Source: UNIVERSITY OF MAINE submitted to NRP
REFINEMENT OF SOIL AND NUTRIENT MANAGEMENT SYSTEMS FOR POTATO CROPPING SYSTEMS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
0132136
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 1998
Project End Date
Sep 30, 2004
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF MAINE
(N/A)
ORONO,ME 04469
Performing Department
PLANT, SOIL, & ENVIRONMENTAL SCIENCES
Non Technical Summary
(N/A)
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1021310106025%
1021310114025%
2051310106025%
2051310114025%
Goals / Objectives
Objective 1. Refine current soil- and tissue-testing criteria for use in Maine potato cropping systems. (1a) Refinement of soil- and tissue-testing guidelines for phosphorus management in potato cropping systems. (1b) Refinement of potassium fertilization guidelines for maximization of potato-processing quality. Objective 2. Determine if organic soil amendments, crop rotation, and supplemental irrigation can be effective management tools for enhancing potato quality, productivity, and nutrient utilization in Maine. (2a) Determine the effects of crop rotation and soil amendment (compost and manure) on potato soils and crop productivity. (2b) Study crop rotation effects and the residual effects of compost and papermill sludge on potato soils and crop productivity.
Project Methods
Soil test calibration studies will be conducted over several years using potato (Solanum tuberosum L.) as the test crop. Sites with varying soil phosphorus (P) and potassium (K) levels will be used. At each site varying rates of at-planting P or K fertilizer will be applied as treatments. Nutrient uptake, leaf and petiole nutrient concentrations, crop yields, and crop quality will be measured. For the P studies, we will focus on calibration of the current soil test procedure (Modified Morgan) and assessing the potential of other methods for improving our ability to predict the responsiveness to fertilizer P. The K studies will also includ calibration of existing soil test procedures, but will focus on the impact of nutrient management on bruise susceptibility, processing quality, and ascorbic acid content. Studies will also be conducted on the use of organic soil amendments (compost, manure, papermill sludge) and crop rotation as means of improving the productivity of the potato crop. Water-stable aggregate, bulk density, and nutrient content of the soils will be monitored, in addition to crop yield, tuber quality, nutrient uptake, and disease incidence.

Progress 10/01/98 to 09/30/04

Outputs
Foliar boron increased US1 yield of Russet Burbank by 3.3 t/ha during 2003, while banded B had no significant effect. The response was similar for all three foliar B timings (tuber initiation, early bulking, or mid bulking). Boron did not have any dramatic effects on the tuber quality attributes measured to date. Foliar analysis showed that the early-bulking treatment was the most effective at increasing leaf and petiole B concentrations. Zinc (foliar or banded) had no significant effects on potato yield or quality during 2005. Foliar analysis showed that the banded at-planting and early-bulking foliar treatments effectively increased leaf and petiole Zn concentrations. The 2003 growing season was relatively wet (29.5 cm of rainfall from June 1 to August 31); however, even with the high rainfall we observed a significant yield response (1.8 t/ha total and 2.2 t/ha US1) to supplemental irrigation in our Russet Burbank experiment. Yield of large-size tubers increased; however, there was a marked decrease in tuber specific gravity from 1.080 to 1.076. Incidence of hollow heart also increased (2.6 versus 6.9%). Potash fertilization rate did not have strong effects on yield or tuber size on this site; however, increasing rates of potash fertilizer strongly depressed tuber specific gravity (0.003 per 112 kg/ha potash). Increasing rates of potash fertilization were associated with decreased incidence of hollow heart. Broadcast applications, whether just after planting or just before hilling were effective at supplying potassium to the crop; however, uptake occurred with early timings. We observed few significant interactions between supplemental irrigation and potash treatment; however, the lowest specific gravities in our studies have been observed when high rates of potash have been combined with the use of supplemental irrigation. The results from our studies are being used to update fertilization recommendations for processing potato production.

Impacts
This project is focused on improving the management of potato crops in Maine and the United States. The information generated helps potato growers manage their crops so that high quality potatoes are produced while conserving soils and optimizing purchased inputs.

Publications

  • Dalton, T.J., G.A. Porter, and N. Winslow. 2004. Risk management strategies in humid production regions: a comparison of supplemental irrigation and crop insurance. Agric and Resource Econ Rev 33:173-185.
  • Porter, G.A., A. Siver, and P. Ocaya. 2004. Potassium fertilization affects fry color, internal defect incidence, blackspot bruise susceptibility, and tuber calcium concentration. Amer J Potato Res 81: 82-83 (Abst)


Progress 10/01/02 to 09/30/03

Outputs
From 2000 to 2002, we studied current-season (0, 224, or 448 kg/ha) potash and long-term potash fertilizer program effects on yield, quality, and nutrient uptake of non-irrigated Atlantic potatoes. Soil-test K levels on these plots ranged from 130 to 225 kg/ha (2.4 to 4.4% base saturation) depending on the long-term potash fertility program (medium-low to medium soil-test potassium levels based on University of Maine criteria). Current-season potash had much stronger effects on tuber quality than did soil potassium. Chip color improved dramatically as the potash rate increased from 0 to 224 kg/ha and more slowly as the rate increased to 448 kg/ha. Internal defects incidence (hollow heart, brown center, and blackspot bruise) declined dramatically as potash rate increased. Increased potash results in higher tuber potassium, calcium, and magnesium concentrations. For example, tuber calcium concentration increased by 22 to 33%. Additional studies were conducted with Russet Burbank, Shepody, and Snowden from 1999 to 2002. Fry color improved in response to increasing potash rates, while Russet Burbank and Snowden blackspot bruise susceptibility declined. Tuber tyrosine, a key biochemical ingredient in blackspot bruise development, declined as potash rate increased. These studies show that increasing potash rates can improve most tuber quality attributes; however, it is well known that higher potash rates decrease tuber specific gravity and this was certainly true in our studies. Over the 11 experiments, each 32 kg/ha of potash decreased specific gravity by about 1 points. Despite this negative effect, the specific gravity of Atlantic and Snowden remained very high at all potash rates. Petiole and leaf samples were collected from these studies and analyzed for mineral nutrient contents. Tissue testing criteria are being developed to maximize tuber yield and quality.

Impacts
This project is focused on improving the management of potato crops in Maine and the United States. The information generated helps potato growers manage their crops so that high quality potatoes are produced while conserving soils and optimizing purchased inputs.

Publications

  • No publications reported this period


Progress 10/01/01 to 09/30/02

Outputs
During 1999, we initiated studies on the effects of K fertilization on potato yield and quality attributes for potato processing. K fertilizer rate studies were conducted from 1999 to 2002. Potassium fertilizer did not significantly affect tuber yields 1999; however, yield increased significantly on two of four sites during 2000 and 2001. During 2002, yields were increased by potassium when potatoes were irrigated, but not when they were grown without irrigation. Tuber size has typically been increased as the rate of potassium fertilizer has increased and fry color has generally improved as well. Specific gravity declined in response to at-planting K (4.4 to 6.2 points per 134 kg/ha of potash) and broadcast K (2.7 to 3.2 points per 134 kg/ha potash). During 2002, potassium decreased specific gravity at a rate of 2.2 points per 112 kg/ha of potash under nonirrigated conditions and by 3.90 points per 112 kg/ha of potash under irrigated conditions. Blackspot bruise susceptibility has generally decreased with increasing rates of potassium fertilizer. Tuber phenolic concentrations have decreased significantly in response to potassium while ascorbic acid concentration has not been affected. Tuber tyrosine concentrations decreased linearly with increasing rates of potassium fertilizer during 2000. Tyrosine concentration of tubers was negatively correlated with tuber potassium for Snowden during 1999 and Russet Burbank and Shepody during 2000. For Snowden during 1999 and Russet Burbank and Shepody during 2000 there was also a decrease in blackspot bruise susceptibility as tuber potassium concentration increased. These studies demonstrate that potassium chloride fertilizers can affect the phenolic pools that are responsible for melanin formation in bruise potato tubers. By applying optimum rates of these fertilizers growers can increase tuber size, improve fry color, and reduce bruise susceptibility. These improvements will come at the expense of some reductions in tuber specific gravity.

Impacts
This project is focused on improving the management of potato crops in Maine and the United States. The information generated helps potato growers manage their crops so that high quality potatoes are produced while conserving soils and optimizing purchased inputs.

Publications

  • Grandy, A.S., G.A. Porter, and M.S. Erich. 2002. Organic amendment and rotation crop effects on the recovery of soil organic matter and aggregation in potato cropping systems. Soil Sci Soc Am J 66:1311-1319.
  • Griffin, T.S. and G.A. Porter. 2002. Changing soil carbon and nitrogen pools in intensively tilled rotations. American Society of Agronomy Abstracts, November 10-14, 2002 (abst).


Progress 10/01/00 to 09/30/01

Outputs
Research on nutrient management, crop rotation, and soil amendment use in potato production continued during 2001. Soil analyses indicate that the low organic matter inputs and intensive tillage of a potato crop quickly decrease soil structure and organic matter. Soil water stable aggregate content averaged 14.9% (wt. basis) after potatoes compared to 22.2% after rotation crops in an experiment that began in 1996. Water stable aggregate content was highest in the least intensive potato rotation (potatoes every third year) whether we look at the potato (19.2%) or the timothy/clover (32.1%) phase of the rotation. The three-year rotation also higher soil organic matter than the shorter rotations. A two-year rotation with a single year of organic amendment (papermill sludge and compost) application during 1996 also had relatively high levels of organic matter and total carbon. Continuous potatoes had the lowest soil water stable aggregate and organic matter content. We are surprised at how quickly extending the rotation to three years and including one year of timothy/clover (which adds organic matter and provides a full year without tillage) has improved soil organic matter and structure. The crop yield data clearly show the seasonal fluctuation in yields results primarily from erratic rainfall and that soil improvement approaches (crop rotation and soil amendment) cannot substitute for an adequate water supply; however, the soil management treatments have resulted in yield differences. Either the amended treatment or the three-year rotation have topped the yield rankings in each of the past five years. The continuous potato treatment has quickly dropped to the bottom of the yield ranking. Relative to the standard two-year rotation, the average annual U.S.#1 yield response to amendment treatment has been +2.1 t/ha over the past five years, while the average has been +1.57 t/ha for the 3-yr rotation. The two-year vegetable rotation has been equal to the standard rotation, while the continuous potato treatment has averaged -2.8 t/ha relative to the standard. Legume green manure crops grown in two-year rotation with potatoes provided 44 to 66 kg/ha of fertilizer N replacement value when compared to a two-year, potato-grain rotation. These crops significantly increased soil inorganic N levels, but they did not affect soil organic matter, soil structure, or readily mineralizable soil N. Tuber size tended to increase with increasing rate of N. During 1999, we initiated studies on the effects of K fertilization on potato yield and quality attributes for potato processing. K fertilizer rate did not significantly affect tuber yields 1999; however, yield increased significantly on two of four sites during 2000 and 2001. Fry color has generally improved as rate of K fertilizer has increased. Specific gravity declined in response to at-planting K (4.4 to 6.2 points per 134 kg/ha of potash) and broadcast K (2.7 to 3.2 points per 134 kg/ha potash). Tuber phenolic concentrations have also decreased significantly while ascorbic acid concentration has not been affected.

Impacts
This project is focused on improving the management of potato crops in Maine and the United States. The information generated helps potato growers manage their crops so that high quality potatoes are produced while conserving soils and optimizing purchased inputs.

Publications

  • Porter, G.A., J.A. Sisson, and E. H. van Cingel. 2001. Potassium source and micronutrient effects on yield and quality of Maine-grown processing potatoes. Am J Potato Res 77:415-416 (abst).


Progress 10/01/99 to 09/30/00

Outputs
Research on supplemental irrigation, nutrient management, crop rotation, and soil amendment use in potato production continued during 2000. Soil amendment programs with cull potato compost and beef manure increased yield by 1.8 t per ha when no irrigation was used and had no significant effects under irrigation during 1999. Plots that were annually amended with compost and manure since 1992 had significantly greater soil organic carbon levels, light fraction organic matter, water soluble carbohydrates, water stable aggregates, and gravimetric soil moisture; however, potato yields were equal among the amendment regimes during 1999. In a second experiment studying the effects of crop rotation length and soil amendments, Superior potatoes grown in a two-year rotation with oats were significantly higher yielding (4.54 t/ha) when the soils were amended three years earlier with paper mill sludge and cull potato compost. A three-year rotation (potato-grain-green manure) resulted in significantly higher yields than continuous potatoes (28.9 vs 22.9 t ha-1), but was statistically equal in yield to a two-year, potatoes-grain rotation (25.4 t/ha). Soil bulk density was significantly decreased by the amendments. Legume green manure crops grown in two-year rotation with potatoes provided 44 to 66 kg/ha of fertilizer N replacement value when compared to a two-year, potato-grain rotation. These crops significantly increased soil inorganic N levels, but they did not affect soil organic matter, soil structure, or readily mineralizable soil N. These crops would prove beneficial in potato production systems with reduced availability of fertilizer N; however, they did not result in improved potato yields compared to crops fertilized with the optimum rate of N fertilizer. This is probably due to their minimal effects on soil physical properties. During 1999, we initiated studies on the effects of K fertilization on potato yield and quality attributes for potato processing. We observed few effects of K fertilizer rate on total yields during 1999; however, specific gravity and size of tubers were strongly affected by K fertilization. Our study is also focusing on the relationships between plant K concentration, fry color, bruise susceptibility, and tuber biochemistry (e.g. ascorbic acid, phenolic, and tyrosine content). Results from these analyses should be available during 2001.

Impacts
This project is focused on improving the management of potato crops in Maine and the United States. The information generated helps potato growers manage their crops so that high quality potatoes are produced while conserving soils and optimizing purchased inputs.

Publications

  • Grandy, A.S., M.S. Erich, and G.A. Porter. 2000. Suitability of the anthrone-sulfuric acid reagent for determining water soluble carbohydrates in soil water extracts. Soil Biol Biochem 32:725-727.
  • Plotkin, J.M.B. 2000. The effects of green manure rotation crops on soils and potato yield and quality. M.S. thesis, University of Maine, 107 pp.


Progress 10/01/98 to 09/30/99

Outputs
A three-year study on the effects of potassium source and micronutrients was completed during 1998. Over three growing seasons potassium sulfate plus micronutrients (3.36 kg/ha zinc and 0.56 kg/ha boron) significantly increased plant vigor at vine desiccation, total yield (4.14 tons per ha), U.S. #1 yield, and tuber size. KCl, SulPoMag plus KCl, and potassium sulfate applied alone had no significant effect on these characteristics. The treatments had inconsistent effects on fry color. The micronutrient treatment resulted in significant increases in foliar boron and zinc concentrations. Research on supplemental irrigation timing and frequency, crop rotation, and soil amendments continued during 1999. Averaged over four potato varieties during 1998, supplemental irrigation beginning at tuber initiation increased yields by 6.9 t per ha (19%) over the non-irrigated check. Irrigation also significantly increased tuber specific gravity. Supplemental irrigation increased hollow heart incidence in all varieties except Superior. Delaying supplemental irrigation until August reduced hollow heart incidence, but also decreased yield response to 4.0 t per ha. Differential frequency treatments had relatively few effects on yield and quality. Soil amendment programs with cull potato compost and beef manure increased yield by 3.0 t per ha when no irrigation was used and by 4.3 t per ha under irrigation. Plots that were annually amended with compost and manure since 1992 had significantly greater soil organic carbon levels, light fraction organic matter, water soluble carbohydrates, water stable aggregates, and gravimetric soil moisture. Soil bulk density was significantly decreased by the amendments. Soil organic carbon and light fraction organic matter declined significantly after one season without amendments; however, each remained significantly higher in amended than in unamended plots. Water stable aggregate content and soil bulk density were not affected by a one year break in the soil amendment program. These observations confirm that the soil amendments have important residual effects on soil quality and crop yield. Although long-term changes in soil properties have been consistent among experiments, only 1 of 3 experiments conducted during 1998 showed residual yield effects from past soil amendment treatments.

Impacts
Results from this project are geared toward improving the management of the potato crop in Maine and the northeast. Refined nutrient management recommendations will allow growers to optimize yield and quality, while eliminating excess inputs and reducing costs. Organic soil amendments and effective rotation crops can replace chemical fertilizer, improve soil quality, and improve yields. Refined irrigation recommendations can help growers improve the efficiency of input use.

Publications

  • Porter, G.A., G.B. Opena, W.B. Bradbury, J.C. McBurnie, and J.A. Sisson. 1999. Soil management and supplemental irrigation effects on potatoes: I. Soil properties, tuber yield, and quality. Agronomy Journal 91: 416-425.
  • Opena, G.B. and G.A., Porter. 1999. Soil management and supplemental irrigation effects on potatoes: II. Root growth. Agronomy Journal 91:426-431.
  • Grandy, A.S., G.A. Porter, and M.S. Erich. 1999. Soil amendment, rotation crop, and irrigation effects on soil physical and chemical properties in a potato cropping system. Agronomy Abstracts 91: (abst.)
  • Porter, G.A., J.A. Sisson, and E. van Cingel. 1999. Potassium source and micronutrient treatments affect yield and quality of processing potatoes. Proceedings of the Northeast Potato Technology Forum, pp. 24-26 (abst).


Progress 10/01/97 to 09/30/98

Outputs
Research on supplemental irrigation timing and frequency, crop rotation, and soil amendments continued during 1998; however, most results from 1998 are not available at this time. Averaged over four potato varieties during 1997, supplemental irrigation beginning at crop emergence or tuber initiation increased US#1 yields by 6.8 t per ha and also increased tuber specific gravity. Supplemental irrigation increased hollow heart incidence in Russet Burbank and Atlantic. Delaying supplemental irrigation until August reduced hollow heart incidence, but also decreased yield response to 2.5 t per ha. Differential frequency treatments had relatively few effects on yield and quality. Soil amendment programs with cull potato compost and beef manure increased yield by 3.8 t per ha when no irrigation was used and by only 1.0 t per ha under irrigation. Plots that were annually amended with compost and manure since 1992 had significantly greater soil organic carbon levels, light fraction organic matter, water soluble carbohydrates, water stable aggregates, and gravimetric soil moisture. Soil bulk density was significantly decreased by the amendments. Yields were increased by the soil amendment program even when no current-season amendment application occurred. Soil organic carbon and light fraction organic matter declined significantly after one season without amendments; however, each remained significantly higher in amended than in unamended plots. Water stable aggregate content and soil bulk density were not affected by a one year break in the soil amendment program. These observations confirm that the soil amendments have important residual effects on soil quality and crop yield. A two-year study on phosphorus soil-test calibration was completed during 1997. Only 1 of 11 sites testing >25 kg per ha plant available P (modified Morgan extract) showed a significant yield response to P fertilizer. Averaged over sites, apparent P-use efficiency was >60% at the 56 kg per ha P fertilizer rate and declined to <20% at the 224 kg P per ha. Applications not exceeding 56 kg per P ha would adequately utilize residual soil P, maintain high yields and quality, and result in high P-use efficiency.

Impacts
(N/A)

Publications

  • Grandy, A. S. 1998. Soil amendment, rotation crop, and irrigation effects on soil physical and chemical properties in a potato cropping system. M.S. thesis, University of Maine; Orono. 107 pp.
  • Fitzgerald, C.B. 1998. Soil phosphorus in Aroostook County (Maine) potato cropping systems: organic matter effects and residual phosphorus contributions. M.S. thesis, University of Maine; Orono. 124 pp.
  • Merrick, L.C., B.G. Schatz, D.H. Putnam, G.Aksland, G.A. Porter, C.J. Simon, and D.H. Lambert. 1998. Agronomic evaluation of white lupin germplasm for northern latitude grain production. 1998 Agron. Abstracts p 54 (abst).
  • Porter, G.A. and B. Bradbury. 1998. Supplemental irrigation timing effects on tuber quality. Proceedings of the Northeast Potato Technology Forum. 6:36-37 (abst).
  • Porter, G.A., and J.A. Sisson. 1997. Cull potato compost and fertilizer rate effects on potato nutrient uptake and tuber yields. Am Potato J 74:459 (abst.)
  • Porter, G.A., and J.A. Sisson. 1997. Seedpiece spacing, fertilizer rate, and green sprouting effects on stem numbers, tuber set, yield, and quality of three russeted potato varieties. Am Potato J 74:459 (abst.)
  • Fitzgerald, C.B., G.A. Porter and M.S. Erich. 1997. Response of potatoes to residual soil phophorus and phosphorus fertilizer in Aroostook County, Maine. Am Potato J 74:429 (abst.)
  • Porter, G.A., J.A. Sisson, and B. MacFarline. 1997. Potato weed control and vine desiccation studies at Aroostook Research Farm - 1997. AES Departmental Mimeo 97-01.
  • Porter, G.A., J.A. Sisson, B. MacFarline, and P. Wardwell. 1997. MKP soil-applied fertilizer and foliar fertilization experiment on Shepody potatoes at Aroostook Research Farm - 1997. AES Departmental Mimeo 97-03.
  • Porter, G.A., J.A. Sisson, B. MacFarline, and P. Wardwell. 1997. Malting barley variety and management trial at Aroostook Research Farm - 1997. AES Departmental Mimeo 97-04.
  • Porter, G.A. and W.B. Bradbury. 1998. Supplemental irrigation timing effects on tuber quality. Maine Potato News, March 1998.


Progress 10/01/96 to 09/30/97

Outputs
Research on potato response to supplemental irrigation timing and frequency continued. A second experiment examining effects of soil management on soil properties was also continued. Tuber yield, quality, and soil test results from both studies are unavailable. A 6-year study on soil management was completed. Cull potato compost was applied annually to Caribou loam soil in studies conducted from 1991-96. Application rates of 0, 11.2, 22.4 and 33.6 Mg ha-1 were used. Potatoes were planted in a 2-year rotation with barley, just after compost was surface incorporated into soil. From 1994-96, potatoes received at-planting fertilizer rates of either 147-112-112 (kg ha-1 each of N-P2O5-K2O) or 202-202-202 plus micronutrients. Compost application over 6-year period has increased soil organic matter (from 3.2 to 4.3%), increased cation exchange capacity, and increased soil test levels of calcium, potassium, phosphorus, and manganese. Yields were significantly increased by compost applications in 2 of past 3 years. Average yields for 4 compost rates from 1994-96 were 32.9, 34.6, 36.4, and 37.7 t ha-1. Yields were increased by high fertilization rate during all 3 years; however, response to compost application was not affected by rate of fertilizer during any growing seasons. Uptake of potassium increased significantly with increasing compost rates. Nitrogen and phosphorus uptake also increased, but less dramatically. The high fertilizer rate treatment increased uptake of most nutrients.

Impacts
(N/A)

Publications

  • Zhang, L., G.A. Porter and R.J. Bushway. 1997. Ascorbic acid and glycoalkaloid content of Atlantic and Superior potato tubers as affected by supplemental irrigation and soil amendments. Am Potato J
  • Porter, G.A. 1997. Cropland Irrigation Conservation Research/Demonstration Program. Interim Final Research Report (Project 013-01A-2005-012 and 014- 01A-2005-012). June 1997.
  • Porter, G.A., E. Groden, and M.C. Marra. 1996. Ecological management of potato cropping systems. SARE/ACE Final Report (Project LNE93-36/ANE93-18). December 1996.
  • Porter, G.A., J.A. Sisson, and B. MacFarline. 1996. Potato weed control and vine desiccation studies at Aroostook Research Farm - 1996. AES Departmental Mimeo 96-01.
  • Porter, G.A., J.A. Sisson, B. MacFarline, and P. Wardwell. 1996. Soda nitrate and soda potash experiments on potatoes at Aroostook Research Farm - 1996. AES Departmental Mimeo 96-03.
  • Porter, G.A., J.A. Sisson, B. MacFarline, and P. Wardwell. 1996. Foliar magnesium bicarbonate experiments on potatoes at Aroostook Research Farm - 1996. AES Departmental Mimeo 96-04.


Progress 10/01/95 to 09/30/96

Outputs
A supplemental irrigation experiment studied if timing and frequency of irrigation could be important factors in development of internal tuber quality problems, in Atlantic, Superior, Russet Burbank, and Shepody. Brown center development was not affected by irrigation treatments; hollow heart incidence in long-tuber-type varieties increased when supplemental irrigation was begun in July. Increases were observed also in round-white varieties. Incidence of hollow heart was significantly reduced when irrigation was delayed until early August; frequency of irrigation had little effect on hollow heart incidence. Despite relatively high rainfall during 1996, yields were increased by an average of 5.3 t ha-1 by supplemental irrigation. Another experiment studied the duration of soil management effects on soil properties and potato yields. Organic matter additions continued to result in increased soil organic matter, water stable aggregates, and nutrient levels, while decreasing soil bulk density. Plots receiving long-term amendment applications yielded 37.2 t ha-1 compared to 31.9 t ha-1 on nonamended plots. One year after amendment applications ceased, previously amended plots had lost 20% of their organic carbon, but still displayed better soil physical properties than nonamended. Yields in these plots were significantly better than unamended plots, but equal to those that continued to receive amendments. Results indicate benefits will be gained for at least 1 full cycle after loading.

Impacts
(N/A)

Publications

  • Fitzgerald, C.B., M.S. Erich, and G.A. Porter. 1996. Phosphorus status of soil in two potato cropping systems with different levels of organic amendment. Agronomy Abstracts.
  • Porter, G.A., and J.A. Sisson. 1996. Response of four potato varieties to supplemental irrigation in Maine. American Potato J. 73 (abst).
  • Ganske, D., G. Porter, and J.R.C. Leavitt. 1996. Weed control in potatoes (Solanum tuberosum) in Maine with rimsulfuron. Proc. Northeast Weed Sci. Soc. (abst.).
  • Porter, G.A. 1996. Irrigation and soil management research at Aroostook FArm. Maine Potato News (March).
  • Porter, G.A., J.S. Sisson, and B. MacFarline. 1995Summary of potato weed controland vine desiccation trials--1995. AES Departmental Mimeo 95-01.


Progress 10/01/94 to 09/30/95

Outputs
Results from 1994 and 1995 showed dramatic positive effects of supplemental irrigation on tuber yields and tuber size. Increased incidence of hollow heart was the major negative tuber quality effect of supplemental water, although increased tuber decay was present during 1993 and 1994. In a separate experiment, soil improvement strategies using compost and manure increased soil nutrient levels, water stable aggregate content, and decreased soil bulk density. Tuber yield increases due to soil management were significant during 1994 and 1995 and represented 83 and 48% of the yield increase obtained with supplemental irrigation in a standard oat rotation. Studies continued on the N timing effects on uptake and N use efficiency in contrasting variety types of during 1995. Response of the late-season Russet Burbank variety is being compared to the early-season Superior variety. 15N-depleted N fertilizer is being used to track uptake from fertilizer vs soil sources. Results from the tracer and %N analyses are not available at this time; however, yield data from 1994 indicate that yield of both varieties was optimized at 179 kg N ha-1. Yields did not differ significantly among the application timings (all at planting vs. partially sidedressed). Our experiment documenting N benefits of green manure crops completed its 4th growing season. Results from 1994 continued to indicate that the green manure crops provide a substantial N benefit to the potato crop and increased yields by 6.8 t/ha in check plots.

Impacts
(N/A)

Publications

  • Porter, G.A., and J. McBurnie. 1995. Aroostook Farm soil and water management studies, Part B, crop growth, yield, and quality. Proc. CE Maine Potato Conf.
  • Porter, G.A., J.A. Sisson, and B. MacFarline. 1994. Summary of weed control and vine desiccation trials, 1994. Unit Mimeo 94-1.
  • Opena, G.B. 1995. Response of Superior potatoes to soil management and irrigation. M.S. thesis, Univ. of Maine, Orono.
  • McBurnie, J., and G.A. Porter 1995. 1995. Aroostook Farm soil and water management studies, Part A. Proc. CE Maine Potato Conf.
  • McBurnie, J., and G.A. Porter 1995. Soil and water management research progress in Maine. Proc. Agric. Sci. & Tech. Workshop, Truro, N.S.
  • McBurnie, J., and G.A. Porter. 1995. Aroostook water and soil management project--A soils perspective. Proc. NE Potato Tech. Forum 3:39-40.
  • McBurnie, J., G.A. Porter, and W.B. Bradbury. 1995. Crop water management through soil improvement. American Water Resources Assoc. Ann. Spring Symp., Salt Lake City.
  • Opena, G.B., L. Zhang, and G.A. Porter. 1995. Response of Superior potatoes to soil management and irrigation. Am. Potato J. 72: 645-646.
  • Porter, G.A., and J. McBurnie. 1995. Potato crop responses to soil and water management. Proc. NE Potato Technology Forum. 3:36-37.


Progress 10/01/93 to 09/30/94

Outputs
Nitrogen timing effects on nitrogen uptake and nitrogen use efficiency in contrasting variety types is the focus of a new experiment initiated during 1994. This study utilizes 15N- depleted nitrogen fertilizer to track uptake from fertilizer versus soil sources. Application timings being compared are at- planting versus sidedress at early emergence or tuber initiation. Response of the late-season Russet Burbank variety is being compared to the early-season Superior variety. Results from the initial year of experimentation are not available at this time. Our experiment documenting nitrogen benefits of green manure crops (clover and lupins) completed its fourth growing season during 1994. Results from 1993 indicated that potato yields following lupins were significantly higher (3.8 t/ha) following lupins than the other rotation crops. The green manure crops (clover or lupins) provided a substantial nitrogen benefit to the potato crop (67 to 90 kg/ha) and increased yields (relative to a grain rotation) by up to 15.9 t/ha in check plots receiving no N fertilizer. Legume N appears to become available later in the growing season than fertilizer N. The consequences of this delayed release on plant N uptake, leaf area production, dry matter allocation, tuber growth and tuber sugar levels were investigated in our 1993 and 1994 experiments. Results are not available at this time.

Impacts
(N/A)

Publications

  • PORTER, G.A. 1994. Cull potato compost application and its effects on soil properties, nutrient uptake, and tuber yields. Am. Potato J. 71:694. (Abst.).
  • OPENA, G.B., L. ZHANG, AND G.A. PORTER. 1994. Soil amendment and crop rotation effects on growth and yield of Superior potatoes. Am. Potato J. 71:692. (Abst.).
  • PORTER, G.A. 1994. Compost and manure effects on potato yield and nutrient uptake. Proc. Northeast Potato Technology Forum, Vol. 2. (Abst.).
  • PORTER, G.A., AND J.A. SISSON. 1994. Differential tolerance of potato varieties to postemergence DPX-E9636 and metribuzin. Proc. NE Weed Sci. Soc. 48:107. (Abst.).
  • SISSON, J.A., AND G.A. PORTER. 1994. Ground-crack and postemergence DPX-E9636 applications for weed control in potatoes. Proc. NE Weed Sci. Soc. 48:108. (Abst.).
  • PORTER, G.A., J.C. MCBURNIE, F. DRUMMOND, AND M.N. BEDAIWY. 1994. Potato soil and water management project. Progress report submitted to Aroostook Soil & Water Management Board.
  • PORTER, G.A., AND J.A. SISSON. 1994. Horticultural evaluation of transgenci Atlantic, Shepody, and Russet Burbank potatoes. Project report submitted to Hybritech Seed International.
  • PORTER, G.A., J.A. SISSON, AND B. MACFARLINE. 1994. Summary of weed control and vine desiccation trials--1993. Unit Mimeo 93-1.


Progress 10/01/92 to 09/30/93

Outputs
Nitrogen fertilization experiments for 1992 provided evidence that N sidedress applications should be applied at emergence. Later timing has proven beneficial for later varieties, but reduced yields 5.0 t/ha in more determinate, mid-season varieties during 1992, perhaps due to poor N uptake at the later timings. Studies planned for 1994 will measure N timing effects on uptake and N use efficiency in contrasting variety types. Green manure crops (clover and lupins) provided a substantial N benefit to potato crop during 1992 and increased yields (relative to a grain rotation) by 11.9 t/ha in check plots receiving no N fertilizer. Legume N appears to become available later in growing season than fertilizer N. The effects of delayed release on plant N uptake, leaf area production, dry matter allocation, tuber growth and tuber sugar levels were investigated in 1993. Tuber sugar levels increased in response to N fertilizer during 1992. Increased tuber sugar levels were detrimental to tuber fry color through short-term storage; effect was less prominent from long-term storage. Cool, moist growing conditions during 1992 appear to have decreased tuber maturity and enhanced N's effect on tuber sugars. No storage temperature by N interactions have been observed. Increased K fertilization has decreased sugar levels and improved chip color. Weed control studies continued to emphasize herbicide evaluations and refinement of a weed management threshold model.

Impacts
(N/A)

Publications

  • PORTER, G.A., AND J.A. SISSON. 1993. Yield, market quality and petiole nitrate concentration of non-irrigated Russet Burbank and Shepody potatoes in response to sidedressed nitrogen. Am. Potato J. 70:101-116.
  • LEACH, S.S., G.A. PORTER, R.V. ROURKE, AND W.M. CLAPHAM. 1993. Effects of moldboard plowing, chisel plowing and rotation crops on the rhizoctonia disease of white potato. Am. Potato J. 70: 329-337.
  • PORTER, G.A. 1993. Soil and fertilizer potassium effects on yield, specific gravity and chip color of Atlantic potatoes. Am. Potato J. 70: (abst.).
  • PORTER, G.A. 1993. Management effects on potato yield and quality. Proc. of Northeast Potato Technology Forum. 1:12 (abst).
  • GREEN, B.F. 1993. Impacts of nitrogen application and defoliation by Colorado potato beetle on leaf area, dry weight partitioning, nitrogen distribution and yield in 'Superior' potatoes. M.S. thesis. University of Maine, Orono.
  • PORTER, G.A., J.A. SISSON, AND B. MACFARLINE. 1992. Summary of weed control and vine desiccation trials-1992. Mimeo 92-1.


Progress 10/01/91 to 09/30/92

Outputs
Petiole nitrate testing guidelines have been established for 2 late-maturing varieties and experiments completed this year will finalize guidelines for 2 early varieties. Nitrogen fertilizer use efficiency for at-planting application has been calculated at 60% under our conditions. Research shows strong relationships among soil test K levels, tuber size, yields, specific gravity and leaf K content. Yields were maximized with moderate fertilizer potash applications even on soils testing relatively high in potash. Yields were highest when leaf K at flowering was >3.50% and specific gravity declined linearly as leaf K increased. Green manure crops provided little nitrogen to potatoes during 1991. Clover and lupins returned 3930 and 3790 kg ha-1 of dry matter, respectively, and 107 and 112 kg N ha-1, respectively. Using potato N uptake, the clover crop provided 50 kg N ha-1. Yield data showed a fertilizer N equivalence of only 30 kg N ha-1. Legume N is more effectively partitioned to haulm tissues than tubers due to timing of its availability. N did not affect tuber sugar levels or french fry color during 1990. High N fertilizer rates increased tuber sucrose and glucose levels and decreased processing quality during 1991. Increased K fertilization levels have decreased sugar levels and improved chip color. Nutrient management and storage temperature display interactive effects on sugar levels. Weed control studies emphasize herbicide evaluations and refinement of weed management threshold model.

Impacts
(N/A)

Publications

  • PORTER, G.A., J.A. SISSON AND B. MACFARLINE. 1992. Summary of weed control and vine desiccation trials - 1992. Unit Mimeo 92-1.
  • PORTER, G.A., AND SISSON, J.A. 1992. A comparison of gluphosinate, endothall and diquat for potato vine desiccation. Proc. Northeastern Weed Science Soc. 46:72 (abst).
  • VAN CINGEL, E.H. 1992. Nitrogen equivalence of rotation crops and its effect on potato yield and tuber maturation. M.S. thesis, University of Maine, Orono.
  • PORTER, G.A., TINDALL, T.T., AND SISSON, J.A. 1992. Nitrogen uptake from soil and fertilizer by potatoes grown in rotation with barley/forage legume intercrops. Am. Potato J. 69:604(abst).
  • PORTER, G.A., SISSON, J.A. AND MARRA, M.C. 1992. Mustard density effects on potato yield and tuber size. Proc. Northeastern Weed Science Soc. 46:22 (abst).


Progress 10/01/90 to 09/30/91

Outputs
Nitrogen management studies directed at increasing N utilization from soil and crop residues continued during 1991. Petiole nitrate testing guidelines have been established for two late-maturing varieties and current experiments are refining guidelines for two early varieties, Superior and Atlantic. These early varieties were grown with 0 to 200 kg N ha(superscript -1) and petiole samples were collected over a 40-d period and analyzed for nitrate content. Yield and quality data are being related to petiole nitrate levels to establish critical petiole nitrate levels. In other studies, soil test levels of K were strongly related to tuber size, yields, specific gravity and leaf K content. Yields were maximized when 150 kg potash ha(superscript -1) were applied and when soils were relatively high in potash. Yields were highest when leaf K was />=/3.50%. Specific gravity and % leaf K were linearly related. Research on tuber carbohydrate metabolism continued during 1991. Tubers were collected from three field experiments at 7 to 14 d intervals and analyzed for glucose, fructose, sucrose and dry matter content. N did not affect tuber sugar levels or french fry color during 1990; however, increased K levels decreased sugar levels and improved chip color. Storage temperature affected tuber sugar levels and processing quality in all studies during 1990. N levels increased tuber sucrose and glucose levels during 1991. This response probably resulted from interactive effects of water stress and N on tuber maturation.

Impacts
(N/A)

Publications

  • PORTER, G.A. and SISSON, J.A. 1991. Response of Russet Burbank and Shepody potatoes to nitrogen fertilizer in two cropping systems. Am Potato J 68:425-443.
  • PORTER, G.A. and SISSON, J.A. 1991. Petiole nitrate content of Maine-grown Russet Burbank and Shepody potatoes in response to varying nitrogen rate. Am Potato J 68-493-505.
  • VAN CINGEL, E.H. and PORTER, G.A. 1991. The effect of nitrogen on post-harvest processing quality of potato tubers. Agronomy Abstracts :163 (abst).
  • PORTER, G.A. and SISSON, J.A. 1991. Weed control in potatoes with DPX-E9636, gluphosinate, and paraquat. Proc Northeastern Weed Science Soc 45:85 (abst).
  • PORTER, G.A., SISSON, J.A. and BUCK, M. 1991. Summary of weed control and vine desiccation trials - 1991. Unit Mimeo 91-1.


Progress 10/01/89 to 09/30/90

Outputs
Nitrogen management studies directed at increasing N utilization from soil and previous crop residues continued during 1990. Petiole nitrate testing guidelines have been established for two late maturing varieties. Current experiments have been directed at refining the guidelines for early varieties. Two early varieties were grown with 0 to 200 kg N ha. Petiole samples were collected over a 40-d period during mid-season and analyzed for nitrate content. Yield and quality data will be related to petiole nitrate levels to establish testing criteria. Research on tuber carbohydrate metabolism continued during 1990 with studies of the effects of N, potash, and micronutrients on tuber sugar levels. Tubers were collected from three field experiments at 7 to 14 d intervals and analyzed for glucose, fructose, sucrose and dry matter content. Samples were also placed in storage so that sugar content and processing quality can be monitored. Although tuber sugar data have not been compiled, yield data collected during 1990 indicate a significant 25 to 30 cwt/A response to supplemental boron on a Maine soil managed for pH 6.0. Results from 1989 continued to document that N affects tuber sugar levels during early growth, but that these differences decline as harvest maturity approaches and do not affect processing quality from storage.

Impacts
(N/A)

Publications

  • PORTER, G.A. and SISSON, J.A. 1990. Metribuzin and paraquat combinations for control of broadleaf weeds and quackgrass in Maine potatoes. Proceedings of the Northeastern Weed Science Society 44:153 (abst).
  • PORTER, G.A., SISSON, J.A. and BUCK, M. 1989. Summary of weed control and vine desiccation trials. Mimeo 89-01.
  • PORTER, G.A. and SISSON, J.A. 1990. Petiole nitrate content of Maine-grown Russet Burbank and Shepody potatoes in response to varying nitrogen management. Am Potato J (in-press).
  • PORTER, G.A. and SISSON, J.A. 1990. Response of Russet Burbank and Shepody potatoes to nitrogen fertilizer in two cropping systems. Am Potato J (In press).
  • PORTER, G.A. and SISSON, J.A. 1990. Petiole nitrate content of Maine-grown Russet Burbank and Shepody potatoes in response to varying nitrogen management. Am Potato J 67:572-573 (abst).


Progress 10/01/88 to 09/30/89

Outputs
Field experiments over the past few years have been directed at quantifying the nitrogen rate response of selected potato varieties grown in cropping systems with and without legumes used in the rotation. We have established that fertilizer rates can be reduced from 25 to 50% in rotations containing legumes and that reduced fertilizer use is necessary in order to maintain tuber quality (specific gravity and tuber uniformity). Field experiments along these lines were continued during 1989 with the Russet Burbank, Shepody, and Superior varieties. Due to site differences in nitrogen response and nitrogen supplying capability of the soil, we have been investigating petiole and soil testing procedures which might be used to fine-tune nitrogen applications for specific sites. Petiole testing for nitrate when combined with seasonal applications of nitrogen has been most promising to date. We are continuing to expand our database on petiole nitrate levels and their relationship to fertilization practices and crop yield, while also investigating total nitrogen analysis of leaflets and soil nitrate testing as tools for use in potato nitrogen management. Studies have been initiated in which the potato plant's physiological responses to nitrogen are being examined. Photosynthetic rates per unit leaf area have not been significantly influenced by nitrogen while leaf area of the canopy dramatically increases.

Impacts
(N/A)

Publications

  • MARRA, M.C., GOULD, T.D. and PORTER, G.A 1989. A computable economic threshold model for weeds in field crops with multiple pests, quality effects, and uncertain spray period length. Northeast Journal of Agricultural & Resource Economics.
  • PORTER, G.A. and SISSON, J.A. 1989. Growth and dry matter partitioning of Russet Burbank and Russette potatoes subjected to varying nitrogen fertilizer rates. AM. Potato J. 66:540 (Abst).
  • PORTER, G.A. and SISSON, J.A. 1989. Rate response of Russet Burbank, Shepody, and Russette potatoes to nitrogen fertilizer in two cropping systems. Am. Potato J. 66:540-541 (Abst).
  • MARRA, M.C., GOULD, T.D. and PORTER, G.A. 1988. A computable economic threshold model for weeds in field crops with multiple pests, quality effects, and uncertain spray period length. Am. J. Agric. Economics. 70(5):1185(Abst).
  • PORTER, G.A., SISSON, J.A. and BUCK, M. 1988. Summary of Weed Control and Vine Desiccation trials. Mimeo 88-01.


Progress 10/01/87 to 09/30/88

Outputs
A series of field experiments were conducted during the 1986-88 growing seasons to study the effects of nitrogen management on potato growth, yield, and quality. Nitrogen fertilization rates in excess of 179 kg/ha have consistently reduced Russet Burbank yields, but have not reduced yields of Russette and Shepody. Growth analysis has revealed that yield reductions in Russet Burbank were due to delayed tuber growth and increased dry matter partitioning to stem tissues. Fertilizer replacement studies following red clover have indicated that overall nitrogen fertilizer rates can be reduced by 25-50% following red clover without experiencing yield or quality reductions. In fact, quality (specific gravity, fry color, tuber shape) may be significantly reduced if nitrogen rates are not reduced in these rotations. Fertilizer rate reductions. Fertilizer rate reductions in legume-containing rotations may be best achieved via a combination of delayed nitrogen applications and tissue testing. Our studies have shown that following oats, early-season petiole nitrate levels are strongly related to nitrogen rate and decrease rapidly with time. Following clover, petiole nitrate levels are poorly correlated with nitrogen fertilizer rate, until August, and decrease slowly through the growing season. Delayed nitrogen applications have generally not affected potato yields, but have increased quality of Ruset Burbank tubers.

Impacts
(N/A)

Publications

  • MARRA, M.C. and PORTER, G.A. 1988. An economic threshold model of postemergence herbicide decisions for potatoes in the Northeast. Final Report to NPIAP. April 29, 1988.
  • MARRA, M.C., GOULD, T.D. & PORTER, G.A. 1988. Postemergence herbicide decisions for round-white potatoes. Proc. NE Agricultural and Resource Economics Association (Abst.) in-press.
  • PORTER, G.A., PARKS, J.D. and LAMOREAU, M.F. 1987. Summary of weed control trials - 1987. Mimeo 87-01.
  • MARRA, M.C., GOULD, T.D. and PORTER, G.A. 1988. A computable economic threshold model for weeds in field crops with multiple pests, quality effects, and an uncertain spraying period length. Amer. J. Agric. Econ. (Abst.) In Press.