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How many acres of soybeans are needed?

Published April 21, 2014

URBANA, Ill. – The USDA’s survey of U.S. crop producers last month revealed intentions to plant 81.493 million acres of soybeans this year. That is 3.765 million more than reported as planted or intended to be planted in June of last year, 4.96 million more than actually planted in 2013, and 4.042 million more than the previous record acreage in 2009. Planting intentions exceed last year’s acreage in every major soybean state except Missouri, with the largest increases reported for Minnesota, Nebraska, and North Dakota.  A slightly smaller percentage of plantings will likely be double-cropped acreage because soft red-winter wheat acreage was reported to be down by 16 percent from acreage of a year ago

According to University of Illinois agricultural economist Darrel Good, the large increase in soybean planting intentions reflects strong world demand for soybeans and the resulting high prices of soybeans relative to other crops, particularly corn.

“As the planting season gets underway, the job of the markets is to direct final planting decisions of major spring-planted crops,” Good said. “That is a complicated process surrounded by a lot of uncertainty about the nature of the growing season and resulting yields, as well as uncertainty about the strength of demand for U.S. crops during the year ahead. That demand strength depends on the magnitude of production in the rest of the world and a number of economic and political developments. There are differing and changing assessments of all of these factors. The market, however, must direct planting decisions without knowing the outcome of these important factors.  Ideally, production would be at levels that provide ‘reasonable’ prices for both producers and consumers of the crops and some level of reserves at the end of the year,” he said.

The USDA projects consumption of U.S soybeans and soybeans imported in to the United States during the current marketing year at 3.36 billion bushels, equal to the record consumption during the 2009-10 marketing year. Good said that consumption is large in spite of continued high prices and back-to-back record production of soybeans in the rest of the world during the 2012-13 and 2013-14 marketing years. World consumption of soybeans during the current marketing year is projected at a record 9.884 billion bushels, 40 percent more than consumed 10 years ago. 

“Much of the growth in world consumption has occurred in China, up 130 percent in 10 years,” Good said. “Although it may not be reasonable to expect Chinese consumption to continue to grow at the pace of the past 10 years, there is no sign of a reversal in consumption. The United States should continue to have a large share of exports to China even with another large South American crop in 2015. Record-high livestock prices and a likely increase in biodiesel production should keep domestic soybean consumption large as well,” he said.

According to Good, under the assumptions of “reasonable” prices, large South American production, and slower but continued growth in world soybean consumption during the year ahead, consumption of U.S. and imported soybeans should be at least as large as during the current marketing year. With stocks of soybeans at the start of the 2014-15 marketing year at the projected level of 135 million bushels, a 50 million bushel decline in marketing-year imports from the record level of this year, and a more comfortable level of year-ending stocks near 185 million bushels, the 2014 U.S. soybean crop would have to total 3.395 billion bushels to accommodate consumption of 3.36 billion bushels. That would be 106 million bushels larger than the 2013 crop and 36 million bushels larger than the record crop of 2009. With a favorable growing season and a U.S. average yield near-trend value of 44.2 bushels, a crop that size would require 76.8 million harvested acres of soybeans. The difference between planted and harvested acreage varies from year to year, depending primarily on the extent of adverse weather. The average difference in the previous 10 years was 970 thousand acres. With larger planted acreage and normal weather, abandonment near 1 million acres might be expected in 2014.  A crop of 3.395 billion bushels would require planted acreage of about 77.8 million.

“It could be argued that the projection of marketing-year consumption used here is too conservative under the assumption of lower prices,” Good said. “If use is 100 million bushels larger, planted acreage would need to be near 80.1 million under the other assumptions.  Additionally, the market may need to encourage even more acreage to reflect the risk of an average yield below-trend value. For example, consumption of 3.46 billion bushels and a yield of 43 bushels per acre would require planted acreage near 81.3 million acres. That is marginally less than reported planting intentions.

“Over the past 10 years, planted acreage of soybeans in the United States has differed by as much as 3.3 million acres from March intentions and the market still has some time to influence the magnitude of acreage in 2014,” Good said. “Unless conditions change dramatically it appears that planting intentions reported last month are fully adequate to meet consumption needs at more modest price levels than experienced during the past three marketing years.”

 

Do soybeans need nitrogen fertilizer?

Published April 18, 2014
soybean rows

URBANA, Ill. – According to a University of Illinois crop sciences researcher, there has been a great deal of interest recently in the idea of using nitrogen fertilizer during the growing season to increase soybean yields.

“This is somewhat surprising given that there has been so little evidence from published and unpublished reports showing that this practice increases yields, let alone provides a return on the cost of doing this,” said Emerson Nafziger.

Soybean plants in most Illinois fields produce nodules when roots are infected by Bradyrhizobium bacteria early in the season, Nafziger said. Bacteria growing inside these nodules are fed by sugars coming from the plant. “In one of the more amazing feats in nature, these bacteria are able to break the very strong chemical bond between nitrogen atoms in atmospheric nitrogen gas (nitrogen gas makes up some 78 percent of the air but is inert in that form.) This ‘fixed’ nitrogen is available to the plant to support growth,” he said.

The soybean crop has a high requirement for nitrogen; the crop takes up nearly 5 pounds of nitrogen per bushel, and about 75 percent of that is removed in the harvested crop. Nafziger explained that it is generally estimated that in soils such as those in Illinois, nitrogen fixation provides 50 to 60 percent of the nitrogen needed by the soybean crop. A small amount of nitrogen comes from atmospheric deposition, including some fixed by lightning. The rest comes from the soil, either from that left over from fertilizing the previous corn crop or from soil organic matter mineralization carried out by soil microbes.

Nitrogen fixation takes a considerable amount of energy in the form of sugars produced by photosynthesis in the crop. “Estimates of the amount of energy this takes range widely but could be in the vicinity of 10 percent of the energy captured in photosynthesis, at least during part of the season,” Nafziger said. “Because photosynthesis also powers growth and yield, it seems logical that the crop might not be able to produce enough sugars to go around, especially at high yield levels, and that either yields will suffer or nitrogen fixation will be reduced.”

Would adding nitrogen fertilizer fix this problem and result in higher yields?

Nafiziger explained that he has looked at adding nitrogen fertilizer in a series of trials over the past several years, with some of the research funded by the Illinois Soybean Association. These studies involve application of urea, in some cases with Agrotain® (urease inhibitor) or as ESN (slow-release nitrogen) during mid-season, usually in July.

Yields ranged widely among these studies, from in the 30s to nearly 90 bushels per acre. But in only one case did adding nitrogen fertilizer significantly increase yield (by 6 bushels per acre), he said. There was no relationship between yield level and response to nitrogen fertilizer.

“These results provide no support for the idea that the higher the yield, the more response to fertilizer nitrogen. In fact, yields above 70 bushels seemed more likely to show yield decreases from adding nitrogen, though these differences were small and not statistically significant,” he said. 

While these results don’t prove that adding nitrogen fertilizer can’t increase soybean yields, Nafziger said it’s clear that it shows that an increase cannot be expected.

“It is possible that soils often contain more nitrogen than we realize, especially under good mineralization conditions, which are also good growing conditions. It is also possible that we don’t really understand the photosynthetic capacity of soybeans under field conditions, and that our guessing that yield is limited by photosynthetic rates when the plant is also fixing its own nitrogen is just incorrect,” he said.

The usual signal of nitrogen deficiency in crops – light green leaves – is rarely seen in soybean plants during the period of pod setting and seed filling, unless the crop is under prolonged drought stress. Late in seed filling, leaves start to mobilize their nitrogen as chlorophyll and photosynthetic proteins break down and much of this nitrogen moves to pods and into seeds as photosynthesis winds down. Nafziger said if there was a way to get more nitrogen into the leaves early in this process, it might be possible to maintain photosynthesis longer and move more material into seeds. “But it is clear that getting this to happen consistently will be difficult, especially under an unpredictable water supply,” he said.

“Until and unless we find a way to learn to make nitrogen application to soybeans work consistently, or in most cases to work at all, this practice increases both economic and environmental risk. Under dry late-season conditions, such as those we experienced in 2013, much of the nitrogen we apply will fail to get into the plant, but will stay in the soil and become part of the mobile pool of soil nitrogen going into the fall,” Nafziger said.

The crop scientist recommends putting in strip trials in farm fields to get a better look at nitrogen on soybeans over a wide range of fields and soils. He explained that these can be done using aerial or ground application but that ground application is easier to track.

Researchers question published no-till soil organic carbon sequestration rates

Published April 18, 2014
corn plants

URBANA, Ill.  For the past 20 years, researchers have published soil organic carbon sequestration rates.  Many of the research findings have suggested that soil organic carbon can be sequestered by simply switching from moldboard or conventional tillage systems to no-till systems. However, there is a growing body of research with evidence that no-till systems in corn and soybean rotations without cover crops, small grains, and forages may not be increasing soil organic carbon stocks at the published rates.

“Some studies have shown that both moldboard and no-till systems are actually losing soil organic carbon stocks over time,” said University of Illinois soil scientist Ken Olson who led the review.

The review was conducted by a team of senior researchers from universities in Illinois, Wisconsin, Iowa, and Ohio who studied the published soil science and tillage literature related to soil organic carbon sequestration, storage, retention, and loss. After examining hundreds of original research and summary papers, 120 papers on all sides of the soil organic carbon sequestration, storage, retention, and loss issue were selected for review and analysis.

Olson explained that the difference between the no-till and moldboard plots at the end of a long-term study is only a measure of net soil organic carbon storage difference between treatments and does not support soil organic carbon sequestration claims. No-till systems on sloping and eroding sites retain more soil organic carbon in the surface from 0 to 15 centimeters when compared to moldboard as a result of less disturbance and less soil erosion and transport of soil organic carbon-rich sediment off the plots.

“The subsurface layers also need to be sampled and tested to the depth of rooting or 1 or 2 meters,” Olson said. “That no-till subsurface layer is often losing more soil organic carbon stock over time than is gained in the surface layer.”

During the analysis of the work, Olson said that it became apparent that there were a number of reasons for the conflicting findings, including the definition of soil organic carbon sequestration used by different researchers.

The team proposed the definition of soil sequestration be: the process of transferring CO2 from the atmosphere into the soil of a land unit through unit plants, plant residues, and other organic solids, which are stored or retained in the unit as part of the soil organic matter (humus). To claim soil organic carbon sequestration, management practices must lead to an increase in the net soil organic carbon from a previous pre-treatment baseline measurement and result in a net reduction in the CO2 levels in the atmosphere.  Carbon not directly originated from the atmosphere (from outside the land unit) cannot be counted as sequestered soil organic carbon. These external inputs may include organic fertilizers, manure, plant residues, topsoil, or natural input processes such as erosion of a sloping soil and sediment-rich carbon deposition on a soil located on a lower landscape position or in a waterway. The land unit could be a plot, plot area, parcel, tract, field, farm, landscape position, landscape, wetland, forest, or prairie with defined and identified boundaries.

The team identified a number of other methodological factors that could lead to errors in reported soil organic carbon sequestration rates, including: using inappropriate experimental methods; not collecting and testing the deeper surface layers; lack of soil bulk density measurements; not accounting for carbon in amendments being loaded on the plots from external sources; use of different soil organic carbon laboratory methods  over the long-term study; effects of soil erosion; transport and deposition on the experimental tillage plots;  lack of sloping and eroding sites included in summary studies; natural variability that was not captured by the sampling scheme; only sampling the plot areas once when trying to determine rate of change; insufficient frequency of sampling; and relying on an assumption that after 100 years of cultivation and before the tillage treatment was applied that the soil organic carbon had dropped 20 to 50 percent but was now at a steady state.

Olson said that aeration, drainage, tillage, disturbance, more intensive crop rotations, use of synthetic fertilizers, erosion and lack of cover crops can all result in reduced soil organic carbon stocks.

Because it would take 20 to 50 more years to design and run such a study, the team found a long-term study that had all the required soil property data collected for the root zone or to a depth of 1 or 2 meters from before the tillage treatments were applied and sampled frequently during and at the end of the study. This study is located at U of I’s Dixon Springs Agricultural Center with tillage plots that are part of a North Central Region Soil Erosion and Productivity Committee study and located on a Grantsburg soil with a fragipan at 75 centimeters, moderately eroded, on 6 percent slopes and with six replications.

Olson said that the accuracy of determining soil organic carbon sequestration depends on the method used. “In this review, both the paired comparison method and the pre-treatment soil organic carbon method were tested using the same plots and experiment,” he said.

The results of this comparison showed that the paired-method (no-till compared to moldboard) overestimated soil organic carbon sequestration as compared to pre-treatment method, where both no-till and moldboard compared to the same pre-treatment baseline.  “Another flaw in the paired comparison method is that the results could not be validated where no pre-treatment baseline is available,” Olson said.

The team of researchers recommend: (1) that researchers trying to determine and measure soil organic carbon sequestration rates no longer use the comparison method and adopt the pre-treatment soil organic carbon method, and (2) that existing long-term studies that researchers want to use to determine soil organic carbon sequestration rates be stopped temporarily and sampled following the soil organic carbon sequestration protocol outlined in their article.

“Because these long-term studies are used for crop-yield determinations they need to be re-started without interruption, and soil sampling can be done during the non-growing season,” Olson said. “Then the long-term experiments can be used to measure soil organic carbon sequestration rates.”

“Experimental Consideration, Treatments, and Methods in Determining Soil Organic Carbon Sequestration Rates,” authored by Kenneth R. Olson, Mahdi M. Al-Kaisi, Rattan Lal, and Birl Lowery, was published in Soil Science Society of America Journal and is available free at https://www.soils.org/publications/sssaj/pdfs/78/2/348.

“Soil organic carbon sequestration, storage, retention and loss in U.S. croplands: Issues paper for protocol development,”  authored by Kenneth R. Olson, was published in Geoderma is available  free at http://www.sciencedirect.com/science/article/pii/S0016706112004211.

 

Illinois Wheat Association hosting winter wheat tour

Published April 16, 2014
wheat

URBANA, Ill. - Illinois wheat growers will have an opportunity this May to tour winter wheat fields in order to make observations that will factor into yield estimates of the 2014 winter wheat crop.

The Illinois Wheat Association (IWA) is hosting the Southern Illinois Winter Wheat Tour on Wednesday, May 28. The tour will include field checks during the day with an evening report session at Brownstown Agronomy Research Center. Prior to the evening meal, yield estimates will be calculated and attendees will have an opportunity to view wheat variety and seed treatment trials. Fred Kolb, University of Illinois professor of small grain breeding; Emerson Nafziger, U of I professor and Extension agronomist; and Robert Bellm, U of I Extension educator in commercial agriculture  and crops, will be on hand to discuss wheat development and wheat diseases. 

Tour participants will meet at 9 a.m. at one of four locations: Siemer Milling Co., 111 W. Main St., Teutopolis (217-857-3131); Mennel Milling Co. of Illinois, 415 E. Main St., Mt. Olive (217-999-2161); Wehmeyer Seed Co., 7167 Highbanks Rd., Mascoutah (618-615-9037); and Wabash Valley Services Co., 1562 Illinois 1, Carmi (812-483-2966). Participants are asked to call in advance with the location from which they would like to depart.

Reservations for dinner must be made by May 23 and can be done by contacting the IWA office at 309-557-3619 or by email at cblary@ilfb.org.

Those wishing to take samples on their own and join the group for the dinner and wrap-up are also asked to contact the IWA by May 23. IWA will provide the tour instructions to those taking independent samples. Sampling procedures can be found on the wheat website at http://www.illinoiswheat.org/events.html.

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