Browsing by Author "Chim, Bee K."

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    Biochemical and physiological responses of Cannabis sativa to an integrated plant nutrition system
    Filho, Jose F. Da Cunha Leme; Thomason, Wade E.; Evanylo, Gregory K.; Zhang, Xunzhong; Strickland, Michael S.; Chim, Bee K.; Diatta, Andre A. (2020-11)
    The illegal status of cannabis (Cannabis sativa L.) post-World War II resulted in a lack of research on agricultural practices. However, there is a resurgence of interest in cannabis due to diverse uses such as a rich source of cellulosic/woody fiber and construction uses, seed oil, bioenergy and pharmaceutical properties. The principle of an integrated plant nutrition system (IPNS) is to enable adaptation of plant nutrition and soil fertility management to local site characteristics, attempting to optimize use of inorganic, organic and biological resources. This project investigated the individual and combined use of inorganic, organic and biological fertilizer resources on cannabis before and after a period of moderate water stress. We evaluated the individual and combined effects of commercial synthetic fertilizer, humic acid (HA), manure tea and bioinoculant as inorganic, organic and biological resources, respectively on cannabis growth and physiological parameters. Our hypothesis was that the synergetic effects of HA + biofertilizers would improve cannabis growth. When compared to the control, the application of HA and biofertilizer alone, or in combination, increased plant height, chlorophyll content and photosynthetic efficiency by 55, 8 and 12%, respectively, after water stress. Cannabis biomass of treated plants was rarely different from the control. The combined application of HA + biofertilizer resulted in additive, but not synergistic, increases in measured parameter. Future research should focus on the effects of biostimulants on CBD/THC content due to the potential impact on the production of secondary metabolites in plants under stress.
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    Effect of organic biostimulants on cannabis productivity and soil microbial activity under outdoor conditions
    Da Cunha Leme Filho, Jose F.; Chim, Bee K.; Bermand, Cameron; Diatta, Andre A.; Thomason, Wade E. (2024-03-26)
    In 2019 and 2020, we investigated the individual and combined effects of two biofertilizers (manure tea and bioinoculant) and one humic acid (HA) product on cannabis biochemical and physiological parameters and soil CO2 evolution under outdoor conditions. Our hypothesis was that HA would increase the microbial activity in the biofertilizers and synergy of both compounds would promote better plant performance and stimulate soil microbial activity. In 2020, the individual and combined application of biofertilizers and HA increased cannabis height, chlorophyll content, photosynthetic efficiency, aboveground biomass, and bucked biomass by 105, 52, 43, 122, and 117%, respectively. Impacts were greater under suboptimal growing conditions caused by planting delay experienced in 2020. In 2019, planting date occurred in-between the most favorable period and chlorophyll content and photosynthetic efficiency were the only parameters influenced by the application of biostimulants. The discrepancies between the two growing seasons reinforce the evidence of other studies that biostimulants efficacy is maximized under stress conditions. This study could not conclusively confirm that the combined use of biofertilizer + HA is a superior practice since affected plant parameters did not differ from application of the compounds singly. Similarly, only one biofertilizer + HA treatment increased soil microbial activity. More research is needed to define optimum rates and combinations of biofertilizer and stimulants for cannabis.
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    An integrated plant nutrition system (IPNS) for corn in the Mid-Atlantic USA
    Da Cunha Leme Filho, Jose Franco; Thomason, Wade E.; Evanylo, Gregory K.; Zhang, Xunzhong; Strickland, Michael S.; Chim, Bee K.; Diatta, Andre A. (2021-03-16)
    Current trends in agriculture have moved toward more sustainable cultivation systems with higher efficiency of input use. A variety of materials, derived from different resources, can serve as a crop nutrient sources. An Integrated Plant Nutrition System (IPNS) uses the combined and harmonious use of inorganic, organic and biological nutrient resources to maximize efficiency of inputs. We evaluated the effects of commercial nitrogen (N) fertilizer, humic acid compounds (HA), compost/manure teas and bioinoculants as inorganic, organic and biological resources, respectively and their synergy over three years on corn (Zea mays L.) in the Mid-Atlantic USA. The individual and combined application of HA and biofertilizer following the IPNS influenced corn height and leaf greenness to varying degrees, most likely due to biostimulant effects. In 2017, corn height, NDVI, greenness and vigor responded positively to biostimulant application to varying magnitudes and growth stages, however grain yield and nutrient content were not affected. In combined studies from 2018 and 2019 corn height was not impacted by biostimulant application but NDVI, photosynthetic efficiency, greenness and vigor were increased at different doses and corn growth stages. The combined use of HA + biofertilizer (Microlife Humic + Microgeo) was the only treatment leading to increased grain yield. This study demonstrates that the individual and combined application of HA and biofertilizer can influence corn growth and vigor at various points during the growing season. However, the current study cannot conclusively confirm that the integrated use of HA and biofertilizers (IPNS) is a better practice than the application of each compound individually.