master seminar on role of biochar on enhancing the crop productivity.pptx

the presentation discusses the role of biochar in enhancing crop productivity and heavy metal remediation. Soil contamination with heavy metals is a major concern due to its harmful effects on soil, microbial diversity, groundwater, and agricultural productivity, ultimately affecting human health and environment (Gogoi et al., 2021). Managing heavy metal is a bit difficult due to its persistent nature. On the other hand, intensive agricultural practices such as indiscriminate use of agrochemicals over the years have led to soil degradation, reducing crop yield. Suitable management options need to be explored to enhance crop yield sustainably. In this situation, biochar, a multipurpose carbonaceous material, has shown concurrently promising results in improving crop yield regardless of standard or stressful conditions and managing the heavy metals from the soil. Biochar refers to the carbon-rich solid product when biomass is thermally decomposed under anoxic conditions i.e., pyrolysis (Lehmann et al., 2006). It has a highly porous structure, a large surface area, and plenty of surface functional groups. Due to such properties, biochar plays a prominent role in immobilizing heavy metals and reduces their bioavailability in soil. Possible mechanisms for heavy metal remediation include: 1) direct/non-mediated mechanisms i.e., ion exchange, electrostatic attraction, precipitation and complexation, 2) indirect/ mediated mechanism i.e., reduced mobility of heavy metal as a result of biochar impact on pH, CEC, mineral composition and soil organic carbon in soil (Mansoor et al., 2021). The application of lantana biochar has reduced the available heavy metals Zn, Ni, Co, Cu, Mn, Cd, and Pb contents by 48.4%, 41.4%, 36.9%, 35.7%, 34.3%, 33.2% and 30.4% respectively in soil due to surface adsorption and precipitation caused by an increase in soil pH (Masto et al., 2013). Abbas et al. (2017) reported that as compared to the control, Cd concentration in wheat grains decreased by 26%, 42% and 57% after the application of 1.5%, 3.0%, and 5.0% rice straw biochar, respectively. The adsorption capacity of biochar can be further enhanced by chemical and physical modification (Wang and Wang, 2019). Biochar application improves water and nutrition retention in soil, promotes microbial activity and creates a fertile environment that is favourable for plant growth and development. Pandian et al. (2016) reported that applying biochar to acidic red soil favoured good soil physical, chemical and biological environment, and these positive changes influenced growth and yield attributes and yield. Given the numerous benefits of biochar, the government should establish policies to encourage its application in soil.
Keywords: Heavy metal, crop yield, biochar, soil.


References
Abbas, T., Rizwan, M., Ali, S., Zia-ur-Rehman, M., Qayyum, M. F., Abbas, F., ... & Ok, Y. S. (2017). Effect of biochar on cadmium bioavailability and uptake in wheat (Triticum aestivum L.) grown in a soi

1. Treatment N uptake (Kg/ha) P uptake (Kg/ha) K uptake (Kg/ha) Kernal yield (t/ha) Stover yield (t/ha) Benefit-cost ratio 2018 2109 2018 2109 2018 2109 2018 2109 2018 2109 2018 2109 Biochar Control 87.0 88.0 14.4 14.8 70.1 69.9 3.53 3.69 5.41 5.48 1.26 1.30 Biochar @ 5 t/ha 113.2 113.5 17.9 18.2 92.2 91.4 3.93 4.06 6.49 6.53 1.11 1.14 Biochar @ 10 t/ha 128.3 129.1 20.1 20.3 103.5 104.5 4.14 4.21 6. 79 6.99 0.90 0.90 Biochar @ 15 t/ha 141.8 140.4 23.8 23.6 115.9 114.0 4.43 4.49 7.02 7.07 0.76 0.76 SEm ± 3.61 4.75 0.47 0.39 2.79 2.90 0.07 0.08 0.16 0. 15 0.01 0.02 CD (P=0.05) 10.5 12.0 1.32 1.42 7.29 7.74 0.20 0.26 0.45 0.42 0.06 0.07 INM 100% RDN 117.7 110.5 18.7 17.3 95.5 90.4 4.01 3.98 6.41 6.40 1.12 1.14 75% RDN + 25% FYM 125.6 117.8 21.4 18.8 100.7 95.4 4.15 4.10 6.56 6.52 1.07 1.09 50% RDN + 50% FYM 109.5 125.1 17.1 21.5 90.2 99.1 3.87 4.25 6.31 6.63 0.83 0.85 SEm ± 3.53 4.63 0.44 0.35 2.69 2.78 0.06 0.07 0.14 0.16 0.01 0.01 CD (P=0.05) 9.20 11.6 1.30 1.34 7.85 7.24 0.21 0.40 0.40 0.48 0.05 0.06 INM: Integrated nutrient management; FYM: farm yard manure; RDN : recommended dose of nitrogen Indian Journal of Agronomy Umiam , Meghalaya Gudade et al ., 2022 Fig. 18: Effects of biochar levels and integrated-nutrient-management practices on total nutrient uptake, yield and economics of maize crop

2. CONTENT Introduction Biochar and its Importance Production of biochar Properties of biochar Application method Enhancing crop productivity H eavy metal remediation Modified biochar Research findings Fu ture prospective Conclusion

3. INTRODUCTION At present day agriculture is challenged to fulfil two main objectives - Achieving food security for the ever-growing population. Attaining sustainability with an emphasis on preserving and restoring soil and natural resources, improving soil quality and mitigating climate change. The sustenance of soil resources is f urther challenged by the accumulation of heavy metals in agricultural soil which is contributed by the increasing rate of industrialization and urbanization as well as over application of agrochemicals. For improvement of crop productivity and efficient management of heavy metals polluted soils, biochar, one of the organic materials, is currently being exploited.

4. BIOCHAR AND ITS IMPORTANCE Biochar is a carbon-rich and porous substance formed due to the thermo-chemical conversion of biomass at temperatures around 350-700°C under limited oxygen conditions (i.e., Pyrolysis) ( Amonette and Joseph, 2009). Biochar was introduced from the dark soil of the Amazon basin known as Terra Preta de Indio which was identified by Wim Sombroek , 1966. The Amazonian terra preta soils have higher soil fertility than other soils due to intentional addition of biochar from “ slash and char ” agriculture practices. ( Spokas et al., 2012) Typical profiles of ‘Terra Preta ’ ( a ) and Oxisol ( b ) sites ( Glaser et al., 2001)

5. Lehmann and Joseph, 2015.

6. Biochar is typically rich in carbon. Certain levels of organic C forms known as fused aromatic ring structures which are formed during pyrolysis are key to biochar properties with respect to mineralization and adsorption ( kleber et al, 2015). Biochar is used as soil amendments and has multiple beneficial effects. Apart from carbon, biochar also contains hydrogen (H), oxygen (O), nitrogen (N), calcium (Ca), magnesium (Mg), phosphorus (P) and potassium (K) that can improve crop productivity ( Alkharabsheh et al., 2021) . The porous structure of biochar, source:(left photo) S. Joseph; (right photo) Yamamoto

7. The carbon cycle The biochar cycle Green plants remove CO 2 from the atmosphere via photosynthesis and convert it into biomass. When the plants decompose after death or if the biomass is burned as a renewable alternative to fossil fuels most of this carbon is released back to the atmosphere. Approximately 50% of the carbon is captured and stored as biochar, while the remaining portion is transformed into co-products of renewable energy before being released back into the atmosphere. Most of the carbon returns to the air Half of the carbon is retained in the soil Adapted from Biochar Solutions Inc., 2011

8. Production of Biochar Feedstock used for biochar production types attributes example Woody biomass low dampness low debris less voidage high density and calorific value Tree and forestry residues. Non woody biomass high debris high dampness high voidage low density and calorific value. Animal waste ( cattle manure, poultry litter) Industrial solid waste ( cardboard waste, paper mill waste) Municipal waste (sewage and sludge) Agriculture residues and agro-industrial waste (sugarcane bagasse, rice straw and husk, wheat straw, corn stover, switch grass)

9. Method of production Thermochemical conversion of biomass is a common technique for biochar production. It includes pyrolysis, hydrothermal carbonization, gasification, and torrefaction. Most common is pyrolysis

10. technique Temperature (˚C ) Residence time Yield of biochar (%) Yield of bio-oil (%) Syngas production (%) references Pyrolysis (slow) 300-700 <2s 35 30 35 Pyrolysis (fast) 500-1000 Hour day 12 75 13 Hydrothermal carbonization 180-300 1-16 h 50-80 5-20 2-5 Gasifiacation 750-900 10-2o s 10 5 85 torrefication 290 10-60 min 80 20 Flash carbonization 300-600 <30 min 37 - - Pyrolysis converts waste biomass into value-added products like biochar, syngas and bio oil. During pyrolysis, the lignocellulosic such as cellulose, hemicellulose, lignin, etc. undergo reaction processes like depolymerization, fragmentation and cross-linking at specific temperatures which result in a different state of produc t like solid, liquid and gas. Table no. 2: Thermochemical conversion techniques and their process conditions.

11. Methods of production

12. PROPERTIES OF BIOCHAR Large surface area High total pore volume Consists of macropores (1000-0.5 µm pore diameter), mesopores (0.05-0.002 µm) and micropores (0.05- 0.0001 µm). 80 % of total pore volume are micropores Hydrophobic in nature due to removal of polar functional group Hold more water because of porous structure. Inversely correlated with porosity Biomass converts into a brittle substance Improved grindabilty compared to raw material Highly porous structure Low bulk density T he development of a porous structure leads to a decrease in thermal conductivity of biochars compared to their parent biomass

13. decreased O/C and H/C ratios as oxygen and hydrogen are released High carbon content, low hydrogen and oxygen Increased energy content due to high carbon content High fixed carbon (50-60%) as the volatile matter is driven off in high temperatures. Basic in nature due to detachment of acidic functional group (carboxyl, hydroxyl or formyl group) High as it directly depends on charged surface functional groups and surface area Ash content depends on parent biomass and is mainly composed of K, Na, Ca, Mg , P, etc. Includes carboxyl -COOH(–COO-) or hydroxyl –OH(–O-) groups which effect the adsorption capacity

14. Biochar properties are greatly influenced by pyrolysis temperature and type of feedstock

15. Materials Used for Producing Biochar pH Total C (%) Total N (%) C: N Ratio Ca (cmol/kg) Mg ( cmol /kg) P (cmol/kg) K ( cmol /kg) CEC ( cmol /kg) Paper mill waste (waste woodchip) 9.4 50.0 0.48 104 6.2 1.20 - 0.22 9.00 Green waste (grass, cotton trash and plant prunings ) 9.4 36.0 0.18 200 0.4 0.56 - 21.00 24.00 Eucalyptus biochar 82.4 0.57 145 1.87 4.69 Poultry litter (450 C) 9.9 38.0 2.00 19 37.42 11 Poultry litter (550 C) 13 33.0 0.85 39 5.81 11 Wood biochar 9.2 72.9 0.76 120 0.83 0.20 0.10 1.19 11.90 Hardwood sawdust 66.5 0.3 221 Source: Jha et al, 2010 Table 3: Properties of biochar derived from different sources.

16. Application method Selection of biochar application method largely depends on the availability of labour and farming system ( Duku , Gu, and Hagan 2011 ). Different methods of application Band placement Uniform topsoil mixing Top dressing Use of planting holes Mi xing with crop residue, compost, manure, and seed

17. Sr. No. Chemical properties Biochar(0 t ha -1 ) Biochar(10 t ha -1 ) Biochar(15 t ha -1 ) Biochar(20 t ha -1 ) 1 pH 6.4 7.1 7.34 8 2 Carbon (g kg -1 ) 1.22 5.56 6.54 7.64 3 Nitrogen (g kg -1 ) 0.45 1.46 1.5 1.52 4 C:N 2.75 3.82 4.36 5.02 5 Phosphorous (g kg -1 ) 0.12 0.15 0.18 0.16 6 Potassium 0.12 0.14 0.15 0.17 7 Calcium ( cmol (+) kg -1 ) 0.38 0.49 0.56 0.63 8 Magnesium ( cmol (+) kg -1 ) 0.24 0.38 0.44 0.51 9 CEC ( cmol (+) kg -1 ) 0.75 0.92 1.14 1.27 Uzoma, K.C., Inoue, M., Andry, H., Fujimaki, H., Zahoor, A. and Nishihara, E. (2011), Effect of cow manure biochar on maize productivity under sandy soil condition. Soil Use and Management, 27: 205-212.

18. Despite years of researches, the interaction between biochar and crop productivity is poorly understood. ( Spokas et al., 2012) The effect of biochar on soil fertility and productivity differs from soil organic matter because, unlike SOM, much of the organic portion of biochar has a long residence time. ( lehman et al., 2015)

19. Enhancing crop productivity Biochar application improves soil fertility and hence enhances crop productivity ( Lehmann and Joseph 2015)

20. Modified biochar Source: Wang and wang, 2019