Abstract
An interesting feedstock for energy purposes is plant biomass due to its renewability, widespread availability and relatively low cost. One plant with a high and versatile use potential is maize. Plants used for energy production can be grown in polluted areas, e.g., with iron. The aim of the study was to determine the effect of humic acids (HAs) on the yield, calorific value and other energy parameters and chemical composition of maize biomass applied as a phytostabiliser on iron-contaminated soil. The soil was contaminated with iron at 0, 250, 500 and 750 mg kg−1. The HAs were added to the soil in the following amounts: 0, 0.3, 0.6 and 0.9 g kg−1 of soil. Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass and very strongly reduced plant height (42%), dry matter yield (95%) and energy production of maize biomass (90%), the SPAD index at the fifth leaf unfolded stage (44%) (as opposed to the stem elongation stage), sodium, magnesium and phosphorus contents, and increased calcium, potassium and nitrogen contents of maize. The application of HAs to the soil had a positive and very large effect on both the height and biomass parameters studied, resulting in an increase in plant height (22%), dry matter yield (67%) and energy production from maize biomass (62%). Changes in the heat of combustion and calorific value of the biomass were minimal but positive. HAs contributed to a decrease in the value of the SPAD index during the stem elongation phase of maize and in the content of all macronutrients in maize biomass as a result of a reduction in the effect of iron on macronutrient content and to a significant increase in maize dry matter yield in plots with their application. The application of HAs appears to be an effective adjunct in the phytostabilisation of iron-contaminated soils by growing crops for energy purposes.
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Claims 14
Claim · model-written summary
Soil iron contamination had relatively little effect on the heat of combustion and calorific value of maize biomass.
- Treatment
- Soil contamination with irone1
- Outcome
- heat of combustion and calorific value of biomasse1
- Qualifier
- relatively little effecte1
Zea maysNot reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass”
e2“a high and versatile use potential is maize”
Claim · model-written summary
Soil iron contamination very strongly reduced maize plant height by 42%.
- Treatment
- Soil contamination with irone1
- Outcome
- plant heighte1
- Direction
- very strongly reducede1
- Value
- 42%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass and very strongly reduced plant height (42%), dry matter yield (95%) and energy production of maize biomass (90%), the SPAD index at the fifth leaf unfolded stage (44%) (as opposed to the stem elongation stage), sodium, magnesium and phosphorus contents, and increased calcium, potassium and nitrogen contents of maize”
Claim · model-written summary
Soil iron contamination very strongly reduced maize dry matter yield by 95%.
- Treatment
- Soil contamination with irone1
- Outcome
- dry matter yielde1
- Direction
- very strongly reducede1
- Value
- 95%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass and very strongly reduced plant height (42%), dry matter yield (95%) and energy production of maize biomass (90%), the SPAD index at the fifth leaf unfolded stage (44%) (as opposed to the stem elongation stage), sodium, magnesium and phosphorus contents, and increased calcium, potassium and nitrogen contents of maize”
Claim · model-written summary
Soil iron contamination very strongly reduced energy production of maize biomass by 90%.
- Treatment
- Soil contamination with irone1
- Outcome
- energy production of maize biomasse1
- Direction
- very strongly reducede1
- Value
- 90%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass and very strongly reduced plant height (42%), dry matter yield (95%) and energy production of maize biomass (90%), the SPAD index at the fifth leaf unfolded stage (44%) (as opposed to the stem elongation stage), sodium, magnesium and phosphorus contents, and increased calcium, potassium and nitrogen contents of maize”
Claim · model-written summary
Soil iron contamination very strongly reduced the SPAD index of maize at the fifth leaf unfolded stage by 44%, as opposed to the stem elongation stage.
- Organ / stage
- fifth leaf unfolded stagee1
- Treatment
- Soil contamination with irone1
- Outcome
- SPAD indexe1
- Direction
- very strongly reducede1
- Value
- 44%e1
- Qualifier
- as opposed to the stem elongation stagee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass and very strongly reduced plant height (42%), dry matter yield (95%) and energy production of maize biomass (90%), the SPAD index at the fifth leaf unfolded stage (44%) (as opposed to the stem elongation stage), sodium, magnesium and phosphorus contents, and increased calcium, potassium and nitrogen contents of maize”
Claim · model-written summary
Soil iron contamination decreased sodium, magnesium and phosphorus contents of maize.
- Treatment
- Soil contamination with irone1
- Outcome
- sodium, magnesium and phosphorus contentse1
- Direction
- very strongly reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass and very strongly reduced plant height (42%), dry matter yield (95%) and energy production of maize biomass (90%), the SPAD index at the fifth leaf unfolded stage (44%) (as opposed to the stem elongation stage), sodium, magnesium and phosphorus contents, and increased calcium, potassium and nitrogen contents of maize”
Claim · model-written summary
Soil iron contamination increased calcium, potassium and nitrogen contents of maize.
- Treatment
- Soil contamination with irone1
- Outcome
- calcium, potassium and nitrogen contentse1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Soil contamination with iron had relatively little effect on the heat of combustion and calorific value of biomass and very strongly reduced plant height (42%), dry matter yield (95%) and energy production of maize biomass (90%), the SPAD index at the fifth leaf unfolded stage (44%) (as opposed to the stem elongation stage), sodium, magnesium and phosphorus contents, and increased calcium, potassium and nitrogen contents of maize”
Claim · model-written summary
Humic acid application increased maize plant height by 22%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The application of HAs to the soil had a positive and very large effect on both the height and biomass parameters studied, resulting in an increase in plant height (22%), dry matter yield (67%) and energy production from maize biomass (62%)”
Claim · model-written summary
Humic acid application increased maize dry matter yield by 67%, a significant increase.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The application of HAs to the soil had a positive and very large effect on both the height and biomass parameters studied, resulting in an increase in plant height (22%), dry matter yield (67%) and energy production from maize biomass (62%)”
Claim · model-written summary
Humic acid application increased energy production from maize biomass by 62%.
- Treatment
- application of HAs to the soile1
- Outcome
- energy production from maize biomasse1
- Direction
- increasee1
- Value
- 62%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The application of HAs to the soil had a positive and very large effect on both the height and biomass parameters studied, resulting in an increase in plant height (22%), dry matter yield (67%) and energy production from maize biomass (62%)”
Claim · model-written summary
Humic acid application changed the heat of combustion and calorific value of maize biomass minimally but positively.
- Treatment
- The application of HAs to the soile3
- Outcome
- heat of combustion and calorific value of the biomasse1
- Direction
- increaseinferrede1
- Qualifier
- minimal but positivee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Changes in the heat of combustion and calorific value of the biomass were minimal but positive”
e2“a high and versatile use potential is maize”
e3“The application of HAs to the soil”
Claim · model-written summary
Humic acids decreased the SPAD index of maize during the stem elongation phase.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“HAs contributed to a decrease in the value of the SPAD index during the stem elongation phase of maize”
Claim · model-written summary
Humic acids decreased the content of all macronutrients in maize biomass, as a result of a reduced effect of iron on macronutrient content.
- Treatment
- HAse1
- Outcome
- content of all macronutrients in maize biomasse1
- Direction
- decreasee1
- Qualifier
- as a result of a reduction in the effect of iron on macronutrient contente1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“HAs contributed to a decrease in the value of the SPAD index during the stem elongation phase of maize and in the content of all macronutrients in maize biomass as a result of a reduction in the effect of iron on macronutrient content”
Claim · model-written summary
Humic acid application appears to be an effective adjunct in phytostabilisation of iron-contaminated soils by growing maize for energy.
- Outcome
- phytostabilisation of iron-contaminated soilse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The application of HAs appears to be an effective adjunct in the phytostabilisation of iron-contaminated soils by growing crops for energy purposes”
e2“a high and versatile use potential is maize”
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