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Anaerobic digestion of organic wastes produces solid residues known as digestates, which have potential as a fertilizer and soil amendment. The majority of research on digestate focuses on their fertilizer value. However, there is a lack of information about additional effects they may have on plant growth, both positive and negative. Understanding the effects of digestate on plant growth is essential to optimizing their use in agriculture and helping close the loop of material and energy balances. This greenhouse study evaluated the effects of two different digestates, a food waste digestate (FWD) and a lignocellulosic biomass digestate (LBD); a liquid fertilizer; and various combinations of fertilizer and digestates on plant growth, nutrient uptake and nutrient use efficiency (NUE) of Brassica juncea (kai choy) plants. It also evaluated potential negative attributes of the digestates, including salinity and possible biohazards. Combinations of LBD and fertilizer performed as well or slightly better than the fertilizer control for most parameters, including aboveground biomass and root length. These same combinations had significantly higher nitrogen use efficiency than the fertilizer control. Inhibitory effects were observed in 100% LBD treatments, likely due to the high electrical conductivity of the media from digestate application. Based on this research, LBD could partially replace mineral fertilizers for kai choy at up to 50% of the target nitrogen rate and may lead to increased plant growth beyond mineral fertilizers. FWD could replace up to 100% of the target nitrogen application, without causing significant negative effects on plant growth. Increasing the use of digestates in agriculture will provide additional incentives for the anaerobic digestion process, as it produces two valuable products: biogas for energy and digestate for fertilizer.
Jacqueline Jamison; Samir Khanal; Nhu Nguyen; Jonathan Deenik. Assessing the Effects of Digestates and Combinations of Digestates and Fertilizer on Yield and Nutrient Use of Brassica juncea (Kai Choy). Agronomy 2021, 11, 509 .
AMA StyleJacqueline Jamison, Samir Khanal, Nhu Nguyen, Jonathan Deenik. Assessing the Effects of Digestates and Combinations of Digestates and Fertilizer on Yield and Nutrient Use of Brassica juncea (Kai Choy). Agronomy. 2021; 11 (3):509.
Chicago/Turabian StyleJacqueline Jamison; Samir Khanal; Nhu Nguyen; Jonathan Deenik. 2021. "Assessing the Effects of Digestates and Combinations of Digestates and Fertilizer on Yield and Nutrient Use of Brassica juncea (Kai Choy)." Agronomy 11, no. 3: 509.
Biochar has important biogeochemical functions in soil—first as a means to sequester carbon, and second as a soil conditioner to potentially enhance soil quality and fertility. Volatile matter (VM) content is a property of biochar that describes its degree of thermal alteration, which can have a direct influence on carbon and nitrogen dynamics in soil. In this study, we characterized the VM in biochars derived from two locally sourced feedstocks (corncob and kiawe wood) and evaluated the relationship of VM content to nitrogen transformations and culturable fungal biomass. Using 13C nuclear magnetic resonance (NMR) spectroscopy, we found that the VM content of biochar primarily consisted of alkyl (5.1–10.1%), oxygen-substituted alkyl (2.2–6.7%), and phenolic carbon (9.4–11.6%). In a series of laboratory incubations, we demonstrated that corncob biochars with high VM (23%) content provide a source of bioavailable carbon that appeared to support enhanced viable, culturable fungi (up to 8 fold increase) and cause nitrogen immobilization in the short-term. Corncob biochar with bioavailable VM was nitrogen-limited, and the addition of nitrogen fertilizer resulted in a four-fold increase in total hydrolytic enzyme activity and the abundance of culturable fungal colonies. In contrast, kiawe biochar with an equivalent VM content differed substantially in its composition and effect on these same biological parameters. Therefore, the rapid measurement of VM content is too coarse to differentiate chemical composition and to predict the behavior of biochars across feedstocks and production methods.
Tai Maaz; William Hockaday; Jonathan Deenik. Biochar Volatile Matter and Feedstock Effects on Soil Nitrogen Mineralization and Soil Fungal Colonization. Sustainability 2021, 13, 2018 .
AMA StyleTai Maaz, William Hockaday, Jonathan Deenik. Biochar Volatile Matter and Feedstock Effects on Soil Nitrogen Mineralization and Soil Fungal Colonization. Sustainability. 2021; 13 (4):2018.
Chicago/Turabian StyleTai Maaz; William Hockaday; Jonathan Deenik. 2021. "Biochar Volatile Matter and Feedstock Effects on Soil Nitrogen Mineralization and Soil Fungal Colonization." Sustainability 13, no. 4: 2018.
Kawika B. Winter; Yoshimi M. Rii; Frederick A. W. L. Reppun; Katy DeLaforgue Hintzen; Rosanna A. Alegado; Brian W. Bowen; Leah L. Bremer; Makena Coffman; Jonathan L. Deenik; Megan J. Donahue; Kim A. Falinski; Kiana Frank; Erik C. Franklin; Natalie Kurashima; Noa Kekuewa Lincoln; Elizabeth M. P. Madin; Margaret A. McManus; Craig E. Nelson; Ryan Okano; Anthony Olegario; Pua'Ala Pascua; Kirsten L. L. Oleson; Melissa R. Price; Malia Ana J. Rivera; Kuulei S. Rodgers; Tamara Ticktin; Christopher L. Sabine; Celia M. Smith; Alice Hewett; Rocky Kaluhiwa; Māhealani Cypher; Bill Thomas; Jo-Ann Leong; Kristina Kekuewa; Jean Tanimoto; Kānekoa Kukea-Shultz; A. Hiʻilei Kawelo; Keliʻi Kotubetey; Brian J. Neilson; Tina S. Lee; Robert J. Toonen. Collaborative research to inform adaptive comanagement: a framework for the Heʻeia National Estuarine Research Reserve. Ecology and Society 2020, 25, 1 .
AMA StyleKawika B. Winter, Yoshimi M. Rii, Frederick A. W. L. Reppun, Katy DeLaforgue Hintzen, Rosanna A. Alegado, Brian W. Bowen, Leah L. Bremer, Makena Coffman, Jonathan L. Deenik, Megan J. Donahue, Kim A. Falinski, Kiana Frank, Erik C. Franklin, Natalie Kurashima, Noa Kekuewa Lincoln, Elizabeth M. P. Madin, Margaret A. McManus, Craig E. Nelson, Ryan Okano, Anthony Olegario, Pua'Ala Pascua, Kirsten L. L. Oleson, Melissa R. Price, Malia Ana J. Rivera, Kuulei S. Rodgers, Tamara Ticktin, Christopher L. Sabine, Celia M. Smith, Alice Hewett, Rocky Kaluhiwa, Māhealani Cypher, Bill Thomas, Jo-Ann Leong, Kristina Kekuewa, Jean Tanimoto, Kānekoa Kukea-Shultz, A. Hiʻilei Kawelo, Keliʻi Kotubetey, Brian J. Neilson, Tina S. Lee, Robert J. Toonen. Collaborative research to inform adaptive comanagement: a framework for the Heʻeia National Estuarine Research Reserve. Ecology and Society. 2020; 25 (4):1.
Chicago/Turabian StyleKawika B. Winter; Yoshimi M. Rii; Frederick A. W. L. Reppun; Katy DeLaforgue Hintzen; Rosanna A. Alegado; Brian W. Bowen; Leah L. Bremer; Makena Coffman; Jonathan L. Deenik; Megan J. Donahue; Kim A. Falinski; Kiana Frank; Erik C. Franklin; Natalie Kurashima; Noa Kekuewa Lincoln; Elizabeth M. P. Madin; Margaret A. McManus; Craig E. Nelson; Ryan Okano; Anthony Olegario; Pua'Ala Pascua; Kirsten L. L. Oleson; Melissa R. Price; Malia Ana J. Rivera; Kuulei S. Rodgers; Tamara Ticktin; Christopher L. Sabine; Celia M. Smith; Alice Hewett; Rocky Kaluhiwa; Māhealani Cypher; Bill Thomas; Jo-Ann Leong; Kristina Kekuewa; Jean Tanimoto; Kānekoa Kukea-Shultz; A. Hiʻilei Kawelo; Keliʻi Kotubetey; Brian J. Neilson; Tina S. Lee; Robert J. Toonen. 2020. "Collaborative research to inform adaptive comanagement: a framework for the Heʻeia National Estuarine Research Reserve." Ecology and Society 25, no. 4: 1.
Winter, K. B., N. K. Lincoln, F. Berkes, R. A. Alegado, N. Kurashima, K. L. Frank, P. Pascua, Y. M. Rii, F. Reppun, I. S. S. Knapp, W. C. McClatchey, T. Ticktin, C. Smith, E. C. Franklin, K. Oleson, M. R. Price, M. A. McManus, M. J. Donahue, K. S. Rodgers, B. W. Bowen, C. E. Nelson, B. Thomas, J.-A. Leong, E. M. P. Madin, M. A. J. Rivera, K. A. Falinski, L. L. Bremer, J. L. Deenik, S. M. Gon III, B. Neilson, R. Okano, A. Olegario, B. Nyberg, A. H. Kawelo, K. Kotubetey, J. K. Kukea-Shultz, and R. J. Toonen. 2020. Ecomimicry in Indigenous resource management: optimizing ecosystem services to achieve resource abundance, with examples from Hawaiʻi. Ecology and Society 25(2):26. https://doi.org/10.5751/ES-11539-250226
Kawika B. Winter; Noa Kekuewa Lincoln; Fikret Berkes; Rosanna A. Alegado; Natalie Kurashima; Kiana L. Frank; Puaʻala Pascua; Yoshimi M. Rii; Frederick Reppun; Ingrid S.S. Knapp; Will C. McClatchey; Tamara Ticktin; Celia Smith; Erik C. Franklin; Kirsten Oleson; Melissa R. Price; Margaret A. McManus; Megan J. Donahue; Kuulei S. Rodgers; Brian W. Bowen; Craig E. Nelson; Bill Thomas; Jo-Ann Leong; Elizabeth M. P. Madin; Malia Ana J. Rivera; Kim A. Falinski; Leah L. Bremer; Jonathan L. Deenik; Sam M. Gon Iii; Brian Neilson; Ryan Okano; Anthony Olegario; Ben Nyberg; A. Hiʻilei Kawelo; Keliʻi Kotubetey; J. Kānekoa Kukea-Shultz; Robert J. Toonen. Ecomimicry in Indigenous resource management: optimizing ecosystem services to achieve resource abundance, with examples from Hawaiʻi. Ecology and Society 2020, 25, 1 .
AMA StyleKawika B. Winter, Noa Kekuewa Lincoln, Fikret Berkes, Rosanna A. Alegado, Natalie Kurashima, Kiana L. Frank, Puaʻala Pascua, Yoshimi M. Rii, Frederick Reppun, Ingrid S.S. Knapp, Will C. McClatchey, Tamara Ticktin, Celia Smith, Erik C. Franklin, Kirsten Oleson, Melissa R. Price, Margaret A. McManus, Megan J. Donahue, Kuulei S. Rodgers, Brian W. Bowen, Craig E. Nelson, Bill Thomas, Jo-Ann Leong, Elizabeth M. P. Madin, Malia Ana J. Rivera, Kim A. Falinski, Leah L. Bremer, Jonathan L. Deenik, Sam M. Gon Iii, Brian Neilson, Ryan Okano, Anthony Olegario, Ben Nyberg, A. Hiʻilei Kawelo, Keliʻi Kotubetey, J. Kānekoa Kukea-Shultz, Robert J. Toonen. Ecomimicry in Indigenous resource management: optimizing ecosystem services to achieve resource abundance, with examples from Hawaiʻi. Ecology and Society. 2020; 25 (2):1.
Chicago/Turabian StyleKawika B. Winter; Noa Kekuewa Lincoln; Fikret Berkes; Rosanna A. Alegado; Natalie Kurashima; Kiana L. Frank; Puaʻala Pascua; Yoshimi M. Rii; Frederick Reppun; Ingrid S.S. Knapp; Will C. McClatchey; Tamara Ticktin; Celia Smith; Erik C. Franklin; Kirsten Oleson; Melissa R. Price; Margaret A. McManus; Megan J. Donahue; Kuulei S. Rodgers; Brian W. Bowen; Craig E. Nelson; Bill Thomas; Jo-Ann Leong; Elizabeth M. P. Madin; Malia Ana J. Rivera; Kim A. Falinski; Leah L. Bremer; Jonathan L. Deenik; Sam M. Gon Iii; Brian Neilson; Ryan Okano; Anthony Olegario; Ben Nyberg; A. Hiʻilei Kawelo; Keliʻi Kotubetey; J. Kānekoa Kukea-Shultz; Robert J. Toonen. 2020. "Ecomimicry in Indigenous resource management: optimizing ecosystem services to achieve resource abundance, with examples from Hawaiʻi." Ecology and Society 25, no. 2: 1.
The soil's ability to support plant and animal life while regulating atmospheric, water, and ecosystem cycles makes it a vital living resource to the planet and its health. Assessments of soil health are used to support the management of sustainable soils and functions, encompassing both a soil's inherent and dynamic qualities, which impact and are impacted by the surrounding ecosystem, and are subject to human influence. Improvements upon soil health assessment tests allow for specificity among soil diversity to optimize efforts in sustainable agricultural management, climate change mitigation, and environmental studies worldwide.
Hannah L. Hubanks; Jonathan L. Deenik; Susan E. Crow. Getting the Dirt on Soil Health and Management. Reference Module in Earth Systems and Environmental Sciences 2018, 1 .
AMA StyleHannah L. Hubanks, Jonathan L. Deenik, Susan E. Crow. Getting the Dirt on Soil Health and Management. Reference Module in Earth Systems and Environmental Sciences. 2018; ():1.
Chicago/Turabian StyleHannah L. Hubanks; Jonathan L. Deenik; Susan E. Crow. 2018. "Getting the Dirt on Soil Health and Management." Reference Module in Earth Systems and Environmental Sciences , no. : 1.
Few data are available on dual burden of under and over nutrition of children in the Pacific region. The objective was to examine prevalence of stunting at birth and current stunting and their relationship to obesity in US Affiliated Pacific (USAP) jurisdictions. Cross sectional survey with cluster sampling by community. 5558, 2-8 years olds were measured in 51 communities in 11 USAP jurisdictions. The main outcome measures were stunting at birth, current stunting and obesity by body mass index. Prevalences of stunting at birth, current stunting and obesity were determined, adjusting for age distribution and community clustering. Differences by among age, sex, race and jurisdiction income levels were evaluated by chi-square analysis. Relationships of stunting at birth and current stunting with obesity were examined using a hierarchical model accounting for the study design. Prevalences were stunting at birth 6.8% (Standard Error, SE = 0.9%), current stunting 1.4% (SE = 0.2%) and obesity 14.03.8% (SE = 0.9%). Obesity was highest in upper middle income jurisdictions (UMIJ) at 17.5%. Stunting at birth differed by race (p = 0.0001) with highest prevalence among Native Hawaiian/Pacific Islanders (10.7%). Prevalence of stunting at birth was different by jurisdiction income level with 27.5% in lower middle income jurisdictions (LMIJ), and 22.2% in UMIJ, and 5.5% in higher than high income jurisdictions (HIJ) at 5.5% (p < 0.0001). Prevalence of current stunting was higher in LMIJ than HIJ (p = 0.001), although children with current stunting were less likely to have been stunted at birth. The association between stunting at birth and current stunting was negative (OR = 0.19, 95% CI: 0.05-0.69). Currently stunted children were marginally less likely to be obese than not stunted children in the USAP, where the prevalence of current stunting is low. Stunting (at birth and current) was highest in LMIJ, while UMIJ jurisdictions had the highest dual burden of malnutrition (that is the highest combination of both stunting at birth and obesity). National Institutes for Health clinical trial # NCT01881373 (clinicaltrials.gov).
Rachel Novotny; Fenfang Li; Rachael Leon Guerrero; Patricia Coleman; Aifili J. Tufa; Andrea Bersamin; Jonathan Deenik; Lynne R Wilkens. Dual burden of malnutrition in US Affiliated Pacific jurisdictions in the Children’s Healthy Living Program. BMC Public Health 2017, 17, 483 .
AMA StyleRachel Novotny, Fenfang Li, Rachael Leon Guerrero, Patricia Coleman, Aifili J. Tufa, Andrea Bersamin, Jonathan Deenik, Lynne R Wilkens. Dual burden of malnutrition in US Affiliated Pacific jurisdictions in the Children’s Healthy Living Program. BMC Public Health. 2017; 17 (1):483.
Chicago/Turabian StyleRachel Novotny; Fenfang Li; Rachael Leon Guerrero; Patricia Coleman; Aifili J. Tufa; Andrea Bersamin; Jonathan Deenik; Lynne R Wilkens. 2017. "Dual burden of malnutrition in US Affiliated Pacific jurisdictions in the Children’s Healthy Living Program." BMC Public Health 17, no. 1: 483.
Quality assurance plays an important role in research by assuring data integrity, and thus, valid study results. We aim to describe and share the results of the quality assurance process used to guide the data collection process in a multi-site childhood obesity prevalence study and intervention trial across the US Affiliated Pacific Region. Quality assurance assessments following a standardized protocol were conducted by one assessor in every participating site. Results were summarized to examine and align the implementation of protocol procedures across diverse settings. Data collection protocols focused on food and physical activity were adhered to closely; however, protocols for handling completed forms and ensuring data security showed more variability. Quality assurance protocols are common in the clinical literature but are limited in multi-site community-based studies, especially in underserved populations. The reduction in the number of QA problems found in the second as compared to the first data collection periods for the intervention study attest to the value of this assessment. This paper can serve as a reference for similar studies wishing to implement quality assurance protocols of the data collection process to preserve data integrity and enhance the validity of study findings. Trial registration: NIH clinical trial #NCT01881373
Ashley Yamanaka; Marie Kainoa Fialkowski; Lynne Wilkens; Fenfang Li; Reynolette Ettienne; Travis Fleming; Julianne Power; Jonathan Deenik; Patricia Coleman; Rachael Leon Guerrero; Rachel Novotny. Quality assurance of data collection in the multi-site community randomized trial and prevalence survey of the children’s healthy living program. BMC Research Notes 2016, 9, 432 .
AMA StyleAshley Yamanaka, Marie Kainoa Fialkowski, Lynne Wilkens, Fenfang Li, Reynolette Ettienne, Travis Fleming, Julianne Power, Jonathan Deenik, Patricia Coleman, Rachael Leon Guerrero, Rachel Novotny. Quality assurance of data collection in the multi-site community randomized trial and prevalence survey of the children’s healthy living program. BMC Research Notes. 2016; 9 (1):432.
Chicago/Turabian StyleAshley Yamanaka; Marie Kainoa Fialkowski; Lynne Wilkens; Fenfang Li; Reynolette Ettienne; Travis Fleming; Julianne Power; Jonathan Deenik; Patricia Coleman; Rachael Leon Guerrero; Rachel Novotny. 2016. "Quality assurance of data collection in the multi-site community randomized trial and prevalence survey of the children’s healthy living program." BMC Research Notes 9, no. 1: 432.
The thermal conversion of sewage sludge to biochar offers a promising alternative use for a hazardous waste material with potential benefits to agricultural productivity and soil quality. Three short-term greenhouse experiments were conducted to evaluate the effect of corn cob (CC) and sewage sludge (SS) biochars, with their anaerobically treated counterparts, on soil properties and plant growth in an infertile Oxisol. The anaerobically treated SS biochar showed the greatest concentration of bioavailable essential nutrients, but treatment only resulted in increased yields for the SS biochar in the first crop in the absence of added fertilizer. Both CC and SS biochars in combination with fertilizer doubled plant growth compared to the control in the first crop cycle, produced no significant effect in the second cycle, and more than tripled plant growth for the SS biochars in the third cycle. High ash content with high nutrient contributions (especially P) and a persistent liming effect explain the benefits of the SS biochars to plant growth. The SS biochar showed promise in mitigating the negative effects of soil Mn toxicity. Sewage sludge biochars reduced Cd bioavailability and had no significant effect on the bioavailability of other potentially toxic metals compared to the control.
Jonathan L. Deenik; Michael J. Cooney. The Potential Benefits and Limitations of Corn Cob and Sewage Sludge Biochars in an Infertile Oxisol. Sustainability 2016, 8, 131 .
AMA StyleJonathan L. Deenik, Michael J. Cooney. The Potential Benefits and Limitations of Corn Cob and Sewage Sludge Biochars in an Infertile Oxisol. Sustainability. 2016; 8 (2):131.
Chicago/Turabian StyleJonathan L. Deenik; Michael J. Cooney. 2016. "The Potential Benefits and Limitations of Corn Cob and Sewage Sludge Biochars in an Infertile Oxisol." Sustainability 8, no. 2: 131.
Joshua H.S. Silva; Jonathan L. Deenik; Russell S. Yost; Gregory L. Bruland; Susan E. Crow. Improving clay content measurement in oxidic and volcanic ash soils of Hawaii by increasing dispersant concentration and ultrasonic energy levels. Geoderma 2015, 237-238, 211 -223.
AMA StyleJoshua H.S. Silva, Jonathan L. Deenik, Russell S. Yost, Gregory L. Bruland, Susan E. Crow. Improving clay content measurement in oxidic and volcanic ash soils of Hawaii by increasing dispersant concentration and ultrasonic energy levels. Geoderma. 2015; 237-238 ():211-223.
Chicago/Turabian StyleJoshua H.S. Silva; Jonathan L. Deenik; Russell S. Yost; Gregory L. Bruland; Susan E. Crow. 2015. "Improving clay content measurement in oxidic and volcanic ash soils of Hawaii by increasing dispersant concentration and ultrasonic energy levels." Geoderma 237-238, no. : 211-223.
Although surveillance data are limited in the US Affiliated Pacific, Alaska, and Hawaii, existing data suggest that the prevalence of childhood obesity is similar to or in excess of other minority groups in the contiguous US. Strategies for addressing the childhood obesity epidemic in the region support the use of community-based, environmentally targeted interventions. The Children’s Healthy Living Program is a partnership formed across institutions in the US Affiliated Pacific, Alaska, and Hawaii to design a community randomized environmental intervention trial and a prevalence survey to address childhood obesity in the region through affecting the food and physical activity environment.
Lynne R Wilken; Rachel Novotny; Marie K Fialkowski; Carol J Boushey; Claudio Nigg; Yvette Paulino; Rachael Leon Guerrero; Andrea Bersamin; Don Vargo; Jang Kim; Jonathan Deenik. Children’s Healthy Living (CHL) Program for remote underserved minority populations in the Pacific region: rationale and design of a community randomized trial to prevent early childhood obesity. BMC Public Health 2013, 13, 944 -944.
AMA StyleLynne R Wilken, Rachel Novotny, Marie K Fialkowski, Carol J Boushey, Claudio Nigg, Yvette Paulino, Rachael Leon Guerrero, Andrea Bersamin, Don Vargo, Jang Kim, Jonathan Deenik. Children’s Healthy Living (CHL) Program for remote underserved minority populations in the Pacific region: rationale and design of a community randomized trial to prevent early childhood obesity. BMC Public Health. 2013; 13 (1):944-944.
Chicago/Turabian StyleLynne R Wilken; Rachel Novotny; Marie K Fialkowski; Carol J Boushey; Claudio Nigg; Yvette Paulino; Rachael Leon Guerrero; Andrea Bersamin; Don Vargo; Jang Kim; Jonathan Deenik. 2013. "Children’s Healthy Living (CHL) Program for remote underserved minority populations in the Pacific region: rationale and design of a community randomized trial to prevent early childhood obesity." BMC Public Health 13, no. 1: 944-944.
The fate of fertilizer nitrogen (N) in flooded agroecosystems is difficult to predict given the multitude of potential N transformation pathways. In particular, rhizosphere effects are known to play a significant role in N cycling, but are especially difficult to quantify in large emergent macrophytes. To address these issues, we utilized a whole core 15NH4+ perfusion technique with porewater equilibrators for the extraction of 14+15N–NO3−, NH4+, and N2. Sub-surface denitrification was found to be an important N loss pathway in wetland sediments vegetated with aerenchymatous taro (Colocasia esculenta) versus bare sediments. Driven by hypothesized thermo-osmotic mechanisms linked to photosynthesis, diurnal O2 transport into the sub-surface stimulated nitrification–denitrification in the extensive root rhizosphere. Porewater denitrification rates were also positively influenced by airflow across leaf surfaces. Depth-integrated porewater denitrification rates in this system were very high, ranging from 23 to 845 μmol N2 m−2 h−1. The N cycling functional genes nosZ and amoA were found at high abundances throughout the sub-surface with nirS dominating nitrite reduction in these sediments. Overall we were able to account for >82% of added 15NH4+ in the vegetated cores over a ten-day incubation through both plant incorporation and surface/sub-surface coupled nitrification–denitrification. In summary, these results suggested (1) that oxygen flux through the taro stem and root system into the flooded sediment may be an important driver of nitrification and coupled denitrification in these systems, and (2) that oxygen flux is mediated by air movement (wind) and the diurnal light-cycle related to photosynthesis.
C. Ryan Penton; Jonathan L. Deenik; Brian N. Popp; Gregory L. Bruland; Pia Engstrom; Derek St. Louis; James Tiedje. Importance of sub-surface rhizosphere-mediated coupled nitrification–denitrification in a flooded agroecosystem in Hawaii. Soil Biology and Biochemistry 2013, 57, 362 -373.
AMA StyleC. Ryan Penton, Jonathan L. Deenik, Brian N. Popp, Gregory L. Bruland, Pia Engstrom, Derek St. Louis, James Tiedje. Importance of sub-surface rhizosphere-mediated coupled nitrification–denitrification in a flooded agroecosystem in Hawaii. Soil Biology and Biochemistry. 2013; 57 ():362-373.
Chicago/Turabian StyleC. Ryan Penton; Jonathan L. Deenik; Brian N. Popp; Gregory L. Bruland; Pia Engstrom; Derek St. Louis; James Tiedje. 2013. "Importance of sub-surface rhizosphere-mediated coupled nitrification–denitrification in a flooded agroecosystem in Hawaii." Soil Biology and Biochemistry 57, no. : 362-373.
The sandy carbonatic soils of Pacific atolls are considered infertile and poorly suited to agriculture. The Republic of the Marshall Islands is comprised predominantly of atolls, and there is scant information on the fertility status of the Marshall Island soils. We conducted a survey of the soils to quantify chemical properties and determine significant trends related to soil distribution and climate. A total of 116 surface (0–15 cm) soil samples from 13 atolls and 42 subsoil (15–45 cm) samples from five of the atolls were analyzed for pH, electrical conductivity (EC), organic carbon (OC), total nitrogen (TN), cation exchange capacity (CEC), and nutrient levels. A missing element study in the greenhouse on a typical soil from Majuro Atoll was conducted to rank soil nutrient deficiencies. There were some strong differences in soil chemical properties between the two depths, but not necessarily between the two soil series constituting the sampled soils. Soil chemical properties were not affected by a strong rainfall gradient running from the southern (≈ 4000 mm) to the northern (≈ 1350 mm) atolls, but human activity had a significant effect on some properties. Soils located near the center of islands tend to show higher concentrations of OC than soils located along the ocean exposed shoreline. The missing element study indicated that the soil was deficient in Cu, P, N, S, and K. Potassium was the most serious nutrient constraint whereas the micronutrients Fe, Mn, Zn, and B did not limit maize growth significantly in a greenhouse pot experiment. Interpreting soil test data on atoll soils, however, remains difficult for two reasons: (i) the soil tests have not been calibrated with crop growth, and (ii) standard soil tests may not be applicable to the unique physical and chemical properties of atoll soils.
J.L. Deenik; R.S. Yost. Chemical properties of atoll soils in the Marshall Islands and constraints to crop production. Geoderma 2006, 136, 666 -681.
AMA StyleJ.L. Deenik, R.S. Yost. Chemical properties of atoll soils in the Marshall Islands and constraints to crop production. Geoderma. 2006; 136 (3-4):666-681.
Chicago/Turabian StyleJ.L. Deenik; R.S. Yost. 2006. "Chemical properties of atoll soils in the Marshall Islands and constraints to crop production." Geoderma 136, no. 3-4: 666-681.