Odhiambo, J. J. O.Lusiba, S. G.Khethani, Thakhani2024-10-182024-10-182024-09-06Khethani, T. 2024. Effect of biochar derived from different feedstocks on nitrogen retention availability, and uptake by a maize crop. . .https://univendspace.univen.ac.za/handle/11602/2739MSCAGR (Soil Science)Department of Plant and Soil SciencesNitrogen (N) is an essential nutrient for most crops and can be provided directly by fertilisation or indirectly through atmospheric deposition, fixation, all of which can then be converted to nitrate through mineralization and nitrification. Incomplete N utilisation by crops leaves residual soil nitrate, which is water soluble and susceptible to leaching into groundwater, particularly in regions dominated by light-textured sandy soils with low WHC. Application of biochar (BC) can potentially have a significant impact on nitrogen retention and availability. BC is a charcoal-like substance that’s made by burning organic material from agricultural and forestry wastes (also called biomass) in a controlled process called pyrolysis. Biochar can increase organic matter content, act as a liming agent, add basic cations and micronutrients, improve water holding capacity, and release nutrients gradually to the growing plant. This study evaluated the effect of BC derived from different feedstock on nitrogen retention and availability. Two experiments’, laboratory (column leachate) and nursery experiments were conducted at the University of Venda Soil Science Laboratory and the School of Agriculture Experimental Farm, respectively. The treatments in both experiments 1 and 2 consisted of a factorial combination of BC from three different feedstocks (acacia, hay, and poultry litter) and three BC application rates (0%, 1%, and 2%). In experiment 1, the levels of NH4+ and NO3- leached from and retained in the soil were determined in the laboratory experiment before and after 70-day leaching period. The columns were first filled with three kilograms of the soil-BC mixture based on the previously mentioned treatments, giving rise to an initial bulk density of roughly 1.5 g/cm3. A single fertiliser application with 100 mg of solutioned ammonium nitrate (NH4NO3) was applied to each column. The fertilizer was applied to each column's surface in uniform drips after being diluted in 5 millilitres of distilled water. In the laboratory, the columns were maintained at room temperature, or roughly 23 °C. Every two weeks, 200 ml of distilled water was added to each column through a funnel that was placed above the center of each column. To aid in the dispersal of the water drips, filter papers were placed on the soil surface of the columns. Columns were allowed to drain freely during the leaching process, and all leachate samples were collected in foil-wrapped Erlenmeyer flasks to minimize evaporative loss. For 10 weeks (seventy days), columns were leached every two weeks. Every two weeks, the leachates were collected and chilled before analysis to minimize the growth of algae. Leachates were collected every two weeks, and the pH and electrical conductivity (EC) were measured. The leachate samples were then filtered through Whatman No. 42 filter paper to measure the amounts of nitrite (NO3-) and ammonium (NH4+). In experiment 2, which was conducted in a nursery, 5 kg of soil was placed in pots measuring 25 cm in height and 25 cm in diameter. Maize (Zea mays L.) was used as a test crop and harvested 56 days after planting. xviii The measurements made in this experiment were dry matter (kg) and nitrogen uptake (kg/ha). A uniform application of nitrogen fertilizer (LAN) at a rate of 100 kg N/ha was given to each pot. The soils were treated with BC as per the stated application rates and ammonium nitrate fertilizer one week prior to planting. The treatments were arranged in a completely random design (CRD) The pots were wetted to 60% field capacity (FC) and allowed to dry out for 24 hours prior to planting. Three maize seeds were planted in each pot. After watering, the pots were filled to 60% of their field capacity (FC). After being allowed to develop for a maximum of eight weeks (56 days), maize crops were collected, dried, weighed, ground, and the N content determined. In experiment 1, the current study's findings show that using BC can significantly reduce the leaching of highly mobile nutrients like NH4+ and NO3-. The total amount of leachates collected increased by 46% and 42% at the 1% and 2% biochar application rates, respectively. The amount of ammonium and nitrate retained increased by 1.62% and 16.2% at a 2% rate of application, respectively. In comparison to the control, where no BC was added, BC significantly reduced ammonium leaching at 1% on days 56-70 and 2% (w/w) in BC-amended soils. Biochar increased EC in all BT and retained NH4+ and NO3-. In experiment 2, this study has shown that feedstock type significantly affects biomass accumulation and N uptake. Biomass yield and N uptake increased in the order poultry litter > acacia > hay. Increasing biochar rates from 0 to 2% increased biomass accumulation and N uptake. In summary, biochar type and rate of application have a potential effect on N leaching and retention in the soil, as well as the biomass and N uptake and therefore these factors should be considered when biochar is used as a soil amendment, especially for N management in agricultural systems.1 online resource (xxv, 44 leaves)enUniversity of VendaBiocharNotrogen (N)UCTDNitrogen retentionNitrogen availabilityDissertationKhethani T. Effect of biochar derived from different feedstocks on nitrogen retention availability, and uptake by a maize crop. []. , 2024 [cited yyyy month dd]. Available from:Khethani, T. (2024). <i>Effect of biochar derived from different feedstocks on nitrogen retention availability, and uptake by a maize crop</i>. (). . Retrieved fromKhethani, Thakhani. <i>"Effect of biochar derived from different feedstocks on nitrogen retention availability, and uptake by a maize crop."</i> ., , 2024.TY - Dissertation AU - Khethani, Thakhani AB - Nitrogen (N) is an essential nutrient for most crops and can be provided directly by fertilisation or indirectly through atmospheric deposition, fixation, all of which can then be converted to nitrate through mineralization and nitrification. Incomplete N utilisation by crops leaves residual soil nitrate, which is water soluble and susceptible to leaching into groundwater, particularly in regions dominated by light-textured sandy soils with low WHC. Application of biochar (BC) can potentially have a significant impact on nitrogen retention and availability. BC is a charcoal-like substance that’s made by burning organic material from agricultural and forestry wastes (also called biomass) in a controlled process called pyrolysis. Biochar can increase organic matter content, act as a liming agent, add basic cations and micronutrients, improve water holding capacity, and release nutrients gradually to the growing plant. This study evaluated the effect of BC derived from different feedstock on nitrogen retention and availability. Two experiments’, laboratory (column leachate) and nursery experiments were conducted at the University of Venda Soil Science Laboratory and the School of Agriculture Experimental Farm, respectively. The treatments in both experiments 1 and 2 consisted of a factorial combination of BC from three different feedstocks (acacia, hay, and poultry litter) and three BC application rates (0%, 1%, and 2%). In experiment 1, the levels of NH4+ and NO3- leached from and retained in the soil were determined in the laboratory experiment before and after 70-day leaching period. The columns were first filled with three kilograms of the soil-BC mixture based on the previously mentioned treatments, giving rise to an initial bulk density of roughly 1.5 g/cm3. A single fertiliser application with 100 mg of solutioned ammonium nitrate (NH4NO3) was applied to each column. The fertilizer was applied to each column's surface in uniform drips after being diluted in 5 millilitres of distilled water. In the laboratory, the columns were maintained at room temperature, or roughly 23 °C. Every two weeks, 200 ml of distilled water was added to each column through a funnel that was placed above the center of each column. To aid in the dispersal of the water drips, filter papers were placed on the soil surface of the columns. Columns were allowed to drain freely during the leaching process, and all leachate samples were collected in foil-wrapped Erlenmeyer flasks to minimize evaporative loss. For 10 weeks (seventy days), columns were leached every two weeks. Every two weeks, the leachates were collected and chilled before analysis to minimize the growth of algae. Leachates were collected every two weeks, and the pH and electrical conductivity (EC) were measured. The leachate samples were then filtered through Whatman No. 42 filter paper to measure the amounts of nitrite (NO3-) and ammonium (NH4+). In experiment 2, which was conducted in a nursery, 5 kg of soil was placed in pots measuring 25 cm in height and 25 cm in diameter. Maize (Zea mays L.) was used as a test crop and harvested 56 days after planting. xviii The measurements made in this experiment were dry matter (kg) and nitrogen uptake (kg/ha). A uniform application of nitrogen fertilizer (LAN) at a rate of 100 kg N/ha was given to each pot. The soils were treated with BC as per the stated application rates and ammonium nitrate fertilizer one week prior to planting. The treatments were arranged in a completely random design (CRD) The pots were wetted to 60% field capacity (FC) and allowed to dry out for 24 hours prior to planting. Three maize seeds were planted in each pot. After watering, the pots were filled to 60% of their field capacity (FC). After being allowed to develop for a maximum of eight weeks (56 days), maize crops were collected, dried, weighed, ground, and the N content determined. In experiment 1, the current study's findings show that using BC can significantly reduce the leaching of highly mobile nutrients like NH4+ and NO3-. The total amount of leachates collected increased by 46% and 42% at the 1% and 2% biochar application rates, respectively. The amount of ammonium and nitrate retained increased by 1.62% and 16.2% at a 2% rate of application, respectively. In comparison to the control, where no BC was added, BC significantly reduced ammonium leaching at 1% on days 56-70 and 2% (w/w) in BC-amended soils. Biochar increased EC in all BT and retained NH4+ and NO3-. In experiment 2, this study has shown that feedstock type significantly affects biomass accumulation and N uptake. Biomass yield and N uptake increased in the order poultry litter > acacia > hay. Increasing biochar rates from 0 to 2% increased biomass accumulation and N uptake. In summary, biochar type and rate of application have a potential effect on N leaching and retention in the soil, as well as the biomass and N uptake and therefore these factors should be considered when biochar is used as a soil amendment, especially for N management in agricultural systems. DA - 2024-09-06 DB - ResearchSpace DP - Univen KW - Biochar KW - Notrogen (N) KW - Nitrogen retention KW - Nitrogen availability LK - https://univendspace.univen.ac.za PY - 2024 T1 - Effect of biochar derived from different feedstocks on nitrogen retention availability, and uptake by a maize crop TI - Effect of biochar derived from different feedstocks on nitrogen retention availability, and uptake by a maize crop UR - ER -