ASSESSMENT OF THE MINERAL NUTRITIONAL VALUE OF VEGETABLE CROPS GROWN IN ORGANIC OR CONVENTIONAL SYSTEMS OF FARMING

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1017983
• Project Start Date: Oct 18, 2018
• Project End Date: Sep 30, 2021
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF MASSACHUSETTS
(N/A)
AMHERST,MA 01003

Performing Department
Stockbridge School of Agriculture

Non Technical Summary
People depend on vegetables to provide major portions of the nutrition for healthy diets. For several years, the mineral nutrient elemental concentrations in vegetables has declined. The decline has been associated with the development of new cultivars of vegetables that have lower concentrations of nutrients than heirloom cultivars. Breeding of crops for accumulation of nutrients has potential for developing nutrient-rich vegetables but has not received much attention in genetic improvement of vegetables. Cultural practices may give great and practical process for enhancing nutrient concentrations in vegetables, and cultural practices concerning fertilization to enhance nutrients in vegetables will be a priority in this project. Organic fertilization of crops is required for certification of organic produce. Producing equal yields and equal nutrient contents in organically fertilized vegetables compared to vegetables fertilized with chemicals are challenges. The research in this project will evaluate cultural methods that may be employed to enrich nutrient contents in vegetables through practices of fertilization organically or conventionally.This project includes a series of related experiments to assess nutrient accumulation in vegetables, primarily lettuce, in response to selection of cultivars of crops and management of fertilization. Organic fertilization will be compared to conventional practices of fertilization to determine growth and composition of lettuce in field plot and greenhouse investigations. Investigations concerning hydroponic production and modification of soil-based or peat-based media with organic or microbial amendents will be conducted to assess the effects of these amendments on productivity and nutrient composition of produce from vegetables.

Animal Health Component

60%

Research Effort Categories

Basic

30%

Applied

60%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	0199	1060	100%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
0199 - Soil and land, general;

Field Of Science
1060 - Biology (whole systems);

Keywords

vegetables

organic

nutrients

lettuce

shade

hydroponics

Goals / Objectives
The objectives of this project are (1) To assess the accumulation of nutrients in crops grown with of organic fertilizers of differing composition of total nitrogen, phosphorus, and potassum, (2) To assess the accumulation of nutrients in crops grown with amendments to alter the organic matter contents of soils, and (3) To assess the yield and composition of vegetables grown under solar panels.For Objective 1, experiments will be conducted in the greenhouse and in the field with leafy vegetables to investigate if the mineral nutrient content of these foods can be enriched through fertilization of the crops. This research will address investigations of mineral nutrients, suggested to include phosphorus, calcium, magnesium, potassium, iron, manganese, copper, and zinc, which the investigators have the capability of analyzing in their laboratories. The research will emphasize investigations with lettuce (Lactuca sativa L.) that can be cycled rapidly in greenhouse or field production. For Objective 2, this research will be conducted in greenhouses with soil-based or peat-based media that have been amended with compost or biochar. Compost will be obtained from production on campus or purchased from local vendors. Biochar will be obtained from local vendors. These investigations will concentrate on leafy vegetables, particularly lettuce of different phenotypes, because of their adaptability for production in containers and space limitations in greenhouses. For Objective 3, research will be conducted with loose-leaf lettuce grown under solar panels. The site of the panels is at the University of Massachusetts research farm in South Deerfield. Photosynthetically active radiation will be measured under the panels. Yield and compostion of lettuce in plots under the panels and in adjacent replicated plots with no shading will be assessed. Fertilization will be with a complete fertilizer supplying N at 100 kg ha-1. Nitrogen, P, K, Ca, and Mg will be determined in the produce.

Project Methods
Experiments will be conducted in the greenhouse and in the field with leafy vegetables to investigate if the mineral nutrient content of these foods can be enriched through fertilization of the crops. This research will address investigations of mineral nutrients, suggested to include phosphorus, calcium, magnesium, potassium, iron, manganese, copper, and zinc, which the investigators have the capability of analyzing in their laboratories. The research will emphasize investigations with lettuce that can be cycled rapidly in greenhouse or field production. Lettuce will be grown until it is of marketable sizeVegetable crops will be provided with complete nutrition from fertilizers that are available commonly for organic or conventional fertilization of crops. Organic fertilizers will include seed meals, animal by-products (dried blood, farm manures, feather meal), and compost. A complete chemical fertilizer will be a conventional fertilizer in the investigation. The elemental nutrient composition (Total and nitrate-N, P, K, Ca, Mg, and selected micronutrients) of the plants will be determined in edible parts the crops by Kjeldahl analysis, colorimetry, and plasma spectrophotometry.Many growers are trying to produce crops in containers on the ground or hard surfaces, on decks, or on rooftops in urban areas. Because of the costs of materials and labor for buying and handling media, media are being used for two or more crops in succession. Nutritional disorders are apparently limiting productivity in the second season particularly with organic production. A study will be conducted with peat-based medium that has been fertilized with organic fertilizers, such as seed meal, bloodmeal, and dehydrated farm manure for the first crop and grown in a greenhouse. The second crop will be grown in the same medium. Fertilization of the second crop will be with no additional fertilization or with fish emulsion or with water-soluble fertilizer (such as 20-10-20 Peat-lite Special) to provide organic and conventional fertilization. Radish (Raphanus sativus L.) or loose-leaf lettuce will be used. Radish is suggested because of the small amount of fibrous roots that will be residual in the containers. These crops will be assessed for productivity and composition of minerral elements.A commercially available organic fertilizer that is acceptable for hydroponic production of lettuce will be compared with a conventional hydroponics solution. This study will be in containers filled with an inert medium that is fertilized repeatedly to simulate hydroponic production. Loose-leaf lettuce or romaine lettuce will be the test crop for greenhouse production. The medium will be a peat-based medium to which nutrition is supplied with the fertilizer solutions on a daily basis. The medium will supply no nutrients to the crop, but an unfertilized treatment will be included to assess nutrient supply from the medium. The lettuce will be assessed for productivity and composition.An experiment will assess the value of mycorrhizal enhancement of peat-based medium on the acquisition by plants for poorly soluble nutrients. This experiment will assess phosphorus-containing fertilizers of differing solubilities. Sparingly soluble rock phosphate and bone meal will be compared with moderately soluble triple superphosphate (dibasic calcium phosphate). Additions of phosphorus will be variable from 400 to 1600 mg L-1 of medium. Growth and phosphorus composition of the crop will be assessed by growth assessment and by colorimetric analysis to compare the phosphorus-supplying power of these fertlizers in the presence or absence of mycorrhizae in the medium. Lettuce phenotype of loose-leaf and crisphead will be grown to marketable size. This experiment also will be conducted with potassium-containing sources of differing availabilities of potassium to include rock dust (greensand or granite dust), kelp, and potassium chloride to represent organic (rock dusts, kelp) and chemical fertilizers (KCl). The rock dusts are sparingly soluble whereas the potassium in kelp and potassium chloride is water soluble. The same lettuce cultivars for the phosphorus experiment will be used. Growth and potassium composition of the crop will be assessed by spectrophotometry to compare the potassium-supplying power of these fertlizers in the presence or absence of mycorrhizae in the medium.Research will be conducted in greenhouses with soil-based or peat-based media that have been amended with organic matter. Sphagnum peat moss, compost, or biochar will be added to soil to formulate a medium for growth of crops in greenhouses. Compost or biochar will be added to the peat-based medium. Compost will be obtained from production on campus or purchased from local vendors. Biochar will be obtained from local vendors. These investigations will concentrate on lettuce cultivars because of their adaptability for production in containers and space limitations in greenhouses.Research will be conducted to see if farm land can serve dual purposes of being a site for solar panels and also as a place for production of vegetables underneath the panels. Research will be conducted with loose-leaf lettuce grown under solar panels. The site of the panels is at the University of Massachusetts research farm in South Deerfield. Clusters of 12 panels with spacing of 0.6 m to 1.5 m are in place. The low-end of the panels is 2.3 m from the ground. The lettuce will be grown in replicated plots under the panels for two or more growing seasons to assess experimental error due to variations in growing season. Photosynthetically active radiation will be measured under the panels. Yield and compostion of lettuce in plots under the panels and in adjacent replicated plots with no shading will be assessed. Fertilization will be with a complete fertilizer supplying N at 100 kg ha-1. Nitrogen, P, K, Ca, and Mg will be determined in the produce to assess nutritional value for human diets.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:The targeted audience is plant and soil scientists with interests in crop productivity and mineral nutritional value of fruits and vegetales. The audience includes growers and scientists who want to improve the yield and nutrient composition of food crops through selection of crop varieties and regimes of fertilization with organic and conventional fertilizers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate students worked on all of the research projects for which results are reported here. Students learned techniques of experimental design, statistical analyses, laboratory chemistry, and writing skills. The education and training of these individuals helped to give scientists for future work in crop production and improvement. How have the results been disseminated to communities of interest?Presentations were made to audiences of scientists at regional and national meetings of professional societies. Articles were published in journals of plant and soil science. What do you plan to do during the next reporting period to accomplish the goals?Further research on enriching vegetables with elements that are important in human nutrition. Selection of crop varieties and fertilization regimes that enrich nutrients in vegetables will continue in the greenhouse and fields. Studies on remove sensing of crops in fields will be initiated to assess the nutritional status of growing crops prior to their harvest for produce.

Impacts
What was accomplished under these goals? A one-time, large application of biochar (charcoal) could increase soil carbon (C) content and improve overall soil quality. Afield study evaluated the influence of sugar maple hardwood biochar on soil nematode communities and the relationship of soil nematode communities and soil nutrient concentrations. Nematodes communities were sampled and identified in soils without biochar application and soil amended with an application of 8% by weight (equivalent to 160 Mg ha-1). The application of 8% biochar did not change the abundance of nematodes but affected some nematode communities. Compared to the unamended soil, biochar-amended soil had lower plant parasitic nematode populations and higher abundance of predatory nematodes. T Higher soil acidity and addition of substantial amounts of magnesium, calcium, potassium, and manganese in the biochar-amended soils was recorded after biochar application. Effects of varying the ammonium:nitrate ratios in nutrient solutions and effects of calcium carbonate buffering on plant mass and accumulation of potassium and calcium were studied with two lettuce (Lactuca sativa L.) cultivars, Two Star and Red Deer Tongue, in a greenhouse hydroponics experiment. The supply of ammonium-N ranged from 0% to 100% of the total nitrogen in the nutrient solution at 0.015M total N supplied as nitrate and ammonium. Proportions of ammonium-N greater than 50% of total N nutrition severely curtailed growth and calcium and potassium accumulation for both cultivars. Growth and composition of the two cultivars did not differ in response to nitrogen nutrition. The acidity of the nutrient solution increased as the proportion of ammonium increased. Application of calcium carbonate buffering improved growth in solutions containing ammonium, but plants did not attain the amount of growth and nutrient accumulation achieved with solely nitrate nutrition. Ammonia emissions from farm manures are of substantial environmental concerns in use of the manures in in crop production . Planting of cover crops for conservation of ammonia from fall, surface-applied manure could benefit farmers by retaining nitrogen (N) for use by crops in the spring growing season. A two-year study with three weekly planting dates of winter rye (Secale cerealeL.) in the fall as a cover crop was assessed for effects on mitigating ammonia volatilization and on growth and recovery of N by forage rape (Brassica napus L.). Cover cropping significantly limited volatilization compared with no cover crop. The highest rates of ammonia volatility occurred in the first 24 hours after spreading in all planting dates. The greatest cover crop biomass and N accumulation came from manure applied at an early planting date. Delaying cover crop planting from early-September to mid-October with no manure application suppressed cover crop biomass by about 40%. Forage rape yielded more biomass after cover crop with manure application than after no cover crop and manure application. Agrivoltaic (AV) systems are dual-use land systems that consist of elevated solar panels with crops grown underneath. They offer a solution to the increasing demand for food production and clean renewable energy in an expanding world. The main concern regarding AV systems is the reduced availability of light to crops below the panels. Research to date has shown that AV systems are quite productive with total energy and crop production exceeding the outputs of either system/method alone and with crop production that is not significantly reduced if solar panel density is decreased. Research has also shown that panels effect the microenvironment below the panels. The research that has been conducted so far considers altering panel density to increase radiation to the crops by varying the distance between rows of panels in an AV solar array. This study examines an AV system's productivity using different inter-panel spacings (gaps) of 2, 3, 4, and 5 feet (AV plots) and a full sun control plot to determine what spacing (gap) between panel clusters within rows is optimal for crop production. It also examines the AV systems effect on crop nutrient levels and the microenvironment (such as soil water content and leaf temperature below the panels). The crops studied will be Swiss chard, kale, peppers, and broccoli. Ultimately, it was found that AV plots biomass crop yields were significantly reduced for Swiss chard, kale, and pepper when compared against the control plot but not for broccoli. Only Kale exhibited a linear trend of increasing biomass with increasing solar radiation due to increased gap spacing between panels. Within the AV plots with differing shade levels Swiss chard, pepper and broccoli did not show a trend in biomass with decreasing shade in AV systems. For the kale and broccoli, the 4ft and 5ft gaps yielded the highest biomass of the AV shaded plots. Nutrient levels tended to increase with more shade but was only significant for Swiss chard Nitrogen and Phosphorus levels. Tests of soil water content indicated that there was no difference in the experimental plots soil water overall with changing gap spacings but, when considering specific areas under the panels, there were differences in soil water content. The middle area directly below panels in the AV plots had lower soil water content when compared to the middle area of the control plot while the right area had higher soil water content when compared to the control plot right area. Leaf temperatures in the AV plots only differed (were higher) from the control plots on sunny days not cloudy.

Publications

• Type: Book Chapters Status: Published Year Published: 2019 Citation: Barker, A. V., and M. L. Stratton. 2019. Nutrient density of fruits as a function of soil fertility. In Srivastava, A. K. and C. X. Hu (eds.). Fruit Crops: Diagnosis and Management of Nutrient Constraints. Amsterdam: Elsevier.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Weil, S., A. V. Barker, O. R. Zandvakili, and F. Etemadi. 2020. Plant growth and calcium and potassium accumulation in lettuce under different nitrogen regimes of ammonium and nitrate nutrition. Journal of Plant Nutrition 44(2):270-281.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Akbari, P., S. Herbert, M. Hashemi, A. Barker, O. R. Zandvakili, and Z.E. Bistgani. 2020. Winter Annual Rye Seeding Date Influence on Nitrogen Recovery and Ammonia Volatilization from Late Fall Surface-Applied Manure. Agronomy 10(7):Article 931
• Type: Theses/Dissertations Status: Published Year Published: 2020 Citation: Kristen Oleskewicz. 2020. The Effects of Inter-panel Spacing on Crop Biomass Yields, Nutrients, and the Microenvironment in a Dual-Use Agrivoltaic System. Masters Thesis, University of Massachusetts, Amherst.

Progress 10/18/18 to 09/30/19

Outputs
Target Audience:The target communities were agronomists and horticulturists with interests in crop production, soil fertility, plant nutrition, and nutritional value of plant-based foods for humans. These communities were address with presentations of information at meetings of scientific societies and publication of articles in journals of professional societies and in independent scientific journals. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate students working directly on this project or cooperatively with other investigators had opportunities to publish papers in scientific journals under the direction of the principal investigator. One graduate student is working yet on the project, and two other have been graduated with doctoral degrees and are working in teaching and research at universities in the USA. How have the results been disseminated to communities of interest?The information from investigations on this project have been published in scientific journals and presented at meetings of professional societies. What do you plan to do during the next reporting period to accomplish the goals?Research will continue with investigations of the effects of fertilization and selection of crop varieties on the accumulation of nutrients in plant- derived foods. Assessments of the nutrient status of crops by remote sensing and colorimetry will be continued.

Impacts
What was accomplished under these goals? In greenhouse and field studies, the yield and compostion of lettuce grown with organic and conventional fertilizers were assessed.In the greenhouse, fertilizers were blood meal, feather meal, cottonseed meal, alfalfa meal, sewage sludge, compost, cow manure, a chemical fertilizer, and a treatment without fertilizer. Lettuce yield was higher for plants receiving fertilizers than with no fertilizer and increased with increased nitrogen (N) applications, but high applications of ammoniacal fertilizers such as blood meal, feather meal, or ureasuppressed yields.Total Nand nitrate increased in leaves as N supply increased with all fertilizers. Small changes in leaf nutrient contents other than N occurred among or with increased application of the various fertilizers. The soil carbon dioxide release and ammonia volatilization were high from fertilizers with high N concentrations. Increasing N application resulted in higher concentration of NH4-N in lettuce. Organic fertilizers and urea were equally effective in supporting growth and affecting nutrient accumulation in lettuce if sufficient N was supplied. Organic fertilizers with high N increased lettuce growth at lower applications than those with low N content. In hydroponics culture, lettuce growth was higher with Hoagland and Arnon solution than with the organic fertilizer or with no fertilization. The organic fertilizer increased growth above no fertilizer applied. With hydroponic solutions to grow lettuce, Hoagland and Arnon solution gave the highest concentration of nitrogen, potassium, magnesium, and iron in the lettuce whereas lettuce grown with a commercial hydroponic organic fertilizer had the highest phosphorus. Plant nutrient accumulation differed only slightly among the cultivars of iceberg, cos, and loose leaf phenotypes. Hoagland and Arnon solution produced high nitrate in leaves. Nitrate concentrations with organic or no fertilization were low. Loose head or loose leaf cultivars had higher nitrate than romaine or iceberg.Results of field work with fertilizers are complete and under analysis. A fieldevaluated sugar maple hardwood charcoal (biochar) as a soil amendment forsweet cornproduction. Applications of biochar were 0, 40, 80, 120, and 160 Mg ha-1. Soil pH increased from pH 5.8 to 6.7 with increased biochar additions. The percent base saturation was increased due to the retention of calcium, magnesium, and potassium. Soil phosphate availability increased. Sweet corn yield was depressed with applications above 40Mg ha-1. The micro- and macronutrient concentrations in leaf, pod, and seed of faba bean varieties were characterized in a field study with six cultivars of faba bean. The highest concentrations N, P, K, and Zn were in the seeds of all of the varieties. However, the highest accumulation of Ca, Mg, Fe, and Mn was in the leaves. An investigation on the value of hydrothermically modified feldspar as a potassium-containing fertilizer was conducted in cooperation with the Massachusetts Institution of Technology. The results showed that the modified feldspar was an equally effective fertilizer as potassium chloride for fertilization of tomato. Two chapters in books were written on nutrient density in fruits and on properties of fertilizers in general.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Cole, E. J., O. R. Zandkavili, B. Xing, M. Hashemi, A. V. Barker, and S. J. Herbert. 2019. Effects of hardwood biochar on soil acidity, nutrient dynamics, and sweet corn productivity. Communications in Soil Science and Plant Analysis 50:1732-1742.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zankvakili, O. R., A. V. Barker, M. Hashemi, F. Etemadi, W. R. Autio, and Sarah Weis. 2019. Growth and nutrient and nitrate accumulation of lettuce under different regimes of nitrogen fertilization. Journal of Plant Nutrition 42:1575-1593.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zandkavili, O. R., A. V. Barker, M. Hashemi, and F. Etemadi. 2019. Biomass and nutrient concentration of lettuce grown with organic fertilizers. Journal of Plant Nutrition 42:444-457.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zandkavili, O. R., A. V. Barker, M. Hashemi, and F Etemadi. 2019. Comparisons of commercial organic and chemical fertilizer solutions on growth and composition of lettuce. Journal of Plant Nutrition 42:990-1000.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Etemadi, F., M. Hashemi, A. V. Barker, O. R. Zandkavili, and X. B. Liu. 2019. Agronomy, nutritional value, and medicinal application of faba bean (Vicia fava L.). Horticultural Plant Journal 5:170-182.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Akbari, P., S. J. Herbert, M. Hashemi, A. V. Barker, and O. R. Zandkavili. 2019. Role of cover crops and planting dates for improved weed suppression and nitrogen recovery in no till systems. Communications in Soil Science and Plant Analysis 50:1722-1731.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Barker, A. V., Md J. Meagy, T. E. Eaton, E. Jahanzad, and G. Bryson. 2019. Improvement of mineral nutrient content of tomato through selection of cultivars and soil fertility. Journal of Plant Nutrition 42:928-941.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Ciceri, D., T. C. Close, A. V. Barker, and A. Allanore. 2019. Fertilizing properties of potassium feldspar altered hydrothermically. Communications in Soil Science and Plant Analysis 50:482-491.
• Type: Book Chapters Status: Published Year Published: 2019 Citation: Barker, A. V. 2019. Fertilizers. In Worsfold, P., C. Poole, A. Townsend, and M. Miro (eds.). Encyclopedia of Analytical Science (3rd ed.). Vol. 3, 134-144. Amsterdam: Elsevier. Chapter
• Type: Book Chapters Status: Awaiting Publication Year Published: 2019 Citation: Barker, A. V., and M. L. Stratton. Nutrient density of fruits as a function of soil fertility. In Srivastava, A. K. and C. X. Hu (eds.). Fruit Crops: Diagnosis and Management of Nutrient Constraints. Amsterdam: Elsevier. Published after October 1, 2019.