Progress 10/01/02 to 09/30/08

Outputs
OUTPUTS: The experiment was conducted as described each year of the project. Plant samples and soil samples were taken and analyzed. Crop yields were determined. One graduate student (Ellen Mallory) conducted research on several facets of this project and received her Ph.D. in 2007 (Mallory, E.B. 2007. Crop/livestock integration effects on soil quality, crop production, and soil nitrogen dynamics. Ph.D. Thesis. University of Maine, Orono). Data from this research was a source of information disseminated at the following meetings: Mallory, E.B. and T.S. Griffin. 2008. On-farm assessment of soil quality in integrated potato-dairy systems. p. 56. In Abstracts. Plants & Soils: Montreal '08. A joint meeting of the Canadian Society of Agronomy, Canadian Society for Horticultural Science, and the Northeastern Branch of Crops, Soils, and Agronomy. July 13-16, 2008. Montreal, Canada; Mallory, E.B. 2008. A Perspective on Sustainable Agriculture in Maine. Presentation to the Maine Highlands Farmers, Dover-Foxcroft, ME, November 19, 2008; Sharifi, M., B.J. Zebarth, D.L. Burton, G.A. Porter, and C.A. Grant. 2008. Effect of rotation crop on soil nitrogen mineralization potential and soil nitrogen supply in a two-year potato cropping system. Proceedings of the Northeast Potato Technology Forum, Fredericton, New Brunswick, Canada. March 12, 2008 (Abst.). . PARTICIPANTS: This project has provided a site for numerous graduate studies throughout the years; one Ph.D. thesis was completed in 2007 using data and soil samples from this project. Primary participating researchers have been University of Maine faculty. However USDA-ARS scientists have been involved as well, most actively Dr. Tim Griffin, who was a co-advisor of Dr. Ellen Mallory, who recently completed her Ph.D. thesis. TARGET AUDIENCES: Growers and the broader potato industry learned about alternative pest and soil management systems for potato production through published reports and oral presentations. The information will help growers make informed decisions about the integrating their production systems with animal-based agricutlure. The results show that amended soil management systems can improve yield stability while also reducing the reliance on chemical fertilizers. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The seven-year (2001-2007) average potato yield was 33 cwt A-1 higher for amended than nonamended despite the fact that little or no yield improvement in amended is generally observed during relatively wet growing seasons. Tuber quality has generally been similar in the both soil management systems except for a higher incidence of scab in amended systems. This yield differential has been observed despite the fact that the average N, P2O5, and K2O fertilizer rates have been reduced by 59, 100, and 87% in the amended system as a result of current year and residual soil nutrients from the amendments. Mallory and Griffin (2007) hypothesized that repeated, long-term additions of organic materials would not only increase stocks of mineralizable soil N, but also bring about changes in soil characteristics that influence N dynamics. They conducted an aerobic incubation of the amended and nonamended soil to explore how soil amendment history affects the transformation and availability of recently added manure and fertilizer N. When no N was added, net mineralization in the historically amended soil was twice that in the historically nonamended soil, mostly due to differences in soil total N stocks. When N sources were added, ammonium consumption, net N mineralization, and estimated N pools were affected by both soil amendment history and N source, with a significant interaction between the two factors. Historically amended soil reduced the availability of recently added N relative to the nonamended soil. This reduction occurred in the active pool for manure and in the slow pool for fertilizer N and appeared to be related to the timing of C availability. This study provided the first evidence that that the effects of soil amendment history on the availability of N from organic and inorganic N sources can be as important in scale and duration as N source effects. Reduced insect pressure on plants grown in manure-amended soils decreases both the costs of purchasing insecticides and the negative environmental effects of using toxic chemicals.

Publications

• Sharifi, M., B.J. Zebarth, D.L. Burton, G.A. Porter, and C.A. Grant. 2008. Organic amendment history and crop rotation effects on soil nitrogen mineralization potential and soil nitrogen supply. Agronomy Journal 100:1562-1572.
• Sharifi, M., B.J. Zebarth, D.L. Burton, C.A. Grant, G.A. Porter, J.M. Cooper, Y. Leclerc, G. Moreau, and W.J. Arsenault. 2007. Evaluation of laboratory- based measures of soil mineral nitrogen and potentially mineralizable nitrogen as predictors of field-based estimates of soil nitrogen supply in potato production. Plant and Soil 301:203-214.
• Mallory, E.B. and T.S. Griffin. 2007. Impacts of soil amendment history on nitrogen availability from manure and fertilizer. Soil Science Society of America Journal 71:964-973.

Progress 10/01/06 to 09/30/07

Outputs
A soil management system designed to improve soil quality through the addition of organic amendments provided the optimal combination of enhanced potato yields and reduced the year-to-year yield variability in a 13 year analysis of data from this project. Soil analyses show that the amended system has significantly higher soil organic matter, cation exchange capacity, Modified Morgan available P, and soil-test K, Mg, and Ca. Soil pH, S, B, and Zn were also significantly increased by the amendment program and it has also consistently increased soil aggregation and lowered soil bulk density. These research plots were used as a resource to evaluate the effectiveness of laboratory-based measure of soil mineral N and potentially mineralizable N as predictors of soil N supply to subsequent potato crops. A combination of pre-plant mineral N plus N mineralized in the first two weeks of incubation was proposed as the most robust measure of N availability to subsequent potato crops. Even though the 2006 growing season had high rainfall, we saw a 52 cwt/A (18%) yield increase in the amended management system compared to nonamended. The incidence of powdery scab root galls was significantly increased in the amended system, but we observed much lower incidence in the 4-yr rotation than the 2-yr rotation during the past two years. The amended system slightly increased scab incidence in the 4-yr rotation plots, but dramatically increased it in the plots that had potatoes appearing every other year. Amended soil management plots had significantly higher specific gravity and slightly smaller tuber size than conventional soil management during 2006, but otherwise had comparable tuber quality. Soil management system did not affect incidence early blight, late blight, or rhizoctonia, but amendments increased white mold incidence, powdery scab root gall incidence, and scab incidence on tubers. The amended soil management system had numerically lower CPB populations, but significantly greater European corn borer damage and higher potato aphid populations than the check treatment. The crop rotation treatments had no significant effects on yield during 2005 and 2006. The four-year rotation tended to have fewer external tuber defects. We have also seen very few effects of the rotation treatments on diseases and insects in this experiment; however, the incidence of powdery scab galls was lower in the 4-year rotation than in the 2-year rotation during 2005 and 2006.

Impacts
Growers and the broader potato industry leared about alternative pest and soil management systems for potato production through published reports and oral presentations. The information will help growers make informed decisions about the integrating their production systems with animal-based agricutlure. The results show that amended soil management systems can improve yield stability while also reducing the reliance on chemical fertilizers. Unfortunately, soil P builds up to very high levels in soils that are amended at this intensity. Incidence of some pest problems tends to be lower in these systems, while other pest problems can be aggravated. Longer rotations helped reduce the impact of some diseases, but did not increase overall yields. Soybeans and alfalfa can be successfully incorporated into crop rotations in northern Maine.

Publications

• Mallory, E.B. and G.A. Porter. 2007. Potato yield stability under contrasting soil management strategies. Agronomy J 99: 501-510.
• Sharifi, M., B. Zebarth, D.L. Burton, G.A. Porter, and C.A. Grant. 2007. Organic amendment and crop rotation effects on indices of potentially mineralizable nitrogen in a potato cropping system. Proceedings of the Northeast Potato Technology Forum, Charlottetown, Prince Edward Island, Canada. March 14, 2007 (Abst.).
• Lambert, D. and G.A. Porter. 2007. Long-term effects of organic matter amendments on soil-borne diseases of potatoes. Proceedings of the Northeast Potato Technology Forum, Charlottetown, Prince Edward Island, Canada. March 15, 2007 (Abst.).
• Griffin, T., G.A. Porter, M.S. Erich, and E. Mallory. 2007. Balancing soil health and nutrient inputs. Proceedings of the Mid Atlantic Vegetable and Fruit Conference. Syracuse, NY. February 2007.

Progress 10/01/05 to 09/30/06

Outputs
A soil management system designed to improve soil quality through the addition of organic amendments provided the optimal combination of enhanced potato yields and reduced the year-to-year yield variability. Potato yields in the amended soil management system (manure, compost, green manure, and supplemental fertilizer) were equal to or up to 55% higher than yields in the contrasting nonamended soil system (synthetic fertilizer) in all but one year of a 13-year analysis. Yield stability was also enhanced in the amended system compared with the nonamended system, as demonstrated by lower coefficients of variation of total and U.S.#1 potato tuber yield. Stability analysis indicated that yields in the amended system were less influenced by adverse growing conditions, particularly low rainfall. Total and U.S. #1 treatment yields in the poorest yielding year were 65% and 53% of maximum yields, respectively, in the amended system compared with 44% and 45% in the nonamended system. Yields and yield stability were also influenced by pest management system and cultivar, but not rotation. Analysis of the 13 years of potato yield data indicated that not only are potato tuber yields higher in the amended versus the nonamended soil plots, the consistency, or stability, of those yields is also higher. These results indicate that management practices that improve soil quality can enhance potato yield stability, as well as potato yields, by reducing the impact of adverse growing conditions. Plant disease monitoring conducted over a 10-year period shows that white mold tends to be more of a problem in the amended system than the nonamended system, significantly so in 2006. White mold incidence has not been strongly affected by pest management system or crop rotation. Rhizoctonia stem and stolon incidence has not been consistently affected by soil management, pest management, or crop rotation length. Incidence of powdery scab root galls has been higher in amended compared to nonamended plots during every year except 2006. Pest management system has not affected powdery scab incidence on roots; however, extending the crop rotation from two to four years has significantly decreased root gall incidence. Powdery scab incidence on tubers decreased from 9.7 percent in the two year rotation to 0.6 percent in the four year rotation during 2005. Yield and quality results from the 2006 growing season will be available soon.

Impacts
This project is designed to provide information on the costs, productivity, and environmental impacts of alternative cropping strategies for potato. A pest management system using integrated pest management and synthetic pesticides is compared to a more biologically-oriented system. A soil management system centered on chemical fertilizer use is compared with one that relies heavily on manure and soil organic matter. Crop rotations of varying length and integration with feed and forage production are also studied.

Publications

• Olanya, O. M., D.H. Lambert, and G.A. Porter. 2006. Effects of pest and soil management systems on potato diseases. Amer J Potato Res. 83:397-408.
• Piper, A., M.S. Erich, G.A. Porter, and T.S. Griffin. 2006. Root growth effects on soluble C and P in manured and non-manured soils. Plant and Soil 283: 359-372.
• Alyokhin, A. and R. Atlihan. 2005. Reduced fitness of the Colorado potato beetle (Coleoptera: Chrysomelidae) on potato plants grown in manure-amended soil. Environmental Entomology 34: 963-968.
• Hoshide, Aaron K. Ph.D. 2005. Re-integrating crops and livestock in Maine: An economic analysis of the potential for and profitability of integrated agricultural production. University of Maine, Orono.
• Sharifi, M., B.J. Zebarth, D.L. Burton, G.A. Porter, and C.A. Grant. 2006. Effect of crop rotation and organic amendment on soil nitrogen mineralization potential. 8th World Soil Science Conference, Philadelphia, PA (July 2006, Abst)
• Griffin, T., G.A. Porter, M.S. Erich, and E. Mallory. 2006. Soil Nutrient Accumulation in Amended Potato Systems. Proceedings of the Northeast Potato Technology Forum, Bangor, ME. March 16, 2006. (Abst)
• Alyokhin, A., R. Atlihan, G. Porter, E. Groden, and F. Drummond. 2005. Plant-mediated effects of soil amendments on the Colorado potato beetle. Acadian Entomological Society Annual Meeting, Fredericton, NB. (Abst)

Progress 10/01/04 to 09/30/05

Outputs
This project evaluates alternative pest management systems [IPM-based (IPM) vs. Environmentally-friendly(ENV)] and soil management systems [non-amended (CHK) versus one that uses manure (AMD)]. It also compares the following rotation systems: 1) standard, two-year potatoes-barley rotation; 2) four-year extended, potatoes-soybean-barley-timothy/alfalfa; 3) four-year intensive, potato-soybean-potatoes-barley. ENV provided comparable Colorado potato beetle (CPB) control compared to IPM; however, populations of potato-colonizing aphids and flea beetle damage were higher in ENV. Crop rotation schedule did not affect insect populations. AMD resulted in numerically lower populations of all CPB stages than CHK. AMD had significantly higher European corn borer damage. Very little white mold, early blight or late blight was observed during 2005. Incidence of powdery scab root galls was 23% in AMD compared to 1% in CHK. Gall incidence did not differ between IPM and ENV, but were significant between the amended standard rotation (19%) compared to the 4 yr rotation (5%). Stem and stolon Rhizoctonia infections were not affected by treatment. August weed biomass was similar in CHK vs AMD treatments, but was considerably greater in ENV (59 g/sq-m) compared to IPM (25 g/sq-m; P = 0.054). Weeds were particularly problematic in the ENV barley (151 g/sq-m); in contrast, weed control was excellent in ENV potato and soybean (11 and 14 g/sq-m). A multivariate ordination technique has been used to examine pest and soil management effects on the weed community. CHK had excessive inorganic soil N prior to active crop uptake. In contrast, AMD displayed continued mineralization of a much larger soil organic N pool after crop senescence, indicating a need for a fall trap crop. Over the 14 years of this project, AMD plots have received a net P input of >800 kg/ha, compared to < 200 kg/ha for CHK. Total soil P increased by about 20% in AMD compared to 6% in CHK. Greater increases in soluble P, Mehlich 3 extractable P, and Modified Morgan extractable P were observed for AMD relative to CHK. The relationship between extractable P and soluble P is similar for AMD and CHK, indicating that AMD primarily affects P loading rather than relative availability. AMD had significantly higher soil pH, organic matter, P, K, Mg, Ca, S, B, Zn, and CEC than CHK during 2004. AMD increased total yield (35.4 vs 33.5 t/ha, p<0.07), but not US1 yield in 2004. Scab incidence was increased in AMD compared to CHK (4.0 vs. 1.1%, p<.05). AMD had higher specific gravity than CHK (1.099 vs. 1.092, p<.01). There were no significant effects of crop rotation or pest management on potato yield or quality. AMD had equal or higher yields than CHK in 12 of the last 13 years. Yields in AMD were less variable (as measured by coefficient of variation and stability analysis) due in part to improved soil characteristics that buffered rainfall deficits.

Impacts
This project is designed to provide information on the costs, productivity, and environmental impacts of alternative cropping strategies for potato. A pest management system using integrated pest management and synthetic pesticides is compared to a more biologically-oriented system. A soil management system centered on chemical fertilizer use is compared with one that relies heavily on manure and soil organic matter. Crop rotations of varying length and integration with feed and forage production are also studied.

Publications

• Erich, M.S., T.S. Griffin, G.A. Porter, and E.B. Mallory. 2005. The effect of phosphorus loading on degree of phosphorus saturation and phosphorus fractions in soils from a long term cropping systems study. American Society of Agronomy, Salt Lake City, UT (Abstract).
• Mallory, E.B. and T. Griffin. 2005. Seasonal nitrogen availability from current and past applications of manure and fertilizer. 2005 Annual Meeting, Northeastern Branch American Society of Agronomy and Soil Science Society of America. July 10-13. Storrs, CT (Abstract).
• Stark, J.C. and G.A. Porter. 2005. Potato nutrient management in sustainable cropping systems. Amer J Potato Res 82:329-338. Alyokhin, A. G. Porter, E. Groden, and F. Drummond. 2005. Colorado Potato Beetle response to soil amendments: A case in support of the mineral balance hypothesis? Agric Ecosys & Env 109:234-244.
• Ohno, T., T.S. Griffin, M. Liebman, and G.A. Porter. 2005. Chemical characterization of soil phosphorus and organic matter in different cropping systems in Maine, U.S.A. Agriculture, Ecosystems, and Environment 105: 625-634.
• Piper, Allison. Root length affects soluble carbon and phosphorus in a rotational cropping system. August, 2005. M.S. thesis.

Progress 10/01/03 to 09/30/04

Outputs
This project evaluates alternative pest management systems [IPM-based (IPM) vs. Environmentally-friendly(ENV)] and soil management systems [non-amended (CHK) versus one that uses manure (AMD)]. It also compares the following rotation systems: 1) standard, two-year potatoes-barley rotation; 2) four-year extended, potatoes-soybean-barley-timothy/alfalfa; 3) four-year intensive, potato-soybean-potatoes-barley. During 2004, Bacillus thuringiensis and Beauveria bassianna were used in ENV for Colorado Potato Beetle (CPB) control and pyrethrum was used for aphid control. ENV resulted in lower CPB levels compared to IPM. The opposite was true for potato-colonizing aphids. AMD had a negative numerical impact on CPB, but unlike other recent seasons, the effect was not significant in 2004. Crop rotation did not affect insect populations. Late blight incidence was low and not affected by treatments. Rhizoctonia incidence on stems was significantly higher in AMD (21%) than CHK (9%), a situation not seen since 1993. Pest management and crop rotation had no significant effect on rhizoctonia stem infection. The incidence of rhizoctonia stolon infection did not differ significantly among treatments. Sclerotinia white mold incidence was not affected by treatments in 2004. Powdery scab galls were found on 77% of the root systems in AMD, but only 20% in CHK. Infection did not vary by pest management or rotation treatments. Weed control continues to be a problem in the BIO soybeans, which contained 170 g m-2 total weed biomass, compared to the barley and forage rotation crops with 47 g m-2, and 29 g m-2, respectively. Weed biomass in BIO rotation crops was similar between soil management systems. Current research efforts involve analyses of the weed seed bank data to characterize the weed community. A 9-month laboratory incubation study was completed investigating the response of AMD and CHK soil to different N sources. AMD soil more rapidly transformed NH4 and increased NO3 concentration than CHK. AMD soil decreased the availability of N from a net mineralizing manure, either through enhanced immobilization or denitrification due to readily available C. The patterns of N availability in AMD and CHK are being studied. Root length density (RLD) was significantly higher in CHK than AMD. Forage had significantly higher RLD than barley or potato. In July 2004, there was a positive relationship between soluble soil C and soluble soil P levels. AMD had significantly higher soil pH, organic matter, P, K, Mg, Ca, S, B, Zn, and CEC than CHK during 2003. The differences in organic matter (4.6 versus 2.7%), modified Morgan P (60.4 versus 37.2 kg/ha), Mg (543 versus 317 kg/ha), and Ca (3370 versus 1997 kg/ha) were particularly striking. Pest and soil management systems did not significantly affect total or US1 yields in 2003. Scab incidence was significantly increased in AMD compared to CHK (1.6 vs. 0.1%). AMD had significantly higher specific gravity than CHK (1.096 compared to 1.091). There were no significant effects of crop rotation or pest management on potato yield or quality.

Impacts
This project is designed to provide information on the costs, productivity, and environmental impacts of alternative cropping strategies for potato. A pest management system using integrated pest management and synthetic pesticides is compared to a more biologically-oriented system. A soil management system centered on chemical fertilizer use is compared with one that relies heavily on manure and soil organic matter. Crop rotations of varying length and integration with feed and forage production are also studied.

Publications

• Gallandt, E.R. 2004. Soil-improving practices for ecological weed management. in Weed Biology and Management, Inderjit, ed. Kluwer Academic Publishers, The Netherlands. pp. 267-284.
• Griffin, T.S. and G.A. Porter. 2004. Altering soil carbon and nitrogen stocks in intensively tilled two-year rotations. Biology and Fertility of Soils 39:366-374.
• Mallory, E.B. and T. Griffin. 2004. Soil amendment history effects on N availability from fertilizer and manures. Annual Meeting Abstracts, American Society of Agronomy, October 31-November 4, 2004. Seattle WA (abstract).
• Piper, A., M.S. Erich, G.A. Porter, T. Griffin. Root length affects soluble carbon and phosphorus in a rotational cropping system. Annual Meeting Abstracts, American Society of Agronomy, October 31-November 4, 2004. Seattle WA (abstract).

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

Outputs
This project evaluates alternative pest management systems [IPM-based (IPM) vs. Environmentally-friendly(ENV)] and soil management systems [non-amended (CHK) versus one that uses manure (AMD)]. It also compares the following rotation systems: 1) standard, two-year potatoes-barley rotation; 2) four-year extended, potatoes-soybean-barley-timothy/alfalfa; 3) four-year intensive, potato-soybean-potatoes-barley. During 2003, Bacillus thuringiensis and Beauveria bassianna were used in ENV for Colorado Potato Beetle (CPB) control and pyrethrum was used for aphid control. Densities of Colorado potato beetle (CPB), flea beetles, potato-colonizing aphids, and their natural enemies were estimated weekly within each plot. IPM and ENV insect pest management approaches resulted in similar pest populations. Crop rotation treatments did not affect insect populations. AMD had a negative impact on CPB, with approximately twice as many beetles found in the CHK plots as in the AMD plots. This is consistent with the last two years of observations and supports our earlier suggestion that amended soils may provide a better environment for soil-borne CPB pathogens. No foliar late blight was found and incidence of foliar early blight was negligible. Rhizoctonia incidence on stolons was reduced 38% in AMD compared to CHK. Rotation treatments also affected Rhizoctonia stolon lesion incidence (37% reduction in the 4-year relative to the 2-year rotation). Sclerotinia white mold incidence was significantly higher in the AMD compared to CHK plots and also was higher in potato grown following alfalfa. Powdery scab galls were found on 14% of the root systems in AMD plots, but was not found in the CHK plots. Based on sampling conducted on 30 July, weed control in potatoes grown in a 2-year rotation was excellent was unaffected by soil management (grand mean 0.01 g per sq-meter). Weed biomass in crops grown in the 4-yr rotation was similar in CHK versus AMD soil management systems (44 and 37 g per sq-meter, respectively). Weed biomass was significantly affected by crop. Weed control in potato was excellent, with an average of 4 g total weed biomass per sq-meter. This compares to the intermediate level of weed biomass in soybean and forage rotation crops (26 and 38 g per sq-meter, respectively), and the greatest amount of weed biomass in the barley rotation crop (94 g per sq-meter). Density of total germinable seeds was measured within the ENV plots and was significantly greater following 2002 soybean and barley (7,323 and 7,153 germinable weed seeds per sq-meter, respectively) than following forage or potato (2,977 and 1,872 germinable weed seeds per sq-meter, respectively). Despite improved weed control achieved with pre-emergence spring-tine harrowing and two cultivations, the germinable weed seed bank continues to be high following soybean. Crop yield and soil analysis data are not available at this time.

Impacts
This project is designed to provide information on the costs, productivity, and environmental impacts of alternative cropping strategies for potato. A pest management system using integrated pest management and synthetic pesticides is compared to a more biologically-oriented system. A soil management system centered on chemical fertilizer use is compared with one that relies heavily on manure and soil organic matter. Crop rotations of varying length and integration with feed and forage production are also studied.

Publications

• No publications reported this period