plant tissue analysis (see Table3). This would suggest the drought of the summer of 2010 prohibited the nutrient rebound expected for the NI(mulched)group.

Third, analysis of the sunflower seeds(see Table 4) shows some statistical differences. The Crude Protein(CP) and Digestible Protein(Dig.P) is slightly higher with the I treatment, which might suggest that there was more N available with the I treatment. This is confirmed possibly by the higher grain yields of the I vs NI treatment(see Table 5). There is also a statistical difference for Calcium(Ca) and Phosphorus(P). The I treatment had a higher Phosphorus value of 0.74% vs 0.71% in the NI treatment. Moreover, The NI treatment had higher Calcium values at 0.36% vs 0.29% I treatment. This apparent difference is hard to explain and may not be important.

Fourthly,there was only one statistical difference for the extruded sunflower pellets (see Table 6). Potassium(K) was greater for the NI treatment. I have no explanation for this difference.

Fifthly,There were some interesting differences in Oil Quality between the two treatment groups (see Table 7). Quality Standard for Rapeseed Oil as a Fuel(RK-qualitats standard,Table 8) is included for comparison. The H sample is the NI treatment group. Because the use of Cetane number as a marker of fuel quality for DIN purposes is now considered invalid, we have provided data on composition variables that can be used to gauge the quality of the oil, the extent of thermal,oxidative and hydrolytic degradation that have a bearing on combustion, fuel flows during cold conditions, and storage stability. The higher oxidative stability numbers of 7.48 and 6.92 it-hours shows that our oils are very resistant to degradation vs the min of 5.0. Both samples were higher than the acceptable viscosity of 38mm2/sec: I value of 39.21 and 38.63 for NI sample; this may relate to the unfiltered diglycerides in the samples. A high acid number was found with the I sample of 4.20 vs 1.80 NI. vs 2.0max. This could cause higher gumming, corrosion and could be caused by a hydrolytic degradation by aging, processing or bacterial. There was a higher moisture value for the I sample at 0.21 vs 0.10 NI vs 0.075 % mass max. Moisture is bound or can have some solubility in oil. There was not a statistical difference in the seeds dry matter between the two experimental groups suggesting seed moisture is not the explanation for the difference.

The Ash was higher in the I sample at 0.064 vs 0.004 NI vs 0.01 %mass max. Ash would represent calcium/magnesium or salts. We see 1.96% mass I vs 1.04 NI samples with measurement of diglycerides. This could be a sign that there was some hydrolytic degradation of the oil to diglycerides from the triglyceride oil structure. This could be because of hot H2O,enzymes or other sources of hydrolysis.

The ToTox measurement is used to assess oxidation of sample. the I sample was 26.9 vs 10.1 NI sample. Canola/rapeseed have lower values. All these oil quality results and differences could relate to submitted unfiltered samples because not enough oil was available to run through our bag and cartridge filtration system. I can not explain the other differences. However, all results suggest a better oil quality for the NI produced oil vs I produced oil, unfiltered. This may be significant as to oil differences related to fuel quality and how they were produced-----but still is unexplained.The flash point of sunflower oil was not determined, but is around 274'C, higher than rapeseed and could connote more power as a SVO fuel.

Lastly, Table 9 correlates to oil yield results for each sample group. (See discussion in Economics section below.)

The major condition during the project that probably had a significant impact on our results was the Summer drought of 2010.

This had a speculative impact on the study in a number of ways.

-First, as noted above in the results, the drought would contribute to a an attenuation of biomass degradation on the non-incorporated group, which we saw blooming 1 week later than incorporated group and not having any rebound of nutrients on second plant tissue samples of July 20th and lower Crude & Digestible protein values for the NI seeds.

-Secondly, the drought dropped our yields considerably, but especially with the non-incorporated groups.

-Thirdly, did the drought have an effect on the oil quality by encouraging hydrolysis and higher diglycerides in the I oil, which could ultimately effect fuel quality with higher viscosity? We see more degradation changes in the incorporated group's oil and this may relate to that group's delay for harvest 1 week longer to accommodate the NI groups longer time to maturity.

The second conditional impact was that the Welter forage peas 4010 did not all die with the roller-crimping. This would allow the peas to continue growing till maturity or being killed by the drought. This would affect the sunflower vegetative growth 2 ways: competition for available nutrients,thus inhibiting growth ,but also presenting to a lesser degree,a continued source of nitrogen fixation that would promote sunflower vegetative growth.We believe that it was the irregular surface in the NI treatment group that prevented adequate crushing of the peas, but it could have been the resistant nature of this pea variety?

Thirdly,the no-till planting of sunflower seeds into an uneven surface(the mold-board plowed field) created an unforeseen non-controlled variable in the experiment. The I groups were seeded into relatively flat seed beds.

Fourthly, the rate of 2 bushels per acre cereal rye was too low for adequate mulching to provide weed control. We would recommend 3 1/2 bushels/acre of rye alone or slightly less with additional peas. This failure ,plus the drought, caused an explosion of the late summer annual weeds like ragweed.

The obvious economic advantage to this project is the ability of a farmer to grow his own fuel. Converting a diesel engine to run on vegetable oil(SVO) is safe and can be done by any relatively handy individual. As compared to Biodiesel, where one converts the fuel to fit the engine, safety is a primary concern: toxic chemicals,fire hazards, and the safe disposal of non-fuel related byproducts (glycerol and methanol-laden water from washing fuel). Moreover, one loses about 20% of the energy value of the vegetable oil in the form of glycerol during the conversion to Biodiesel.

Most referenced oil yields for oil-seed sunflowers puts a maximum potential value of around 99 gallons per acre pre-pressing. In our project, we were seeing a 55% press efficiency resulting in around 330ml/1# Incorporated seed. With our yields on this dry year we produced around 62 gallons of SVO per acre with the Incorporated treatment group. This value should be higher during a regular year and can be increased on press type and speed of extrusion. The production of the extruded pellet as a valuable product beyond the oil must not be understated. The extruded pellet can serve three potential uses: raw feedstock for ethanol production,valuable feed source with a crude protein of around 26%, and as a biomass fuel with a high BTU.

Oil-Seed Sunflowers can be grown organically in southeastern Pennsylvania and can serve as a valuable energy crop. I believe on a normal year both experimental techniques would yield similar yields and crop quality. However, one must follow the rules of adequate mulch with 3 1/2 bushels/acre of cereal rye(less with peas) and a level planting surface. Economically, the NI group would save significant amounts of fuel and in addition, would be more ecologically friendly in preventing erosion and fuel combusted . Moreover, this study suggests a possible higher fuel quality for SVO produced with this experimental group.

• Table 7 Oil Quality Analysis
• Table 5 Sunflower Seed Yields
• Table 9 Volume(ml per1#seed) of Pressed Sunflower Oil
• Table 2 Nutrient Sufficiency Range for Sunflower Leaf
• Tables1,3,4,6
• Table 8 Quality Standard for Rapeseed Oil