Potato Research - UNIV OF WISCONSIN

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
204	1310	1060	100%

Progress 10/01/98 to 09/30/11

Outputs
OUTPUTS: Data summarization and manuscript preparation continued. No new field or laboratory works was started. PARTICIPANTS: Co-authors: E.T. Cooley, B. Lowery, K. Kelling, P.E. Speth, F.W. Madison, W.L. Bland, A. Tapsieva, and F.J. Arriaga. TARGET AUDIENCES: Potato growers. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
This study attempts to improve nutrient use and efficiency and grower profitability while reducing the risk of environmental degradation from nutrient use. Nutrient sources include commercial fertilizer and manure.

Publications

Kelling, K.A., and P.E. Speth. 2010. Effectiveness of ACA rates on potatoes raised in irrigated sandy soil. Commun. Soil Sci. and Plant Anal. 41:2143-2153.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: We continued to rework and summarize data with the objective of preparing manuscripts for publication in refereed journals. No new field or laboratory work was started. PARTICIPANTS: Co-Authors: E.T. Cooley, B. Lowery, K. Kelling, P.E. Speth, F.W. Madison, W.L. Bland, A. Tapsieva and F.J. Arriaga. TARGET AUDIENCES: Potato Growers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
This study attempts to improve nutrient use and efficiency and grower profitability while reducing the risk of environmental degradation from nutrient use. Nutrient sources include commercial fertilizer and manure.

Publications

Cooley, E.T., B. Lowery, K. A. Kelling, P.E. Speth, F.W. Madison, W.L. Bland, and A. Tapsieva. 2009. Surfactant use to improve soil water distribution and reduce nitrate leaching in potatoes. Soil Sci. 174:321-329.
Arriaga, F.J., B. Lowery, and K.A. Kelling. 2009. Surfactant impact on nitrogen utilization and leaching in potatoes. Amer. J. Pot. Res. 86:383-390.

Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: We continued to rework and summarize data with the objective of preparing manuscripts for publication in refereed journals. No new field or laboratory work was started. Two papers were published in 2008, two other papers were accepted for publication and one is in review. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Fellow scientists, farmers and agribusinesses. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
This study attempts to improve nutrient use and efficiency and grower profitability while reducing the risk of environmental degradation from nutrient use. Nutrient sources include commercial fertilizer and manure.

Publications

Beegle, D.B., Kelling, K.A., and Schmitt, M.A. 2008. Nitrogen from animal manures. Chapt. 21, p. 823-881. In Nitrogen in Agricultural Systems, Schepers, J.S., W.R. Raun, R.F. Follett, R.H. Fox, and G.W. Randall (eds). Agronomy Monograph 49, ASA, CSSA, SSSA, Madison, WI.
Munoz, G.R., Kelling, K.A., Rylant, K.E., and Zhu, J. 2008. Field evaluation of nitrogen availability from fresh and composted manure. J. Environ. Qual. 37:944-955.

Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: Work this year consisted of; continuation of data summarization and workup of our previously conducted soil fertility experiments with the ultimate objective of preparation of manuscripts for publication in scientific journals. Two new manuscripts were submitted to journals for consideration; of these, one is published and the second has been accepted. PARTICIPANTS: Phil Speth and Peter Wakeman (both specialists in the Soil Science Department). TARGET AUDIENCES: The groups that would benefit are the potato farmers and the potato industry of Wisconsin and nationally. This would also include the fertilizer and crop protection industry and their representatives. Also, the Potato Association of America and the Wisconsin Potato Vegetable Growers Association.

Impacts
The study attempts to improve nutrient use efficiency and grower profitability while reducing the risk of environmental degradation from nutrient use. Nutrient sources include commercial fertilizer and manure.

Publications

Laboski, C.A.M., and K.A. Kelling. 2007. Influence of fertilizer management and soil fertility on tuber specific gravity: A review. Amer. J. Potato Res. 84:283-290.
Cooley, E.T., B. Lowery, K.A. Kelling, and S. Wilner. 2007. Water dynamics in drip and overhead sprinkler irrigated potato hills and development of dry zones. Hydrol. Process. 21:2390-2399.

Progress 01/01/06 to 12/31/06

Outputs
Work this past year consisted of continuation of data summarization and workup of our previously conducted soil fertility experiments with the ultimate objective of preparation of manuscripts for publication in scientific journals. Three new manuscripts were submitted to journals for consideration. All are currently in review. No new field or laboratory work was initiated.

Impacts
Each of these studies attempt to improve nutrient use efficiency and grower profitability while reducing the risk of environmental degradation from nutrient use. Nutrients sources include commercial fertilizer and manure.

Publications

Cusick, P.R., K.A. Kelling, J.M. Powell and G.R. Munoz. 2006. Estimates of residual dairy manure nitrogen availability using various techniques. J. Environ. Qual. 35:2170-2177.
Cusick, P.R., J.M. Powell, K.A. Kelling, R.F. Hensler and G.R. Munoz. 2006. Dairy manure N mineralization estimates from incubations and litterbags. Biol. Fertil. Soils 43(2):145-152.

Progress 01/01/05 to 12/31/05

Outputs
Activity in 2005 in this program centered on getting work from our potato and manure research, which had been previously used in extension activities, published in scientific journals. A small amount of field work was continued with Birl Lowery on the use of surfactants in potato production systems on irrigated sands.

Impacts
This worked helped formulate recommendations on use of manure in potato production systems, nutrient availability of dairy manure and improved nitrogen use efficiency for potatoes and other fertility issues.

Publications

Starr, G.C., E.T. Cooley, B. Lowery, and K.A. Kelling. 2005. Soil water fluctuations in a loamy sand under irrigated potato. Soil Sci. 170:77-89.
Curless, M.A., K.A. Kelling, and P.E. Speth. 2005. Nitrogen and phosphorus availability from liquid dairy manure to potatoes. Amer. J. Potato Res. 82:287-297.
Peters, J.B., P.E. Speth, K.A. Kelling, and R. Borge. 2005. Effect of soil pH on soybean yield. Proc. Wisconsin Fertilizer, Aglime and Pest Management Conf. 44:134-138.
Cusick, P.R., J.M. Powell, K.A. Kelling, G.R. Munoz, and R.F.Hensler. 2005. Nitrogen availability from dairy manure. Proc. Wisconsin Fertilizer, Aglime and Pest Management Conf. 44:310-316.
Jordan, M.O., B. Lowery, K.A. Kelling, and P.E. Speth. 2005. Summary of groundwater quality data under potato-corn-soybean rotation. Proc. Wisconsin Fertilizer, Aglime and Pest Management Conf. 44:135-141.
Schulte, E.E., L.M. Walsh, K.A. Kelling, L.G. Bundy, W.L. Bland, R.P. Wolkowski, J.B. eters, and S.J. Sturgul. 2005. Management of Wisconsin Soils. (5th ed.) UWEX Publ. no. A3588.

Progress 01/01/04 to 12/31/04

Outputs
Activities in 2004 in this program included 1) completion of the evaluation of the effect of hill shape on N use efficiency of potatoes; and 2) the evaluation of various surfactants for improving N fertilizer use efficiency. Both evaluations were conducted as field trials at Hancock ARS in cooperation with Birl Lowery. In previous years the data clearly supported the concept of improved fertilizer N (and perhaps water) utilization with a more blocked hill compared to a pointed or rounded potato hill. However, these results were confounded by the time at which the hills are formed. In 2004 all hills were formed at the same time. Although yields were generally quite low (<300 cwt/a) the highest tuber yields and quality were obtained with a standard shaped hill formed about the time of plant emergence. This experiment has clearly shown that a late hilling at early tuberization is detrimental to yield and quality. Evaluation of the surfactants continues to show some promise as a technique for improving N use efficiency, however; in a very strong leaching year, such as the early part of the 2004 growing season, this benefit is apparently diminished. No clear response was seen to the use of the surfactants in 2004.

Impacts
This work will result in recommendations for earlier timing of the hilling operation unless the additional tillage is needed for weed control. If more attention is given by growers to forming more broad, blocky hills, they may be able to improve the use efficiency of fertilizer N by about 5%. Such advances are dependent on avoiding over-applications to these environmentally sensitive areas.

Publications

Kelling, K.A., B. Lowery, P.E. Speth, and M.O. Jordan. 2004. Improving nitrogen use efficiency for potatoes. Proc. Wisconsin Annual Potato Meeting 17:127-135.
Kelling, K.A., and P.E. Speth. 2004. Nitrogen recommendations for new Wisconsin varieties. Proc. Wisconsin Annual Potato Meeting 17:111-122.
Lowery, B., M.O. Jordan, K.A. Kelling, and P.E. Speth. 2004. Use of surfactants to improve water and nitrate use efficiency and decrease leaching. Proc. Wisconsin Annual Potato Meeting 17:123-125.
Kelling, K.A. 2004. Nitrogen management suggestions for new Wisconsin potato varieties. Wisconsin CommonTater. April. p. 22-23.
Lowery, B., K.A. Kelling, and P.E. Speth. 2004. Effect of anionic surfactant application time on potato nitrogen use efficiency on sandy soils. Proc. Potato Assn. America Annual Meeting, Scottsbluff, NE. p. 26.

Progress 01/01/03 to 12/31/03

Outputs
This research was conducted as a series of related experiments, namely: 1) investigations into improved nitrogen use efficiency of potatoes, and 2) effect of certain non-conventional soil and plant additives on potatoes. The potato nitrogen (N) work examined three aspects of potato N management intended to improve the fertilizer N use efficiency of 1) including a nonionic surfactant on improving N use efficiency; 2) evaluation of best N rate and timing for several Wisconsin breeding selections; and 3) evaluation of hill shape for N management. Use of surfactant in 2003 showed substantial benefits in tuber yield, size and N uptake when applied on the hill at emergence, but little or no benefit when applied at planting. Evaluation of the surfactant effects on soil water and groundwater N concentrations are on-going. Evaluation of the best N rate and timing for three of Wisconsin's advance breeding lines [W1836-3, W1201 (now named MegaChip), and W1773-7] were compared to the N needs for the standard varieties Russet Burbank and Snowden. Evaluation of nonconventional soil additives Novozyme NZBPP01 and CK Life Sciences NutriSmart showed some improvements in yield and especially tuber size with 4 or 8 oz/acre of Novozyme applied twice; however, no benefits were seen from the application of the fertilizer substitute NutriSmart.

Impacts
This work is developing management systems that improve nutrient use efficiency and decrease cost of production and the potential of N contamination of the groundwater in these environmentally sensitive areas.

Publications

Curless, M.A. and Kelling, K.A. 2003. Preliminary estimates of itrogen availability from liquid dairy manure to potato. HortTechnology 13(4):593-597.
Kelling, K.A. 2003. Update on use of nonconventional additives on potatoes. p. 47-49. In Proc. Mid-Atlantic Fruit and Vegetable Convention, 4-6 Feb. 2003, Hershey, PA.
Curless, M.A. and Kelling, K.A. 2003. Use of manure in potato production. p. 56-58. In Proc. Mid-Atlantic Fruit and Vegetable Convention, 4-6 Feb. 2003, Hershey, PA.
Curless, M.A., Kelling, K.A., James, R.V. and Stevenson, W.R. 2003. Effect of manure timing on potato yield, quality and disease. Proc. Wis. Potato Mtg. 16-115-124.
Lowery, B., Nehls, T., Arriaga, F., Jordan, M. and Kelling, K. 2003. Use of surfactant to improve water and nitrogen use efficiency. Proc. Wis. Potato Mtg. 16:125-130.
Kelling, K.A., Jordan, M., Arriaga, F.J., Lowery, B. and Speth, P.E. 2003. Evaluation of hill shape for improving nitrogen use efficiency. Proc. Wis. Potato Mtg. 16:247-256.
Kelling, K.A. 2003. Update on use of nonconventional additives. p. 19-24. Proc. Wis. Muck Crops Mtg.
Kelling, K.A., Speth, P.E., Arriaga, F.J. and Lowery, B. 2003. Use of a nonionic surfactant to improve nitrogen use efficiency of potato. Acta Hort 619:225-232.

Progress 01/01/02 to 12/31/02

Outputs
This research was conducted as a series of related experiments, namely: 1) investigations into improved nitrogen use efficiency of potatoes; 2) use of manure in potato production; and 3) effect of certain non-conventional soil and plant additives on potatoes. The potato N work examined four aspects of potato nitrogen management intended to improve the fertilizer nitrogen use efficiency: 1) evaluation of Quadris impacts on optimal N rate and timing; 2) efficacy of including a nonionic surfactant on improving N use efficiency; 3) evaluation of best N rate and timing for several Wisconsin breeding selections; and 4) evaluation of hill shape for N management. Unlike the previous two years, results for 2002 showed that while the use of fumigant increased yield, the addition of Quadris to the fungicide program did not have much of an effect perhaps due to substantial insect pressure. We also saw no improvement in N use efficiency by the crop where the surfactant was applied. The manure potato experiments evaluating the apparent nitrogen and phosphorus availability from dairy manure to potatoes showed that the manure rates had the highest yield and quality from the whole experiment and therefore could not be calibrated against the fertilizer treatments. Movement and accumulation of nutrients from both sources were also extensively monitored. The second part of this study evaluated the influence of low or high rate of fall manure applications on the incidence and severity of potato scab for several potato varieties that represent a range of scab susceptibilities. This experiment, conducted at Antigo and Rhinelander, showed little effect of treatment on scab levels at Antigo but a distinct effect of manure level on scab severity at Rhinelander, where the manure was spring-applied. The evaluation of time of manure application (18,7 or 1 month before planting) on scab incidence confirmed more problems where the manure was applied immediately prior to planting. The nonconventional soil additive work for 2002 showed no effect of any of the soil or plant additives on improving crop yield.

Impacts
This work is developing management systems that improve nutrient use efficiency and decrease cost of production and the potential of nitrogen contamination of the groundwater. The manure work may result in substantial reintegration of two disparate agricultural systems.

Publications

Morgan, G.D., W.R. Stevenson, A.E. MacGuidwin, K.A. Kelling, L.K. Binning, and J. Zhu. 2002. Plant pathogen population dynamics in potato fields. J. Nematology 34:180-193.
Kelling, K.A., and P.E. Speth. 2002. Soil conditions favoring micronutrient deficiencies and responses in 2001. Proc. Wisconsin Fertilizer, Aglime and Pest Management Conf. 41:341-349.
Dawson, M.A., and K.A. Kelling. 2002. Use of manure in potato production. Proc. Wisconsin Annual Potato Meetings 15:17-27.
Arriaga, F.J., K.A. Kelling, and B. Lowery. 2002. Use of surfactant to reduce nitrogen inputs and decrease nitrate leaching in potato production. Proc. Wisconsin Annual Potato Meetings 15:97- 98.
Kelling, K.A., and P.E. Speth. 2002. Potato micronutrient responses in 2001. Proc. Wisconsin Annual Potato Meetings 15:99-108.
Kelling, K.A., P.E. Speth, W.R. Stevenson, and R.V. James. 2002. Effect of fumigation and Quadris on nitrogen management. Proc. Wisconsin Annual Potato Meetings 15:167-174.
Kelling, K.A., P.E. Speth, D.I. Rouse, and W.R. Stevenson. 2002. Interaction of crop protectants with potato N management. Proc. Idaho Winter Commodity Schools 34:153-166.
Lowery, B., F.J. Arriaga, and K.A. Kelling. 2003. Use of surfactant to decrease nitrate leaching and improve potato nitrogen use efficiency. Proc. International Union Soil Science, Bangkok, Thailand. In Press.
Kelling, K.A., and P.E. Speth. 2002. Use of urea as a nitrogen source for potatoes. Badger Common'tater, June 02, p. 12, 18 and 20.

Progress 01/01/01 to 12/31/01

Outputs
This research was conducted as a series of related experiments, namely: 1) investigations into improved nitrogen use efficiency of potatoes; 2) use of manure in potato production; and 3) effect of certain non-conventional soil and plant additives on potatoes. The potato N work examined four aspects of potato nitrogen management intended to improve the fertilizer nitrogen use efficiency: 1) evaluation of Quadris impacts on optimal N rate and timing; 2) efficacy of including a nonionic surfactant on improving N use efficiency; 3) evaluation of best N rate and timing for several Wisconsin breeding selections; and 4) evaluation of hill shape for N management. Results for 2001 showed the use of fumigant greatly increased yield and the addition of Quadris to the fungicide program, especially when combined with fumigation, resulted in an additional 40 cwt/acre and may have increased the optimum N rate by about 40 lb N/acre. Irrespective of fumigation or fungicide, splitting the N into only two applications was an advantage in the total yield and size. There was some tendency for apparently better N use efficiency by the crop where the surfactant was applied in that somewhat larger tubers were obtained with less N when the surfactant was included. The manure potato experiments evaluated the apparent nitrogen and phosphorus availability from dairy manure potatoes. Manure or fertilizer N or fertilizer P was applied at several rates. Comparison of yield and quality from both nutrient sources allowed for a determination of the manure N and P availability, with the 2001 results showing that the manure rates had the highest yield and quality from the whole experiment and therefore could not be calibrated against the fertilizer treatments. Movement and accumulation of nutrients from both sources were also extensively monitored. The second part of this study evaluated the influence of low or high rate of fall manure applications on the incidence and severity of potato scab for several potato varieties that represent a range of scab susceptibilities. This experiment conducted at Antigo and Rhinelander showed little effect of treatment on scab levels at Antigo but a distinct effect of manure level on scab severity at Rhinelander where the manure was spring applied. The evaluation of time of manure application (18,7 or 1 month before planting) on scab incidence confirmed more problems where the manure was applied immediately prior to planting. The nonconventional soil additive work for 2001 showed no effect of any of the soil or plant additives on improving crop yield.

Impacts
This work is developing management systems that improve nutrient use efficiency and decrease cost of production and the potential of nitrogen contamination of the groundwater. The manure work may result in substantial reintegration of two disparate agricultural systems.

Publications

NCR 103 Committee (K.A. Kelling, editor). 2001. Nonconventional soil additives: products, companies, ingredients and claims. Dept. of Soil Science, Univ. Wisconsin, Madison.
Kelling, K.A., P.E. Speth and D.I. Rouse. 2001. Influences of fumigation on nitrogen management of potatoes. In Agronomy abstracts (CD-Rom). ASA, Madison, WI.
Dawson, M.A., K.A. Kelling, and W.R. Stevenson. 2001. Field estimate of dairy manure nitrogen availability to potatoes. In Agronomy abstracts (CD-Rom). ASA, Madison, WI.
Conley S.P., L.K. Binning and K.A. Kelling. 2001. Row spacing and fertility affect Russet Burbank, Dark Red Norland, and Snowden yield. Proc. Wisconsin Potato Meeting 14:317-318.
Nehls, T., F. Arriaga, K.A. Kelling and B. Lowery. 2001. Nitrate leaching under different N rates and surfactants and potato yield. Proc. Wisconsin Potato Meeting 14:79085.
Kelling, K.A. and P.E. Speth. 2001. Y2K update on nonconventional additives on potatoes. Proc. Wisconsin Potato Meeting 14:87-95.
Kelling, K.A., P.E. Speth, R.V. James and W.R. Stevenson. 2001. Potato calcium and phosphorus responses at Endeavor, p. 55-60. In Proc. Wisconsin Mint and Muck Mtgs., 26-27 February 2001, Madison, WI
NCR 103 Committee (K.A. Kelling, editor). 2001. Crop responses to AmiSorb in the North Central Region. North Central Regional Research Report 347.
Kelling, K.A., and M.A. Dawson. 2001. Role of manure in potato production. Proc. Wisconsin Potato Meeting 14:67-77.
Kelling, K.A., P.E. Speth, D.I. Rouse and W.R. Stevenson. 2001. Crop protectants and effects on nitrogen needs. Proc. Wisconsin Potato Meeting 14:139-148.
Kelling, K.A. 2001. Interactions between manure and potato production. Proc. Mid-Atlantic Fruit and Vegetable Conv., vol 1, p. 40-42. 30 January - 1 February 2001. Hershey, PA.

Progress 01/01/00 to 12/31/00

Outputs
This research was conducted as a series of related experiments, namely: 1) investigations into improved nitrogen use efficiency of potatoes; 2) use of manure in potato production; and 3) effect of certain non-conventional soil and plant additives on potatoes. The potato N work examined four aspects of potato nitrogen management intended to improve the fertilizer nitrogen use efficiency: 1) Role of ammonium sulfate with other N source combinations on potato yield and quality; 2) evaluation of interaction of fumigation on potato N source and rate responses; 3) evaluation of Quadris impacts on optimal N rate and timing; and 4) efficacy of including a nonionic surfactant on improving N use efficiency. Results for 2000 showed responses to applied N up to 240 to 280 lb N/acre and an advantage to where all of the N was applied as NH42SO4. As in past years, the use of fumigant greatly increased yield; we could not detect differences between N sources or optimum N rate due to the fumigation. The addition of Quadris to the fungicide program, especially when combined with fumigation, resulted in an additional 20 cwt/acre and may have increased the optimum N rate by about 40 lb N/acre. Irrespective of fumigation or fungicide, splitting the N into only two applications was an advantage in the total yield and size. There was some tendency for apparently better N use efficiency by the crop where the surfactant was applied in that top yields and grades were obtained with 60 lb N/acre less with the surfactant. The manure potato experiments evaluated the apparent nitrogen and phosphorus availability from dairy manure potatoes. Manure or fertilizer N or fertilizer P was applied at several rates. Comparison of yield and quality from both nutrient sources allowed for a determination of the manure N and P availability, with the 2000 results showing 18% N availability at the low manure rate. The high manure rate had the highest yield and quality from the whole experiment and therefore could not be calibrated against the fertilizer treatments. Responses to applied P from either source were minimal this season, eliminating the opportunity to do equivalence comparisons. Movement and accumulation of nutrients from both sources were also extensively monitored. The second part of this study evaluated the influence of low or high rate of fall manure applications on the incidence and severity of potato scab for several potato varieties that represent a range of scab susceptibilities. This experiment conducted at Antigo and Rhinelander showed very little scab at either location and no effect of treatment. The nonconventional soil additive work for 2000 showed no effect of any of the soil or plant additives on improving crop yield. In a few cases, such as the use of ACA with Russet Burbank and the sue of Nature's Nutrient at the 50% fertilizer rate, there is a tendency toward seeing a benefit form using the product, but the results were not statistically significant at the 0.10 level.

Impacts
This work is developing management systems that improve nutrient use efficiency and cost of production and decrease the potential of nitrogen contamination of the groundwater.

Publications

Kelling, K.A., and P.E. Speth. 2000. Influence of cation balance on potato production. Proc. Wisconsin Potato Mtgs. 13:155-166.
Kelling, K.A., and P.E. Speth. 2000. Evaluation of two plant additives for improving potatoes. Proc. Wisconsin Potato Mtgs. 13:137-152.
Kelling, K.A. 2000. Research observations on petiole nitrate testing. Proc. Wisconsin Potato Mtgs. 13:175-184.
Kelling, K.A., P.E. Speth, R.V. James and W.R. Stevenson. 2000. Evaluation of calcium and phosphorus sources on muck soils, p. 29-34. In Proc. Wisconsin Mint and Muck Mtgs. 28-29 February 2000.
Kelling, K.A., and P.E. Speth. 2000. Effect of cation balance on potato yield, quality, and tissue concentrations. Amer. J. Potato Res. 77:405.

Progress 01/01/99 to 12/31/99

Outputs
This research was conducted as a series of related experiments, namely: 1) investigations into improved nitrogen use efficiency of potatoes; 2) effect of cation balance on potato yield and quality; and 3) effect of certain non-conventional soil and plant additives on potatoes. N Experiment Results: Where various N sources were examined at different times of application, the source of nitrogen applied at hilling (tuberization) clearly influenced grade and size grade of the harvested tubers. Ammonium sulfate for this second N application resulted in fewer grade A tubers (more culls), but tubers of larger size than did ammonium nitrate. Urea was intermediate between the two. It is likely that less of the ammonium sulfate leached (at least as quickly) during this relatively wet season, which in turn, allowed more tuber bulking but also likely resulted in a greater proportion of off-shape tubers. Somewhat similar trends were seen in the previous year. For neither of the two experiments was the interaction term significant, therefore we cannot conclude that the rate response is different depending on the source used. An examination of various N sources across several fumigation treatments showed that fumigation was much less important in 1999 that in 1998. Although absolute yields increased by 15-30 cwt/a where fumigant was used, statistically this was not significant. As expected most tuber parameters were significantly increased by N additions although responses were not always seen to the highest rate of N applied. It would be difficult from these data to argue that ammonium sulfate would cause a problem when used with spring or fall fumigated fields. The trend for larger tuber size with ammonium sulfate also held true in this trial. Cation Balance Experiment Results: Averaged across the 5 years at 3 locations where this experiment was conducted, it did not demonstrate the expected potato yield and quality responses from added Mg when high levels of Ca or K had been previously applied. Although soil test Mg levels were marginal, apparently adequate Mg was being supplied to the plant. In some cases, the addition of lime or gypsum appeared to reduce tuber yield and quality. At the treatment levels used (1 T/a CaSO4; 3 T/a dolomitic or calcitic lime) the calcitic lime increased soil test and tissue Ca levels more. Overall few tuber differences were seen between the various K sources, but KCl tended to increase tissue K more than K2SO4 or KMgSO4. Nonconventional Additive Results: Experiments with ACA, Fulcrum and Early Harvest generally showed a small yield improvement with ACA and a small tuber size redistribution with Fulcrum on some varieties, but little effect from using Early Harvest. In general, while these materials may have some plant growth regulatory influence on the crop, responses tend to be unpredictable and inconsistent.

Impacts
Fertilizer inputs currently cost potato producers about $150/acre. Although these products may somewhat improve nutrient use efficiency, the major benefits are associated with reduced environmental risk from better N use, especially to groundwater.

Publications

Rehm, G.W., S. Brouder, R. Dowd, D. Franzen, J. Gerwing, G. Hergert, R.G. Hoeft, M. Hotron, J.W. Johnson, K.A. Kelling, D. Mengel, J.E. Sawyer, P. Scharf, D. Warncke, and D. Whitney. 1999. Impact of ACA on crop yield in the North Central Region. NC Regional Research Report 343. 10 p.
Kelling, K.A., L.G. Bundy, S.M. Combs, and J.B. Peters. 1999. Optimum soil test levels for Wisconsin. UWEX Fact Sheet A3030. 8 p.
Kelling, K.A. 1999. Influence of phosphorus fertilization on tuber solids. Badger Common'tater, p. 17-18.
Kelling, K.A. 1999. How much phosphorus do crops need? Proc. Wisconsin Forage Council Symp. 23:22-29.
Kelling, K.A. and P..E. Speth. 1999. Potato responses to ACA on several soils. Proc. Wisconsin Potato Meetings 12:95-104.
Kelling, K.A., R.F. Hensler, and P.E. Speth. 1999. Influence of nitrogen concentration on tuber set and development. Proc. Wisconsin Potato Meetings 12:67-78.
Kelling, K.A. 1999. Wisconsin potato soil fertility studies. Proc. Pennsylvania Cooperative Potato Growers. 24-25 Feb. 1999. State College, PA. P. 13.
Kelling, K.A. and P.E. Speth. 1999. Effect of harvest data on optimum N rate for Norland. Amer. J. Potato Res. 76:374.
Kelling, K.A. and P.E. Speth. 1999. Responsiveness of Russet Burbank to ACA rate. Amer. J. Potato Res. 76:323-324.
Binning, L.K., C.M. Boerboom, L.G. Bundy, T.R. Connell, K.A. Delhaut, H.C. Harrison, K.A. Kelling, D.L. Mahr, S.E.R. Mahr, B.A. Michaelis, W.R. Stevenson, J.L. Wedberg and J.A. Wyman. 1999. Commercial vegetable production in Wisconsin. UWEX Bulletin A3422. 132 p. (major revision of soil fertility sections).