Abstract
Biochar addition to agricultural soils can improve soil fertility, with the added bonus of climate change mitigation through carbon sequestration. Conservation farming (CF) is precision farming, often combining minimum tillage, crop rotation and residue retention. In the present farmer-led field trials carried out in Zambia, the use of a low dosage biochar combined with CF minimum tillage was tested as a way to increase crop yields. Using CF minimum tillage allows the biochar to be applied to the area where most of the plant roots are present and mirrors the fertilizer application in CF practices. The CF practice used comprised manually hoe-dug planting 10-L sized basins, where 10%–12% of the land was tilled. Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics. At a dosage as low as 4 tons/ha, both biochars had a strong positive effect on maize yields in the coarse white aeolian sand of Kaoma, West-Zambia, with yields of 444% ± 114% (p = 0.06) and 352% ± 139% (p = 0.1) of the fertilized reference plots for maize and wood biochar, respectively. Thus for sandy acidic soils, CF and biochar amendment can be a promising combination for increasing harvest yield. Moderate but non-significant effects on yields were observed for maize and wood biochar in a red sandy clay loam ultisol east of Lusaka, central Zambia (University of Zambia, UNZA, site) with growth of 142% ± 42% (p > 0.2) and 131% ± 62% (p > 0.2) of fertilized reference plots, respectively. For three other soils (acidic and neutral clay loams and silty clay with variable cation exchange capacity, CEC), no significant effects on maize yields were observed (p > 0.2). In laboratory trials, 5% of the two biochars were added to the soil samples in order to study the effect of the biochar on physical and chemical soil characteristics. The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an increased base saturation (from <50% to 60%–100%) and cation exchange capacity (CEC; from 2–3 to 5–9 cmol/kg) and increased plant-available water (from 17% to 21%) as well as water vapor uptake (70 mg/g on maize cob biochar at 50% relative humidity).
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Claims 11
Claim · model-written summary
Maize cob biochar at 4 t/ha increased maize yield to 444% ± 114% of the fertilized reference plots in Kaoma sandy soil.
- Treatment
- maize cob biochare1
- Outcome
- maize yieldse0
- Direction
- increaseinferrede0
- Value
- 444% ± 114%e0
- Qualifier
- p = 0.06e0
- Comparator
- fertilized reference plotse0
- Setting
- coarse white aeolian sand of Kaoma, West-Zambiae0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At a dosage as low as 4 tons/ha, both biochars had a strong positive effect on maize yields in the coarse white aeolian sand of Kaoma, West-Zambia, with yields of 444% ± 114% (p = 0.06) and 352% ± 139% (p = 0.1) of the fertilized reference plots for maize and wood biochar, respectively”
e1“Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics”
Claim · model-written summary
Wood biochar at 4 t/ha increased maize yield to 352% ± 139% of the fertilized reference plots in Kaoma sandy soil.
- Treatment
- wood biochare1
- Outcome
- maize yieldse0
- Direction
- increaseinferrede0
- Value
- 352% ± 139%e0
- Qualifier
- p = 0.1e0
- Comparator
- fertilized reference plotse0
- Setting
- coarse white aeolian sand of Kaoma, West-Zambiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At a dosage as low as 4 tons/ha, both biochars had a strong positive effect on maize yields in the coarse white aeolian sand of Kaoma, West-Zambia, with yields of 444% ± 114% (p = 0.06) and 352% ± 139% (p = 0.1) of the fertilized reference plots for maize and wood biochar, respectively”
e1“Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics”
Claim · model-written summary
Conservation farming with biochar amendment can be a promising combination for increasing maize harvest yield in sandy acidic soils.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Thus for sandy acidic soils, CF and biochar amendment can be a promising combination for increasing harvest yield”
t0“Biochar Effect on Maize Yield and Soil Characteristics in Five Conservation Farming Sites in Zambia”
Claim · model-written summary
Maize cob biochar gave a non-significant increase in maize yield to 142% ± 42% of the fertilized reference plots east of Lusaka.
- Treatment
- maize cob biochare1
- Outcome
- yieldse3
- Direction
- increaseinferrede3
- Value
- 142% ± 42%e3
- Qualifier
- p > 0.2e3
- Comparator
- fertilized reference plotse3
- Setting
- east of Lusaka, central Zambiae3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Moderate but non-significant effects on yields were observed for maize and wood biochar in a red sandy clay loam ultisol east of Lusaka, central Zambia (University of Zambia, UNZA, site) with growth of 142% ± 42% (p > 0.2) and 131% ± 62% (p > 0.2) of fertilized reference plots, respectively”
e1“Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics”
Claim · model-written summary
Wood biochar gave a non-significant increase in maize yield to 131% ± 62% of the fertilized reference plots east of Lusaka.
- Treatment
- wood biochare1
- Outcome
- yieldse3
- Direction
- increaseinferrede3
- Value
- 131% ± 62%e3
- Qualifier
- p > 0.2e3
- Comparator
- fertilized reference plotse3
- Setting
- east of Lusaka, central Zambiae3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Moderate but non-significant effects on yields were observed for maize and wood biochar in a red sandy clay loam ultisol east of Lusaka, central Zambia (University of Zambia, UNZA, site) with growth of 142% ± 42% (p > 0.2) and 131% ± 62% (p > 0.2) of fertilized reference plots, respectively”
e1“Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics”
Claim · model-written summary
Maize cob and wood biochar had no significant effect on maize yields in three other soils.
- Treatment
- maize cob biochar and wood biochare1
- Outcome
- maize yieldse4
- Direction
- no_changeinferrede4
- Qualifier
- p > 0.2e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“For three other soils (acidic and neutral clay loams and silty clay with variable cation exchange capacity, CEC), no significant effects on maize yields were observed (p > 0.2)”
e1“Pilot trials were performed with maize cob biochar and wood biochar on five soils with variable physical/chemical characteristics”
Claim · model-written summary
The large increase in maize yield in Kaoma soil was tentatively explained by an increased base saturation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an increased base saturation (from <50% to 60%–100%) and cation exchange capacity (CEC; from 2–3 to 5–9 cmol/kg) and increased plant-available water (from 17% to 21%) as well as water vapor uptake (70 mg/g on maize cob biochar at 50% relative humidity)”
t0“Biochar Effect on Maize Yield and Soil Characteristics in Five Conservation Farming Sites in Zambia”
Claim · model-written summary
Base saturation of the Kaoma soil increased from below 50% to 60%–100% after biochar.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an increased base saturation (from <50% to 60%–100%) and cation exchange capacity (CEC; from 2–3 to 5–9 cmol/kg) and increased plant-available water (from 17% to 21%) as well as water vapor uptake (70 mg/g on maize cob biochar at 50% relative humidity)”
t0“Biochar Effect on Maize Yield and Soil Characteristics in Five Conservation Farming Sites in Zambia”
Claim · model-written summary
Cation exchange capacity of the Kaoma soil increased from 2–3 to 5–9 cmol/kg after biochar.
- Outcome
- cation exchange capacitye5
- Direction
- increaseinferrede5
- Value
- from 2–3 to 5–9 cmol/kge5
- Setting
- Kaoma soile5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an increased base saturation (from <50% to 60%–100%) and cation exchange capacity (CEC; from 2–3 to 5–9 cmol/kg) and increased plant-available water (from 17% to 21%) as well as water vapor uptake (70 mg/g on maize cob biochar at 50% relative humidity)”
t0“Biochar Effect on Maize Yield and Soil Characteristics in Five Conservation Farming Sites in Zambia”
Claim · model-written summary
Plant-available water of the Kaoma soil increased from 17% to 21% after biochar.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an increased base saturation (from <50% to 60%–100%) and cation exchange capacity (CEC; from 2–3 to 5–9 cmol/kg) and increased plant-available water (from 17% to 21%) as well as water vapor uptake (70 mg/g on maize cob biochar at 50% relative humidity)”
t0“Biochar Effect on Maize Yield and Soil Characteristics in Five Conservation Farming Sites in Zambia”
Claim · model-written summary
Maize cob biochar took up 70 mg/g of water vapor at 50% relative humidity.
- Material
- maize cob biochare5
- Outcome
- water vapor uptakee5
- Value
- 70 mg/ge5
- Qualifier
- at 50% relative humiditye5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“The large increase in crop yield in Kaoma soil was tentatively explained by a combination of an increased base saturation (from <50% to 60%–100%) and cation exchange capacity (CEC; from 2–3 to 5–9 cmol/kg) and increased plant-available water (from 17% to 21%) as well as water vapor uptake (70 mg/g on maize cob biochar at 50% relative humidity)”
t0“Biochar Effect on Maize Yield and Soil Characteristics in Five Conservation Farming Sites in Zambia”
The same questions in other papers
biochar · yield · Zea mays (maize)Positive and negative results
174 papers in the same direction as this paper · 15 in the opposite direction · 3 reporting no difference from an alternative
- negative
- no effect
- positive
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