Bill Cox, Section of Crop and Soil Sciences, Cornell University
Soybean seeding depth typically, but not always, affects early plant populations
Most agronomists agree that growers should plant soybeans at the 1.5 inch depth because the seed is vulnerable to drying out at shallower depths and crusting problems at deeper planting depths, both which result in reduced emergence. We conducted a variety x planning date x seeding depth study at the Aurora Research Farm in 2013 and 2014. We planted two soybean varieties on five dates from late April through mid-June at seeding depths of 1.0, 1.5, 2.0, and 2.5 inches. In addition, we conducted field-scale studies with three soybean growers who planted soybean at the same seeding depths. This news article will report on the trends in the early plant populations taken at the V2 (2nd node) stage, about 2 to 5 weeks after planting (depending upon planting date). Eventually, regression analyses will be conducted on the early plant population and yield data at the conclusion of all the studies.
Table 1. Days to emergence, averaged across two soybean varieties, planted on five dates and at four depths at the Aurora Research Farm in Cayuga Co. in 2013 and 2014.
The 1.0 vs. the 1.5 inch seeding depth emerged 0.25 to 1.25 days earlier on the first three planting dates in 2013 (Table 1). In addition, the 1.0 inch seeding depth had ~2,000 to ~11,000 more plants/acre on all planting dates in 2013 (Table 2). Moist conditions ensued after all planting dates in 2013, which negated drying out of the soybean seed at the 1.0 inch depth leading to more rapid and better early stand establishment. Obviously, planting soybeans at the 1.0 inch depth is not a problem and may be a benefit during wet springs.
Table 2. Early plant populations, averaged across two soybean varieties, planted on five dates at four depths and at a seeding rate of ~165,000 seeds/acre at the Aurora Research Farm in Cayuga Co. in 2013 and 2014.
In 2014, however, dry climatic conditions ensued from May 20 until June 10 (0.13 inches of precipitation), which probably contributed to the 0.75 to 1.25 day delayed emergence and ~3,000 to ~25,000 fewer plants/acre at the 1.0 vs. the 1.5 inch depth on the May 19 and June 12 planting dates (Tables 1 and 2). Clearly, planting soybeans at the 1.0 inch depth is a problem for stand establishment when dry conditions prevail during the late spring.
The 2.5 vs. the 1.5 inch seeding depth generally required an additional day for emergence (although an additional 3.75 days were required at the late April planting date in 2013). Also, the 2.5 vs. the 1.5 inch seeding depth mostly had >10,000 fewer plants/acre but there were two exceptions where the 2.5 vs. the 1.0 inch depth had ~5,000 to ~10,000 more plants/acre (May 19, 2013 and May 30, 2014). Dry ensuing conditions after the May 30 planting date in 2014 probably resulted in dry conditions at the 1.5 inch seeding depth, thereby reducing emergence at that depth.
Despite the differences in early plant populations among the seeding depths at the five planting dates, soybean yields did differ among the four seeding depths on the first four planting dates in 2013 (What’s Cropping Up?, vol.24, no.1, 2014, p.1-2). Early plant populations mostly exceeded 120,000 plants/acre for all planting depths (except for the 2.5 inch seeding depth on the April 20 and June 12 planting date in 2013), which apparently were adequate to optimize yields in 2013.
The field-scale studies were planted from May 10 to May 27 in 2013 and from May 24 to June 6 in 2014 (wet May conditions delayed planting at all three farms in 2014). Consequently, soybeans only experienced warm conditions after planting in most of these studies. Nevertheless, soybeans at two farms (Livingston and Tomkins Co.) showed pronounced negative linear responses to seeding depth for early plant populations as indicated by ~9,000 to ~17,000 fewer plants/acre at the 2.5 vs. 1.0 inch seeding depth (Table 3). The Livingston Co. study in both years was on a silty clay loam soil so probably crusting or difficulty in emerging through a heavier soil from a deeper depth explains the consistent 17,000 fewer plants/acre.
Table 3. Early plant populations of soybean planted on three farms at four seeding depths at seeding rates of ~ 130,000 (Cayuga Co.), ~150,000 (Livingston Co.) and ~175,000 (Tomkins Co.) seeds/acre in 2013 and 2014.
The Tompkins Co. study, however, was on a gravelly silt loam soil in both years so crusting problems were probably not the major cause for reduced emergence. Consequently, it is not clear why soybean planted at the 2.5 vs. 1.0 inch depth had ~9,000 fewer plants/acre in 2013 and ~17,000 fewer in 2014. Despite the pronounced negative linear response to seeding depth at Livingston Co. in 2013, seeding depth did not affect yield (yields ranged from 57-59 bushels/acre). Surprisingly, soybean yield showed a negative quadratic response at Cayuga Co. in 2013 (67 and 66 bushels/acre at the 1.0 and 2.5 inch depths, respectively, but only 63-64 bushels/acre at the 1.5 and 2.0 inch depths). Likewise, soybean yield showed a quadratic response (positive) at the Tomkins Co. site in 2013 (yields increased from 59 to 63 bushels/acre as seeding depth increased from the 1.0 to 1.5 inches then decreased to 61 bushels/acre at the deeper depths).
In conclusion, seeding depth affects early plant populations in soybean but the response is not consistent. Apparently, the 1.0 vs. the 1.5 inch seeding depth can result in greater plants/acre if wet conditions ensue after planting. If dry conditions ensue after planting, as at the Aurora Research Farm from May 20 to June 10 or at the Cayuga Co. in 2014 (located 1 mile from the Aurora Research Farm and planted on May 24), the 1.0 seeding depth and maybe the 1.5 inch seeding depth is too shallow, which can result in fewer plants/acre. The data indicates that climatic conditions after planting is equally important as the actual seeding depth in determining optimum seeding depths for soybeans. Unfortunately, climatic conditions in the first 10 days after planting are not predicted with great precision so planting at the 1.5 inch depth appears to be the best compromise.
Prof. Toni DiTommaso, Dept. of Crop and Soil Sciences, showing his enthusiasm to Marilyn Wyman, Issue Leader, CCE Columbia/Greene
Professor Antonio DiTommaso, Cornell Department of Crop and Soil Sciences, in cooperation with the Cornell Cooperative Extension Invasive Species Statewide Program, held a one-day hands-on workshop on weed seedling identification for PRISM partners. Scott Morris, Kathy Howard, and Courtney Stokes, Department of Crop and Soil Sciences, assisted with the workshop. The workshop was held on the Cornell campus on Thursday, May 8 from 9 am – 4 pm. Live seedlings, seeds, mature plants, and photos were used in this very interactive event that included some lecture and presentation, a before and after weed ID “quiz”, hands on seeds, seedlings, and mature plants in the Muenscher greenhouses to view, and a walk in the new weed garden. Weeds, or invasive species, included both agricultural and natural area weeds. General weed management approaches were discussed during the presentations.
Courtney Stokes, grad student, Dept. of Crop and Soil Sciences, discussing invasive species with participants
Nineteen participants came from around NYS, representing 5 of the 8 PRISMs (Partnerships for Regional Invasive Species Management). PRISMs, established by the NYS Department of Environmental Conservation, coordinate invasive species management functions in the 8 PRISM regions throughout the state.
The CCE ISP is a statewide program funded by the NYS Environmental Protection Fund through the NYS Department of Environmental Conservation. The program, established in 2010, provides assistance to the PRISMs, including education for PRISM members and their audiences, on-line resources, and connections to Cornell faculty and CCE Associations. The NY Invasive Species Clearinghouse (www.nyis.info ) is a partnering CCE and NY Sea Grant program that provides on-line resources. The NYS Invasive Species Research Institute, housed in the Cornell Department of Natural Resources, is the third partner in the CCE system supporting PRISMs with the most effective and up to date control of invasive species in NYS.
Kathy Howard, Dept. of Crop and Soil Sciences, discussing grasses with participants
An invasive species is a species that is non-native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health (National Invasive Species Management Plan – 2001 (http://www.invasivespecies.gov/main_nav/mn_NISC_ManagementPlan.html )).
Bill Cox, Department of Crop and Soil Sciences, Cornell University
Emergence of corn hybrids planted on April 14th after encountering cold rain and snow 21 to 30 hours after planting.
Imbibitional chilling injury to corn purportedly occurs when recently planted corn seed imbibes water at temperatures less than 41oF (although some say 50oF) during the first 48 hours after planting. We have planted corn a few times over the last 30 years when temperatures have been in the 40s or upper 30s, even with a little snow falling. Sure, final stands have not been perfect when planting under these conditions, but on almost all occasions, final stands have been satisfactory. So I must pose the question, as once again we have encountered poor conditions shortly after planting in April of 2014, and have had not perfect, but certainly satisfactory corn stands. Do modern hybrids still exhibit imbibitional chilling injury under field conditions?
Table 1. Days to emergence, averaged across two corn hybrids, planted on five dates and at five depths at the Aurora Research Farm in Cayuga Co. in 2014.
We planted two corn hybrids at our recommended seeding rate of ~32,000 kernels/acre at five seeding depths on April 14, April 21, May 7, May 20, and May 31 on a well-drained soil at the Aurora Research Farm in Cayuga Co. We have not had time to conduct statistical analyses on the data nor have we taken early plant population counts on the May 20 and May 31 planting dates yet. We do have days to emergence for the April 14, April 21, May 7, and May 20 planting dates and early plant populations for the first three planting dates.
Table 2. Early plant populations, averaged across two corn hybrids, planted on five dates and at five depths at a seeding rate of ~32,000 plants/acre the Aurora Research Farm in Cayuga Co. in 2014.
When averaged across the two hybrids and five planting depths, corn emergence occurred about 27 days after planting for the April 14 planting date, about 21 days after planting for the April 21 planting date, and about 7 days after planting for the May 7 planting date (Table 1). When averaged across hybrids and planting depths, early plant populations averaged about 27,000 plants/acre for both April planting dates, an average emergence rate of about 85% (Table 2).
Table 3. Hourly temperature and hourly precipitation during the 48 hours after planting two corn hybrids at five planting depths on April 14 at the Aurora Research Farm (read the table from the bottom to the top to track temperature and precipitation during the first 48 hours after planting).
In contrast, early plant populations averaged about 28,500 plants/acre for the May 7 planting date, an average emergence rate of about 90%. Clearly, the May 7 planting date resulted in better stand establishment, but were the April planting dates that unsatisfactory, given the conditions in the first 48 hours after planting corn?
Table 3 indicates that temperatures were in the 70s during the afternoon of April 14. Temperatures, however, dropped into the upper 30s, 21 hours later, accompanied by a cold rain for three hours (8:00-11:00), followed by an accumulating snow for the next few hours (12:00-16:00) on 4/15. Temperatures then dipped down into the lower 20s (a low of 21.7!) during the evening of 4/15 and remained in the 20s throughout the day of 4/16.
Climatic conditions were not as inhospitable after the April 21 planting date but Table 4 indicates that 36 hours (4/22, 3:00) after planting corn, temperatures were in the upper 30s accompanied by a cold rain. Temperatures remained in the upper 30s throughout the day of 4/23.
Both April planting dates thus had temperatures below 41 degrees in the first 48 hours after planting, accompanied by a cold rain and even snow. The field was plowed and harrowed so soil temperatures closely tracked air temperatures, especially in the top 2 inches. Yet, emergence rates averaged 85% for the April planting dates compared with 90% emergence for the May 7 planted corn, which encountered almost ideal conditions in the first 48 hours after planting(temperature range of 52 to 81oF). Was the 5% lower emergence rate for the April planting dates due to imbibitional chilling injury? And if imbibitional chilling reduced emergence by 5%, should it be cause for alarm? Or should we just continue to recommend that growers assume an 85% emergence rate for April-planted corn and a 90% emergence rate for May-planted corn in NY?
Table 4. Hourly temperature and hourly precipitation during the 48 hours after planting two corn hybrids at five planting depths on April 21 at the Aurora Research Farm (read the table from the bottom to the top to track temperature and precipitation during the first 48 hours after planting).
One criticism of inferring that modern hybrids may no longer exhibit imbibitional chilling injury, based on data from this study, is that we examined only two hybrids. In 2012, we planted our corn silage hybrid trial with 82 entries on April 20 at the Aurora Research Farm in Cayuga Co. when the high temperature was 78 oF on the day of planting.
Only 24 hours after planting, Aurora received a cold 0.6 inches of rain, followed by 0.86 inches of precipitation in the form of a 5-inch snow storm during the next 24 hours after planting (Table 5). Obviously, weather conditions were conducive for imbibitional chilling damage during the initiation of the emergence process in the 2012 study.
When averaged across the 82 hybrids entered in the study, early stand establishment averaged 85.4% (Table 6). Stand establishment averaged from about 84 to about 89% for the hybrids from the 12 seed companies. Of the 82 hybrids entered in the study, only six hybrids had stand establishment rates of less than 80% on this drained Lima silt loam soil.
So, I must once again pose the question. Do modern hybrids still exhibit imbibitional chilling injury under field conditions? Based on the circumstantial data from the 2012 and 2014 studies, I would say maybe not. If modern hybrids do exhibit imbibitional chilling injury, the timing of the adverse conditions would have to be so unique and so time-dependent in the first 48 hours after planting that it may not be worth worrying about. Keep in mind that these studies were conducted on well-drained soils. If we had planted corn on poorly drained soils and encountered such weather conditions after planting, corn emergence would have been much lower. But it probably would have been associated with flooding damage and not with imbibitional chilling injury.
Table 5. Weather conditions at the Aurora Research Farm from April 14-April 29 in 2012. Emboldened date indicates the weather conditions on the day of planting.
What happens if soil conditions are conducive for a mid-April planting date next year but very cool wet weather (even snow) is forecast for the next few days? I will continue to plant corn any time after April 10-15, provided soil conditions are dry,the location does not experience late spring killing frosts (< 28 degrees after May 15 or so)andthe soils are well-drained and do not readily flood.
Table 6. Stand establishment rates of 82 hybrids from 12 seed companies planted on April 20th, 2012, 2 days before a 5-inch snow storm.
I would adjust my seeding rate to account for only 85% emergence and plant at a soil depth of 1.5-2.00 inches. Let’s hope that most corn growers in NY get that opportunity next year and don’t have to go through another spring like this year!!!!
Bianca Moebius-Clune, Margaret Ball, Harold van Es, and Jeff Melkonian, Department of Crop and Soil Sciences, Cornell University
Adapt-N is an on-line tool for weather-adjusted precision nitrogen management in corn that has been available to growers in the Northeast and several Midwestern states since 2010 (http://adapt-n.cals.cornell.edu). In 2013, with an uncharacteristically wet spring, the tool successfully adapted N recommendations to account for early-season N dynamics, and further demonstrated its ability to improve farmer profits.
Background
Nitrogen dynamics in corn production are strongly influenced by weather, particularly early-season precipitation. In Northeastern and Midwestern US climates, N mineralizes from soil organic matter earlier than a corn crop is able to take it up. In a dry or normal spring, most of such early-mineralized soil N remains available to a corn crop (Figure 1a), so that growers can reduce N inputs without yield loss as demonstrated in 2011-2012 (Moebius-Clune et al., 2013a).
Figure 1. Early-season N dynamics in corn systems. a) N in organic matter (OM) begins mineralizing before corn is ready to take it up, and contributes significant amounts of nitrogen for crop uptake in normal to dry years. b) In a wet spring, early-mineralized N is easily lost during this critical time period, leading to later-season N shortages if not accounted for with additional sidedressed N. c) Applying N fertilizer or manure early increases the risk of large losses.
However, many growers apply the bulk of their nitrogen inputs before or at corn planting. This means not only that they lose the opportunity to reduce inputs in-season after a dry spring, but that they face significant risk of profit loss due to wet weather. Significant N loss of both early-mineralized and early-applied soil N occur during wet spring weather (Figure 1b and c). N rates must then be adjusted in-season when these losses can be accounted for, in order to maintain corn yield potential.
Adapt-N provides such site-specific in-season N sidedress recommendations. It uses a well-calibrated computer model and information on soil and crop management, along with real-time, high-resolution weather data, to account for a location’s conditions. It also provides insights on soil nitrogen status, gains and losses, and crop growth stage through simulation outputs.
The tool’s accuracy and precision have been evaluated through on-farm trials and improved in response to performance and user feedback (Moebius-Clune et al., 2013a, 2013b, 2013c, 2012). The wet spring encountered in much of the Adapt-N user area in 2013 provided the first chance to test the tool for extreme wet conditions. A summary article for all three years of testing provides averages for 104 trials over 3 years of testing in NY and IA. In this article, we examine Adapt-N’s performance in 2013 New York and Iowa strip trials, guided by the following questions:
1. Do Adapt-N simulations of N losses in wet-spring conditions lead to weather-adaptive N recommendations that are agronomically and economically beneficial to farmers?
2. How do the model’s recommendations affect environmental N losses in a wet season?
Methods
We completed 20 replicated strip trials on commercial and research farms, 11 in New York and 9 in Iowa during the 2013 growing season. Trials were conducted in grain and silage corn, in varied tillage systems, with and without manure application, with previous crops of corn or soybean (Table 1). Most participants applied small amounts of starter or preplant N, with the majority of total grower rates applied at sidedress. Sidedress treatments involved at least two rates of nitrogen, a “Grower-N” rate based on current grower practice, and an “Adapt-N” rate based on a simulation run just prior to sidedressing.
Table 1. Background information on 2013 on-farm strip trials implemented in NY and IA to compare current Grower N application rates with rates recommended by the Adapt-N tool.
Growers in IA and NY implemented field-scale strips with 2 to 7 (usually 4) replications per treatment. In several trials (23-25, 27, 61, 62) treatment replicates were reported as composite harvest values due to time and equipment constraints.
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 recommended and Grower-N management practices were estimated through a per-acre partial profit calculation:
Yields were used as measured, regardless of statistical significance, since the statistical power to detect treatment effects is inherently low for whole-field strip trials, but averaging across many trials provides good statistical power for assessing Adapt-N performance. Prices of $0.50/lb N, $5.00/bu grain, $50/T silage were used. (Prices varied across implementation areas, but generally were close to a 10:1 price ratio). Operational costs of sidedressing ($8/ac) were accounted for where only one of the treatments was sidedressed.Agronomic, economic, and simulated environmental outcomes of these trials were used to assess Adapt-N performance.
Results
Agronomic and economic comparisons between Grower-N and Adapt-N treatments for each trial are provided for NY and IA trials in Figure 2, and as averages for agronomic, economic, and environmental performance in Table 2.
Figure 2. Yield and fertilizer use from Grower-N vs. Adapt-N treatments in a) NY and b) IA trials. N rates represent total N in lbs/acre applied as inorganic fertilizer in 2013. Partial profit gain (positive) or loss (negative) from using the Adapt-N recommendation, relative to grower’s current practices. (Yields statistically different at *p < 0.05 or **p < 0.01)
In 2013, in contrast to previous years, Adapt-N rates were higher than Grower-chosen sidedress rates in 73% of NY trials, because the most extreme rainfall occurred primarily after corn planting, in June and early July, when large amounts of mineralized N and early applied N were vulnerable to losses. In Iowa, however, Adapt-N rates were higher than Grower-chosen rates in only 22% of trials, despite the wet spring, because the most extreme rainfall occurred in May and early June, followed by fairly dry conditions in some of the user area. At that time, relatively less of the potentially available N from organic matter had mineralized. The largest losses thus occurred where corn was planted early and preplant N fertilization was high (up to 110lb/ac, trial 63), prior to extreme rainfall. This was only the case in a small number of trials.
Table 2. Agronomic and economic assessment of model performance in 2013. Values are average differences resulting from Adapt-N use (Adapt-N minus Grower-N treatment), such that a negative number indicates a decrease due to Adapt-N, a positive number indicates an increase due to Adapt-N. Profit calculations assume $5.00/bu grain, $50/T silage, $0.50/lb N, and $8/ac operational savings if sidedress was avoided. Silage yields are reported as grain equivalent (1T silage = 8.14 bu grain)
Those who sidedressed the majority of their N in June were able to avoid the extreme losses. Averaging all 20 trials conducted in NY and IA in 2013, total fertilizer applied and environmental losses did not change, while yield increased by +11 bu/ac, and profits increased by $53/ac.
NY trials.Adapt-N recommended increased sidedress rates over the grower’s normal practice in 8 out of 11 NY trials. The difference between Adapt-N recommendations and grower practice (A-G) averaged +20 lbN/ac (-60 to +70 lb N/ac). Yield increased on average by +21 bu/ac (-10 to +58 bu/ac; silage reported as grain equivalent: 1 T silage = 8.14 bu grain). In all cases where Adapt-N recommended a fertilizer increase, higher rates resulted in increased yields and profits. Overall, profits from Adapt-N recommendations increased in 9 out of 11 trials (82%), ranging from -$20 to +$252/ac with an average increase of $94/ac.
Despite significant fertilizer increases, simulated total losses of N over the season (through 12/31/2013) averaged only 8 lb N/ac higher in Adapt-N versus Grower strips (Table 2). Post sidedress losses occur if sidedress N is applied before the crop is large enough to prevent wet soil conditions through high transpiration rates, or if excess N remains at the end of the season. Most of the additional fertilizer recommended by Adapt-N was taken up by the crop after sidedressing, while N applications and losses were reduced in 3 of the trials. In two trials where profit losses did occur, we suspect that the combination of inadequately drained, compacted, poorly aggregated soils and heavy rains caused higher losses than simulated by the model.
Success stories from two growers in particular can be highlighted. Grower Arnold Richardson, working with Keith Severson of CCE Cayuga County, saw significant profit gains of over $100/ac on average from Adapt-N use this year (see Case Study in this volume, https://blogs.cornell.edu/whatscroppingup/?p=759). Dave DeGolyer of Western NY Crop Management Association established several trials of rescue N applications in July with growers Donn and Chad Branton (23-25, Fig 2). The Brantons’ standard N management places nearly all N fertilizer in a deep slot with stabilizer at planting. However, this year demonstrated that such fertilizer is vulnerable to losses during heavy rains despite stabilizer. Adapt-N indicated that more N was needed, even though enough would have been available in a normal year (Fig 1c). By sidedressing an additional 60 lb N/ac, the Brantons saw increases of 25, 42, and 58 bu/ac in three trials and profit gains of approximately $79, $164, and $246/ac due to avoided yield loss. The Brantons have decreased their preplant N applications this spring, and plan to use Adapt-N-informed sidedress rates provided by WNYCMA.
IA trials. Despite the wet spring, Adapt-N recommended fertilizer rate reductions from grower’s normal practice in 7 out of 9 IA trials, in part because most participating IA growers were planning to apply the majority of their N at sidedress. The difference between Adapt-N recommendations and grower practice (A-G) ranged from -40 to +30 lbN/ac with an average change of -19 lb N/ac. Yield changes due to Adapt-N use ranged from -4 to +14 bu/ac with an average of +1 bu/ac. Profits increased on average by $12/ac, ranging from -$6 to +$57/ac, with increases due to Adapt-N in 3 trials, no change ($0 to $1/ac) in 3 trials, and decreases in 3 trials. Simulated total N losses over the season (through 12/31/2013) were lower in Adapt-N versus Grower strips (-9 lb N/ac on average). Similarly to NY results, small profit losses in a few trials with reductions in N rates are likely due to the extreme wet conditions for which the model had not yet been field tested. Improvements in model handling of drainage have been in progress for the 2014 version of Adapt-N. Overall, the fact that Adapt-N was able to decrease N inputs even after such a wet spring without significant yield loss in these 6 trials (-1 bu/ac on average) indicates that Adapt-N accounted for losses successfully, and can inform much more significant N input reductions in Iowa during more normal or dry years, as demonstrated by our 2011 and 2012 trials, when growers plan on sidedressing. It should also be noted that predominant practice of IA growers at this time is to apply N in the fall or spring prior to planting. Such growers would have seen results most like trial 63 in IA, and trials 23-25 in NY (Figure 2), where additional N was needed to make up for rain-induced losses, with increased profits above $50/ac likely.
Figure 2b
Conclusions
2013 on-farm testing in NY and IA further demonstrated the monetary and environmental value of using Adapt-N’s weather-adjusted recommendations.
Key Take Home Points:
Environmental losses due to Adapt-N recommendations in 20 trials, on average, did not increase over grower practice in the wet 2013 season.
Yields increased by 11 bu/ac on average (21 bu/ac in NY, 1 bu/ac in IA).
Profits increased by $53/ac ($94/ac in NY, $12/ac in IA).
In 75% of trials Adapt-N increased or maintained profits compared to grower practice. The model’s ability to handle the impacts of poor drainage has been further improved for 2014.
2013 results demonstrate the value of site-specific, adaptive recommendations provided by Adapt-N. The tool’s site-specific recommendations successfully identified opportunities for N input reductions where possible, and N input increases where agronomically necessary to maintain yield potential following a wet spring.
Results, especially in IA, conservatively estimate possible profit gains in a wet year, because most collaborating growers sidedress the majority of their N. Profit were highest when compared to more common grower practices of large or total preplant applications.
This third year of on-farm testing further confirms the significant advantages growers have when they apply the majority of their N at sidedress time, when economically optimum N rates can be better estimated.
For more information: An in-depth 2014 training webinar on Adapt-N, manual, and further information are available at http://adapt-n.cals.cornell.edu/. The Adapt-N tool can be used from any device with internet access, and as of the 2014 sidedress season is offered through a public-private partnership between Cornell University and Agronomic Technology Corporation for a fee ($1-3/ac, depending on area covered). Users can sign up for an account at http://www.adapt-n.com/products/, and 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 being simulated 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, and MGT Envirotec. We are grateful for the cooperation in 2013 field activities from Keith Severson, Joe Lawrence, Anita Deming, Harry Fefee, Kitty O’Neil, Mike Hunter, and Brent Buchanan of Cornell Cooperative Extension, Bob Schindelbeck of the Cornell Department of Crop and Soil 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, and Frank Moore at MGT Envirotec. We also are thankful for the cooperation of the many farmers who implemented these trials on their farms.
Ball, M., B. Moebius-Clune, H. van Es, J. Melkonian, K. Severson. 2014. New York Farm Delves Deeper with Adapt-N. What’s Cropping Up? blog. [URL verified 6/2/2014].
Margaret Ball, Bianca Moebius-Clune, Harold van Es, Jeff Melkonian, Department of Crop and Soil Sciences, Keith Severson, Cayuga County Cooperative Extension, Cornell University
Arnold Richardson has had his eye on Adapt-N since 2009, when the tool for weather-adapted sidedress nitrogen recommendations first became available. Of a self-described “competitive nature,” the Red Creek, NY farmer is constantly seeking and testing new strategies that can improve his farm system and boost yields and profits. After several years of watching the development of Adapt-N and its success in early on-farm trials, Richardson conducted strip trials of the Cornell nitrogen management tool in three fields in 2013. All three trials increased his yield and profit, and of course, got him thinking about what improvements to make next.
The Richardson Farm crew (left to right): Arnold, Eric, and Ryan Richardson and Nick Humphrey.
Richardson and sons grow grain corn and soybean on 1000 acres near the border of Cayuga and Wayne counties. The mix of rich river bottom loams and stony clay drumlins in their fields requires flexibility and ingenuity in management. The team has significantly changed management practices since inheriting the farm several decades ago. They switched from continuous corn to a corn-soybean rotation, which gave an immediate 20 bu/ac yield bump on corn, says Arnold. They’ve also experimented with various primary tillage tools, switching from moldboard to chisel plow in 1983, then testing strip till, aerator, and most recently “vertical tillage” tools over several years to see what works best in their system. Most recently, the farm’s experiments have included increased seeding rates and a review of their nitrogen management practices.
The Richardsons have long taken a weather-conscious approach to nitrogen management decisions, applying most N as sidedress to better match the timing of crop uptake. “That’s the best time,” says Arnold. “The corn is making big decisions about its future at the 5 – 8 collar stage. We try to help it make good decisions… We’ve got to keep the corn happy all the way through.” They follow a general rule of 1 lb N per 1 bushel expected yield, adjusting for N use efficiency and soybean credits, for an average of around 150 lb N per acre per year over the whole farm. Understanding that weather influences N dynamics, the Richardsons even split their N into earlier and later sidedress applications on sandier fields, to minimize the risk of leaching losses with rain. They ran a few Adapt-N simulations in previous years, usually coming up with recommendations that were lower than or similar to their own rates. However, they had not adjusted their total N rates based on weather until they tested Adapt-N in the field last year.
Keith Severson of Cayuga County Cooperative Extension guided the Richardsons in establishing three Adapt-N strip trials in 2013. The trials were conducted in corn grain following soybean, on Williamson and Ontario silt loams with 2.6% to 3.8% organic matter. All trials received 22 lb N/ac in starter, following the farm’s normal practice. The third trial also received an extra 50 lb N/ac in May, because Richardson wanted to test a practice more similar to that of his neighbors, who apply more of their nitrogen early. Two treatments, replicated four times, were implemented in late June to compare Adapt-N-recommended and Grower-chosen sidedress rates. Due to the unusually wet spring, N leaching and denitrification losses (simulated by Adapt-N) were high. Adapt-N thus recommended sidedress rates 20, 30, and 40 lb/N higher than Richardson’s chosen rates. Yields increased significantly with the higher N rates in all three trials, with gains of 23 to 30 bu/ac. At Richardson’s actual prices ($0.75/lb N and $5.00/bu corn), this translates to profit gains of $91/ac to $122/ac from the use of Adapt-N. Total yields in the trial strips ranged from 162 to 222 bu/ac. As well as implementing the trials, Richardson also followed Adapt-N recommendations on the rest of the farm’s acres, “which resulted in a larger N bill than originally planned, but with a pleasing result yield wise,” he says. One Adapt-N trial plot earned the farm fourth place in the Finger Lakes section of New York State Corn and Soybean Growers’ Association 2013 Yield Contest, at 232 bu/ac.
Yield and profit increases with Adapt-N recommended rates * Difference of Adapt-N minus Grower. Positive number shows increased N applied due to Adapt-N ** Profit calculation using farm’s actual prices ($0.75/lb N and $5.00/bu corn) *** p values below 0.05 are statistically significant (real) yield differences
Richardson’s experience was typical of Adapt-N trials in New York last season. In 8 out of 11 NY 2013 trials, Adapt-N increased N rates over grower practice. Across all trials, growers saw their yields increase by an average of 21 bu/ac with Adapt-N rates 20 lb/ac higher than grower-chosen rates, resulting in profit gains of $94/ac (10:1 price ratio, silage reported as grain equivalent). Adapt-N was able to adjust N rates upward by using site-specific high resolution climate data to simulate the year’s unusually wet spring conditions, and the resulting large leaching and denitrification losses of early-applied fertilizer and early-mineralized organic N. By contrast, in the more normal springs of 2011-2012, Adapt-N simulations were able to correctly identify higher N availability from the same sources. In 56 trials in these years, New York growers gained $31/ac on average by cutting back on 66 lb/ac of unnecessary N applications.
While yield and profit gains are a convincing incentive for the Richardsons to continue to use Adapt-N, the value of Adapt-N runs deeper than just financial on the Richardson farm. Arnold and sons were struck by the tool’s graphs of soil N availability and rainfall, which clearly showed the farm’s weather-related early N losses. Arnold has also “gotten into these what-if scenarios quite a bit,” regularly using his Adapt-N account to play with different management schemes and retrospective simulations.
Graphic output from Adapt-N, showing rainfall, root-zone inorganic nitrogen, and cumulative N losses in one of Richardson’s trials. The large early-season losses are typical of a wet spring.
The biggest lesson in Arnold’s eyes, however, has come from three Cornell Soil Health Test samples that the Richardsons submitted as part of their Adapt-N trials. The farm’s chemical analysis scores were perfect due to years of careful soil test-based management, but new biological and physical measures like aggregate stability, subsurface hardness, and active carbon ranked lower on the test’s scales. “I look at these reds and yellows and think, this is our next project,” said Arnold, indicating his scores for biological and physical measures of soil health. “To help get me to the next level, I’ve got to pay attention.”
For more information: An in-depth 2014 training webinar on Adapt-N, manual, and further information are available at http://adapt-n.cals.cornell.edu/. The Adapt-N tool can be used from any device with internet access, and as of the 2014 sidedress season is offered through a public-private partnership between Cornell University and Agronomic Technology Corporation for a fee ($1-3/ac, depending on area covered). Users can sign up for an account at http://www.adapt-n.com/products/, and 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 being simulated in Adapt-N.
