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ARS Home » Northeast Area » Orono, Maine » New England Plant, Soil and Water Research Laboratory » Research » Research Project #425507

Research Project: Improved Crop Production Systems for the Northeast

Location: New England Plant, Soil and Water Research Laboratory

2018 Annual Report


Objectives
1: Develop crop and cultural management practices to improve crop productivity and economic viability, and reduce diseases for conventional and organic food production systems in the Northeast. 1.1. Develop management practices and cropping systems that maintain or improve productivity and market quality, reduce soilborne and foliar diseases, reduce income variability and economic risk, and improve profitability and competitiveness for potato-based production systems. 1.2. Develop crop, biological, and cultural management practices to improve crop productivity, reduce diseases, and improve economic viability for conventional and organic vegetable production systems. 1.3. Determine activity, mechanisms of action, and improved means of implementation of selected biological and cultural practices for enhanced efficacy, utilization, and sustainability.


Approach
Our approach to improving crop productivity and enhancing economic viability for food production systems in the Northeast is through the development of improved biological and cultural management practices and cropping systems. There are many practices and amendments that have been previously identified, in ours and others research, as providing beneficial responses for these production systems. However, much research is still needed to determine the best ways to utilize and implement these practices in production agriculture. In our own previous research, through long-term cropping systems studies, we determined the areas that are the most crucial constraints to productivity in potato production systems, as well as some factors that were less important. Critical constraints were water availability, soil quality, and disease pressure, whereas previously studied criteria such as fertility and soil physical properties (which has already been well-worked out) were not critical factors. This proposed research is building directly on this previous research, further developing and refining management practices that have shown the greatest potential for reducing soilborne diseases, enhancing soil quality, and improving crop yields in a sustainable manner. Management practices of particular importance include the use of disease-suppressive rotation crops, cover crops, green manures, and biological control organisms. Special emphasis will be placed on the biological processes involved and the role of soil microbial communities in developing disease-suppressive, yield-enhancing cropping systems.


Progress Report
This is the final report for 8030-62660-003-00D, which terminated in September 2018. This project consisted of a series of research studies with the goal of developing crop and cultural management practices to improve crop productivity and economic viability, and reduce diseases for conventional and organic food production systems in the Northeast. In the potato cropping systems portion of the project, previously demonstrated successful principles and practices were incorporated into functional rotation systems that could be utilized by growers for improved productivity and disease control. In these trials, 3-yr rotations focusing on the management goals of soil conservation (through reduced tillage, cover crops), soil improvement (through compost amendment in addition to cover crops and reduced tillage), and disease suppression (through use of disease-suppressive rotations, cover crops, and biological control) were evaluated for effects on soil health, crop productivity, soilborne diseases, soil microbial community characteristics, and economic viability. The soil improvement system resulted in increased potato yield, higher organic matter and other nutrient contents, and higher microbial activity, relative to a standard 2-yr rotation. The disease suppressive system also increased yield and increased microbial activity relative to the standard, and reduced soilborne diseases (black scurf and common scab). Soil microbial community characteristics, as represented by fatty acid profiles and DNA sequencing, were also distinctly different among the cropping systems and may be associated with productivity. Overall, enhanced systems provided comparable or increased net income relative to other 3-yr rotations. These results indicate that soil health management practices can be incorporated into economically viable cropping systems that may enhance sustainability, productivity, and ecosystem function. In addition, organic vegetable trials evaluated different cover crops, biological controls, and other practices on green bean, summer squash, and pepper crops. The benefit of prior cover crops (including mustard green manure, rye/vetch, and a mixed-multi-species cover crop) was demonstrated through increased emergence and yield for all vegetable crops relative to the absence of a cover crop. Biological control amendments, although did not affect yield, reduced leaf necrosis and powdery mildew by 10-30%. Beans were also observed to yield better following squash vs. pepper, and squash yielded better following beans vs. pepper, whereas rotation had no effect on pepper yield. Also, woven plastic fabric used as a ground cover was more reliable and economical than biodegradable paper mulch for control of weeds, and various effects of different soil amendments were also evaluated. These results help define management practices to improve organic vegetable production and provide useful information and options for growers. Overall, this research provides information needed to improve crop production and sustainability for potato and organic vegetable production, which can lead to improved agricultural viability and rural economic vitality in the Northeast.


Accomplishments
1. Incorporating soil health management practices into viable potato cropping systems. Use of longer rotations, disease-suppressive green manures, cover crops, and organic amendments have been shown to increase tuber yield, reduce disease, and improve soil health in previous potato cropping studies. However, such practices need to be implemented in integrated cropping systems that maintain economic viability for growers. ARS researchers in Orono, Maine, examined ways to incorporate effective soil health management practices into practical potato cropping systems through the establishment of enhanced 3-yr rotations addressing the management goals of soil conservation, soil improvement, and disease suppression, in relation to a standard (2-yr) rotation and no rotation. Previously established systems were modified to better fit into grower production systems, and evaluated for their effects on soil properties, tuber yield, soilborne diseases, and economic viability. Overall, the soil improvement system (including compost amendment, reduced tillage, and cover crops) resulted in increased potato yield, higher organic matter and other nutrient contents, and higher microbial activity, relative to the standard rotation. The disease suppressive system also increased yield and microbial activity, and reduced soilborne diseases. Enhanced cropping systems also provided comparable or increased net income relative to other 3-yr rotations. These results demonstrate that soil health management practices can be incorporated into economically viable cropping systems that can enhance sustainability, productivity, and ecosystem function, and lead to improved agricultural viability and vitality for potato production systems.

2. Practical utilization of cover crops, biocontrol organisms, and other management practices in organic vegetable production. Organic vegetable growers have many production management options available, but how to choose and incorporate specific practices into organic cropping systems that will provide greater sustainability, productivity, and viability, has not been well-established. ARS researchers in Orono, Maine, examined the potential benefits of different cover crops, biological control amendments, crop rotations, and other management practices on organic vegetable production, as represented by legume (green bean), cucurbit (yellow squash), and solanaceous (pepper) crops. Results demonstrated the benefits of prior cover crops (mustard green manure, rye/vetch, or a multi-species mixture of 8 different crops), relative to a fallow control, with all cover crops increasing crop emergence, and yield of bean, squash, and pepper by 5-20%. Biological control amendments, which included commercial formulations of Streptomyces, Trichoderma, and Bacillus sp., in general, did not affect yield, but reduced leaf necrosis and powdery mildew by 10-30%. Rotation order also mattered, with beans yielding 8% higher following squash vs. pepper, and squash yielding 15% higher following beans vs. pepper, whereas rotation had no effect on pepper yield. Additional trials demonstrated some advantages of fabric mulch over paper mulch for weed control, and various benefits of different soil amendments. These results help define management practices to improve organic vegetable production and provide useful information and options for growers.

3. Advancing the technologies in detecting, diagnosing, and controlling black leg disease in the U.S through survey, genetic and molecular investigation. Black leg disease of potato, caused by the bacteria Dickeya spp. and Pectobacterium spp., is an emerging disease problem in the U.S. Following a serious outbreak in 2015, blackleg quickly spread throughout the Northeast causing severe economic losses. Little is known about the strains causing these outbreaks in the U.S., their distribution, epidemiology, and effective control measures. As part of a national project, ARS researchers in Orono, Maine, in conjunction with a team of researchers from seven potato-producing states, conducted surveys assessing the extent of the problem, identification of the pathogens involved, improved detection and diagnostic assays, and assessed potential control options. Dickeya spp. were found associated with blackleg affected potatoes in at least 21 states, with D. dianthicola shown to be predominant in the east, and with other species spreading in the west. Several species of Pectobacterium were also responsible for disease, with P. parmentieri, in particular, associated with storage rots in eastern states. Development, refinement and standardization of isolation, detection, and characterization methods resulted in more consistent and reliable detection and identification of these pathogens. Some tolerance to blackleg was observed in potato clones and screening trials clarified chemical control options with activity against these pathogens. In field trials, Dickeya was observed to spread from inocoulated seed potatoes to 13-33% of the progeny tubers, but was not spread during cutting and handling of seed potatoes. These findings make clear the range of pathogens associated with outbreaks of blackleg and provides a foundation for understanding the epidemiology and spread of the disease as well as potential control options.