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Looking Back on the Past 75 Years of Soil Fertility in the t's hard to imagine what the of soil testing was a tool that was world would be like without the chosen to really make a difference in Iyield increases we've seen over many of these places. Simple 'do it the last several decades. A 50- or yourself soil test kits were the start- 60-year period where yields are flat ing point for this effort." seems unthinkable, yet this was The soil test kits used very simple the case in the latter half of the 19th chemistry that still exists. "We're century into the early 20th century currently working with a bunch of before agronomy organized itself as National Guard soldiers from Kan- a scientific discipline and soil-testing sas in Afghanistan, and we're using methods were developed. During this same technology," Mengel said. this year's Leo M. Walsh Soil Fertil- "And I've learned over the last six ity Distinguished Lecture at the months that Afghanistan has very November 2009 Annual Meetings high phosphorus levels because they in Pittsburgh, David Mengel, a pro- were tested with a LaMotte test kit." fessor of agronomy at Kansas State In 1914, Emil Truog, from University and an ASA-SSSA Fel- the University of , low, talked about the period around developed one of the first 1920 through World War II, which soil tests—a zinc sulfide he characterized as the "soil testing/ acidity test for farmers and problem solving era." county agents. "I grew up in the whole era of "It was a simple little test surpluses and concerns about how where you put soil in a little do we get rid of all this stuff we can crucible, added a liquid, produce, but that wasn't the case at boiled it, and with zinc sul- the turn of the 20th century," Mengel fide added, fumes came off said. "Erosion and nutrient depletion that turned a lead acetate pa- were really reducing both productiv- per black," Mengel explained. ity and productive acres in the U.S. "So it was sort of semi-quanti- The Great Depression, Dust Bowl, tative—the blacker it got, the and urbanization would all acceler- more lime you needed. But it ate that trend as we went on into the was a very important tool that was 1930s and 1940s, so the situation was used very widely." much different." In the 1920s and 1930s, Truog and Another thing that was differ- others, such as Roger Bray from the ent was the state of the science at University of Illinois, C.H. Spurway the time. ASA was first organized from Michigan State University, in 1907, and so the discipline of Michael Peech from Cornell, and agronomy was just getting started. M.F. Morgan from University Two years later, the concept of pH of Connecticut, developed field was first introduced. It would be test kit procedures to measure another 20 years until working pH pH, phosphorus, and potassium. meters and glass electrodes became "Most of the kits used either available and another 20 years after some sort of a pH by indicator that before flame photometers were dye, the Truog test, or a thiocya- widely used in the U.S. nate test to measure pH or acidi- ty," Mengel said. "Phosphorus was The Test Kit Years measured using various dilute ac- "By the early 1900s, agronomists ids, and ... potassium was measured and soil scientists were beginning to turbidimetrically by coboltinitrate look for ways to increase yields and application." restore productivity to what they Many states began equipping their county agents and specialists termed 'exhausted' soils," Mengel The top photo with some of these kits to do field- shows an early soil test said. "Soil testing addressed some of being used on a farm in 1942. Photo those important issues, particularly and farm-based soil testing, Mengel courtesy of Library of Congress Prints and said. Illinois promoted soil testing as Photographs Division, Washington, DC. The middle two acidity and phosphorus and potas- photos show the exterior and interior of a soil fertility train. a "do it yourself" project where its Photos courtesy of David Mengel. The bottom photo shows sium concentrations. The availability a Truog soil test kit. Photo courtesy of David Mengcl.

March 2010V55N03 CSA News 5 county agents encouraged farmers anymore—these people do environ- At the end of World War II, there to bring samples in and then taught mental testing, feed sampling—a lot was a readily available supply of them how to do the tests themselves. of those sorts of things." fertilizer, particularly nitrogen, Hoeft Soil fertility trains soon began These days, large independent explained. The plants that were used traveling the Midwest testing soils labs are becoming the dominant for munitions during the war were for farmers. In addition to "soil doc- players in the soil-testing business now free to be used for something tors," the trains featured exhibits, as the number of state labs rapidly else, and at the same time, the U.S. labs, lectures, and even motion pic- decreases, Mengel said. One of the began using more petroleum. tures. They later evolved into lime downfalls of this is that it has been "Petroleum increased markedly, trains in Indiana and rock phosphate accompanied by a decline in soil- and as a result, so did refineries, and trains in Illinois in the 1930s and testing research. In Mengel's lab, the those refineries had a by-product of 1940s, transporting these materials most recently developed procedure hydrogen," Hoeft said. "And you throughout the state for farmers to they use is the Mehlich-3 phospho- ended up with the petroleum indus- load into their trucks. rus extraction, which was published try getting into the fertilizer market in the late 1970s. because they were using that hydro- Instrumentation and Labs Small labs also began to develop "A lot of our procedures are getting some seniority. Many during this time, particularly at uni- of them are plagued by issues of generation of hazardous versities but also at state agencies and even some businesses, Mengel waste. We need some more additional work going on!' said. Most continued to use soil test kit type technology until the "A lot of our procedures are get- gen in the Haber-Bosch process for mid-1930s. Advances in technology ting some seniority. Many of them ammonia production." in the late 1930s to 1940s led to the are plagued by issues of generation In the late 1950s and early 1960s, development of new, more precise of hazardous waste. We need some anhydrous ammonia was selling for instruments like pH meters and more additional work going on." less than $.05 per pound of nitrogen, glass electrodes, colorimeters, flame w-hJcTThad quite an impact-eojertil- photometers, and procedures like the The Fertilizer Era zefuse, according to Hoeft. lime requirement buffer test. There was plenty of soil fertili "I can remember farmers back Local county or company labs work going on after World War home saying, 'Well, if a little is gooc were common in the late 1930s according to Bob Hoeft, soil fertility a lot is better because as cheap as it is through the 1960s, and many still professor at the University of Uinois we can't get by without it.' The rate exist today. Some were operated by and an ASA-SSSA Fellow and for- were much, much higher than we'/e extension offices, USDA-SCS (now mer ASA president. Hoeft cov ered using today. I don't even want to, NRCS), or by fertilizer dealers or the "fertilizer era," the time roughly say what some of the rates were/-it other companies with farmer clients after the war through the late 1970s was about as much as they could get such as Campbell's Soup. During to early 1980s. He said fertilized sales through those applicators ana not the 1940s and 1950s, most land grant skyrocketed during this period. smoke themselves out of the field." universities established a central or "There were a state soil-testing lab, and in the 1950s number of things and 1960s, many state and regional that happened. i.S. Fertilizer U: co-ops and fertilizer manufacturing One was that by sales organizations established labs. the end of World "Testing volume exceeded 200,000 War II, science re- 14000 samples per year by the 1960s in ally took off a little many states," Mengel said. "Total bit more in terms testing in the U.S. peaked in the mid- of agriculture. We 1960s at about 3 million samples, had a number of -Nitrogen -Phosphorus but if you look at some of the more really talented in- Potassium recent information on soil sampling, dividuals working we're back to that [level] now. in the soil fertility "Private testing companies really area. And farmers started coming into play in the 1960s could easily see 19SO 1960 1970 1990 2000 2010 and 1970s.... Today, many of these the economic re- organizations play a really key role turn to the use of in a lot of states in providing testing fertilizers." Nitrogen, phosphorus, and potassium fertilizer use since services. And it's not just for soils 1950. Graph courtesy of Bob Hoeft.

6 CSA News V55 N03 March 20 Another reason for the increase in followed such as etridiazole (Dwell), fertilizer sales was the shift in agri- dicyandiamide, and ammonium culture from grain/livestock opera- thiosulfate. These products worked, tions to grain only, Hoeft noted. Hoeft said, but in some cases, they "We moved away from livestock still didn't solve the problems of fall operations, and when we did that, application of ammonia. we had the definite need for more Urea came into the market place nitrogen because now we didn't in the 1970s and 1980s, but it didn't have legumes that we were grow- take long for farmers and scientists ing to feed the cattle and we didn't to recognize that it had loss prob- have the manure supply, so it really lems as well. After application, if you pushed us in that direction." didn't incorporate it either physically During this time, ammonia was or with a rain, you could count on the primary fertilizer being used, some loss, Hoeft said. That spurred Hoeft said, but it had its detractors the development of urea additives who said it destroyed soil flora, to inhibit some of the urease fauna, and physical properties and activity. was toxic to plants. Research out of New ways of applying the University of Florida and other fertilizer were also devel- places showed that ammonia did not oped. Early on, much of the have a negative impact on flora and fertilizer being used was fauna unless there was a direct ap- chemically manufactured plication. Work out of Kansas State and came in a bag, which was University showed that ammonia emptied into a drop spreader, was no worse than other nitrogen Hoeft said. Unfortunately, fertilizers in terms of soil physical you couldn't cover many properties. Other research found that acres in a day this way. In the problems with plant toxicity could 1950s, fertilizer manufactur- be mitigated by separating the am- ing shifted from these chemi- monia and the plant in either time or cally manufactured products space. to granulated materials, which * Even as some of these concerns could then be blended. Blending al- with ammonia were being worked lowed the use of spinner spreaders, out, other problems emerged in try- which could cover a lot more ground ing to keep up with the increasing in a short period of time, but they g enough weren't ail that good at distribution, paes to store and move"sthat much according to Hoeft. Next came air- roduct in a very short time p,eriod flow applicators, which did improve in the spring proved difficult. distribution somewhat. "I'm not sure if it was completely However, the distribution of by design, but one thing that was the immobile nutrients phos- done was fertilizer prices in the fall phorus and potassium in the soil were less than fertilizer prices in the became an issue as tillage prac- spring. This encouraged people to tices shifted more to no-till. store it in the soil. We all know today t "That worried a lot of agrono- that that's probably not the best way/ mists," Hoeft said. "To be quite to do it, at least upon some fields. honest, it worried them a lot more But this led to another whole rej than it worried the plant. For .of soil fertility. Tt lead to peoprelook- most plants, it didn't really make for ways to make it^arcr." a whole lot of difference. People these_wayswas to keep wanted to know about using starter the fertilizer in the soil longer by [fertilizer], but they didn't want to slowing down the conversion of am- go back to using the full rates that nducting ab in 1942. monium nitrogen to nitrate nitrogen they had in the past. They wanted to f Library ot Congress Prints and Photographs Division (LCPPD), with nitrification inhibitors. Dow use what some called 'seed placed,' Washington, DC. Dumping fertilizer into a potato seeder. developed the first inhibitor in 1962, others called 'pop up,' and those of Photo courtesy of LCPPD. Anhydrous ammonia fertilizer. Photo courtesy of Howard F. Schwartz, State nitrapyrin (N-Serve). Others soon University. Bugvjood.org. Phosphorus loading into a stream. Photo courtesy of Gyles Randall.

March 201OV55N03 CSA News 7 us who saw it very often called 'pop being a source of nitrates in ground 1996. Research along the Central down.'" and surface waters. Platte River in Nebraska showed Subsequent research showed that "And that brought out the worst rapidly increasing levels of nitrate the seed-placed fertilizers delayed in some of us easy-going scientists," in well water associated with high and reduced emergence. If the plant Randall said. "People who were kind rates of nitrogen fertilizer applied to survived, it grew better, "but you of calm got very feisty and defensive these irrigated soils. Nitrate losses never knew how many were going to all of a sudden because all we'd done to drainage water in and come up," Hoeft said. is measured the yield and profit were more strongly related to benefits to the nitrogen we applied. rate of nitrogen application than to The Environmental Era But Commoner's warning was good time of application or nitrification Gyles Randall, a soil scientist and because it got our attention, and we inhibitors, but nitrogen management professor at the Southern Research started to look at the broader aspect had less effect on nitrate loss than and Outreach Center at the Univer- of nitrogen management." cropping system. sity of Minnesota and an ASA-SSSA During the 1970s and 1980s, Ran- Eutrophication of surface waters Fellow, rounded out the lecture by dall said a good number of research- as evidenced by unsightly algal talking about the last 25+ years, ers and extension people began to growth is often caused by elevated which he labeled the "environmental work on nitrogen management in- levels of phosphorus. Loss of soluble era." cluding sources, placement, uptake, phosphorus to drainage water from Much of the research and educa- and efficiency. At the same time, high rates of manure was docu- tion during this period has focused drainage research facilities were be- mented by Cornell scientists in the on the loss of nitrogen and phospho- ing developed around the world to early 1980s, according to Randall. rus from fertilizer and manure. Loss- help track the movement of nitrogen Further research in Canada, Den- es of nitrogen as nitrate to ground through the soil and into subsurface mark, England, and New Zealand and surface water and into the air as drainage. Researchers also began since 1995 has shown high levels of ammonia, nitrogen gas, and nitrous investigating how cropping systems dissolved ortho-phosphate in drain- oxide have been, measured around affect nitrogen loss. The data showed age water associated with manure the world. Phosphorus losses to that the both the discharge of water and fertilizer applied under specific surface waters by various pathways out of tile lines and the nitrogen con- soil conditions. Randall said a lot of have also received a lot of attention. centration in that water were quite a this research has been translated into Randall pointed to early work by bit higher from the row crop annuals state reports and extension bulletins L.D. Owens from the USDA-ARS in than from the perennials. that have helped reduce losses of ni- 1960 and later work by R.J. Olsen "When multiplying increased trogen and phosphorus. and colleagues from the University flow times increased concentration, "We have accomplished much by of Wisconsin in 1970 that led to a bet- one finds 30 to 50 times more loss providing packages of agronomic, ter understanding of the movement out of the corn and soybean system economic, and environmental infor- of nitrogen through soils. Later in the than the perennials," Randall said. mation. We've definitely strength- 1970s, he said Barry Commoner, an During the 1980s and 1990s, ened state nutrient guidelines and ecofogist from Washington Universi- considerable research was being identified appropriate BMPs. These ty in St. Louis, MO, and others began conducted to determine the role of are being used when addressing ni- pointing the finger at agriculture as nitrogen rate, time of application, trogen and phosphorus impairments and nitrification in streams through the total maxi-

SOIL NO3-N. ppm inhibitors on ni- mum daily load process and when 15 o s 10 is trate movement developing the P index. Other ex- SEPTEMBER 9, in well-drained amples include developing nitrogen 1963 soils as well as to management policies in Nebraska's streams through Natural Resource Districts and pro- tile drainage. viding insight into agriculture's con- High rates of ni- tribution to high nitrate levels in the trogen applied and hypoxia in the to deep silt loam Gulf of Mexico. soils in the early "I think the research and educa- 1970s produced tion that was conducted during the very high nitrate 'environmental era' has been greatly Graph from a paper by R.J. Olsen et al. in 1970 (Soil Sci. Soc. concentrations beneficial to farmers, the general Am. J. 34: 448-452) showing movement of nitrate nitrogen in between 40 and 65 public, and our natural resources. a fallowed Plainfield sand over an eight-month period fol- ft deep in south- This work will be increasingly im- lowing application of ammonium nitrate on 1 Aug. 1968. western Iowa by portant in the future."

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