Corn and soybeans are typically planted sometime in May and mature from mid-to late September. Consequently, their growing seasons in NY are considered to occur from May 1 through September 30, with the understanding that an additional ~100 growing degree days (GDD) can be accumulated in October before the first fall frost; offsetting the loss of ~100 GDD from May 1 until either crop is planted. The 2014 growing season started slowly for both crops because of wet conditions during the first 20 days of May in most grain corn and soybean growing regions. Consequently, only 15% of corn and less than 1% of soybeans had been planted in NY by May 15th. The second half of May was dry in most regions so 58% of corn and 31% of soybean had been planted by June 1. By June 8th, 79% of corn and 46% of soybean had been planted by June 8th. Consequently, almost half of the NY corn crop (probably 75% of the grain corn crop) did not accumulate the typical 300 GDD that most grain corn and soybean regions receive in May. In addition, growing conditions were cool from mid-July though most of September and there were reports of isolated frost in some parts of the state on the morning of September 19th. So what is the outlook for grain corn and soybeans in NY in 2014?
In many respects, the 2014 growing season was similar to the 2013 growing season; mostly wet soil conditions in the spring and summer, followed by cool August and September conditions, and even a light frost in isolated pockets of the State in mid-September, although not in the major grain corn and soybean growing regions. So let’s examine both growing seasons and see if the 2014 crops will be similar to the 138 bushel/acre corn crop (3rd highest state average on record) and the 48 bushel/acre soybean crop (tied for the highest state average on record) in 2013. About 70% of the grain corn and 85% of NY soybeans are grown in western NY and the Finger Lakes regions so my discussion will mostly be in the context of the growing season in those regions.
The second half of May and the month of June were exceedingly wet in 2013 (Table 1), resulting in drowned out grain corn in poorly drained areas of many fields. In addition, the somewhat poorly drained areas of most fields had stunted corn that was yellow during grain-filling because most of the pre-plant or at planting N fertilizer denitrified. Despite ideal growing conditions for the remainder of the 2013 growing season (more than adequate precipitation in July and August and below normal growing degree days from July 20 through September, Table 2), the damage had been done. So instead of the projected 150 bushel/acre grain corn yield ,based on grower surveys in October and November (who apparently were just looking at the high-yielding corn in the drained areas), the final crop came in at 138 bushels/ acre because of the early-season damage to the crop. Soybeans, on the other hand, are not quite as sensitive to wet soils in June and can fill in somewhat if gaps occur due to drainage problems. Consequently, soybean yields came in 1 bushel/acre higher than the projected 47 bushel/acre crop, based soybean grower surveys in October and November.
What about the 2014 crops? Well, the late planting of corn in 2014 may have been been a blessing in disguise (because both crops avoided the wet May conditions and most of the ensuing problems that the 2013 crops suffered from). Despite somewhat wet June soil conditions, only the poorly drained areas (and not the somewhat poorly drained areas of each field) suffered some stunting of growth and much less denitrification of pre-plant or at planting fertilizer N compared to the 2013 growing season. In addition, July was wet as was the first half of August in most regions so corn was essentially stress-free through the early grain-filling period. Some grain corn fields did encounter dry conditions during September but temperatures were cool so minimal stress would have been incurred. Likewise, soybeans never experienced any real drought stress in August and September because of the cool conditions. Consequently, based on soil and growing conditions in 2014, the September projected 2014 corn yield of 150 bushels/acre and a record soybean crop of 49 bushels/acre in NY might be right on.
But what about the late planting date for both crops, coupled with the perceived cool growing season? Will that hurt the 2014 corn crop and reduce the projected yield from 150 bushels/acre to 138 bushels/acre as in 2013? Believe it or not, western, eastern and northern regions of NY had above average growing degree days from June 1 through September 30 so delayed planting in those regions are not much of a concern (Table 2). In the Finger Lakes region, however, total GDD from June 1 until September 30 were about 100 below normal (Table 2), raising concerns about crop maturity. Most grain corn and soybean fields in Western NY and the Finger Lakes fortunately have not had a frost event and no frost is in the forecast through mid-October for those regions. In addition, both regions have already accumulated an additional 50-60 GDD through the first 5 days of October. Consequently, if the growers scaled back their hybrid maturity and the crop silked out by early August, enough GDD should have accumulated before a frost so grain corn should mature, albeit with delayed harvest well into November. If growers did not scale back their hybrid maturity when planting grain corn during the first week of June in the Finger Lakes, maturity could be an issue. Soybeans, on the other hand, respond more to photoperiod when planted in June so even if soybean growers did not scale back maturity, soybeans should make it (a 2.4 Maturity Group that we planted in a planting date study at Aurora on May 29 was at maturity or the R8 growth stage on October 1 and planted on June 11 was at the R8 growth stage on October 7th). So I am not concerned with maturity for most of the soybean crop.
In conclusion, despite another very challenging and yes stressful year from a grower perspective (delayed planting in the spring and fear of potential frost in the fall), yields, according to the grower surveys in September, should come to fruition. The next report is due on October 10th , based on growers surveys in late September, and I hope that the isolated frost reports in the non-major grain corn and soybean growing regions don’t bias the yields down. In fact, light frosts occurred in isolated pockets of these regions on the morning of September 17th in 2013 (31 in Ithaca and Watertown), which escaped the September 19th frost of 2014 (32 in Ithaca and Watertown). So in many respects the 2013 and 2014 growing seasons, including the light September frosts in isolated pockets, were similar, which should bode well for soybean yields. For grain corn, the blessing in disguise of the delayed planting date probably reduced crop damage during vegetative growth compared to 2013,, resulting in 5-6% higher State yields or about 150 bushels/acre. We won’t really know until the crops are in the bin so let’s hope for a great harvest season for both crops.
Bianca Moebius-Clune, Margaret Ball, Harold van Es, Jeff Melkonian – School of Integrative Plant Science, Soil and Crop Sciences Section – Cornell University
Adapt-N is an on-line tool that provides location-specific, weather-adjusted nitrogen (N) recommendations for corn. At sidedress time, critical early-season weather that strongly influences actual N needs is incorporated into the recommendation. To accomplish this, the tool uses 1) a simulation model that was developed and calibrated through field research over several decades, 2) high resolution 2.5 x 2.5 mile daily temperature and precipitation information, and 3) soil and crop management information entered via a web interface on any internet-capable device. Adapt-N’s cloud-based environment (central data server, high security, and accessibility through desktop, laptop and mobile devices, future embedding in other farm software) offers a user-friendly experience.
We conducted a total of 104 strip trials in 2011, 2012, and 2013 in New York and Iowa (Figure 1) to beta test Adapt-N for its ability to improve recommendations for corn N need at sidedress time. Yield data and simulated losses across trials show that the Adapt-N tool significantly increased grower profits, while decreasing N inputs and environmental losses, as summarized in this article. In 2014, Adapt-N was commercialized through a public-private partnership between Cornell University and Agronomic Technology Corporation (ATC, see http://www.adapt-n.com/). The partnership aims to sustain and broaden the tool’s availability, customer service, usability, and integration with existing farm management technologies, while allowing for continued research and development at Cornell University.
We completed 67 replicated strip trials in New York (14 in 2011; 42 in 2012; 11 in 2013) and 37 trials in Iowa (9 in 2011; 19 in 2012; 9 in 2013) on commercial and research farms throughout each state (Figure 1. One 2012 trial in Minnesota is included with the Iowa trials).
Sidedress treatments involved at least two rates of nitrogen, a conventional “Grower-N” rate based on current grower practice (G) and an “Adapt-N” recommended rate (A). An Adapt-N simulation was run for each field just prior to sidedressing to determine the optimum weather-adjusted N rate.
Yields were measured by weigh wagon, yield monitor, or in a few cases by representative sampling (two 20 ft x 2 row sections per strip). Partial profit differences between the Adapt-N and Grower-N practices were estimated using prices of $0.50/lb N, $5/bu grain, $50/T silage, and $8/ac operational savings if sidedress was avoided in either the Adapt-N or Grower treatment. Yields were used as measured, regardless of statistical significance, since the statistical power to detect treatment effects for a single experiment is inherently low.
Total N losses to the environment (atmosphere and water) and N leaching losses were simulated by Adapt-N for each N treatment, through the end of each growing season. End dates for N loss simulation were October 30, 2011 (NY trials only), December 15, 2012, and December 31, 2013.More detailed descriptions of each year’s methods and results were provided in previous WCU articles (Moebius-Clune et al., 2012, 2013, and 2014).
Agronomic and Economic Comparison
Adapt-N rates resulted in average N input reductions of 52 lbs/ac in NY, 29 lbs/ac in IA, and 44 lbs/ac overall (Table 1). Profit gains from the use of Adapt-N were considerable. Profits increased in 81% of all NY trials, in 70% of all IA trials, and in 77% overall when growers followed Adapt-N recommendations (Figure 2). Profit gains of $30/ac on average ($37/ac in NY, $17/ac in IA) were obtained most frequently due to reductions in N inputs, without significant yield loss: +1 bu/ac on average across all trials. Most collaborating growers were already using progressive N management including sidedressing, so that benefits achieved in these trials can be considered to be a conservative estimate of potential benefits of using Adapt-N. Benefits will be higher for growers who currently use few N best management practices.
Decreased N rates: Adapt-N recommended a lower N rate than grower practice in 84% of trials, by 60 lbs/ac on average (Table 1). Such recommendations occurred after a normal or dry spring, when N from spring mineralization or early fertilizer applications remains available to the crop. Yield losses were generally minor, averaging -2 bu/ac across trials with N reductions, and leading to profit gains in 79% of cases – on average $23/ac (Table 1, Figures 2 and 3). This implies that a grower is about four times more likely to achieve increased profit from a reduced Adapt-N rate than from their current higher rate. This statistic includes all trials over three years, although model improvements have been made each year based on trial information, such that actual probabilities of increased profit with reduced N inputs are likely further improved for future years.
Increased N rates: Even larger profit gains of $65/ac on average were achieved when Adapt-N recommended increasing N inputs over the grower’s current practice in 16% of trials. Consequent average yield increases of 17 bu/ac across these trials were achieved for an average additional 38lb/ac fertilizer application (Table 1). Such higher recommendations occurred primarily in 2013 ($94/ac profit on average in NY 2013 trials), and in select locations in other years, after a wet spring. Needs for additional N were correctly identified in 65% of these cases, resulting in significant yield and profit increases. In 35% of cases, on the other hand, the additional N was not needed. In almost all of these cases, unpredictable post-sidedress drought decreased yield potential below the expected yield that was used for the recommendation at the time the sidedress rate decision had to be made (Moebius-Clune et al., 2013).
Profit loss when under-fertilizing (from reduced yields) is generally larger than when over-fertilizing (from unnecessary fertilizer application). Thus lower recommendations to account for potential future yield-limiting events cannot be justified for economical sidedress recommendations. By contrast, pre-sidedress weather events affecting yield potential and N availability are known, and Adapt-N can effectively manage this risk. Therefore, the chances of over-recommending N inputs are somewhat higher than those of under-recommending, further decreasing risk of profit loss. For illustration, overall, profit gains greater than $50/ac occurred in 29 cases, while losses greater than $50/ac were determined in only 2 cases (Figure 3).
Adapt-N reduced N rates in 84% of cases, by 60 lbs N/ac on average, resulting in simulated reductions in total N losses to the environment by the end of the growing season of 34 lbs/ac, and leaching losses by 10 lbs N/ac (Table 1). Further losses of residual excess N generally occur over the winter and spring months when crop uptake ceases, soil water is recharged, and saturation or near-saturation occur, particularly in the Northeast. Thus the simulated reductions are a low estimate of actual environmental loss reductions, which are likely closer to the difference in applied N. In 16% of trials, where Adapt-N increased N rates, by 38 lbs/ac on average, total N losses increased on average by only 16 lbs/ac, and leaching losses by 3 lbs/ac. Further over-winter losses in these cases are lower, because much of the additional applied N was taken up by the crop to produce the increased yield, and thus would not be lost.
Lessons for Expert Use of Adapt-N from three years in the field
Growers can decrease risk of N deficiency, environmental losses, and yield losses, and increase profit margins. To optimize Adapt-N use, we recommend the following:
Plan to apply the majority of fertilizer nitrogen at sidedress time instead of prior to or at planting. If manure is applied prior to planting or when enhanced efficiency products are used, aim for conservative rates.
Monitor the field’s N status and account for early season weather impacts on N availability by using Adapt-N’s daily updates.
Supply input information on soil and crop management that is representative of each management unit (e.g. test soil and manure based on representative samples, keep good records of operations, estimate expected yield as the second-highest out of 5 years of accurate yield information). For each management unit, measure soil organic matter at least every 3 years, ideally to a 12” depth.
If appropriate, adapt input information at the time of sidedressing to account for seasonal influences, such as decreased yield potentials or shallow rooting depths from extreme wet conditions.
Use the most recent Adapt-N recommendation available on sidedress day. Apply sidedress N between V6 and V12, depending on N and equipment availability. Generally, later sidedressing with high-clearance applicators allows for more accurate recommendations. Variable rate applicators can be used to adjust Adapt-N simulations for management units in fields.
Use Adapt-N scenario simulations after the growing season to learn more about how weather and management influence N availability.
In the long term, manage for healthy soils and use Adapt-N to account for N contributions from high organic matter levels and deep root zones.
Three consecutive growing seasons involving 104 on-farm strip trials demonstrate that Adapt-N is an effective tool for N management in corn systems, with average profit gains of at least $30/ac. With model improvements and increased expert use of the tool, we estimate that profit gains over current grower practices can be expected in at least four out of five cases. Adapt-N generally correctly identified cases when either decreased or increased N was needed to maintain yields. The tool also provides a strong incentive to shift N applications to sidedress time when weather impacts can be accounted for in the model. By using Adapt-N, growers can contribute to solving persistent problems with greenhouse gas emissions, groundwater pollution, and hypoxia in our estuaries, while increasing profits in both wet and dry years.
For more information: Recorded webinars, a manual, and other Adapt-N training materials are available at http://adapt-n.cals.cornell.edu/. The Adapt-N tool is accessible through any device with internet access, now from the team’s commercial partner, Agronomic Technology Corporation, at http://www.adapt-n.com/ (cost is about $1-3/ac, depending on area covered). Adapt-N users can elect to receive email and/or cell phone alerts providing daily updates on N recommendations and soil N and water status for each management unit in Adapt-N.
Acknowledgements: This work was supported by funding from the NY Farm Viability Institute, the USDA-NRCS Conservation Innovation Program, the International Plant Nutrition Institute, McKnight Foundation, Walton Family Foundation, USDA-NIFA, MGT Envirotec, and USDA-SARE. We are grateful for the cooperation in field activities from Keith Severson, Kevin Ganoe, Sandra Menasha, Joe Lawrence, Anita Deming, Harry Fefee, Kitty O’Neil, Mike Hunter, and Brent Buchanan of Cornell Cooperative Extension, Bob Schindelbeck of the Cornell Section of Soil and Crop Sciences, Mike Davis at the Willsboro Research Farm, Dave DeGolyer, Dave Shearing and Jason Post at Western NY Crop Management Association, Eric Bever and Mike Contessa at Champlain Valley Agronomics, Eric Young at Miner Institute, and Peg Cook at Cook’s Consulting in New York, and from Shannon Gomes, Hal Tucker, Michael McNeil, and Frank Moore at MGT Envirotec. We also are thankful for the cooperation of the many farmers who implemented these trials on their farms.