Tuesday, December 16, 2008

Fertilizer prices suddenly collapse in late 2008

The International Center for Soil Fertility (IFDC) reports that, with the exception of potash, world fertilizer prices have dropped dramatically.

Gregory explains why fertilizer prices fell so rapidly in late 2008. "The high fertilizer prices caused 'demand destruction.' Farmers were unable or unwilling to pay two or three times the prices of early 2007." Collapse of the global credit market, a trade recession, and slowdown in world economic growth worsened the situation. Demand for fertilizers fell and stocks accumulated. Fertilizer manufacturers cut back on production.

"But potash prices have stayed high due to its shortage and difficulties in transporting Russian potash because of an enormous and expanding sinkhole near the Silvinit mines," Gregory says. "Demand for potash increased from 2006 through 2008, and potash inventories are now 37% lower than over the past 5 years."

A couple of thoughts I will be researching.

First, if lower demand has translated to lower utilization, this should show up as reduced inventories of 2008 commodity crops, like rice, soybeans, and wheat, and reduced supply of perishable fruit crops like bananas.

Second, with fertilizer prices now low, this would be a excellent time to replenish African soil fertility, currently in crisis. Especially in consideration of a possible reduction in 2009 food inventories world wide.

(recycled from nscss.org)

New wiki for experimental hydrology

Calling all experimental hydropedologists. A vast room of poster presentations greeted thousands of scientists at the American Geophysical Union’s annual autumn meeting on Dec. 15 in San Francisco – including one announcing an “experimental hydrology Wiki” website. The wiki was created last year by Llja Tromp-van Meerveld of Simon Fraser University in Burnaby, British Columbia and Theresa Blume of the University of Potsdam in Germany. Originally designed to meet the needs of doctoral students, the wiki is now open to assist a range of environmental researchers, from hydrology to related fields in science and engineering. And hydropedology. The website is: www.experimental-hydrology.net. Soil moisture is used as a prominent, and encouraging, example.

(recycled from nscss.org)

Saturday, December 13, 2008

Pedology and CO2

In a previous post I provided an oblique link to a news release: Climate Change Alters Ocean Chemistry. It makes reference to conditions resonating with the theory of biorhexistacy:

The research team, which included Caldeira, Elizabeth M. Griffith and Adina Paytan of the University of California, Santa Cruz, plus two other colleagues, studied core samples of deep oceanic sediment recovered from the Pacific Ocean Basin. By analyzing the calcium isotopes in grains of the mineral barite in different layers, they determined that between 13 and 8 million years ago the ocean’s calcium levels shifted dramatically. The shift corresponds to the growth of the Antarctic ice sheets during the same time interval. Because of the huge volume of water that became locked up in the ice cap, sea level also dropped.

“The climate got colder, ice sheets expanded, sea level dropped, and the intensity, type, and extent of weathering on land changed,” explains Griffith.

“This caused changes in ocean circulation and in the amount and composition of what rivers delivered to the ocean,” adds Paytan. “This in turn impacted the biology and chemistry of the ocean.”

These folks are saying that momentous changes in oceanic chemistry recorded in the sediment record must have been predicated by equally momentous changes in soil chemistry, changes tied to both atmospheric carbon dioxide content and climatic conditions.

From a pedologist's view, it is clear that under the expanded humid, warm, stable conditions envisioned by H. Erhart for biostasis, we would see deeper residual soils and more rapid formation of argillic horizons. In terms of soil taxonomic orders (USDA), more intense chemical weathering would cause the expansion of inceptisols at the expense of mollisols, ultisols at the expense of alfisols, and oxisols at the expense of ultisols.

Caldeira and company tie warm climate to higher river calcium content, but strongly implicate higher atmospheric carbon dioxide as the primary driver of increased chemical weathering. Atmospheric carbon dioxide levels do not appear to be part of Erhart's construct, but could certainly enhance these pedogenetic trends.

Acid rain alarm bells are ringing faintly in the distance at this point. But it is a false alarm. Rain water pH is due mostly to equilibrium with atmospheric carbon dioxide. The carbonic acid formed buffers rain drop pH to 5.6, and higher atmospheric carbon dioxide increases the carbonic acid content, but it doesn't lower pH below 5.6. Other constituents accomplish that. Thus increased atmospheric carbon dioxide isn't being implicated in some futuristic acid rain scenario.

Oxisols, ultisols and spodosols would increase in extent with increased soil weathering. But could it also mean lower plant disease, and more nutritious crops? Increased carbonic acid would drive faster pedogenesis, as would increased the biological activity stimulated by higher carbon dioxide. For soil, that would mean a richer solute content in the soil water, more rapid formation of secondary minerals, more eluviation or translocation of minerals with percolation. To the list of pedological shifts at the soil order level, we can add the expansion of spodosols at the expense of inceptisols.

Something very positive can be expected for soil that is not captured in the shifting soil order paradigm. For plants and soil microbes, richer solute content would mean greater availability of mineral nutrients. In soil husbandry and slow food circles, higher mineral availability translates to healthier soil, lower plant disease, and more nutritious harvests. What the shifting soil order paradigm does signal is that soils will be at greater risk of losing their fertility to leaching. Having the soil chockablock full of biochar will be essential to mitigate this last effect. Let's start now.

(Recycled from nscss.org)


The Theory of Biorhexistasy describes climatic conditions necessary for periods of soil formation (pedogenesis) separated by periods of soil erosion. Proposed by pedologist H. Erhart in 1951, the theory defines two climatic phases: biostasy and rhexistasy.

If I recall, H. Erhart figured this out while on the Congo river contemplating a low sediment load in a high rainfall, potentially highly erosive setting. Impressive. There is a soil science truism that clean water is hungry water, and can't wash across or through the land without taking some with. From a soil scientist's perspective, water is soil in highly dilute form. (So is air.)

Reading between the lines, I don't think Erhart had a research budget much beyond travel expenses. He simply deduced from what he knew of tropical weathering that the river had to be laden with dissolved minerals, calcium especially, washed from the soil by percolating rain water. Groundbreaking as that was in its own right, he didn't stop there. Using induction, he reasoned that when similar conditions dominated it ages past, rivers would have delivered abundant calcium to ancient seas subsequently (at the close of the age, perhaps) yielding vast limestone deposits. He saw these ages as lush, moist, and warm with accelerated chemical weathering accompanied by the formation of deep soils. Biostasy. Between periods of biostasy, he envisioned conditions dominated instead by physical weathering: severe fluctuations in temperature and moisture, sparse vegetation, shallow exposed soils, rivers choked with sediments, but with low solute content. This insight informs interpreting endokarstic sediments(Yves Quinif) in Europe where stalacite formation is observed to be greatest, and with least sediment, during interglacial periods due to higher dissolved calcium content, and less soil erosion.

Simply as a mental exercise, consider a scenario where atmospheric carbon dioxide hits 1200 ppm 200 years from now. In the context of biorhexistasy, what is going to dominate? biostasy, rhexistasy or will it be something well outside H. Erhart's elegant construct? Considering that the Congo and the sediment laden Nile coexist in the same age, it is certainly conceivable that biorhexistasy will continue to play out differently based on location, with neither dominating. But the undeniable effect of higher carbon dioxide is higher chemical weathering. So maybe rhexistasy during the transition, followed by biostasy.

(Recycled from nscss.org)

Monday, July 07, 2008

Soil Management - 9 Crop Specific Guidelines

Searching on the term "soil husbandry", I came across this rather concise web presentation on environment-sensitive farming. It covers a wide variety of crops, cropping systems and soil types, so I am sure most will find something in here that is new. For me it was tramlines. Enjoy!

Wednesday, June 25, 2008

Garden Char Processing

I've added some photos to Flickr on how I currently prepare my charcoal for add ing to garden soil. This is in support of the Biochar for Gardeners FAQ.

I am lightly soaking (shallow soak, lots of turning to keep surfaces moist) my charcoal to precondition it for a crush-and-chop reduction and then screening. To soak, I add soluble mineral fertilizer and fish emulsion. Once in the soil, these will stimulate biologic conditioning and will help prevent stalled plant growth due to induced N deficiency, a concern with direct use of fresh char in the garden.

Also, regarding the mineral fertilizer, I have it in the back of my mind that adding ammonium sulphate (a common ingredient in off-the-shelf soluble fertilizer formulations) to the soak water will boost water penetration. I am thinking this might help because ammonium sulphate is used hold farm chemicals on waxy plant surfaces (like thistle), and because saltier water generally tends to penetrate further and faster into problem soils. I am encouraged to think that ammonium sulphate helps to overcome fresh charcoal's water repellency, even if only to a slight degree.

Wednesday, June 11, 2008

Soil pH and Plant Nutrients

Doug Edmeades gives out sound advice on pH.

It used to be believed (going back to the early days of soil science) that the ‘ideal’ soil was neutral: neither acid nor alkaline it had a pH of 7.0. This early belief still prevails especially in Charlatanville. However, with the benefit of much subsequent research our view of the ideal soil pH has changed.

First, it is now known that different plants have different tolerance to acidity. Restricting the discussion to pasture species, browntop is very tolerant to acidity which is one reason why it thrives in undeveloped soils. Ryegrasses are more sensitive and like a higher pH. Clovers are more sensitive again and, of the legumes, lucerne is very fussy. Our pastoral agriculture is focussed on growing clover-ryegrass and the optimal pH is 5.8-6.0 – this is the pH at which pasture production and especially clover production is optimised. In contrast, a straight lucerne stand requires a pH of about 6.5.

Liming pastoral soils above pH 6.0 is not recommended for several reasons. First, there is no benefit in terms of production and it can have detrimental effects on both pasture production and animal health. As the soil pH increases the availability of soil molybdenum (Mo) increases and thus the pasture Mo content increases. This can, in some cases, induce copper deficiency in animals. Also, increasing the soil pH above 6.0 reduces the concentration of soil zinc (Zn) and manganese (Mn) concentrations. This can result in induced Zn and Mn deficiency. Liming soils, contrary to popular belief, is not always beneficial!

He also works up a sensible New Zealander's criticism of liming to "fix" the Ca:Mg:K ratio.

Lime is typically calcium carbonate. For us in New Zealand the active ingredient in lime is the carbonate not the calcium (Ca). Our soils fortunately are rich in Ca – indeed often awash with Ca – a result of their origin (from the sea) and youthfulness (not very weathered).

Given that the benefits of liming are related to the change in soil pH then it should be obvious that the only useful guide and hence measurement for the requirement of lime is the soil pH. This is the adopted science-based approach used in New Zealand.

So what about all this base saturation ratio argument? In the 1930s there were two competing theories about plant nutrition. One said that the ratio of the nutrients Ca, Mg, K and Na was important. These were measured as the proportion of the soil cation exchange capacity (CEC) – the ability of a soil to store these nutrients called cations. Thus your hear some say that the Ca saturation of a soil is 50% meaning that 50% of the CEC was occupied by Ca. The other theory was that plants did not care what the ratio of nutrients were – the plant was fine providing the minimum amount of each nutrient was present. This is called the Sufficiency Theory distinguishing it from the Ratio Theory.

After almost 80 years of research the jury is definitely in. The Ratio Theory is not consistent with observations and hence is now set aside. Indeed we now know that using the Ratio Theory as a basis for fertiliser recommendations can be and often is misleading. For example the Base Saturation Ratios of Ca in most New Zealand soils would suggest they are Ca deficient. The fact is they are not and Ca deficiency has never been recorded in New Zealand.

There are other problems with the Ratio Theory. It applies to only 3 nutrients (Ca, Mg and K – appreciating that Na is not required for plant growth (except on some crops such as sugar beet).

What about all the other 13 plant nutrients? Also we now know that soils have variable charge – this realization has occurred within my 30-year career. The consequence is that the CEC depends on the pH at which it is measured. The old method still used by the quack brigade measures the CEC at surprise, surprise the “ideal” soil pH of 7.0. This inflates the CEC thus reducing the base saturation ratios, especially for Ca. By sticking to this now disproved methodology the quacks can be certain that the soil test results will say the Ca base saturation ratio is low therefore apply my product because it contains Ca.

My region's soils are similarly well supplied with calcium. My agricultural consultancy mentors taught me to be skeptical of the Ca:Mg:K approach to evaluating soil nutrient status. In my region it was used to justify expensive formulations of foliar applied applied calcium, or to justify adding expensive soluble calcium to the irrigation water on soils with a good supply of calcium. Normally on high value crops in good years when adding extra nutrients for insurance has legs. Charlatans is not too strong a word. Back in the 1980's these folks would use A&L Laboratories, well established, amny offices, with an excellent professional reputation, and which reported Ca:Mg:K in a ratios friendly format. I'll bet this is still the case. You can't beat something like that for conferring legitimacy, can you?

The originator of the ratios approach, soil scientist William Albrecht was a brilliant observer of nature with a considerable body of work which still gets a lot of play. The basic premise of Albrecht's 1938 Loss of Soil Organic Matter and Its Restoration is solid: it takes a ready supply of soil calcium and nitrogen to build soil organic matter. His concepts continue to be stretched beyond to the breaking point both by well meaning folks exchanging advice on organic farming methods, as well as in efforts to sell product to the unsuspecting. Yet we don't read much in the way of criticism of the ratios approach. It is excellent of Doug Edmeades to voice his concern.

Monday, June 09, 2008

No Miracles

Charcoal cannot replace the need for adding mineral nutrients.

I am an unabashed charcoal enthusiast. Used properly, adding charcoal to soil improves biomass production and soil health. Sometimes dramatically when soil productivity is low. Certainly part of the effect is increased nitrogen use efficiency: less N lost to nitrification and leaching. Charcoal also tends to be associated with higher post harvest soil levels of P and K for reasons that are not entirely clear. Perhaps this effect also is due to increased efficiency.

Most TP enthusiasts, myself included, are convinced that the most mysterious effects from adding charcoal relate to soil biology, more than they relate to direct physical and chemical effects, although those realms play important roles also. And, in keeping with my previous post, it seems clear to me that increased energy efficiency is a critical bit here. Plants and microbes are growing more biomass with less effort for reasons that can't be entirely explained by traditional nutrient-based perspectives. Yes, the charcoal adds potassium, yes it raises soil pH, yes it increases soil water and nutrient holding capacity. But the results speak to more, much more.

The behavior of charcoal amended soil seems to defy the limits of the soil-biology system understood by traditional science. However, it would be entirely foolish to think that simple soil nutritional requirements are not still in play. Nutrient deficiencies limit living systems. Charcoal may promote efficiencies that help stretch the budget in regards to those limits, but in the end, the most limiting nutrient before adding charcoal is probably still going to be the most limiting nutrient after adding charcoal.

What got me thinking about this was consulting soil scientist Doug Edmeades’ posts on soil organic matter. The first, Carbon farming: take-off or rip-off, explored how carbon sequestration efforts can cut both ways. The second, Soil Organic Matter Matters, hits on the most-limiting-nutrient.

Pasture plants need 16 nutrients. Without all 16 the clover will disappear, the pasture will be N deficient, the quality grasses will fail, pasture production would collapse followed by a need to cut back the stocking rate and, given sufficient years, a farm would be back to native pastures and bush. In the process soil carbon levels would decline.

Collapsed pasture production is no idle threat. We know that the collapse of legumes in pasture systems in Europe and in the eastern US helped motivate the expansion of the western US. Against that historical backdrop, Benjamin Franklin famously demonstrated sulfur deficiency when he added gypsum to alfalfa to form the words "This has been plastered". Doug Edmeades mentions this because soil carbon sequestration enthusiasts seem to have temporarily lost track of these limits. The same caution applies to charcoal.

There is great potential for increasing productivity through judicious use of charcoal. However, TP enthusiasts must not lose sight of the fact that charcoal cannot replace the need for adding mineral nutrients.

Sunday, June 08, 2008

Dynamic Earth blogs on Soil Science

Eric, over at Dynamic Earth is blogging on about soil science.

Soils are a lot like pornography: you know em when you see em, but everyone has a hard time agreeing on a definition.

True that. Eric's posts are a pretty quick study (its a blog after all) of a complex subject, and he does an admirable job of organizing the popular understanding of soil. I shouldn't expect, but I always look for, even the briefest nod to including energy as fascinatingly important to the understanding of soil, at least as equally fascinating as the physical, chemical, and biological characteristics.

Soil classification is only a beginning in pursuing a deeper understanding of the more dynamic characteristics of the soil resource. Nikiforoff's 1959 definition of soil as the "excited skin of the sub aerial part of the earth's crust". (ref) speaks to that energy. We all recognize that soil involves energy but we have been slow to engage in an understanding of that energy as a component of the dynamic earth.

Most of what has been studied regarding energy in soil is in relation to remediation of contaminants, preventing corrosion, waste treatment, and wetland chemistry: small but practical subsets of the knowledge we need. And we do use energy states and gradients to characterize soil (redox, pE), so it is not like energy is ignored. It is just that the labels we present it under do not communicate energy. Wetland chemistry, bioremediation, phytoremediation, geobiochemistry, soil ecology: these are not terms that alerts one to the fact that energy is the fundamental driver. That our soil projects are nonetheless successful points to the simplicity of the soil problems we have been addressing up until now. As we are challenged to better understand the energy dynamics of the earth, this is certain to change.

ref: C. C. Nikiforoff. 1959. "Reappraisal of the soil: Pedogenesis consists of transactions in matter and energy between the soil and its surroundings". Science 129: 186-196.

Sunday, June 01, 2008

Hephzibah Sludge

Been following the sludge story from Hephzibah, Ga.? If you work in support of biosolids, like I do, you should be.

Andy McElmurray, a farmer in Hephzibah, Ga., fed his dairy cows silage that had been fertilized with sewage sludge laced with heavy metals. More than 300 of them died.

In February, a federal judge ordered the Department of Agriculture to compensate McElmurray for losses incurred when his land was poisoned between 1979 and 1990 by applications of Augusta, Ga., sewage sludge. That sludge contained levels of arsenic that were two times higher than EPA standards allow; of thallium (a heavy metal used as rat poison) that were 25 times higher; and of PCBs that were 2,500 times higher.

What's more, milk from his neighbor's dairy farm was sent to market with thallium levels 120 times higher than those allowed by the EPA in public drinking water.

In his ruling, U.S. District Judge Anthony Alaimo was particularly critical of the EPA and the University of Georgia for having endorsed "unreliable, incomplete and, in some cases, fudged" data about the Augusta sludge. That corrupt data was presented to the National Academy of Sciences, which then cited it in their July 2002 assertion that sewage sludge does not pose a risk to public health.

Alaimo wrote, "Senior EPA officials took extraordinary steps to quash scientific dissent, and any questioning of EPA's biosolids program."

Our biosolids have incredible fertilizer value in terms of phosphorus and nitrogen, which is what pulls me into the mix. But it is valuable only to the degree that it can be trusted. Some biosolids can be trusted, some cannot. Let's do this thing, people.

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.


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.


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.


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.


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.


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.


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.


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


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.

Thursday, April 10, 2008

The Charcoal Vision

I want to shout this from the rooftops.

A Win–Win–Win Scenario for Simultaneously Producing Bioenergy, Permanently Sequestering Carbon, while Improving Soil and Water Quality by David A. Laird, USDA-ARS, National Soil Tilth Laboratory

Processing biomass through a distributed network of fast pyrolyzers may be a sustainable platform for producing energy from biomass. Fast pyrolyzers thermally transform biomass into bio-oil, syngas, and charcoal. The syngas could provide the energy needs of the pyrolyzer. Bio-oil is an energy raw material (~17 MJ kg–1) that can be burned to generate heat or shipped to a refinery for processing into transportation fuels. Charcoal could also be used to generate energy; however, application of the charcoal co-product to soils may be key to sustainability. Application of charcoal to soils is hypothesized to increase bioavailable water, build soil organic matter, enhance nutrient cycling, lower bulk density, act as a liming agent, and reduce leaching of pesticides and nutrients to surface and ground water. The half-life of C in soil charcoal is in excess of 1000 yr. Hence, soil-applied charcoal will make both a lasting contribution to soil quality and C in the charcoal will be removed from the atmosphere and sequestered for millennia. Assuming the United States can annually produce 1.1 x 109 Mg of biomass from harvestable forest and crop lands, national implementation of The Charcoal Vision would generate enough bio-oil to displace 1.91 billion barrels of fossil fuel oil per year or about 25% of the current U.S. annual oil consumption. The combined C credit for fossil fuel displacement and permanent sequestration, 363 Tg per year, is 10% of the average annual U.S. emissions of CO2–C.

Sunday, March 30, 2008

Soil organisms help ranchers

Intense, low duration grazing builds soil vitality, and increases soil organic matter.

Formulaically, the process described by Manske is very simple; what happens as a result is not.

A rancher chooses three pastures on which to graze the cattle. Starting in the first pasture, the cattle graze for 15 days, and then move on to the next pasture. This is repeated and the cattle find themselves in the third pasture.

Once the cattle leave the first pasture, the soil organisms go to work, converting the organic nitrogen into mineral nitrogen and feeding the plants, building their crude protein.

“Just by changing the management from focusing on dry matter poundage to managing those soil organisms, you can increase the productivity of your land,” Manske said. (Source)

Well observed.

Rhizosperic soil can get awfully puny under long duration grazing. Topsoil pales and topsoil depth is lost, but not to sediment discharge or wind erosion. The in-situ transformation of topsoil to not-topsoil results in the discharge of soil carbon to the atmosphere. The good news is that, unlike wind erosion, water erosion, sheet erosion, or gully erosion erosion, this yet-to-be-named variant of topsoil erosion is reversible.

Friday, March 28, 2008

Washington State Biochar Research

Washington State University researchers will produce biochar (a residue potentially used as a soil amendment) from low temperature pyrolysis of biomass materials. The biochar will be tested for its potential to store carbon, evaluated for any growth effects on plants in the greenhouse, and assessed for economic impacts. Research on biochar has shown promise in long-lasting carbon storage and improved crop production. This research will be the first rigorous study of biochar use in agricultural soils in this state. (Source)

Sunday, March 16, 2008

Stop Polluting My Biosolids

We would be well served if we stopped manufacturing unnecessary body soaps and scents. They end up in sludge, er biosolids and, as is necessary, on the land, where they can have unintended consequences. Let's just stop manufacturing the offending molecules.

Thursday, February 14, 2008

Home Buyers Will Pay for Soil, Won't Pay For Dirt

In 2003, the Snohomish County Public Works Department published a remarkable manual with a simple title: Building Soil (pdf). Promoting sediment-free stormwater, it encouraged builders to embrace the wisdom of retaining native soil and vegetation, and to question the value of turning soil into dirt for no good reason. From a building perspective, soil is a valuable construction material manufactured from a low cost/ low value soil resource feedstock. The thinking goes like this: Manipulating soil tidies up a site and adds value. Stormwater regulations interfere with the ability to add value, thus the disconnect.

Enter t
he Washington Organic Recycling Council which has a new site, www. buildingsoil.org, with a new and refreshingly non-regulatory spin for convincing builders to buy into the principles in the Building Soil manual. The pitch goes like this: Avoiding disturbance around the building footprint, in a sense, doing nothing, confers a marketable value on that soil resource.

New home buyers say they are happy to pay more for a healthy, easy to care for landscape – and that starts with the soil.
A timely message in a buyers' market.