Friday, May 23, 2008

New Gardening with Biochar FAQ

Note: Bio-char, agrichar, and charcoal are interchangeable terms when it comes to the intentional use of charcoal in the garden.

The argument for encouraging biochar use as a ubiquitous household practice is compelling: Improved garden soil will increase food production where it has the most impact on energy demand. Implementing charcoal manufacture at a household level draws in a supply of yard prunings and workbench scraps that otherwise would be lost to non-charcoal alternatives.

Unfortunately, finding even the most basic information on how to implement biochar use as a personal sustainability practice is discouragingly time consuming. In response I have started up a FAQ, a collaborative wiki, building on the efforts of the TP enthusiast community (1, 2, 3). Maybe you, the concerned gardening public, can help us thresh out the most important questions that need asking. Leave a comment here or at the FAQ. Here's my favorite bit from what has been posted so far:

2.05 What are some less smokey approaches to making charcoal for the gardener?

Choose your feedstock wisely. No matter what technique you use to make charcoal, choosing uniformly sized, dry woody material produces the highest yields. Uniformity is one reason that colliers will routinely use coppiced hardwoods.

Inverted Downdraft Gassification. For a cleaner burning configuration, consider a Top Lit Updraft (TLUD) technique, also referred to as an inverted downdraft gassification. The technique looks simple but in reality it involves some fairly sophisticated principles (PDF). That doesn't prevent success using common materials and dead simple design. Take that same open barrel configuration, tweak the design per the aforementioned sophisticated principles, and now light it from the top instead of the bottom. This takes a different skill set than lighting from the bottom but its also not that difficult to master. A little vaseline or ethanol on a cotton ball can work wonders for starting up. Once the fire gets going, the top layer of wood burns, creating charcoal, naturally. The heat from the top layer burning warms the wood below it releasing combustible and noncombustible gases which flow up into the charcoal layer. Glowingly hot charcoal has a wondrous ability to strip oxygen molecules from of anything that passes over it, so it converts the water into hydrogen, and the carbon dioxide into carbon monoxide. These two gases are flammable. They join with the other flammable gases released from the fuel. These ignite as they mix with air coming into the top of the open barrel above the charcoal layer. The result is a scrubbed gas-fed flame that is much more controlled, and which burns substantially cleaner and hotter than can be achieved with the bottom lit burn barrel. (Source). Insufficient oxygen below the combustion zone impedes loss of the charcoal despite the high temperature flame immediately above it. This allows charcoal to build up faster than it is consumed, at least until the pyrolysis zone reaches the bottom of the fuel column. The downside is that, while wondrously clean burning, a TLUD is challenged to achieve yields above 20% charcoal-to-fuel.

Folke Günther's simple TLUD-fired Retort. A retort works by restricting the air supply to the target feed stock for the duration of the burn. An outside heat source pyrolyzes the retort contents, small openings in the retort allow wood gas to escape, but restrict the flow of oxygen in. While retorts are capable of very high yield efficiency, the open flame used to fire the retort is not as clean as can be achieved with a gasifier. In small retorts, a further inefficiency is that wood gas generated from the retort can end up blowing by the combustion zone without being burned. Folke Günther's elegant solution is to combine a TLUD with a retort. This is easily the cleanest burning and highest yielding method we know of to make garden-sized batches of charcoal.

(Source)

Friday, May 02, 2008

Trends in Soil Science Education: Looking Beyond the Number of Students

From swcs.org:

Decreasing student numbers-along with related causes and concerns- is a common topic of discussion in the international soil science community. Such discussion is seldom quantitative. Here we present long-term student numbers (in undergraduate courses as well as MS and PhD graduates) of soil science departments in North America, Europe, and Oceania. A previous study by P. Baveye and co-workers had shown that in the United States and Canada student numbers fell by 40% in more than 80% of the universities between 1992 and 2004. The United States and Canada experienced an increase in female students in soil science between 1992 and 2004. Meanwhile, the number of foreign students has decreased. Student numbers have also decreased in New Zealand. Numbers at Dutch universities decreased in the early 1990s but have since stabilized. Two of three Australian universities had increasing numbers of students for undergraduate courses as well as MS and PhD graduates. Currently in the Netherlands almost half of all MS soil science graduates are female, while in the 1970s and up to the mid-1980s 80% or more of soil science graduates were male. It seems that teaching is becoming more general (more introductory courses to a range of other disciplines), while soil science research is experiencing an opposite trend: specialization. INTERNATIONAL SURVEY

A questionnaire was sent to 43 colleagues at universities in Europe, North America, South America, Africa, and Oceania. We requested long-term data (>25 years) on student numbers between 1980 and 2005. Twelve responses were received.

One of the aims of this research was to quantify trends in student numbers, and it is therefore unfortunate that we were not able to get data from several countries in which soil science is highly important or had made major contributions. For example, no response was obtained from the United Kingdom, where only a few soil science departments have remained; others have closed, have been relabelled, or have been merged with other departments.

It is a tedious job to extract the type of information requested; this may have contributed to the low response rate. In addition, some of those who received the survey might have felt uncomfortable with the results and were not to keen to have them published even though we tried to make it as anonymous as possible. Baveye et al. (2006), who surveyed 61 universities in the United States and Canada, found that some universities could not respond because their legal counsel found it unethical and inappropriate to release information about graduate students.That could be another reason for the limited response in our study.

As only 12 universities responded, the results presented here may not be representative of the whole globe. Here we discuss the main trends and speculate on their possible causes, followed by some discussion on the future of soil science education and student numbers.

STUDENTS IN SOIL SCIENCE

North America

Baveye et al. (2006) surveyed 61 soil science departments in the United States and Canada in 1992 and in again in 2004. The total number of soil science graduates (MS and PhD) in 1992 and 2004 is depicted in figure 1. The number of PhD students decreased (-63%). Of the 36 institutions that responded, 5 universities had increased enrollment, 1 university had constant enrollment, and 30 had decreased enrollment.

A major trend was the increase in the number of female students for both MS and PhD graduates (figure 2).The number of foreigners decreased (figure 3). In 1992, it was found that female students were almost exclusively interested in environmental applications, while male students and students from rural areas were more interested in agricultural issues.

We also received 25 years of student data from a university in the Midwestern United States. Figure 4 presents the number of students in three different courses. The "Soils" course is made of about 10% majors in agronomy, so 90% of the students are outside agronomy and soils. The "Soil Fertility" course is made of majors in agronomy or turf science, and the agronomy major includes those with specific interest in soil science.The "Environmental Quality" course is a general education course; it is within the list of courses that students select to broaden their perspective and to get exposed to environmental issues related to soil. Undergraduate students come from production, business, consulting, plant breeding, and soil and environmental sciences. Some of the production, consulting, and business students may be soil science oriented.

Europe

In the Netherlands, serious soil investigations were started by W.C.H. Staring in the mid-180Os, followed by J. Van Baren in Wageningen, and DJ. Hissink in Groningen in the early 190Os. Soil science rapidly expanded in the mid-1900s with university courses in Amsterdam, Groningen, Utrecht, and Wageningen and the establishment of research institutes (Bouma and Hartemink 2002). After World War II, the number of soil scientists was very large and the knowledge base of Dutch soil science grew enormously. In 1998, there were 23 soil scientists per 100,000 ha (247,000 ac) agricultural land in the Nedierlands compared with 3 in France and Denmark and 6 in the United Kingdom (van Baren et al. 2000).

Currently, soil science is taught at five Dutch universities, although not all have majors in the subject. Enrollment of first year earth science students is depicted in figure 5; these first year students include those who will study geology or petrology. The general trend is that numbers declined from the early 1990s but more or less stabilized since the late 1990s,The number of master's level graduates with a soil science major at Wageningen University is given in figure 6. The number of Dutch master's level students (Ingenieurs [Ir] is the Dutch equivalent of MS) peaked in the mid1990s, decreased, but then had another peak in 2004. The number of foreign MS soil science graduates was around 10 for most of the 1990s.

The most remarkable shift has been in the ratio between male and female soil science graduates (figure 7). Up to the mid-1980s, 80% or more of soil science graduates were men; from then on, the women- to-men ratio increased and has been around 50% to 55% in the past six years (with the exception of 2002). A similar trend, although starting later, happened with the foreign MS students; 70% of soil science graduates in 2005 were female (figure 8).The MS program used to be a two-year program, so there were no graduates every other year from the start of the foreign MS program at Wageningen University in 1972 until it changed to an 18-month program in the 1980s (hence, the gaps in the graph).

The ratio of foreign versus national MS/Ir soil science students is plotted in figure 9. In the 1970s and 1980s, about 40% to 50% of all soil science graduates were foreigners; thereafter, the share of foreigners decreased (except for the year 2000). In the past five years, foreign MS students were less than 40% of all soil science graduates at Wageningen University.

Oceania

Survey responses were received from three universities in Australia and one in New Zealand.

Soil science is taught in 16 universities in Australia. For our study, information on soil science courses and undergraduate, MS, and PhD theses was received from of three universities (in Adelaide, Brisbane, and Sydney).

The University of Adelaide has trained soil scientists since the Waite Agricultural Institute opened in 1924. Since World War II, the university has produced on average at least one graduate in soil science per year at BS honors, MS, and PhD levels. The number of BS honors and PhD graduates has increased since 1995 to about 4 to 5 per year. The number of soil science theses for BS honors, MS, and PhD levels is presented in figure 10.

The number of students attending the "Introductory Soils" and "Soil-Plant Relationships" courses more than halved between 2000 and 2006 at the University of Queensland, Brisbane (figure 11). The trend is comparable to the data from the United States (figure 4), but these are short-term data; longer term data have shown that interannual fluctuation is considerable.

At the University of Sydney, the second year course is an introductory one on soil properties and processes. The third year course is an applied course focusing on soil mapping, soil geography, and environmental issues. The fourth year consists of a large research project and three separate more advanced courses on soil chemistry, soil physics, and pedology. The number of BS students in second and third year soil science courses increased between the early 1990s and 2005. Student numbers in the fourth year is steady. The number of MS and PhD 'graduates has fluctuated considerably in the past two decades, but the number of PhD students is larger now than in the late 1980s and early 1990s (figure 12).

In New Zealand, soil science is taught at six universities. Figure 13 presents data from one university on student enrollment in soil science courses at the second, third, and fourth year. There is a general increase from the early 1980s to a peak in the mid-1990s, after which the numbers in the second and third years decreased to the level of the early 1980s. The large numbers in mid-1990s probably reflect baby boom echo-that is, an overall surge in young people heading to university. The soil science enrollment decline from early 2000s mirrors a decline in enrollment at the whole university. SOIL SCIENCE TRENDS

The main trends include decreasing numbers of soil science students in several parts of the world, a shift in MS/PhD, male/ female, and foreigner/national student ratios, and increased teaching to other disciplines.

Numbers of Soil Science Students

The number of soil science students declined in some but not in all universities, and some differences exist between countries. In the United States and Canada, the number of students decreased by 40% in about 80% of the universities, while in Australia two out of three showed a steady increase in student numbers attending soil science courses and the number of graduates. In a university in New Zealand, the number of soil science students has decreased recently, while in the Netherlands that decrease happened 10 years earlier and student numbers are steady now. Kenya and Tanzania have experienced decreasing numbers as well, despite the importance of agriculture for 80% of the population (Ngugi et al. 2002). Considerable variation was found in the annual number of students attending courses or graduating. The fluctuation in student numbers is partly due to overall university enrollment and number of high school graduates.

In the United States and Canada, the number of soil science PhDs is decreasing relative to the number of MS graduates. In other parts of the world (e.g., the Netherlands and Australia), it is more or less the other way around: fewer students are graduating at the BS honors or MS levels, and the number of PhD graduates in soil science is increasing. In part this has to do with lower increased undergraduate education in the developing world, while students are more likely to go on for doctoral education in Europe and Australia.

If we assume that total number of students has not decreased, then the decline in soil science students is absolute. However, at some universities the decline in soil science student numbers may mirror the decline in overall enrollments. All in all, students seem to prefer other studies (business, law, and medicine), and these are generally viewed as moneymaking degrees.The decline is not unique to soil science but has also occurred in geology, geography, weed science, chemistry (Baveye et al. 2006), and several other disciplines such as physics. In 2003, less than 500 US citizens earned physics PhDs, die lowest number since the early 1960s (Nature, December 1, 2005). Overall, there is a strong growth in information science, medicine, and computer science and little student growth in engineering, mathematics, and physical sciences.

External factors include high school education systems, societal and university changes, and more internal factors such as links to agriculture, the relabelling of the discipline, and "the failure to excite" factor. In many countries, soil science has maintained strong links with agriculture, while the interest in agriculture in the developed world has diminished. That has several causes, including there being enough food but also because there are far fewer farmers and many of them have higher degrees themselves (in the Netherlands, 20% of the farmers have a university or polytechnic degree). In other words, fewer academics are needed in agriculture- so they think.

Other problems start at high school. In the Netherlands, for example, the high school curriculum was rearranged 10 years ago into different profiles.These profiles (e.g., nature and technology, culture and society) contain six to eight fixed subjects and replaced the classic model in which high school students chose their own set of subjects. Now it appears that with certain profiles it is not possible to study soil science. High school students with an interest in physical geography cannot take the profile that contains geography as that profile lacks the subjects necessary to be admitted to a soil science course at a university. A combination of essential science subjects with geography is not possible. So there is a mismatch between what high schools deliver and what universities require, at least for some university soil science courses. Another problem is that many geography teachers at high school are social geographers with little interest or encouragement in physical geography.

National/Foreigner Student Ratios

The share of foreign students is decreasing in the United States and Canada, which is related to the increased difficulties for foreigners to enter the United States (Baveye et al. 2006). In 2001, 200,000 visas were authorized for highly skilled workers, but that had shrunk to 65,000 by 2004. At the American consulate in Chennai, India, the wait to just get a visa interview is more than five months. The United States has always attracted a large number of foreign students and greatly benefited from the import of highly skilled people. According to The Economist (May 6, 2006), 3,000 of the technology firms created in Silicon Valley since the 1980s (that is more than 30% of the total) were founded by entrepreneurs with Indian or Chinese roots. We are not for certain how much the visa restriction and the perceived antagonisms aflfect student mobility and choices, but the Australians, Canadians, and Swiss-countries that are not known to have the same level of obstacles as the United States-have been successful in attracting foreign talent.

Male/Female Student Ratios

Soil science courses and graduations have become increasingly dominated by female students. Clearly, our science is emancipating, and it appears that the encouragement for females to take the science subjects (maths, physics, chemistry) at high schools is starting to pay off. There may also be deeper rooted problems with males at high schools. Several people in the Netherlands suspect that enrollment of males into university is decreasing as they are more likely to fail either at high school or first year at university; females may be better organized, harder working, and stronger in language and nontechnical skills. Another cause could be that soil science is now much more attractive to young women than it was 10 or 20 years ago. In any case, the next generation of soil scientists will be more dominated by women, but that is currently not reflected in leading positions. For example, less than 10% of all International Union of Soil Sciences officers (65 people) in 2006 were women. Articles have been recently published on the achievements of women in soil science in the United States (Levin 2005) and Russia (Prikhod'ko 2006), but little attention has been given to the emerging trends in female students. That will likely change.

Is the current male dominance in soil science (for as long as it takes) an exception? Overall, science is male dominated. In the United Kingdom, for example, less than 4% of tenured physics professors are women (Institute of Physics 2006). Most science department heads are male.

Soils Research Specialization

Highly active university departments routinely attract students as there is an exciting field of research, sufficient funds, and a good research infrastructure for nurturing and educating students and the next generation of scientists. Funding research is a political issue that differs widely between countries (Brumfiel 2006). Globally, three regions take the lead when it comes to funding: United States, Japan, and Western Europe. The United States dominates research funding in the sciences globally, spending almost $145 billion (euro100 billion) on research and development in 2006, more than any other country or region. About 60% of that is defense related. The 25 countries of the European Union spend more than $85 billion (euro59 billion) per year on research. Yet science budgets in the United States, Germany, France, and Japan have been stagnant in recent years. In contrast, scientific research budgets in China have increased by 16% in 2004, in South Korea by 10% in 2005, and in India by 25% recently. The collective research budgets of China, South Korea, and India are less than one-quarter that of the United States, but that will change (Brumfiel 2006). Funding patterns affect scientific disciplines and education; changes in funding amounts and priorities have an impact on everything from the content of university courses offered to the types of employment opportunities that are available for graduates.

In many countries, government funding for soil research has decreased since the 1980s (Hartemink 2002; Mermut and Eswaran 1997; Tinker 1985). In part, this was due to the economic policies of the Thatcher government in the United Kingdom, resulting in privatization and the rule-of-market forces affecting many facets of society including the sciences (Tinker 1985). In part, it was due to the strong link between soil science and agriculture (Baveye et al. 2006).As the interest in agriculture was reduced in much of the developed world (there was ample food, agriculture was perceived to be harmful for the environment), so fell the interest in soil science. The decline in soil science was also due to its inability to cope with the new challenges. Some in the soil science community were split internally about the definition of the kandic or ferralic horizon, and there was a lack of answers for real-word problems or hard data useful for other disciplines. These trends have been observed in many countries, though with some exceptions (Bouma and Hartemink 2002).

Different departments have coped differently with rapid changes in society, and many have relabelled their activities to break away from agriculture or have merged ' with other departments into schools of natural resources or food production. Just like departments of agronomy have been renamed departments of plant or crop and soil sciences (Raun et al. 1998), so have many departments of soil science been renamed in the past century. Table 1 attempts to list some common names of soil science departments in the English- speaking world and how they changed over time. This timeline reflects relabelling but also expansion of the discipline. It is hard to say what is fashionable, but the "Department of Soil and Crop Sciences" is certainly not a popular name at the moment. All in all, it seems that soil is not a too favorable word in the naming of departments; in many cases, it has been replaced by land, earth, or environment. Despite the fact that there are far fewer active soil scientists than two decades ago and that there are fewer soil scientists trained in several parts of the world, the number of soil science publications still increases (Hartemink 2001). Between 1994 and 2006, the number of soil science publications in peer-reviewed journals doubled. No doubt there is some recycling of ideas and dilution of research results over several papers, but the quantity of soil-related publications is an indication that much soil research goes on and there are many global and local issues, now and in the future, to which soil science can contribute (Minasny et al. 2007).

The Aging of Soil Science

Not only are soil science departmental names retiring, so are its people. The aging of the workforce is a common problem in much of the developed world (Lutz and Qiang 2002). The aging of the workforce is noticeable in many departments and soil research centers. Asked what he thought of the 18th World Congress of Soil Science, an Elsevier salesman responded, "Lots of old people, perhaps not a sign of vigorousness" (Philadelphia, July 2006).

We have data on age distribution in the soil science community from the United States, the Netherlands, and Denmark.

In the United States, 44% of the members of the Soil Science Society of America are over 50 years of age and male (figure 14). The older generation is male dominated, while most of the younger members are female.

In 2002, a questionnaire was sent to the 466 members of the Dutch Society of Soil Science. In total 152 people responded (32%). The average age was 52 years and more than 16% of the respondents were above 65 years of age. Only 2% of respondents were younger than 25 years, and 9% reported being between 26 and 35 years old. Student members equalled only 1% (Boshoven and Hartemink 2003).

In Denmark, 50% of Danish Soil Science Society members (70 in total) are over 50 years old, and about one-fifth is between 25 and 40 years of age (O. Borggaard, personal communication, 2007).

The increasing age of soil science society members may be due to (1) the lack of influx from a younger generation, which would indicate a lack of soil science graduates, and/or (2) younger soil scientists not joining learned societies in the same proportions as the previous generation. In any case, the decline in soil science graduates has been a matter of concern and is discussed at soil science meetings and conferences.

CONCLUSIONS

Funding, politics, and the vigorousness of a scientific discipline all affect student numbers. Choices differ greatly between individuals, universities, and nations, but some general principles apply: students are attracted by the vigorousness and chirpiness of a subject (some may call it sexiness) and the possibility of getting a position (perhaps even well paid) after a university degree has been obtained.

The number of publications with hard data on student numbers is limited (it is not good publicity), but there has been some attention to soil science education, particularly in the United States (Baveye et al. 1994), but also in Australia (Smiles et al. 2000), India (Rao et al. 2000), and Africa (Ngugi et al. 2002;Temu et al. 2004).As far as we know, the first paper showing trends in the number soil science students was by Taskey ( 1994), who showed a severe decline in student enrollment from about 170 students in the late 1970s to around 45 in the late 1980s at a university in California.The faculty responded by establishing three new concentrations under the soil science degree program: land resources, environmental management, and environmental science and technology. As a result, soil science enrollment nearly tripled within two years (Taskey 1994).

While our research is specializing with advances in several subdisciplines, our teaching is generalizing: more and more soil science is being taught as part of other science curricula (e.g., ecology). We also see that soil science is being taught by other departments and that soil research is conducted by other disciplines (e.g., geology).

The soil science community should be worried by the declining numbers of soil science students (McBratney 2006).

It is our impression that current soil science graduates have no problems finding employment, and there is a shift from the public to the private sector in job opportunities. But will these trends. continue? What expertise is needed in the near and further future and does our soil science teaching yield capable graduates?

The most difficult task ahead is not to convince policy makers and land users on the need for adequate and up-to-date soil information but to make sure that there are enough young soil scientists equipped with the latest techniques and insights to address future issues. Convincing students that soil science is a valuable study is an important part of that.

ACKNOWLEDGEMENTS

Some of the results in this article were presented at the "Innovation, Speculation and Disneyfication in Soil Science Education" symposium during the 18th World Congress of Soil Science. We are most grateful to David Lowe, Eric Brevik, Oliver Chadwick, Philippe Baveye, Chuck Rice, Neil Menzies, Cameron Grant, Martin Gerzabek, Bern Andeweg, and Marian Bos Boers for digging through university files and providing us with the number soil science students and graduates. Ole Borggaard of the Danish Society of Soil Science and Susan Chapman of the Soil Science Society of America are thanked for the information on the age distribution of their members.

AUTHORS

Alfred E. Hartemink, Alex. McBratney, and Budiman Minasny

REFERENCES

Baveye, P., W.J. Farmer, and T.J. Logan, eds. 1994. Soil Science Education: Philosophy and Perspectives. Madison WI: Soil Science Society of America.

Baveye, P., A.R. Jacobson, S.E. Allaire, J.P. Tandarich, and R.B. Bryant. 2006.Whither goes soil science in the United States and Canada? Soil Science 171:501-518.

Boshoven, E., and A.E. Hartemink. 2003. De NBV enquete. NBV Nieuwsbrief 9:6-10.

Bouma, J., and A.E. Hartemink. 2002. Soil science and society in the Dutch context. Netherlands Journal of Agricultural Science 50:133-140.

Brumfiel, G. 2006. The scientific balance of power-Show us the money. Nature 439:646-647.

Hartemink, A.E. 2001. Look at it this way-Publishing science: past, present and the future. Oudook on Agriculture 30:231-237.

Hartemink, A.E. 2002, Soil science in tropical and temperate regions-Some differences and similarities. Advances in Agronomy 77:269-292.

Institute of physics. 2006. Women in University Physics Departments-A Site Visit Scheme 2003-2005. London: Institute of Physics,

Levin, M.J. 2005. Women in Soil Science (USA). In Encyclopedia of Soils in the Environment, vol. 4, ed. D. Hillel et al., 345-352. Amsterdam: Elsevier.

Lutz, W., and R. Qiang. 2002. Determinants of human population growth. Philosophical Transactions of the Royal Society of London B 357:1197-1210.

McBratney, A.B. 2006. Musings on the future of soil science (in 1k words). In The Future of Soil Science, ed. A.E. Hartemink, 86- 88.Wageningen: International Union of Soil Science.

Mermut, A.R., and H. Eswaran. 1997. Opportunities for soil science in a milieu of reduced funds, Canadian Journal of Soil Science 77:1-7.

Minasny, B., A.E. Hartemink, and A. McBratney. 2007. Soil science and the h index. Scientometrics 73:257-264.

Ngugi, D., A. Isinika, A. Temu, and A. Kitalyi. 2002. Agricultural Education in Kenya and Tanzania (1968-1998). Nairobi: RELMA (Sida).

Prikhod'ko, VE. 2006. Role of women in Russian soil science, Eurasian Soil Science 39:342-343.

Rao, D.R., R.V. Kumari, and E. Haribabu. 2000. Agricultural education in India: A sociological perspective. Oudook on Agriculture 29:177-184.

Raun, WR., N.T. Basta, J.A. Hattey, H. Zhang, and G-V. Johnson. 1998. Changing departmental names from agronomy to plant, crop, and soil sciences. Journal of Natural Resources and Life Sciences Education 27:113-116.

Smiles, D.E., I. White, and CJ. Smith. 2000. Soil science education and society. Soil Science 165:87-97.

Taskey, R.D. 1994. Revision and rescue of an undergraduate soil science program. In Soil Science Education: Philosophy and Perspectives, ed. P. Baveye et al., 21-27. Madison, WI: Soil Science Society of America.

Temu, A.B., S. Chakeredza, K. Mogotsi, D. Munthali, and R. Mulinge, eds. 2004. Rebuilding Africa's Capacity for Agricultural Development: The Role of Tertiary Education. Nairobi: ICRAF.

Tinker, PB. 1985. Soil science in a changing world. Journal of Soil Science 36:1-8.

van Baren, H., A.E. Hartemink, and P.B. Tinker. 2000. 75 years the International Society of Soil Science. Geoderma 96:1-18.

Alfred E. Hartemink is head of the World Soil Museum, ISRIC- World Soil Information, Wageningen, the Netherlands. Alex McBratney and Budiman Minasny are on the faculty of Agriculture, Food and Natural Resources, University of Sydney, Sydney, Australia.

Copyright Soil and Water Conservation Society May/Jun 2008

(c) 2008 Journal of Soil and Water Conservation. Provided by ProQuest Information and Learning. All rights Reserved.

Source: Journal of Soil and Water Conservation

Thursday, May 01, 2008

Make dirt more better

Soil has a problem. It is eroding faster than it is being made. That's a given in these times of relative geologic stability. Most soil was formed in depositional material. Without sedimentary deposits being exposed by tectonic processes, without substantial volcanic ash fall, without the continental glaciation producing silt, and without the global wind storms and cataclysmic post-glacial flooding to redistribute that silt, we basically have to wait on the next climate change re-boot for our next era of major soil replenishment. In these trying times on the downhill slide from peak soil resources, we'll have to make better soil from the soil that we have left.