Enhanced phosphorus fertilizers (Carbond P® and Avail®) supplied to maize in hydroponics

Summerhays, Jeffrey S.; Jolley, Von D.; Hill, Michael W.; Hopkins, Bryan G.

doi:10.1080/01904167.2017.1384007

Cited by 8 publications

(13 citation statements)

References 27 publications

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“…If the crop did not respond to P, it can be concluded that it would be unlikely to respond to a P fertilizer enhancer (Hopkins, 2015;Summerhays et al, 2017).…”

Section: Resultsmentioning

confidence: 99%

“…We see evidence of this with other chemicals, such as with organic acids (Hopkins, 2015;Tan, 2014). This bond would have to be strong enough to prevent reaction with soil cations and yet be able to release the P at the root surface and/or internally.…”

Section: Mode Of Actionmentioning

confidence: 98%

“…It is also clear that this mode of action is related to P nutrition and not biostimulating effects (Dudenhoeffer et al, 2012;Guertal and Howe, 2013;Summerhays et al, 2017). Several have suggested that the proposed mode of action for AVAIL is not theoretically practical (Karamanos and Puurveen, 2011;Chien et al, 2014;Chien and Rehm, 2016).…”

Section: Mode Of Actionmentioning

confidence: 99%

“…Research at the University of Wisconsin (Carrie A.M. Laboski, personal communication, 2010;Murphy and Sanders, 2007) found that AVAIL-coated fertilizer increased P solubility in soil solution through the middle of the season when applied to potato. In a hydroponics study, Summerhays et al (2017) found adding AVAIL did not affect maize (Zea mays L.) biomass yields, suggesting: (i) AVAIL is nontoxic to plants at the label rates, (ii) AVAIL does not stimulate physiological growth in the presence of ample nutrients, and (iii) any impact AVAIL has on P uptake and plant growth must be related to impacts on soil P chemistry. Although there have been various claims about the plant physiological effects of AVAIL, such as being a biostimulant, there is no evidence for such claims in the scientific literature.…”

Section: Core Ideasmentioning

confidence: 99%

“…Thus, rather than concluding that many previous studies found no yield response from AVAIL because the proposed mode of action was incorrect, our results indicate that there was often no yield response because AVAIL was frequently evaluated under such conditions where no effect would be expected. Assuming the only benefit of the polymer is enhanced soil P solubility (Summerhays et al, 2017), it would be expected that adding any material which increases P solubility would not benefit the crop if the response plateau had already been reached. Dunn and Stevens (2008) and Hopkins (2013) showed responses to AVAIL at low P rates, but the effect disappeared at higher rates.…”

Section: How Should Phosphorus Use Efficiencymentioning

confidence: 99%

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AVAIL Phosphorus Fertilizer Enhancer: Meta‐Analysis of 503 Field Evaluations

et al. 2018

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Core Ideas Meta‐analysis shows a significant yield increase of 2.1% with AVAIL+P fertilizer.Many AVAIL studies were not conducted under P responsive conditions.Likelihood of response increases with low soil test P and P rate and extreme pH.Average yield response increases to 4.6% when only likely to respond sites included.Enhanced efficiency fertilizer should be evaluated under P responsive conditions. AVAIL, a maleic‐itaconic copolymer acid marketed to enhance P fertilizers, has been studied on a variety of crop species. Data from all known field studies comparing P fertilization with and without AVAIL was amassed into a meta‐analysis of 503 field observations. The average yield increase was a modest, although statistically significant, 2.1% (P < 0.0001). However, only 116 of these observations were conducted under conditions where a positive yield response to a P enhancement product would be expected– that is, low soil test phosphorus (STP), strong alkaline or acid pH, and low P fertilizer rate. As such, the data was parsed into a subset of only those observations that were evaluated under responsive conditions, resulting in a greater magnitude of a yield response to AVAIL at 4.6% (P < 0.0001). Further parsing of the data, by eliminating any data not published in refereed or thesis/dissertation sources resulted in an average increase of 5.8% (P = 0.0039). AVAIL effectively increased yields when used appropriately under conditions where a P response was expected. Testing enhanced efficiency fertilizer products in a variety of conditions is useful, but the conclusions from the multitude of studies with AVAIL in environments where no response to P fertilizer enhancement product would be expected may lead to erroneous conclusions if the data is not further parsed and categorized. These data demonstrate the importance of applying fundamental soil fertility principles when designing and evaluating fertilizer crop response studies.

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“…If the crop did not respond to P, it can be concluded that it would be unlikely to respond to a P fertilizer enhancer (Hopkins, 2015;Summerhays et al, 2017).…”

Section: Resultsmentioning

confidence: 99%

Section: Mode Of Actionmentioning

confidence: 98%

Section: Mode Of Actionmentioning

confidence: 99%

Section: Core Ideasmentioning

confidence: 99%

Section: How Should Phosphorus Use Efficiencymentioning

confidence: 99%

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AVAIL Phosphorus Fertilizer Enhancer: Meta‐Analysis of 503 Field Evaluations

et al. 2018

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Purple nutsedge management in tomato plasticulture: A study on the effectiveness of preemergence herbicide S‐metolachlor and its co‐application with fertilizer enhancer and chelated iron

Tiwari,

Sapkota,

Boyd

et al. 2024

Agrosystems Geosci & Env

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Purple nutsedge (Cyperus rotundus L.) poses a significant challenge to Florida tomato (Solanum lycopersicum L.) producers due to its ability to puncture plastic mulch, resilient tubers, and rapid rhizome proliferation. Preemergence herbicides effectively suppress purple nutsedge in tomatoes under plastic mulch. Although the impact of co‐application of herbicides with fertilizers has been studied in row crops, its potential in vegetable plasticulture systems remains unexplored. This study aimed to evaluate the effectiveness and crop safety of the preemergence herbicide S‐metolachlor, both as a standalone treatment and in combination with a fertilizer enhancer or chelated iron in tomato plasticulture. Field trials at the University of Florida's Southwest Florida Research and Education Center, Immokalee, FL, involved applying S‐metolachlor at the recommended rate of 1 kg a.i. ha−1 on raised beds before installing plastic mulch. The herbicide was applied as a blanket spray alone, mixed with fertilizer enhancer, and coated on chelated iron fertilizer. Results indicate that using S‐metolachlor alone effectively reduced purple nutsedge density compared to the nontreated control in both trials I and II. Combining S‐metolachlor with fertilizer enhancer or chelated iron resulted in a >30% and 57% reduction in purple nutsedge density, respectively, compared to the nontreated control in trial II. These treatments did not adversely impact chlorophyll content or crop yield (p > 0.05) compared to the nontreated control. Notably, tomato yield significantly (p < 0.05) decreased with increased purple nutsedge density at 4, 8, and 12 weeks after transplanting. Overall, the results from both trials suggest that using S‐metolachlor is an effective approach to reduce purple nutsedge infestation in plastic‐mulched raised beds without negatively impacting tomato health and productivity.

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