Cellulosic ethanol?

Question

This technology proposes to use feedstock such as switchgrass and cornstalks that are now "wasted" by leaving them in the fields. However, it seems to me that leaving this material in the field replenishes the soil as it decomposes. This is a component of the no-till farming technique that has been gaining ground among American farmers. My question has two parts:

If we take that material off the ground, what will we use as fertilizer?

If the answer to part 1 is that we will use more nitrogen fertilizer, then how does this qualify as a renewable energy source since nitrogen fertilizer is usually a petroleum-based product?

Answer 1

Switchgrass is not grown in corn fields.  It grows with little water on poor soil that is unsuitable for higher value crops.

Using cornstalks for energy is a higher value use than for the small nitrogen component.

Cellulosic ethanol is not a complete solution for energy.  But it is one useful tool.  And better than using corn.

Answer 2

President Bush has allocated $1.8 billion dollars in the 2008 budget for research into cellulosic ethanol. A successful cellulosic ethanol program could also use wood fiber or garbage in addition to switchgrass, etc.

Answer 3

We should always retain in place some raw "waste" biomass in the interest of soil health.

The major problem with not returning biomass to the soil is the increased susceptibility to erosion associated with lower soil carbon content.   While one can increase soil carbon simply by promoting higher levels of root and microbial biomass, returning biomass to the soil is often an essential practice for maintaining soil C levels.

Risk of soil erosion due to changes in soil C are ultimately more important than loss of productivity due to change in soil N, although the two are closely connected: Soil C:N ratios tend to self adjust to between 8 and 15, so the extreme loss of one tends to support conditions for some loss in the other.

But to answer the question, If we take these materials off the ground, what will we use for [plant available nutrients]?  I have three alternatives to traditional fertilizer.  Use charcoal to  increase fertilizer use efficiency, use nitrogen fixing crops, and use crops whose seed can be inoculated with phosphorus mining fungi.

The essential soil nutrient management tool to combine with cellulosic biomass production is bio-char (more recently referred to as agrichar).  Applying charcoal to soil increases nitrogen use efficiency by capturing nitrogen otherwise lost to denitrification. Denitrification accounts for roughly half of all nitrogen fertilizer inefficiency (Nitrogen fertilizer use efficiency is only 50% world wide.  The ratio of leaching to denitrification varies with region).  Charcoal also increases soil capacity to hold nutrients against leaching.  The beneficial effect on soil of adding charcoal is greater and lasts longer than the effect of adding the same biomass as raw field waste.

A soil nitrogen building tool is rotation, inter planting or growing for biomass nitrogen fixing crops.  These crops rely on mutualistic rhizospheric bacteria to capture atmospheric nitrogen in exchange for root exudates.

A soil phosphorus building tool is a biofertilizer approach: inoculating seed with select mycorrhizal fungi. This has been shown, most recently in wheat, to increase plant uptake of phosphorus in low phosphorus soils.  More research is needed because mycorrhizal fungi are difficult to grow in the lab.  Disease resistance and improved soil moisture effects  are other benefits of  "biofertilizers".  Returning some biomass C to the soil enhances the effects of biofertilizers. In the context of the question, I see this as an answer if used in conjunction with biochar.

Note 1: I don't pretend that these three alternatives could easily or efficiently replace mined mineral nutrients or natural gas fueled nitrogen fertilizer supplies. To the extent we use mined mineral nutrients or natural gas fueled nitrogen supplies to grow cellulosic biomass, it does not qualify as a renewable energy source.

Note 2: Regardless of bio-char use, etc., we should always retain some raw "waste" biomass in the interest of soil health.

Note 3: Bio-char production can be integrated with the capture of nitrogen from flue gases, infusing the charcoal produced with the captured nitrogen.

Answer 4

The answer is right under your nose. Farmers are using fertilizers now and will continue to do so, and if nitrates are the best so be it. We need a alternatives to gasoline now! We have the minds and the need. Do not let any one tell you it is off in the future. It is just not politically convient because of the oil lobbyist and congress are in bed together. The amount of money invested in the research pales in comparison to what is being spent on the war and other pork barrel projects.. Brazil has solved the problem by offering both 85% eethanol and gas at the pumps and states like Minnesota and other bread basket states have been using it for years. The pollution caused by our automobiles is the main problem. Ethanol would greatly reduce the problems instead of constantly talking about and raving about global climate changes. It is a pollution problem not a shortage of oil or gasoline. Congress needs to aggressively step up research so in as little as one year we can convert to alternative fuels by way of tax breaks and real dollars to enhance and speed up this conversion. Do not talk, act and let your congressional reps to deal with the answers.

Answer 5

Soybeans.

The waste contains Nitrates.

Answer 6

A hay feild can be mowed several times in one summer at least 3-8 depending on where it is. The last cutting they can  cut it a little less long (leaving some sticking up) then mow a 2nd time to leave some for  compost.

Answer 7

cellulosic ethanol is being falsely touted by the bush administration to be the save all alternative method for domestically producing and using fuel in america. this i believe i untrue, firstly there is not enough of the waste to power a significant amount of cars for a long period of time, the process of growing and refining fuel on farms will take away from farm land being used to grow our food supply, this will encourage a massive harmful shift towards clearcutting land and acquiring it for farmland. the whole ethanol as a sustainable fuel is not a very educated idea. in brazil it works due to their growing of the sugar cane crop and the fact that they dont have as many cars as we do. in america with nearly 1 billion cars we dont have the farmland or resources to support ethanol as a fuel. the environmental effects of refining and producing are much more worrysome than what would we use for fertilizer?